FIXME

.gitea/workflows/job.yaml

@@ -0,0 +1,46 @@
++name: Build and Upload APK
+
+on:
+  push:
+    branches:
+      - notevault-3  # Trigger für den Hauptbranch
+  pull_request:
+    branches:
+      - notevault-3  # Trigger für Pull Requests in den Hauptbranch
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      # Schritt 1: Checkout des Repositories
+      - name: Checkout repository
+        uses: actions/checkout@v3
+
+      # Schritt 2: Setup JDK
+      - name: Set up JDK 11
+        uses: actions/setup-java@v2
+        with:
+          java-version: '11'
+
+      # Schritt 3: Installiere Gradle und Baue die APK
+      - name: Build APK
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y wget unzip
+          wget https://services.gradle.org/distributions/gradle-7.4-bin.zip
+          unzip gradle-7.4-bin.zip
+          export PATH=$PWD/gradle-7.4/bin:$PATH
+          ./gradlew clean assembleRelease
+
+      # Schritt 4: Upload der APK
+      - name: Upload APK to Gitea Releases
+        uses: pappasam/gitea-release-action@v1
+        with:
+          gitea_token: ${{ secrets.REGISTRY_PASSWORD }}  # Dein Gitea API-Token
+          gitea_url: 'https://git.fawkes100.de'   # Deine Gitea-URL
+          owner: ${{ secrets.REGISTRY_USER }}             # Dein Gitea-Benutzername
+          repo: 'NoteVault'                  # Dein Repository-Name
+          tag_name: 'v${{ github.sha }}'           # Der Tag für die Version
+          file: 'app/build/outputs/apk/release/app-release.apk'  # Pfad zur APK-Datei
+

.gitignore

@@ -13,3 +13,6 @@
 .externalNativeBuild
 .cxx
 local.properties
+/music_database
+/music_database-shm
+/music_database-wal

.idea/.name

@@ -0,0 +1 @@
+NoteVault

.idea/codeStyles/codeStyleConfig.xml

@@ -1,5 +0,0 @@
-<component name="ProjectCodeStyleConfiguration">
-  <state>
-    <option name="PREFERRED_PROJECT_CODE_STYLE" value="Default" />
-  </state>
-</component>

.idea/dataSources.xml

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
   <component name="DataSourceManagerImpl" format="xml" multifile-model="true">
-    <data-source source="LOCAL" name="music_database" uuid="7fd8322d-6535-44e0-a663-86c7b54f4fbd">
+    <data-source source="LOCAL" name="music_database" uuid="eb23f694-6586-450b-8f6f-a75731d36b96">
       <driver-ref>sqlite.xerial</driver-ref>
       <synchronize>true</synchronize>
       <jdbc-driver>org.sqlite.JDBC</jdbc-driver>
@@ -10,26 +10,6 @@
         <property name="com.intellij.clouds.kubernetes.db.enabled" value="false" />
       </jdbc-additional-properties>
       <working-dir>$ProjectFileDir$</working-dir>
-    </data-source>
-    <data-source source="LOCAL" name="music_database [2]" uuid="6f801a54-4854-4db5-910c-ae63a8207d3e">
-      <driver-ref>sqlite.xerial</driver-ref>
-      <synchronize>true</synchronize>
-      <jdbc-driver>org.sqlite.JDBC</jdbc-driver>
-      <jdbc-url>jdbc:sqlite:$PROJECT_DIR$/music_database</jdbc-url>
-      <jdbc-additional-properties>
-        <property name="com.intellij.clouds.kubernetes.db.enabled" value="false" />
-      </jdbc-additional-properties>
-      <working-dir>$ProjectFileDir$</working-dir>
-    </data-source>
-    <data-source source="LOCAL" name="music_database [3]" uuid="3acbe0c9-6415-4726-8c75-c07350984fcc">
-      <driver-ref>sqlite.xerial</driver-ref>
-      <synchronize>true</synchronize>
-      <jdbc-driver>org.sqlite.JDBC</jdbc-driver>
-      <jdbc-url>jdbc:sqlite:$USER_HOME$/.cache/JetBrains/IntelliJIdea2024.1/device-explorer/Pixel Tablet API 30/_/data/data/core.notevault/databases/music_database</jdbc-url>
-      <jdbc-additional-properties>
-        <property name="com.intellij.clouds.kubernetes.db.enabled" value="false" />
-      </jdbc-additional-properties>
-      <working-dir>$ProjectFileDir$</working-dir>
       <libraries>
         <library>
           <url>file://$APPLICATION_CONFIG_DIR$/jdbc-drivers/Xerial SQLiteJDBC/3.45.1/org/xerial/sqlite-jdbc/3.45.1.0/sqlite-jdbc-3.45.1.0.jar</url>

.idea/deploymentTargetDropDown.xml

@@ -1,13 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<project version="4">
-  <component name="deploymentTargetDropDown">
-    <value>
-      <entry key="NoteVault">
-        <State />
-      </entry>
-      <entry key="app">
-        <State />
-      </entry>
-    </value>
-  </component>
-</project>

.idea/deploymentTargetSelector.xml

@@ -4,6 +4,14 @@
     <selectionStates>
       <SelectionState runConfigName="app">
         <option name="selectionMode" value="DROPDOWN" />
+        <DropdownSelection timestamp="2025-04-10T18:07:32.446414465Z">
+          <Target type="DEFAULT_BOOT">
+            <handle>
+              <DeviceId pluginId="PhysicalDevice" identifier="serial=R52N50NLGRT" />
+            </handle>
+          </Target>
+        </DropdownSelection>
+        <DialogSelection />
       </SelectionState>
     </selectionStates>
   </component>

.idea/gradle.xml

@@ -5,7 +5,7 @@
     <option name="linkedExternalProjectsSettings">
       <GradleProjectSettings>
         <option name="externalProjectPath" value="$PROJECT_DIR$" />
-        <option name="gradleJvm" value="21" />
+        <option name="gradleJvm" value="#GRADLE_LOCAL_JAVA_HOME" />
         <option name="modules">
           <set>
             <option value="$PROJECT_DIR$" />

.idea/runConfigurations.xml

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="RunConfigurationProducerService">
+    <option name="ignoredProducers">
+      <set>
+        <option value="com.intellij.execution.junit.AbstractAllInDirectoryConfigurationProducer" />
+        <option value="com.intellij.execution.junit.AllInPackageConfigurationProducer" />
+        <option value="com.intellij.execution.junit.PatternConfigurationProducer" />
+        <option value="com.intellij.execution.junit.TestInClassConfigurationProducer" />
+        <option value="com.intellij.execution.junit.UniqueIdConfigurationProducer" />
+        <option value="com.intellij.execution.junit.testDiscovery.JUnitTestDiscoveryConfigurationProducer" />
+        <option value="org.jetbrains.kotlin.idea.junit.KotlinJUnitRunConfigurationProducer" />
+        <option value="org.jetbrains.kotlin.idea.junit.KotlinPatternConfigurationProducer" />
+      </set>
+    </option>
+  </component>
+</project>

.idea/uiDesigner.xml

@@ -1,124 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<project version="4">
-  <component name="Palette2">
-    <group name="Swing">
-      <item class="com.intellij.uiDesigner.HSpacer" tooltip-text="Horizontal Spacer" icon="/com/intellij/uiDesigner/icons/hspacer.svg" removable="false" auto-create-binding="false" can-attach-label="false">
-        <default-constraints vsize-policy="1" hsize-policy="6" anchor="0" fill="1" />
-      </item>
-      <item class="com.intellij.uiDesigner.VSpacer" tooltip-text="Vertical Spacer" icon="/com/intellij/uiDesigner/icons/vspacer.svg" removable="false" auto-create-binding="false" can-attach-label="false">
-        <default-constraints vsize-policy="6" hsize-policy="1" anchor="0" fill="2" />
-      </item>
-      <item class="javax.swing.JPanel" icon="/com/intellij/uiDesigner/icons/panel.svg" removable="false" auto-create-binding="false" can-attach-label="false">
-        <default-constraints vsize-policy="3" hsize-policy="3" anchor="0" fill="3" />
-      </item>
-      <item class="javax.swing.JScrollPane" icon="/com/intellij/uiDesigner/icons/scrollPane.svg" removable="false" auto-create-binding="false" can-attach-label="true">
-        <default-constraints vsize-policy="7" hsize-policy="7" anchor="0" fill="3" />
-      </item>
-      <item class="javax.swing.JButton" icon="/com/intellij/uiDesigner/icons/button.svg" removable="false" auto-create-binding="true" can-attach-label="false">
-        <default-constraints vsize-policy="0" hsize-policy="3" anchor="0" fill="1" />
-        <initial-values>
-          <property name="text" value="Button" />
-        </initial-values>
-      </item>
-      <item class="javax.swing.JRadioButton" icon="/com/intellij/uiDesigner/icons/radioButton.svg" removable="false" auto-create-binding="true" can-attach-label="false">
-        <default-constraints vsize-policy="0" hsize-policy="3" anchor="8" fill="0" />
-        <initial-values>
-          <property name="text" value="RadioButton" />
-        </initial-values>
-      </item>
-      <item class="javax.swing.JCheckBox" icon="/com/intellij/uiDesigner/icons/checkBox.svg" removable="false" auto-create-binding="true" can-attach-label="false">
-        <default-constraints vsize-policy="0" hsize-policy="3" anchor="8" fill="0" />
-        <initial-values>
-          <property name="text" value="CheckBox" />
-        </initial-values>
-      </item>
-      <item class="javax.swing.JLabel" icon="/com/intellij/uiDesigner/icons/label.svg" removable="false" auto-create-binding="false" can-attach-label="false">
-        <default-constraints vsize-policy="0" hsize-policy="0" anchor="8" fill="0" />
-        <initial-values>
-          <property name="text" value="Label" />
-        </initial-values>
-      </item>
-      <item class="javax.swing.JTextField" icon="/com/intellij/uiDesigner/icons/textField.svg" removable="false" auto-create-binding="true" can-attach-label="true">
-        <default-constraints vsize-policy="0" hsize-policy="6" anchor="8" fill="1">
-          <preferred-size width="150" height="-1" />
-        </default-constraints>
-      </item>
-      <item class="javax.swing.JPasswordField" icon="/com/intellij/uiDesigner/icons/passwordField.svg" removable="false" auto-create-binding="true" can-attach-label="true">
-        <default-constraints vsize-policy="0" hsize-policy="6" anchor="8" fill="1">
-          <preferred-size width="150" height="-1" />
-        </default-constraints>
-      </item>
-      <item class="javax.swing.JFormattedTextField" icon="/com/intellij/uiDesigner/icons/formattedTextField.svg" removable="false" auto-create-binding="true" can-attach-label="true">
-        <default-constraints vsize-policy="0" hsize-policy="6" anchor="8" fill="1">
-          <preferred-size width="150" height="-1" />
-        </default-constraints>
-      </item>
-      <item class="javax.swing.JTextArea" icon="/com/intellij/uiDesigner/icons/textArea.svg" removable="false" auto-create-binding="true" can-attach-label="true">
-        <default-constraints vsize-policy="6" hsize-policy="6" anchor="0" fill="3">
-          <preferred-size width="150" height="50" />
-        </default-constraints>
-      </item>
-      <item class="javax.swing.JTextPane" icon="/com/intellij/uiDesigner/icons/textPane.svg" removable="false" auto-create-binding="true" can-attach-label="true">
-        <default-constraints vsize-policy="6" hsize-policy="6" anchor="0" fill="3">
-          <preferred-size width="150" height="50" />
-        </default-constraints>
-      </item>
-      <item class="javax.swing.JEditorPane" icon="/com/intellij/uiDesigner/icons/editorPane.svg" removable="false" auto-create-binding="true" can-attach-label="true">
-        <default-constraints vsize-policy="6" hsize-policy="6" anchor="0" fill="3">
-          <preferred-size width="150" height="50" />
-        </default-constraints>
-      </item>
-      <item class="javax.swing.JComboBox" icon="/com/intellij/uiDesigner/icons/comboBox.svg" removable="false" auto-create-binding="true" can-attach-label="true">
-        <default-constraints vsize-policy="0" hsize-policy="2" anchor="8" fill="1" />
-      </item>
-      <item class="javax.swing.JTable" icon="/com/intellij/uiDesigner/icons/table.svg" removable="false" auto-create-binding="true" can-attach-label="false">
-        <default-constraints vsize-policy="6" hsize-policy="6" anchor="0" fill="3">
-          <preferred-size width="150" height="50" />
-        </default-constraints>
-      </item>
-      <item class="javax.swing.JList" icon="/com/intellij/uiDesigner/icons/list.svg" removable="false" auto-create-binding="true" can-attach-label="false">
-        <default-constraints vsize-policy="6" hsize-policy="2" anchor="0" fill="3">
-          <preferred-size width="150" height="50" />
-        </default-constraints>
-      </item>
-      <item class="javax.swing.JTree" icon="/com/intellij/uiDesigner/icons/tree.svg" removable="false" auto-create-binding="true" can-attach-label="false">
-        <default-constraints vsize-policy="6" hsize-policy="6" anchor="0" fill="3">
-          <preferred-size width="150" height="50" />
-        </default-constraints>
-      </item>
-      <item class="javax.swing.JTabbedPane" icon="/com/intellij/uiDesigner/icons/tabbedPane.svg" removable="false" auto-create-binding="true" can-attach-label="false">
-        <default-constraints vsize-policy="3" hsize-policy="3" anchor="0" fill="3">
-          <preferred-size width="200" height="200" />
-        </default-constraints>
-      </item>
-      <item class="javax.swing.JSplitPane" icon="/com/intellij/uiDesigner/icons/splitPane.svg" removable="false" auto-create-binding="false" can-attach-label="false">
-        <default-constraints vsize-policy="3" hsize-policy="3" anchor="0" fill="3">
-          <preferred-size width="200" height="200" />
-        </default-constraints>
-      </item>
-      <item class="javax.swing.JSpinner" icon="/com/intellij/uiDesigner/icons/spinner.svg" removable="false" auto-create-binding="true" can-attach-label="true">
-        <default-constraints vsize-policy="0" hsize-policy="6" anchor="8" fill="1" />
-      </item>
-      <item class="javax.swing.JSlider" icon="/com/intellij/uiDesigner/icons/slider.svg" removable="false" auto-create-binding="true" can-attach-label="false">
-        <default-constraints vsize-policy="0" hsize-policy="6" anchor="8" fill="1" />
-      </item>
-      <item class="javax.swing.JSeparator" icon="/com/intellij/uiDesigner/icons/separator.svg" removable="false" auto-create-binding="false" can-attach-label="false">
-        <default-constraints vsize-policy="6" hsize-policy="6" anchor="0" fill="3" />
-      </item>
-      <item class="javax.swing.JProgressBar" icon="/com/intellij/uiDesigner/icons/progressbar.svg" removable="false" auto-create-binding="true" can-attach-label="false">
-        <default-constraints vsize-policy="0" hsize-policy="6" anchor="0" fill="1" />
-      </item>
-      <item class="javax.swing.JToolBar" icon="/com/intellij/uiDesigner/icons/toolbar.svg" removable="false" auto-create-binding="false" can-attach-label="false">
-        <default-constraints vsize-policy="0" hsize-policy="6" anchor="0" fill="1">
-          <preferred-size width="-1" height="20" />
-        </default-constraints>
-      </item>
-      <item class="javax.swing.JToolBar$Separator" icon="/com/intellij/uiDesigner/icons/toolbarSeparator.svg" removable="false" auto-create-binding="false" can-attach-label="false">
-        <default-constraints vsize-policy="0" hsize-policy="0" anchor="0" fill="1" />
-      </item>
-      <item class="javax.swing.JScrollBar" icon="/com/intellij/uiDesigner/icons/scrollbar.svg" removable="false" auto-create-binding="true" can-attach-label="false">
-        <default-constraints vsize-policy="6" hsize-policy="0" anchor="0" fill="2" />
-      </item>
-    </group>
-  </component>
-</project>

.idea/vcs.xml

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
   <component name="VcsDirectoryMappings">
-    <mapping directory="$PROJECT_DIR$" vcs="Git" />
+    <mapping directory="" vcs="Git" />
   </component>
 </project>

app/build.gradle.kts

@@ -1,16 +1,15 @@
 plugins {
     alias(libs.plugins.android.application)
-
 }
 
 android {
-    namespace = "core.notevault"
+    namespace = "com.stormtales.notevault"
-    compileSdk = 35
+    compileSdk = 34
 
     defaultConfig {
-        applicationId = "core.notevault"
+        applicationId = "com.stormtales.notevault"
-        minSdk = 28
+        minSdk = 29
-        targetSdk = 35
+        targetSdk = 34
         versionCode = 1
         versionName = "1.0"
 
@@ -22,14 +21,10 @@ android {
             isMinifyEnabled = false
             proguardFiles(getDefaultProguardFile("proguard-android-optimize.txt"), "proguard-rules.pro")
         }
-        debug {
-            // Setzt den Manifest-Platzhalter nur für den Debug-Build auf true
-            manifestPlaceholders["usesCleartextTraffic"] = "true"
-        }
     }
     compileOptions {
-        sourceCompatibility = JavaVersion.VERSION_1_8
+        sourceCompatibility = JavaVersion.VERSION_11
-        targetCompatibility = JavaVersion.VERSION_1_8
+        targetCompatibility = JavaVersion.VERSION_11
     }
     buildFeatures {
         viewBinding = true
@@ -45,25 +40,14 @@ dependencies {
     implementation(libs.lifecycle.viewmodel.ktx)
     implementation(libs.navigation.fragment)
     implementation(libs.navigation.ui)
-    implementation(libs.room.common)
+    implementation(libs.room.runtime)
-    implementation("androidx.recyclerview:recyclerview:1.3.2")
+    implementation(libs.annotation)
-    implementation("com.github.chrisbanes:PhotoView:2.3.0")
-    implementation(libs.car.ui.lib)
     testImplementation(libs.junit)
     androidTestImplementation(libs.ext.junit)
     androidTestImplementation(libs.espresso.core)
+    annotationProcessor(libs.room.compiler)
+    implementation("com.github.chrisbanes:PhotoView:2.3.0")
     implementation("com.squareup.retrofit2:retrofit:2.9.0")
     implementation("com.squareup.retrofit2:converter-gson:2.9.0")
     implementation("com.squareup.okhttp3:logging-interceptor:4.9.1")
-
-
-    val room_version = "2.6.1" // Aktuelle Room-Version
-
-    implementation("androidx.room:room-runtime:$room_version")
-    annotationProcessor("androidx.room:room-compiler:$room_version") // Für Annotation Processing
-
-    // Optional: Unterstützung für Kotlin Coroutines oder RxJava
-    implementation("androidx.room:room-ktx:$room_version") // Für Kotlin-Extensions
-    implementation("androidx.room:room-rxjava3:$room_version") // Für RxJava-Unterstützung
-    implementation("androidx.work:work-runtime:2.10.0")
 }

app/src/androidTest/java/com/stormtales/notevault/ExampleInstrumentedTest.java

@@ -1,4 +1,4 @@
-package core.notevault;
+package com.stormtales.notevault;
 
 import android.content.Context;
 import androidx.test.platform.app.InstrumentationRegistry;
@@ -20,6 +20,6 @@ public class ExampleInstrumentedTest {
     public void useAppContext() {
         // Context of the app under test.
         Context appContext = InstrumentationRegistry.getInstrumentation().getTargetContext();
-        assertEquals("core.notevault", appContext.getPackageName());
+        assertEquals("com.stormtales.notevault", appContext.getPackageName());
     }
 }

app/src/main/AndroidManifest.xml

@@ -1,18 +1,17 @@
 <?xml version="1.0" encoding="utf-8"?>
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
           xmlns:tools="http://schemas.android.com/tools">
-    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
     <uses-permission android:name="android.permission.INTERNET" />
     <application
             android:allowBackup="true"
             android:dataExtractionRules="@xml/data_extraction_rules"
             android:fullBackupContent="@xml/backup_rules"
+            android:networkSecurityConfig="@xml/network_security_config"
             android:icon="@mipmap/ic_launcher"
             android:label="@string/app_name"
             android:roundIcon="@mipmap/ic_launcher_round"
             android:supportsRtl="true"
             android:theme="@style/Theme.NoteVault"
-            android:usesCleartextTraffic="true"
             tools:targetApi="31">
         <activity
                 android:name=".MainActivity"
@@ -26,11 +25,10 @@
             </intent-filter>
         </activity>
 
-        <activity android:name=".ui.home.FullScreenImageActivity"
+        <activity android:name=".ui.sheetdisplay.NoteSheetDisplayActivity"
                   android:theme="@style/Theme.AppCompat.NoActionBar">
             <!-- Intent Filter hinzufügen, wenn Activity vom Launcher oder externen Apps aufgerufen werden soll -->
         </activity>
-
     </application>
 
 </manifest>

app/src/main/java/com/stormtales/notevault/MainActivity.java

@@ -0,0 +1,90 @@
+package com.stormtales.notevault;
+
+import android.os.Bundle;
+import android.view.MenuItem;
+import android.view.Menu;
+import android.widget.Toast;
+import androidx.lifecycle.ViewModelProvider;
+import com.google.android.material.navigation.NavigationView;
+import androidx.navigation.NavController;
+import androidx.navigation.Navigation;
+import androidx.navigation.ui.AppBarConfiguration;
+import androidx.navigation.ui.NavigationUI;
+import androidx.drawerlayout.widget.DrawerLayout;
+import androidx.appcompat.app.AppCompatActivity;
+import com.stormtales.notevault.databinding.ActivityMainBinding;
+import com.stormtales.notevault.network.APICallback;
+import com.stormtales.notevault.network.auth.AuthService;
+import com.stormtales.notevault.ui.login.LoginDialog;
+import com.stormtales.notevault.ui.login.LoginViewModel;
+
+public class MainActivity extends AppCompatActivity {
+
+    private AppBarConfiguration mAppBarConfiguration;
+    private ActivityMainBinding binding;
+    private LoginViewModel loginViewModel;
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+
+        binding = ActivityMainBinding.inflate(getLayoutInflater());
+        setContentView(binding.getRoot());
+
+        setSupportActionBar(binding.appBarMain.toolbar);
+        binding.appBarMain.toolbar.setOnMenuItemClickListener(item -> {
+            if (item.getItemId() == R.id.auth_action) {
+                showLoginDialog();
+                return true;
+            }
+            return false;
+        });
+        DrawerLayout drawer = binding.drawerLayout;
+        NavigationView navigationView = binding.navView;
+        // Passing each menu ID as a set of Ids because each
+        // menu should be considered as top level destinations.
+        mAppBarConfiguration = new AppBarConfiguration.Builder(
+                R.id.nav_home, R.id.nav_gallery, R.id.nav_slideshow)
+                .setOpenableLayout(drawer)
+                .build();
+        NavController navController = Navigation.findNavController(this, R.id.nav_host_fragment_content_main);
+        NavigationUI.setupActionBarWithNavController(this, navController, mAppBarConfiguration);
+        NavigationUI.setupWithNavController(navigationView, navController);
+
+        loginViewModel = new ViewModelProvider(this).get(LoginViewModel.class);
+        loginViewModel.setAuthService(new AuthService(getApplicationContext()));
+        loginViewModel.getIsLoggedIn().observe(this, isLoggedIn -> {
+            this.invalidateOptionsMenu();
+        });
+    }
+
+    @Override
+    public boolean onCreateOptionsMenu(Menu menu) {
+        // Inflate the menu; this adds items to the action bar if it is present.
+        getMenuInflater().inflate(R.menu.main, menu);
+        return true;
+    }
+
+    @Override
+    public boolean onSupportNavigateUp() {
+        NavController navController = Navigation.findNavController(this, R.id.nav_host_fragment_content_main);
+        return NavigationUI.navigateUp(navController, mAppBarConfiguration)
+                || super.onSupportNavigateUp();
+    }
+
+    @Override
+    public boolean onPrepareOptionsMenu(Menu menu) {
+        MenuItem loginItem = menu.findItem(R.id.auth_action);
+        if (Boolean.TRUE.equals(loginViewModel.getIsLoggedIn().getValue())) {
+            loginItem.setIcon(R.drawable.logout); // Setze das Logout-Symbol
+        } else {
+            loginItem.setIcon(R.drawable.login); // Setze das Login-Symbol
+        }
+        return super.onPrepareOptionsMenu(menu);
+    }
+
+    public void showLoginDialog() {
+        LoginDialog loginDialog = new LoginDialog(loginViewModel);
+        loginDialog.show(getSupportFragmentManager(), "login");
+    }
+}

app/src/main/java/com/stormtales/notevault/data/MusicDatabase.java

@@ -0,0 +1,33 @@
+package com.stormtales.notevault.data;
+
+import android.content.Context;
+import androidx.room.Database;
+import androidx.room.Room;
+import androidx.room.RoomDatabase;
+import androidx.room.TypeConverters;
+import com.stormtales.notevault.data.entities.NoteSheet;
+import com.stormtales.notevault.data.entities.Song;
+import com.stormtales.notevault.data.dao.SongDao;
+import com.stormtales.notevault.data.sync.DateConverter;
+import com.stormtales.notevault.data.sync.SyncStatusConverter;
+
+@Database(entities = {Song.class, NoteSheet.class}, version = 1, exportSchema = false)
+@TypeConverters({SyncStatusConverter.class, DateConverter.class})
+public abstract class MusicDatabase extends RoomDatabase {
+    public abstract SongDao getSongTable();
+
+    private static volatile MusicDatabase INSTANCE;
+
+    public static MusicDatabase getDatabase(final Context context) {
+        if (INSTANCE == null) {
+            synchronized (MusicDatabase.class) {
+                if (INSTANCE == null) {
+                    INSTANCE = Room.databaseBuilder(context.getApplicationContext(),
+                                    MusicDatabase.class, "music_database")
+                            .build();
+                }
+            }
+        }
+        return INSTANCE;
+    }
+}

app/src/main/java/com/stormtales/notevault/data/dao/SongDao.java

@@ -0,0 +1,87 @@
+package com.stormtales.notevault.data.dao;
+
+import androidx.lifecycle.LiveData;
+import androidx.room.*;
+import com.stormtales.notevault.data.entities.NoteSheet;
+import com.stormtales.notevault.data.entities.Song;
+import com.stormtales.notevault.data.sync.SyncStatus;
+
+import java.util.List;
+
+@Dao
+public interface SongDao {
+    @Insert
+    long insert(Song song);
+
+    @Query("SELECT * FROM song WHERE syncStatus != 1")
+    List<Song> getAllSongs();
+
+    @Update
+    void update(Song song);
+
+    @Insert
+    void insert(List<NoteSheet> noteSheets);
+
+    @Delete
+    void deleteNoteSheets(List<NoteSheet> noteSheets);
+
+    @Query("SELECT * FROM NoteSheet WHERE songID = :songID")
+    List<NoteSheet> getNoteSheetsBySong(int songID);
+
+    @Query("SELECT localFileName FROM NoteSheet WHERE songID = :songID")
+    List<String> getNoteSheetFilesBySongID(int songID);
+
+    @Query("SELECT * FROM Song WHERE syncStatus = :syncStatus")
+    List<Song> getSongsBySyncStatus(SyncStatus syncStatus);
+
+    @Update
+    void updateSongs(List<Song> songs);
+
+    @Query("SELECT * FROM Song WHERE localID IN (:localIDs)")
+    List<Song> getSongsByLocalIDs(List<Integer> localIDs);
+
+    @Query("SELECT * FROM Song WHERE serverID IN (:serverIDs)")
+    List<Song> getSongsByServerIDs(List<String> serverIDs);
+
+    @Query("DELETE FROM Song WHERE serverID IN (:serverIDs)")
+    void deleteSongsByServerIDs(List<String> serverIDs);
+
+    @Query("DELETE FROM SONG WHERE localID IN (:localIDs)")
+    void deleteSongsByLocalIDs(List<Integer> localIDs);
+
+    @Query("SELECT * FROM NoteSheet WHERE songID IN (:localSongIDs)")
+    List<NoteSheet> getNoteSheetsBySongIDs(List<Integer> localSongIDs);
+
+    @Query("SELECT * FROM NoteSheet WHERE songID IN (:songIDs)")
+    List<NoteSheet> getNoteSheetsByLocalFiles(List<Integer> songIDs);
+
+    @Update
+    void updateNoteSheets(List<NoteSheet> uploadedNoteSheets);
+
+    @Query("SELECT localID FROM Song WHERE serverID IN (:serverIDs)")
+    List<Integer> getLocalSongIDsByServerIDs(List<String> serverIDs);
+
+    @Query("SELECT * FROM NoteSheet WHERE serverFileName IN (:serverFileNames)")
+    List<NoteSheet> getNoteSheetsByServerFileNames(List<String> serverFileNames);
+
+    @Query("SELECT * FROM NoteSheet WHERE syncStatus = :status")
+    List<NoteSheet> getNoteSheetsBySyncStatus(SyncStatus status);
+
+    @Query("SELECT * FROM NoteSheet WHERE songID IN (:localSongIDs)")
+    List<NoteSheet> getNoteSheetFilesBySongIDs(List<Integer> localSongIDs);
+
+    @Insert
+    void insertSongs(List<Song> onlyRemoteExistingSongs);
+
+    @Delete
+    void deleteSong(Song song);
+
+    @Query("DELETE FROM NoteSheet WHERE songID = :localID")
+    void deleteNoteSheetsByLocalSongID(int localID);
+
+    @Update
+    void updateNoteSheet(NoteSheet noteSheet);
+
+    @Query("SELECT * FROM NoteSheet WHERE serverFileName =:serverFileName")
+    NoteSheet getNoteSheetByServerFileName(String serverFileName);
+}

app/src/main/java/com/stormtales/notevault/data/entities/NoteSheet.java

@@ -0,0 +1,101 @@
+package com.stormtales.notevault.data.entities;
+
+import androidx.room.Entity;
+import androidx.room.Ignore;
+import androidx.room.PrimaryKey;
+import com.stormtales.notevault.data.sync.SyncStatus;
+
+import java.util.Objects;
+
+@Entity
+public class NoteSheet {
+    @PrimaryKey(autoGenerate = true)
+    private int localID;
+    private int songID;
+    private String localFileName;
+    private String serverFileName;
+    private String hash;
+
+    private SyncStatus syncStatus;
+
+    @Ignore
+    public NoteSheet(String localFileName, String hash) {
+        this.localFileName = localFileName;
+        this.hash = hash;
+        this.syncStatus = SyncStatus.CREATED;
+    }
+
+    @Ignore
+    public NoteSheet(int songID, String localFileName, String serverFileName, String hash) {
+        this.songID = songID;
+        this.localFileName = localFileName;
+        this.serverFileName = serverFileName;
+        this.hash = hash;
+        this.syncStatus = SyncStatus.REMOTE_MODIFIED;
+    }
+
+
+    public NoteSheet() {
+
+    }
+
+    public int getLocalID() {
+        return localID;
+    }
+
+    public void setLocalID(int localID) {
+        this.localID = localID;
+    }
+
+    public String getLocalFileName() {
+        return localFileName;
+    }
+
+    public void setLocalFileName(String localFileName) {
+        this.localFileName = localFileName;
+    }
+
+    public String getHash() {
+        return hash;
+    }
+
+    public void setHash(String hash) {
+        this.hash = hash;
+    }
+
+    public String getServerFileName() {
+        return serverFileName;
+    }
+
+    public void setServerFileName(String serverFileName) {
+        this.serverFileName = serverFileName;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (o == null || getClass() != o.getClass()) return false;
+        NoteSheet noteSheet = (NoteSheet) o;
+        return localID == noteSheet.localID && Objects.equals(localFileName, noteSheet.localFileName) && Objects.equals(hash, noteSheet.hash);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(localID, localFileName, hash);
+    }
+
+    public int getSongID() {
+        return songID;
+    }
+
+    public void setSongID(int songID) {
+        this.songID = songID;
+    }
+
+    public SyncStatus getSyncStatus() {
+        return syncStatus;
+    }
+
+    public void setSyncStatus(SyncStatus syncStatus) {
+        this.syncStatus = syncStatus;
+    }
+}

app/src/main/java/com/stormtales/notevault/data/entities/Song.java

@@ -0,0 +1,131 @@
+package com.stormtales.notevault.data.entities;
+
+import androidx.room.Entity;
+import androidx.room.Ignore;
+import androidx.room.PrimaryKey;
+import com.stormtales.notevault.data.sync.SyncStatus;
+import com.stormtales.notevault.network.sync.models.SongModel;
+
+import java.time.LocalDateTime;
+import java.util.Objects;
+
+@Entity
+public class Song {
+    @PrimaryKey(autoGenerate = true)
+    private int localID;
+
+    private String serverID;
+    private SyncStatus syncStatus;
+    private LocalDateTime syncTime;
+
+    /**Meta Data of Song*/
+    private String title;
+    private String composer;
+    private String genre;
+    private int year;
+
+    @Ignore
+    public Song(String title, String composer, String genre, int year) {
+        this.title = title;
+        this.composer = composer;
+        this.genre = genre;
+        this.year = year;
+        this.syncStatus = SyncStatus.CREATED;
+    }
+
+    @Ignore
+    public Song(SongModel songModel) {
+        this.serverID = songModel.getServerID();
+        this.title = songModel.getTitle();
+        this.composer = songModel.getComposer();
+        this.genre = songModel.getGenre();
+        this.year = songModel.getYear();
+        this.syncStatus = SyncStatus.SYNCED;
+        this.syncTime = LocalDateTime.now();
+    }
+
+    public Song() {
+    }
+
+    @Ignore
+    public Song(String serverID) {
+        this.serverID = serverID;
+        this.syncStatus = SyncStatus.REMOTE_MODIFIED;
+    }
+
+    public int getLocalID() {
+        return localID;
+    }
+
+    public void setLocalID(int localID) {
+        this.localID = localID;
+    }
+
+    public String getServerID() {
+        return serverID;
+    }
+
+    public void setServerID(String serverID) {
+        this.serverID = serverID;
+    }
+
+    public SyncStatus getSyncStatus() {
+        return syncStatus;
+    }
+
+    public void setSyncStatus(SyncStatus syncStatus) {
+        this.syncStatus = syncStatus;
+    }
+
+    public LocalDateTime getSyncTime() {
+        return syncTime;
+    }
+
+    public void setSyncTime(LocalDateTime syncTime) {
+        this.syncTime = syncTime;
+    }
+
+    public String getTitle() {
+        return title;
+    }
+
+    public void setTitle(String title) {
+        this.title = title;
+    }
+
+    public String getComposer() {
+        return composer;
+    }
+
+    public void setComposer(String composer) {
+        this.composer = composer;
+    }
+
+    public String getGenre() {
+        return genre;
+    }
+
+    public void setGenre(String genre) {
+        this.genre = genre;
+    }
+
+    public int getYear() {
+        return year;
+    }
+
+    public void setYear(int year) {
+        this.year = year;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (o == null || getClass() != o.getClass()) return false;
+        Song song = (Song) o;
+        return localID == song.localID && Objects.equals(serverID, song.serverID);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(localID, serverID);
+    }
+}

app/src/main/java/com/stormtales/notevault/data/entities/SongNoteSheet.java

@@ -0,0 +1,15 @@
+package com.stormtales.notevault.data.entities;
+
+import androidx.room.Embedded;
+import androidx.room.Relation;
+
+import java.util.List;
+
+public class SongNoteSheet {
+    @Embedded public Song song;
+    @Relation(
+            parentColumn = "localID",
+            entityColumn = "songID"
+    )
+    public List<NoteSheet> noteSheets;
+}

app/src/main/java/com/stormtales/notevault/data/model/LoggedInUser.java

@@ -0,0 +1,23 @@
+package com.stormtales.notevault.data.model;
+
+/**
+ * Data class that captures user information for logged in users retrieved from LoginRepository
+ */
+public class LoggedInUser {
+
+    private String userId;
+    private String displayName;
+
+    public LoggedInUser(String userId, String displayName) {
+        this.userId = userId;
+        this.displayName = displayName;
+    }
+
+    public String getUserId() {
+        return userId;
+    }
+
+    public String getDisplayName() {
+        return displayName;
+    }
+}

app/src/main/java/com/stormtales/notevault/data/repositories/SongRepository.java

@@ -0,0 +1,86 @@
+package com.stormtales.notevault.data.repositories;
+
+import android.app.Application;
+import android.content.Context;
+import android.os.Handler;
+import android.os.Looper;
+import androidx.lifecycle.LiveData;
+import com.stormtales.notevault.data.MusicDatabase;
+import com.stormtales.notevault.data.dao.SongDao;
+import com.stormtales.notevault.data.entities.NoteSheet;
+import com.stormtales.notevault.data.entities.Song;
+import com.stormtales.notevault.data.sync.SyncStatus;
+import com.stormtales.notevault.utils.NoteSheetsUtil;
+
+import java.io.IOException;
+import java.util.List;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+
+public class SongRepository {
+    private SongDao songDao;
+    public SongRepository(Context context) {
+        MusicDatabase database = MusicDatabase.getDatabase(context);
+        songDao = database.getSongTable();
+    }
+    public void insert(Song song, Callback<Long> callback) {
+        Executors.newSingleThreadExecutor().execute(() -> {
+            long result = songDao.insert(song);
+            Handler mainHandler = new Handler(Looper.getMainLooper());
+            mainHandler.post(()-> callback.onResult(result));
+        });
+    }
+
+    public interface LoadHomeViewModelCallback<T> {
+        void onResult(T result);
+    }
+
+    public void getAllSongs(LoadHomeViewModelCallback<List<Song>> callback) {
+        ExecutorService executorService = Executors.newSingleThreadExecutor();
+        executorService.execute(() -> {
+            List<Song> songs = songDao.getAllSongs();
+            Handler mainHandler = new Handler(Looper.getMainLooper());
+            mainHandler.post(()-> callback.onResult(songs));
+        });
+    }
+
+    public void updateSong(Song song) {
+        Executors.newSingleThreadExecutor().execute(() -> {
+            songDao.update(song);
+        });
+    }
+
+    public void insertNoteSheets(List<NoteSheet> noteSheets) {
+        Executors.newSingleThreadExecutor().execute(() -> {
+            songDao.insert(noteSheets);
+        });
+    }
+
+    public interface Callback<T> {
+        void onResult(T result);
+    }
+
+    public void deleteSong(Song song) {
+        Executors.newSingleThreadExecutor().execute(() -> {
+            song.setSyncStatus(SyncStatus.DELETED);
+            songDao.update(song);
+
+            List<NoteSheet> noteSheets = songDao.getNoteSheetsBySong(song.getLocalID());
+            for(NoteSheet noteSheet : noteSheets) {
+                try {
+                    NoteSheetsUtil.deleteNoteSheet(noteSheet.getLocalFileName());
+                } catch (IOException e) {
+                    throw new RuntimeException(e);
+                }
+            }
+            songDao.deleteNoteSheets(noteSheets);
+        });
+    }
+
+    public void getNoteSheetFilesBySongID(int songID, Callback<List<String>> callback) {
+        Executors.newSingleThreadExecutor().execute(()-> {
+            List<String> noteSheetFiles = songDao.getNoteSheetFilesBySongID(songID);
+            callback.onResult(noteSheetFiles);
+        });
+    }
+}

app/src/main/java/com/stormtales/notevault/data/repositories/SongSyncRepository.java

@@ -0,0 +1,303 @@
+package com.stormtales.notevault.data.repositories;
+
+import android.content.Context;
+import android.os.Handler;
+import android.os.Looper;
+import androidx.recyclerview.widget.AsyncListUtil;
+import com.stormtales.notevault.data.MusicDatabase;
+import com.stormtales.notevault.data.dao.SongDao;
+import com.stormtales.notevault.data.entities.NoteSheet;
+import com.stormtales.notevault.data.entities.Song;
+import com.stormtales.notevault.data.sync.SyncStatus;
+import com.stormtales.notevault.network.sync.models.*;
+import com.stormtales.notevault.utils.NoteSheetsUtil;
+
+import java.io.File;
+import java.io.IOException;
+import java.time.LocalDateTime;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.stream.Collectors;
+
+public class SongSyncRepository {
+    private SongDao songDao;
+    public SongSyncRepository(Context context) {
+        MusicDatabase database = MusicDatabase.getDatabase(context);
+        songDao = database.getSongTable();
+    }
+
+    public void loadCreatedSongs(LoadDataCallback<List<Song>> callback) {
+        Executors.newSingleThreadExecutor().execute(() -> {
+            List<Song> createdSongs = songDao.getSongsBySyncStatus(SyncStatus.CREATED);
+            Handler mainHandler = new Handler(Looper.getMainLooper());
+            mainHandler.post(()-> callback.onResult(createdSongs));
+        });
+    }
+
+    public void loadModifiedSongs(LoadDataCallback<Map<Song, List<NoteSheet>>> callback) {
+        Executors.newSingleThreadExecutor().execute(() -> {
+            Map<Song, List<NoteSheet>> result = new HashMap<>();
+            List<Song> modifiedSongs = songDao.getSongsBySyncStatus(SyncStatus.MODIFIED);
+            for(Song song : modifiedSongs) {
+                List<NoteSheet> noteSheets = songDao.getNoteSheetsBySong(song.getLocalID());
+                result.put(song, noteSheets);
+            }
+            Handler mainHandler = new Handler(Looper.getMainLooper());
+            mainHandler.post(()-> callback.onResult(result));
+        });
+    }
+
+    public void loadDeletedSongs(LoadDataCallback<List<Song>> callback) {
+        Executors.newSingleThreadExecutor().execute(() -> {
+            List<Song> deletedSongs = songDao.getSongsBySyncStatus(SyncStatus.DELETED);
+            Handler mainHandler = new Handler(Looper.getMainLooper());
+            mainHandler.post(()-> callback.onResult(deletedSongs));
+        });
+    }
+
+    public void markCreatedSongsAsSynced(BatchCreateResponse createdSongs) {
+        Executors.newSingleThreadExecutor().execute(() -> {
+            List<Integer> localIDs = createdSongs.getCreateResponses().stream().map(CreateResponse::getLocalID).collect(Collectors.toList());
+            List<Song> requestedSongs = songDao.getSongsByLocalIDs(localIDs);
+
+            for(Song song : requestedSongs) {
+                song.setSyncTime(LocalDateTime.now());
+                song.setSyncStatus(SyncStatus.SYNCED);
+
+                for(CreateResponse createResponse : createdSongs.getCreateResponses()) {
+                    if(createResponse.getLocalID() == song.getLocalID()) {
+                        song.setServerID(createResponse.getServerID());
+                        break;
+                    }
+                }
+            }
+            songDao.updateSongs(requestedSongs);
+        });
+    }
+
+    public void markSongsAsSynced(List<Song> songs) {
+        for(Song song : songs) {
+            song.setSyncStatus(SyncStatus.SYNCED);
+        }
+    }
+
+    public void markModifiedSongsAsSynced(SongModifyBatchResponse modifyBatchResponse) {
+        Executors.newSingleThreadExecutor().execute(() -> {
+            List<String> serverIDs = modifyBatchResponse.getModifiedServerObjects().stream().map(SongModifyResponse::getServerID).collect(Collectors.toList());
+            List<Song> requestedSongs = songDao.getSongsByServerIDs(serverIDs);
+            for(Song song : requestedSongs) {
+                song.setSyncStatus(SyncStatus.SYNCED);
+                song.setSyncTime(LocalDateTime.now());
+
+
+                for(SongModifyResponse modifyResponse : modifyBatchResponse.getModifiedServerObjects()) {
+                    if(modifyResponse.getServerID().equals(song.getServerID())) {
+                        List<NoteSheet> outdatedNoteSheets = songDao.getNoteSheetsByServerFileNames(modifyResponse.getOutdated_note_sheets());
+                        for(NoteSheet noteSheet : outdatedNoteSheets) {
+                            noteSheet.setSyncStatus(SyncStatus.MODIFIED);
+                        }
+                        songDao.updateNoteSheets(outdatedNoteSheets);
+                    }
+                }
+            }
+
+
+            songDao.updateSongs(requestedSongs);
+        });
+    }
+
+    public void markDeletedSongsAsSynced(List<String> remoteDeletedSongs, List<Integer> localDeletedSongs) {
+        Executors.newSingleThreadExecutor().execute(() -> {
+            songDao.deleteSongsByServerIDs(remoteDeletedSongs);
+            songDao.deleteSongsByLocalIDs(localDeletedSongs);
+        });
+    }
+
+    public void getNoteSheetFilesBySongIDs(LoadDataCallback<List<NoteSheet>> callback) {
+        Executors.newSingleThreadExecutor().execute(() -> {
+            List<NoteSheet> noteSheets = songDao.getNoteSheetsBySyncStatus(SyncStatus.CREATED);
+            Handler mainHandler = new Handler(Looper.getMainLooper());
+            mainHandler.post(()-> callback.onResult(noteSheets));
+        });
+    }
+
+    public void markCreatedNoteSheetsAsSynced(List<UploadResponse> uploadResponses) {
+        Executors.newSingleThreadExecutor().execute(() -> {
+            List<String> serverSongIDs = uploadResponses.stream().map(UploadResponse::getServerID).collect(Collectors.toList());
+            List<Integer> localSongIDs = songDao.getLocalSongIDsByServerIDs(serverSongIDs);
+
+            List<NoteSheet> uploadedNoteSheets = songDao.getNoteSheetsBySongIDs(localSongIDs);
+            for(UploadResponse uploadResponse : uploadResponses) {
+                for(NoteSheet noteSheet : uploadedNoteSheets) {
+                    if(new File(noteSheet.getLocalFileName()).getName().equals(uploadResponse.getLocalFile())) {
+                        noteSheet.setServerFileName(uploadResponse.getServerFile());
+                        noteSheet.setSyncStatus(SyncStatus.SYNCED);
+                        break;
+                    }
+                }
+            }
+            songDao.updateNoteSheets(uploadedNoteSheets);
+        });
+    }
+
+    public void loadModifiedNoteSheets(LoadDataCallback<List<NoteSheet>> callback) {
+        Executors.newSingleThreadExecutor().execute(() -> {
+            List<NoteSheet> noteSheets = songDao.getNoteSheetsBySyncStatus(SyncStatus.MODIFIED);
+            Handler mainHandler = new Handler(Looper.getMainLooper());
+            mainHandler.post(()-> callback.onResult(noteSheets));
+        });
+    }
+
+    public void markModifiedNoteSheetsAsSynced(List<UploadResponse> uploadResponses) {
+        Executors.newSingleThreadExecutor().execute(() -> {
+            List<String> serverFileNames = uploadResponses.stream().map(UploadResponse::getServerFile).collect(Collectors.toList());
+
+
+            List<NoteSheet> noteSheets = songDao.getNoteSheetsByServerFileNames(serverFileNames);
+            for(NoteSheet noteSheet : noteSheets) {
+                noteSheet.setSyncStatus(SyncStatus.SYNCED);
+            }
+            songDao.updateNoteSheets(noteSheets);
+        });
+    }
+
+    public void markSongsAsRemotelyModified(List<String> serverIDs, LoadDataCallback<List<Song>> callback) {
+        Executors.newSingleThreadExecutor().execute(() -> {
+            List<Song> songs = songDao.getSongsByServerIDs(serverIDs);
+            List<Song> createdSongs = new ArrayList<>();
+            for(Song song : songs) {
+                song.setSyncStatus(SyncStatus.REMOTE_MODIFIED);
+            }
+
+            for(String serverID : serverIDs) {
+                boolean foundServerSong = false;
+                for(Song song : songs) {
+                    if(song.getServerID().equals(serverID)) {
+                        foundServerSong = true;
+                        break;
+                    }
+                }
+
+                if(!foundServerSong) {
+                    Song song = new Song(serverID);
+                    createdSongs.add(song);
+                }
+            }
+            songDao.updateSongs(songs);
+            songDao.insertSongs(createdSongs);
+            callback.onResult(createdSongs);
+        });
+    }
+
+    public void loadRemotelyModifiedSongs(LoadDataCallback<List<Song>> callback) {
+        Executors.newSingleThreadExecutor().execute(() -> {
+            List<Song> songs = songDao.getSongsBySyncStatus(SyncStatus.REMOTE_MODIFIED);
+            Handler mainHandler = new Handler(Looper.getMainLooper());
+            mainHandler.post(()-> callback.onResult(songs));
+        });
+    }
+
+    public void saveRemoteSongs(List<SongModel> remoteSongs, LoadDataCallback<List<NoteSheet>> callback) {
+        Executors.newSingleThreadExecutor().execute(() ->{
+            List<String> serverIDs = remoteSongs.stream().map(SongModel::getServerID).collect(Collectors.toList());
+            List<Song> songs = songDao.getSongsByServerIDs(serverIDs);
+            List<Integer> localSongIDs = songDao.getLocalSongIDsByServerIDs(serverIDs);
+            List<NoteSheet> noteSheets = songDao.getNoteSheetsBySongIDs(localSongIDs);
+
+            List<Song> onlyRemoteExistingSongs = new ArrayList<>();
+            List<NoteSheet> outdatedNoteSheets = new ArrayList<>();
+            List<NoteSheet> onlyRemoteNoteSheets = new ArrayList<>();
+            for(SongModel songModel : remoteSongs) {
+                boolean found = false;
+                for(Song song : songs) {
+                    if(song.getServerID().equals(songModel.getServerID())) {
+                        found = true;
+                        if(!songModel.isDeleted()) {
+                           song.setSyncStatus(SyncStatus.SYNCED);
+                           song.setSyncTime(LocalDateTime.now());
+
+                           song.setTitle(songModel.getTitle());
+                           song.setComposer(songModel.getComposer());
+                           song.setGenre(songModel.getGenre());
+                           song.setYear(songModel.getYear());
+
+                            for(RemotelyModifiedNoteSheetModel remoteNoteSheet : songModel.getNote_sheets()) {
+                                if(noteSheets.isEmpty()) {
+                                    NoteSheet noteSheet = new NoteSheet(song.getLocalID(), remoteNoteSheet.getFilename(), remoteNoteSheet.getServer_filename(), null);
+                                    onlyRemoteNoteSheets.add(noteSheet);
+                                    outdatedNoteSheets.add(noteSheet);
+                                } else {
+                                    boolean foundNoteSheet = false;
+                                    for(NoteSheet noteSheet : noteSheets) {
+                                        if(remoteNoteSheet.getServer_filename().equals(noteSheet.getServerFileName())) {
+                                            foundNoteSheet = true;
+                                            if(!remoteNoteSheet.getHash().equals(noteSheet.getHash())) {
+                                                outdatedNoteSheets.add(noteSheet);
+                                                break;
+                                            }
+                                        }
+                                    }
+
+                                    if(!foundNoteSheet) {
+                                        NoteSheet noteSheet = new NoteSheet(song.getLocalID(), remoteNoteSheet.getFilename(), remoteNoteSheet.getServer_filename(), null);
+                                        onlyRemoteNoteSheets.add(noteSheet);
+                                        outdatedNoteSheets.add(noteSheet);
+                                    }
+                                }
+
+                            }
+
+                        } else {
+                            removeSong(song);
+                        }
+                    }
+                }
+
+                if(!found) {
+                    Song song = new Song(songModel);
+                    onlyRemoteExistingSongs.add(song);
+                }
+            }
+
+            songDao.updateSongs(songs);
+            songDao.insertSongs(onlyRemoteExistingSongs);
+            songDao.insert(onlyRemoteNoteSheets);
+
+            Handler mainHandler = new Handler(Looper.getMainLooper());
+            mainHandler.post(()-> callback.onResult(outdatedNoteSheets));
+        });
+    }
+
+    private void removeSong(Song song) {
+        List<NoteSheet> noteSheets = songDao.getNoteSheetsBySong(song.getLocalID());
+        for(NoteSheet noteSheet : noteSheets) {
+            try {
+                NoteSheetsUtil.deleteNoteSheet(noteSheet.getLocalFileName());
+            } catch (IOException e) {
+                throw new RuntimeException(e);
+            }
+        }
+        songDao.deleteNoteSheets(noteSheets);
+        songDao.deleteSong(song);
+
+    }
+
+
+
+    public void saveUpdatedNoteSheet(String serverFileName, String localFileName, String hash) {
+        Executors.newSingleThreadExecutor().execute(()-> {
+            NoteSheet noteSheet = songDao.getNoteSheetByServerFileName(serverFileName);
+            noteSheet.setHash(hash);
+            noteSheet.setLocalFileName(localFileName);
+            songDao.updateNoteSheet(noteSheet);
+        });
+    }
+
+    public interface LoadDataCallback<T> {
+        void onResult(T result);
+    }
+}

app/src/main/java/com/stormtales/notevault/data/sync/DateConverter.java

@@ -1,4 +1,4 @@
-package core.notevault.data;
+package com.stormtales.notevault.data.sync;
 
 import androidx.room.TypeConverter;
 

app/src/main/java/com/stormtales/notevault/data/sync/SyncStatus.java

@@ -1,4 +1,4 @@
-package core.notevault.data.sync;
+package com.stormtales.notevault.data.sync;
 
 public enum SyncStatus {
     CREATED,

app/src/main/java/com/stormtales/notevault/data/sync/SyncStatusConverter.java

@@ -1,4 +1,4 @@
-package core.notevault.data.sync;
+package com.stormtales.notevault.data.sync;
 
 import androidx.room.TypeConverter;
 

app/src/main/java/com/stormtales/notevault/network/APICallback.java

@@ -1,7 +1,6 @@
-package core.notevault.sync;
+package com.stormtales.notevault.network;
 
 public interface APICallback {
-
     void onSuccess();
     void onError(String error);
 }

app/src/main/java/com/stormtales/notevault/network/NetworkModule.java

@@ -1,15 +1,16 @@
-package core.notevault.sync;
+package com.stormtales.notevault.network;
 
 import android.content.Context;
 import android.content.SharedPreferences;
-import core.notevault.sync.auth.AuthInterceptor;
+import com.stormtales.notevault.network.auth.AuthInterceptor;
-import core.notevault.sync.auth.TokenManager;
+import com.stormtales.notevault.network.auth.TokenManager;
 import okhttp3.OkHttpClient;
 import okhttp3.logging.HttpLoggingInterceptor;
 import retrofit2.Retrofit;
 import retrofit2.converter.gson.GsonConverterFactory;
 
-public class ApiClient {
+public class NetworkModule {
+    private static final String BASE_URL = "https://notevault.fawkes100.de/";
     private static Retrofit retrofit;
 
     public static Retrofit getRetrofitInstance(Context context) {
@@ -24,11 +25,12 @@ public class ApiClient {
                     .build();
 
             retrofit = new Retrofit.Builder()
-                    .baseUrl("http://192.168.178.30:8000/")
+                    .baseUrl(BASE_URL)
                     .client(client)
                     .addConverterFactory(GsonConverterFactory.create())
                     .build();
         }
         return retrofit;
     }
+
 }

app/src/main/java/com/stormtales/notevault/network/StatusResponse.java

@@ -1,4 +1,4 @@
-package core.notevault.sync;
+package com.stormtales.notevault.network;
 
 public class StatusResponse {
 

app/src/main/java/com/stormtales/notevault/network/auth/AuthAPI.java

@@ -1,15 +1,12 @@
-package core.notevault.sync.auth;
+package com.stormtales.notevault.network.auth;
 
-import core.notevault.sync.StatusResponse;
+import com.stormtales.notevault.network.StatusResponse;
-import core.notevault.sync.auth.apimodel.LoginRequest;
-import core.notevault.sync.auth.apimodel.LoginResponse;
-import core.notevault.sync.auth.apimodel.RegisterRequest;
 import retrofit2.Call;
 import retrofit2.http.Body;
 import retrofit2.http.Headers;
 import retrofit2.http.POST;
 
-public interface AuthService {
+public interface AuthAPI {
 
     @POST("/login/")
     Call<LoginResponse> login(@Body LoginRequest loginRequest);

app/src/main/java/com/stormtales/notevault/network/auth/AuthInterceptor.java

@@ -1,12 +1,9 @@
-package core.notevault.sync.auth;
+package com.stormtales.notevault.network.auth;
 
-import android.content.SharedPreferences;
-import android.util.Log;
 import okhttp3.Interceptor;
 import okhttp3.Request;
 import okhttp3.Response;
 
-
 import java.io.IOException;
 
 public class AuthInterceptor implements Interceptor {

app/src/main/java/com/stormtales/notevault/network/auth/AuthService.java

@@ -1,37 +1,35 @@
-package core.notevault.sync.auth;
+package com.stormtales.notevault.network.auth;
 
 import android.content.Context;
-import core.notevault.sync.APICallback;
+import android.text.TextUtils;
-import core.notevault.sync.ApiClient;
+import com.stormtales.notevault.network.APICallback;
-import core.notevault.sync.StatusResponse;
+import com.stormtales.notevault.network.NetworkModule;
-import core.notevault.sync.auth.apimodel.LoginRequest;
+import com.stormtales.notevault.network.StatusResponse;
-import core.notevault.sync.auth.apimodel.LoginResponse;
-import core.notevault.sync.auth.apimodel.RegisterRequest;
-import core.notevault.sync.auth.apimodel.RegisterResponse;
 import retrofit2.Call;
 import retrofit2.Callback;
 import retrofit2.Response;
 
-public class AuthRepository {
+public class AuthService {
-    private final AuthService authService;
+
+    private final AuthAPI authAPI;
     private final TokenManager tokenManager;
 
-    public AuthRepository(Context context) {
+    public AuthService(Context context) {
-        this.authService = ApiClient.getRetrofitInstance(context).create(AuthService.class);
+        this.authAPI = NetworkModule.getRetrofitInstance(context).create(AuthAPI.class);
         this.tokenManager = new TokenManager(context);
     }
 
-    public void performLogin(String email, String password, APICallback callback) {
+    public void performLogin(String email, String password, LoginCallback callback) {
         LoginRequest loginRequest = new LoginRequest(email, password);
 
-        authService.login(loginRequest).enqueue(new Callback<LoginResponse>() {
+        authAPI.login(loginRequest).enqueue(new Callback<LoginResponse>() {
             @Override
             public void onResponse(Call<LoginResponse> call, Response<LoginResponse> response) {
                 if (response.isSuccessful() && response.body() != null) {
                     String token = response.body().getToken();
                     saveToken(token);
                     // Erfolgsrückmeldung an den Callback senden
-                    callback.onSuccess();
+                    callback.onSuccess(response.body());
                 } else {
                     // Fehlermeldung an den Callback senden
                     callback.onError("Login fehlgeschlagen. Überprüfe Benutzername und Passwort.");
@@ -48,7 +46,7 @@ public class AuthRepository {
 
     public void performRegistration(String email, String username, String password, APICallback callback) {
         RegisterRequest registerRequest = new RegisterRequest(username, password, email);
-        authService.registration(registerRequest).enqueue(new Callback<StatusResponse>() {
+        authAPI.registration(registerRequest).enqueue(new Callback<StatusResponse>() {
 
             @Override
             public void onResponse(Call<StatusResponse> call, Response<StatusResponse> response) {
@@ -77,4 +75,13 @@ public class AuthRepository {
     public void logout() {
         tokenManager.clearToken();
     }
+
+    public boolean isLoggedIn() {
+        return !TextUtils.isEmpty(tokenManager.getToken());
+    }
+
+    public interface LoginCallback {
+        void onSuccess(LoginResponse loginResponse);
+        void onError(String error);
+    }
 }

app/src/main/java/com/stormtales/notevault/network/auth/LoginRequest.java

@@ -1,4 +1,4 @@
-package core.notevault.sync.auth.apimodel;
+package com.stormtales.notevault.network.auth;
 
 public class LoginRequest {
     private String email;
@@ -8,6 +8,4 @@ public class LoginRequest {
         this.email = email;
         this.password = password;
     }
-
-
 }

app/src/main/java/com/stormtales/notevault/network/auth/LoginResponse.java

@@ -1,4 +1,4 @@
-package core.notevault.sync.auth.apimodel;
+package com.stormtales.notevault.network.auth;
 
 public class LoginResponse {
     private String token;

app/src/main/java/com/stormtales/notevault/network/auth/RegisterRequest.java

@@ -1,4 +1,4 @@
-package core.notevault.sync.auth.apimodel;
+package com.stormtales.notevault.network.auth;
 
 public class RegisterRequest {
     private String username;

app/src/main/java/com/stormtales/notevault/network/auth/TokenManager.java

@@ -1,4 +1,4 @@
-package core.notevault.sync.auth;
+package com.stormtales.notevault.network.auth;
 
 import android.content.Context;
 import android.content.SharedPreferences;

app/src/main/java/com/stormtales/notevault/network/sync/SongSyncAPI.java

@@ -0,0 +1,45 @@
+package com.stormtales.notevault.network.sync;
+
+import com.stormtales.notevault.network.auth.LoginRequest;
+import com.stormtales.notevault.network.auth.LoginResponse;
+import com.stormtales.notevault.network.sync.models.*;
+import okhttp3.MultipartBody;
+import okhttp3.RequestBody;
+import okhttp3.ResponseBody;
+import retrofit2.Call;
+import retrofit2.http.*;
+
+import java.time.LocalDateTime;
+
+public interface SongSyncAPI {
+
+    @POST("/sync/songs/create")
+    Call<BatchCreateResponse> syncCreatedSongs(@Body SongCreateBatchRequest songCreateBatchRequest);
+
+    @POST("/sync/songs/modify")
+    Call<SongModifyBatchResponse> syncModifiedSongs(@Body SongModifyBatchRequest songModifyBatchRequest);
+
+    @POST("/sync/songs/delete")
+    Call<BatchModifyResponse> syncDeletedSongs(@Body SongBatchDeleteRequest songBatchDeleteRequest);
+
+    @Multipart
+    @POST("/sync/songs/note_sheet/upload")
+    Call<UploadResponse> uploadNoteSheet(@Part("serverID")RequestBody serverID, @Part("fileName") RequestBody fileName, @Part MultipartBody.Part image);
+
+    @Multipart
+    @POST("/sync/songs/note_sheet/update")
+    Call<UploadResponse> updateNoteSheet(@Part("server_filename") RequestBody server_filename, @Part MultipartBody.Part image);
+
+    @GET("/sync/songs/fetch")
+    Call<FetchResponse> fetchRemoteModifiedSongs(@Query(value = "last_client_sync") String last_client_sync);
+
+    @GET("/sync/songs/get/")
+    Call<SongModel> fetchRemotelyModifiedSongData(@Query(value = "songID") String songID);
+
+    @GET("/sync/songs/get/notesheet/")
+    Call<ResponseBody> downloadNotesheet(@Query("server_filename") String server_filename);
+
+    @Multipart
+    @POST("/ai/regognize/title")
+    Call<AIRecognizedSong> recognizeTitle(@Part MultipartBody.Part image);
+}

app/src/main/java/com/stormtales/notevault/network/sync/SongSyncModule.java

@@ -0,0 +1,154 @@
+package com.stormtales.notevault.network.sync;
+
+import android.content.Context;
+import android.net.Uri;
+import com.stormtales.notevault.data.entities.NoteSheet;
+import com.stormtales.notevault.data.entities.Song;
+import com.stormtales.notevault.data.repositories.SongRepository;
+import com.stormtales.notevault.data.repositories.SongSyncRepository;
+import com.stormtales.notevault.network.sync.models.*;
+import com.stormtales.notevault.ui.gallery.GalleryViewModel;
+import com.stormtales.notevault.utils.NoteSheetsUtil;
+import com.stormtales.notevault.utils.Tupel;
+
+import java.io.File;
+import java.time.LocalDateTime;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.stream.Collectors;
+
+public class SongSyncModule {
+    private SongRepository songRepository;
+    private SongSyncRepository songSyncRepository;
+    private SongSyncService songSyncService;
+    private GalleryViewModel syncViewModel;
+    private Context context;
+
+    public SongSyncModule(Context context, GalleryViewModel syncViewModel) {
+        this.songRepository = new SongRepository(context);
+        this.songSyncRepository = new SongSyncRepository(context);
+        this.songSyncService = new SongSyncService(context);
+        this.syncViewModel = syncViewModel;
+        this.context = context;
+    }
+
+    public void syncCreatedSongs() {
+        songSyncRepository.loadCreatedSongs(result -> {
+            songSyncService.syncCreatedSongs(result, response -> {
+                songSyncRepository.markCreatedSongsAsSynced(response);
+                if(response.getCreateResponses().isEmpty()) {
+                    syncViewModel.finishCreateSongSyncing();
+                } else {
+                    uploadCreatedNoteSheets(result, response);
+                }
+            });
+        });
+    }
+
+    public void uploadCreatedNoteSheets(List<Song> result, BatchCreateResponse response) {
+        List<Integer> songIDs = result.stream().map(Song::getLocalID).collect(Collectors.toList());
+        songSyncRepository.getNoteSheetFilesBySongIDs(noteSheets -> {
+            songSyncService.uploadNoteSheetsOfCreatedSongs(noteSheets, response, uploadResponses -> {
+                songSyncRepository.markCreatedNoteSheetsAsSynced(uploadResponses);
+                syncViewModel.finishCreateSongSyncing();
+            });
+        });
+    }
+
+    public void syncModifiedSongs() {
+        songSyncRepository.loadModifiedSongs(result -> {
+            songSyncService.syncModifiedSongs(result, (FinishSongSyncingCallback<SongModifyBatchResponse>) response -> {
+                songSyncRepository.markModifiedSongsAsSynced(response);
+                uploadModifiedNoteSheets();
+            });
+        });
+    }
+
+    public void uploadModifiedNoteSheets() {
+        songSyncRepository.loadModifiedNoteSheets(modifiedNoteSheets -> {
+            if(modifiedNoteSheets.isEmpty()) {
+                syncViewModel.finishModifiedSongSyncinc();
+            } else {
+                songSyncService.uploadModifiedNoteSheets(modifiedNoteSheets, new SongSyncService.UploadNoteSheetCallback() {
+                    @Override
+                    public void finishUploadNoteSheets(List<UploadResponse> uploadResponses) {
+                        songSyncRepository.markModifiedNoteSheetsAsSynced(uploadResponses);
+                        syncViewModel.finishModifiedSongSyncinc();
+                    }
+                });
+            }
+        });
+    }
+
+    public void syncDeletedSongs() {
+        songSyncRepository.loadDeletedSongs(result -> {
+            songSyncService.syncDeletedSong(result, (remoteDeletedSongs, localDeletedSongs) -> {
+                songSyncRepository.markDeletedSongsAsSynced(remoteDeletedSongs, localDeletedSongs);
+                syncViewModel.finishDeleteSongSyncinc();
+            });
+        });
+    }
+
+    public void fetchRemoteModifiedSongs() {
+        //Todo: Determine Last Client Sync; for testing use LocalDateTime.MIN
+        songSyncService.fetchRemoteModifiedSongs(LocalDateTime.now().minusDays(35), new SongSyncRepository.LoadDataCallback<FetchResponse>() {
+            @Override
+            public void onResult(FetchResponse result) {
+                songSyncRepository.markSongsAsRemotelyModified(result.getServerIDs(), createdSongs -> {
+                    getRemotelyModifiedSongData(createdSongs);
+                });
+
+            }
+        });
+    }
+
+    public void getRemotelyModifiedSongData(List<Song> freshlyCreatedSongs) {
+        songSyncRepository.loadRemotelyModifiedSongs(songs -> {
+            for(Song song : freshlyCreatedSongs) {
+                boolean freshlyCreatedSongFound = false;
+                for(Song s : songs) {
+                    if(s.getServerID().equals(song.getServerID())) {
+                        freshlyCreatedSongFound = true;
+                        break;
+                    }
+                }
+                if(!freshlyCreatedSongFound) {
+                    songs.add(song);
+                }
+
+            }
+            if(songs.isEmpty()) {
+                syncViewModel.finishFetching();
+            } else {
+                songSyncService.getRemotelyModifiedSongData(songs, remoteSongs -> {
+                    if(remoteSongs.isEmpty()) {
+                        syncViewModel.finishFetching();
+                    } else {
+                        songSyncRepository.saveRemoteSongs(remoteSongs, this::downloadNoteSheets);
+                    }
+                });
+            }
+
+        });
+    }
+
+    public void downloadNoteSheets(List<NoteSheet> noteSheets) {
+        for(NoteSheet noteSheet : noteSheets) {
+            songSyncService.downloadNoteSheet(noteSheet, responseBody -> {
+                String localFilename = noteSheet.getServerFileName().substring(36);
+
+                Tupel<String, String> result = NoteSheetsUtil.saveImageFromServer(responseBody, context.getFilesDir());
+                songSyncRepository.saveUpdatedNoteSheet(noteSheet.getServerFileName(), result.getValue00(), result.getValue01());
+            });
+        }
+        syncViewModel.finishFetching();
+    }
+
+    public interface FinishSongCreateSyncingCallback {
+        void finishSongSyncing(BatchCreateResponse response);
+    }
+
+    public interface FinishSongSyncingCallback<T> {
+        void finishSongSyncing(T response);
+    }
+}

app/src/main/java/com/stormtales/notevault/network/sync/SongSyncService.java

@@ -0,0 +1,246 @@
+package com.stormtales.notevault.network.sync;
+
+import android.content.Context;
+import android.util.Log;
+import com.stormtales.notevault.data.entities.NoteSheet;
+import com.stormtales.notevault.data.entities.Song;
+import com.stormtales.notevault.data.repositories.SongSyncRepository;
+import com.stormtales.notevault.network.NetworkModule;
+import com.stormtales.notevault.network.auth.AuthAPI;
+import com.stormtales.notevault.network.sync.models.*;
+import com.stormtales.notevault.ui.gallery.GalleryViewModel;
+import okhttp3.MediaType;
+import okhttp3.MultipartBody;
+import okhttp3.RequestBody;
+import okhttp3.ResponseBody;
+import retrofit2.Call;
+import retrofit2.Callback;
+import retrofit2.Response;
+
+import java.io.File;
+import java.time.LocalDateTime;
+import java.time.format.DateTimeFormatter;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+
+public class SongSyncService {
+    private final SongSyncAPI songSyncAPI;
+    private GalleryViewModel syncStatusViewModel;
+
+    public SongSyncService(Context context) {
+        songSyncAPI = NetworkModule.getRetrofitInstance(context).create(SongSyncAPI.class);
+    }
+
+    public void syncCreatedSongs(List<Song> songs, SongSyncModule.FinishSongCreateSyncingCallback callback) {
+        List<SongCreateRequest> createRequests = new ArrayList<>();
+        for(Song song : songs) {
+            createRequests.add(new SongCreateRequest(song));
+        }
+        SongCreateBatchRequest songCreateBatchRequest = new SongCreateBatchRequest(createRequests);
+        songSyncAPI.syncCreatedSongs(songCreateBatchRequest).enqueue(new Callback<BatchCreateResponse>() {
+            @Override
+            public void onResponse(Call<BatchCreateResponse> call, Response<BatchCreateResponse> response) {
+                callback.finishSongSyncing(response.body());
+            }
+
+            @Override
+            public void onFailure(Call<BatchCreateResponse> call, Throwable throwable) {
+
+            }
+        });
+    }
+
+    public void uploadNoteSheetsOfCreatedSongs(List<NoteSheet> noteSheets, BatchCreateResponse batchCreateResponse, UploadNoteSheetCallback callback) {
+        List<UploadResponse> uploadResponses = new ArrayList<>();
+        for(CreateResponse createResponse : batchCreateResponse.getCreateResponses()) {
+            for(NoteSheet noteSheet : noteSheets) {
+                if(noteSheet.getSongID() == createResponse.getLocalID()) {
+                    File imageFile = new File(noteSheet.getLocalFileName());
+
+                    RequestBody serverID = RequestBody.create(MediaType.parse("text/plain"), createResponse.getServerID());
+                    RequestBody fileName = RequestBody.create(MediaType.parse("text/plain"), imageFile.getName());
+
+                    RequestBody requestFile = RequestBody.create(MediaType.parse("image/**"), new File(noteSheet.getLocalFileName()));
+                    MultipartBody.Part image = MultipartBody.Part.createFormData("image", noteSheet.getLocalFileName(), requestFile);
+
+                    songSyncAPI.uploadNoteSheet(serverID, fileName, image).enqueue(new Callback<UploadResponse>() {
+                        @Override
+                        public void onResponse(Call<UploadResponse> call, Response<UploadResponse> response) {
+                            if(response.isSuccessful() && response.body() != null) {
+                                uploadResponses.add(response.body());
+                                if(uploadResponses.size() == noteSheets.size()) {
+                                    callback.finishUploadNoteSheets(uploadResponses);
+                                }
+                            }
+                        }
+
+                        @Override
+                        public void onFailure(Call<UploadResponse> call, Throwable throwable) {
+
+                        }
+                    });
+                }
+            }
+        }
+    }
+
+    public void syncModifiedSongs(Map<Song, List<NoteSheet>> songs, SongSyncModule.FinishSongSyncingCallback<SongModifyBatchResponse> callback) {
+        List<SongModifyRequest> modifyRequests = new ArrayList<>();
+        for(Map.Entry<Song, List<NoteSheet>> entry: songs.entrySet()) {
+            modifyRequests.add(new SongModifyRequest(entry.getKey(), entry.getValue()));
+        }
+        SongModifyBatchRequest songModifyBatchRequest = new SongModifyBatchRequest(modifyRequests);
+        songSyncAPI.syncModifiedSongs(songModifyBatchRequest).enqueue(new Callback<SongModifyBatchResponse>() {
+            @Override
+            public void onResponse(Call<SongModifyBatchResponse> call, Response<SongModifyBatchResponse> response) {
+                callback.finishSongSyncing(response.body());
+            }
+
+            @Override
+            public void onFailure(Call<SongModifyBatchResponse> call, Throwable throwable) {
+
+            }
+        });
+    }
+
+    public void syncDeletedSong(List<Song> songs, SyncDeletedSongsCallback callback) {
+        List<String> deleteRequests = new ArrayList<>();
+        List<Integer> deletedNotSyncedSongs = new ArrayList<>();
+        for(Song song : songs) {
+            if(song.getServerID() == null) {
+                deletedNotSyncedSongs.add(song.getLocalID());
+            } else {
+                deleteRequests.add(song.getServerID());
+            }
+        }
+
+        SongBatchDeleteRequest songBatchDeleteRequest = new SongBatchDeleteRequest(deleteRequests);
+        songSyncAPI.syncDeletedSongs(songBatchDeleteRequest).enqueue(new Callback<BatchModifyResponse>() {
+            @Override
+            public void onResponse(Call<BatchModifyResponse> call, Response<BatchModifyResponse> response) {
+                if(response.isSuccessful() && response.body() != null) {
+                    callback.finishSongSyncing(response.body().getModifiedServerObjects(), deletedNotSyncedSongs);
+                }
+            }
+
+            @Override
+            public void onFailure(Call<BatchModifyResponse> call, Throwable throwable) {
+
+            }
+        });
+    }
+
+    public void uploadModifiedNoteSheets(List<NoteSheet> modifiedNoteSheets, UploadNoteSheetCallback callback) {
+        List<UploadResponse> uploadResponses = new ArrayList<>();
+        for(NoteSheet noteSheet : modifiedNoteSheets) {
+            RequestBody server_filename = RequestBody.create(MediaType.parse("text/plain"), noteSheet.getServerFileName());
+
+            RequestBody requestFile = RequestBody.create(MediaType.parse("image/**"), new File(noteSheet.getLocalFileName()));
+            MultipartBody.Part image = MultipartBody.Part.createFormData("image", noteSheet.getLocalFileName(), requestFile);
+
+            songSyncAPI.updateNoteSheet(server_filename, image).enqueue(new Callback<UploadResponse>() {
+                @Override
+                public void onResponse(Call<UploadResponse> call, Response<UploadResponse> response) {
+                    if(response.isSuccessful() && response.body() != null) {
+                        uploadResponses.add(response.body());
+                        if(uploadResponses.size() == modifiedNoteSheets.size()) {
+                            callback.finishUploadNoteSheets(uploadResponses);
+                        }
+                    } else {
+                        Log.d("SongSyncService", "Something went wrong");
+                    }
+                }
+
+                @Override
+                public void onFailure(Call<UploadResponse> call, Throwable throwable) {
+                    Log.e("SongSyncService", "Upload failed: " + throwable.getMessage(), throwable);
+                }
+            });
+        }
+    }
+
+    public void fetchRemoteModifiedSongs(LocalDateTime lastClientSync, SongSyncRepository.LoadDataCallback<FetchResponse> callback) {
+        String formattedTime = lastClientSync.format(DateTimeFormatter.ISO_LOCAL_DATE_TIME);
+        songSyncAPI.fetchRemoteModifiedSongs(formattedTime).enqueue(new Callback<FetchResponse>() {
+            @Override
+            public void onResponse(Call<FetchResponse> call, Response<FetchResponse> response) {
+                if(response.isSuccessful() && response.body() != null) {
+                    callback.onResult(response.body());
+                }
+            }
+
+            @Override
+            public void onFailure(Call<FetchResponse> call, Throwable throwable) {
+                Log.d("SongSyncService", "Fetch failed: " + throwable.getMessage(), throwable);
+            }
+        });
+    }
+
+    public void getRemotelyModifiedSongData(List<Song> remotelyModifiedSongs, SongSyncRepository.LoadDataCallback<List<SongModel>> callback) {
+        List<SongModel> songModels = new ArrayList<>();
+        for(Song song : remotelyModifiedSongs) {
+            songSyncAPI.fetchRemotelyModifiedSongData(song.getServerID()).enqueue(new Callback<SongModel>() {
+                @Override
+                public void onResponse(Call<SongModel> call, Response<SongModel> response) {
+                    if(response.isSuccessful() && response.body() != null) {
+                        songModels.add(response.body());
+                        if(songModels.size() == remotelyModifiedSongs.size()) {
+                            callback.onResult(songModels);
+                        }
+                    }
+                }
+
+                @Override
+                public void onFailure(Call<SongModel> call, Throwable throwable) {
+                    Log.d("SongSyncService", "Fetch failed: " + throwable.getMessage(), throwable);
+                }
+            });
+        }
+    }
+
+    public void downloadNoteSheet(NoteSheet noteSheet, SongSyncRepository.LoadDataCallback<ResponseBody> callback) {
+        songSyncAPI.downloadNotesheet(noteSheet.getServerFileName()).enqueue(new Callback<ResponseBody>() {
+            @Override
+            public void onResponse(Call<ResponseBody> call, Response<ResponseBody> response) {
+                if(response.isSuccessful() && response.body() != null) {
+                    callback.onResult(response.body());
+                }
+            }
+
+            @Override
+            public void onFailure(Call<ResponseBody> call, Throwable throwable) {
+                Log.d("SongSyncService", "Download failed: " + throwable.getMessage(), throwable);
+            }
+        });
+    }
+
+    public void recognizeTitle(String firstNoteSheet, RecognizedSongCallback callback) {
+        RequestBody requestFile = RequestBody.create(MediaType.parse("image/jpeg"), new File(firstNoteSheet));
+        MultipartBody.Part image = MultipartBody.Part.createFormData("image", firstNoteSheet, requestFile);
+        songSyncAPI.recognizeTitle(image).enqueue(new Callback<AIRecognizedSong>() {
+            @Override
+            public void onResponse(Call<AIRecognizedSong> call, Response<AIRecognizedSong> response) {
+                callback.onRecognizedSong(response.body());
+            }
+
+            @Override
+            public void onFailure(Call<AIRecognizedSong> call, Throwable throwable) {
+                Log.d("SongSyncService", "Recognition failed: " + throwable.getMessage(), throwable);
+            }
+        });
+    }
+
+
+    public interface SyncDeletedSongsCallback {
+        void finishSongSyncing(List<String> remoteDeletedSongs, List<Integer> localDeletedSongs);
+    }
+
+    public interface UploadNoteSheetCallback {
+        void finishUploadNoteSheets(List<UploadResponse> uploadResponses);
+    }
+
+    public interface RecognizedSongCallback {
+        void onRecognizedSong(AIRecognizedSong aiRecognizedSong);
+    }
+}

app/src/main/java/com/stormtales/notevault/network/sync/models/AIRecognizedSong.java

@@ -0,0 +1,40 @@
+package com.stormtales.notevault.network.sync.models;
+
+public class AIRecognizedSong {
+    private String title;
+    private int year;
+    private String composer;
+    private String description;
+
+    public String getTitle() {
+        return title;
+    }
+
+    public void setTitle(String title) {
+        this.title = title;
+    }
+
+    public int getYear() {
+        return year;
+    }
+
+    public void setYear(int year) {
+        this.year = year;
+    }
+
+    public String getComposer() {
+        return composer;
+    }
+
+    public void setComposer(String composer) {
+        this.composer = composer;
+    }
+
+    public String getDescription() {
+        return description;
+    }
+
+    public void setDescription(String description) {
+        this.description = description;
+    }
+}

app/src/main/java/com/stormtales/notevault/network/sync/models/BatchCreateResponse.java

@@ -0,0 +1,15 @@
+package com.stormtales.notevault.network.sync.models;
+
+import java.util.List;
+
+public class BatchCreateResponse {
+    private List<CreateResponse> createResponses;
+
+    public List<CreateResponse> getCreateResponses() {
+        return createResponses;
+    }
+
+    public void setCreateResponses(List<CreateResponse> createResponses) {
+        this.createResponses = createResponses;
+    }
+}

app/src/main/java/com/stormtales/notevault/network/sync/models/BatchModifyResponse.java

@@ -0,0 +1,15 @@
+package com.stormtales.notevault.network.sync.models;
+
+import java.util.List;
+
+public class BatchModifyResponse {
+    private List<String> modifiedServerObjects;
+
+    public List<String> getModifiedServerObjects() {
+        return modifiedServerObjects;
+    }
+
+    public void setModifiedServerObjects(List<String> modifiedServerObjects) {
+        this.modifiedServerObjects = modifiedServerObjects;
+    }
+}

app/src/main/java/com/stormtales/notevault/network/sync/models/CreateResponse.java

@@ -1,14 +1,9 @@
-package core.notevault.sync.synchronisation.songs.creation;
+package com.stormtales.notevault.network.sync.models;
 
-public class SongCreationResponse {
+public class CreateResponse {
     private int localID;
     private String serverID;
 
-    public SongCreationResponse(int localID, String serverID) {
-        this.localID = localID;
-        this.serverID = serverID;
-    }
-
     public int getLocalID() {
         return localID;
     }

app/src/main/java/com/stormtales/notevault/network/sync/models/FetchResponse.java

@@ -1,14 +1,10 @@
-package core.notevault.sync.synchronisation;
+package com.stormtales.notevault.network.sync.models;
 
 import java.util.List;
 
 public class FetchResponse {
     private List<String> serverIDs;
 
-    public FetchResponse(List<String> serverIDs) {
-        this.serverIDs = serverIDs;
-    }
-
     public List<String> getServerIDs() {
         return serverIDs;
     }

app/src/main/java/com/stormtales/notevault/network/sync/models/NoteSheetModifyRequest.java

@@ -0,0 +1,27 @@
+package com.stormtales.notevault.network.sync.models;
+
+public class NoteSheetModifyRequest {
+    private String serverFileName;
+    private String clientHash;
+
+    public NoteSheetModifyRequest(String serverFileName, String clientHash) {
+        this.serverFileName = serverFileName;
+        this.clientHash = clientHash;
+    }
+
+    public String getServerFileName() {
+        return serverFileName;
+    }
+
+    public void setServerFileName(String serverFileName) {
+        this.serverFileName = serverFileName;
+    }
+
+    public String getClientHash() {
+        return clientHash;
+    }
+
+    public void setClientHash(String clientHash) {
+        this.clientHash = clientHash;
+    }
+}

app/src/main/java/com/stormtales/notevault/network/sync/models/RemotelyModifiedNoteSheetModel.java

@@ -0,0 +1,31 @@
+package com.stormtales.notevault.network.sync.models;
+
+public class RemotelyModifiedNoteSheetModel {
+    private String filename;
+    private String server_filename;
+    private String hash;
+
+    public String getFilename() {
+        return filename;
+    }
+
+    public void setFilename(String filename) {
+        this.filename = filename;
+    }
+
+    public String getServer_filename() {
+        return server_filename;
+    }
+
+    public void setServer_filename(String server_filename) {
+        this.server_filename = server_filename;
+    }
+
+    public String getHash() {
+        return hash;
+    }
+
+    public void setHash(String hash) {
+        this.hash = hash;
+    }
+}

app/src/main/java/com/stormtales/notevault/network/sync/models/SongBatchDeleteRequest.java

@@ -1,11 +1,11 @@
-package core.notevault.sync.synchronisation.songs.deletion;
+package com.stormtales.notevault.network.sync.models;
 
 import java.util.List;
 
-public class SongDeletionBatchRequest {
+public class SongBatchDeleteRequest {
     private List<String> songs;
 
-    public SongDeletionBatchRequest(List<String> songs) {
+    public SongBatchDeleteRequest(List<String> songs) {
         this.songs = songs;
     }
 

app/src/main/java/com/stormtales/notevault/network/sync/models/SongCreateBatchRequest.java

@@ -0,0 +1,20 @@
+package com.stormtales.notevault.network.sync.models;
+
+import java.util.List;
+
+public class SongCreateBatchRequest {
+
+    private List<SongCreateRequest> songs;
+
+    public SongCreateBatchRequest(List<SongCreateRequest> songs) {
+        this.songs = songs;
+    }
+
+    public List<SongCreateRequest> getSongs() {
+        return songs;
+    }
+
+    public void setSongs(List<SongCreateRequest> songs) {
+        this.songs = songs;
+    }
+}

app/src/main/java/com/stormtales/notevault/network/sync/models/SongCreateRequest.java

@@ -0,0 +1,67 @@
+package com.stormtales.notevault.network.sync.models;
+
+import com.stormtales.notevault.data.entities.Song;
+
+public class SongCreateRequest {
+    private int localID;
+    private String title;
+    private String composer;
+    private String genre;
+    private int year;
+
+    public SongCreateRequest(int localID, String title, String composer, String genre, int year) {
+        this.localID = localID;
+        this.title = title;
+        this.composer = composer;
+        this.genre = genre;
+        this.year = year;
+    }
+
+    public SongCreateRequest(Song song) {
+        this.localID = song.getLocalID();
+        this.title = song.getTitle();
+        this.composer = song.getComposer();
+        this.genre = song.getGenre();
+        this.year = song.getYear();
+    }
+
+    public int getLocalID() {
+        return localID;
+    }
+
+    public void setLocalID(int localID) {
+        this.localID = localID;
+    }
+
+    public String getTitle() {
+        return title;
+    }
+
+    public void setTitle(String title) {
+        this.title = title;
+    }
+
+    public String getComposer() {
+        return composer;
+    }
+
+    public void setComposer(String composer) {
+        this.composer = composer;
+    }
+
+    public String getGenre() {
+        return genre;
+    }
+
+    public void setGenre(String genre) {
+        this.genre = genre;
+    }
+
+    public int getYear() {
+        return year;
+    }
+
+    public void setYear(int year) {
+        this.year = year;
+    }
+}

app/src/main/java/com/stormtales/notevault/network/sync/models/SongModel.java

@@ -1,19 +1,15 @@
-package core.notevault.sync.synchronisation.songs.modification;
+package com.stormtales.notevault.network.sync.models;
 
-public class SongModificationRequest {
+import java.util.List;
+
+public class SongModel {
     private String serverID;
     private String title;
     private String composer;
     private String genre;
     private int year;
-
+    private List<RemotelyModifiedNoteSheetModel> note_sheets;
-    public SongModificationRequest(String serverID, String title, String composer, String genre, int year) {
+    private boolean deleted;
-        this.serverID = serverID;
-        this.title = title;
-        this.composer = composer;
-        this.genre = genre;
-        this.year = year;
-    }
 
     public String getServerID() {
         return serverID;
@@ -54,4 +50,20 @@ public class SongModificationRequest {
     public void setYear(int year) {
         this.year = year;
     }
+
+    public List<RemotelyModifiedNoteSheetModel> getNote_sheets() {
+        return note_sheets;
+    }
+
+    public void setNote_sheets(List<RemotelyModifiedNoteSheetModel> note_sheets) {
+        this.note_sheets = note_sheets;
+    }
+
+    public boolean isDeleted() {
+        return deleted;
+    }
+
+    public void setDeleted(boolean deleted) {
+        this.deleted = deleted;
+    }
 }

app/src/main/java/com/stormtales/notevault/network/sync/models/SongModifyBatchRequest.java

@@ -0,0 +1,19 @@
+package com.stormtales.notevault.network.sync.models;
+
+import java.util.List;
+
+public class SongModifyBatchRequest {
+    private List<SongModifyRequest> songs;
+
+    public SongModifyBatchRequest(List<SongModifyRequest> songs) {
+        this.songs = songs;
+    }
+
+    public List<SongModifyRequest> getSongs() {
+        return songs;
+    }
+
+    public void setSongs(List<SongModifyRequest> songs) {
+        this.songs = songs;
+    }
+}

app/src/main/java/com/stormtales/notevault/network/sync/models/SongModifyBatchResponse.java

@@ -0,0 +1,16 @@
+package com.stormtales.notevault.network.sync.models;
+
+import java.util.List;
+
+public class SongModifyBatchResponse {
+
+    private List<SongModifyResponse> modifiedServerObjects;
+
+    public List<SongModifyResponse> getModifiedServerObjects() {
+        return modifiedServerObjects;
+    }
+
+    public void setModifiedServerObjects(List<SongModifyResponse> modifiedServerObjects) {
+        this.modifiedServerObjects = modifiedServerObjects;
+    }
+}

app/src/main/java/com/stormtales/notevault/network/sync/models/SongModifyRequest.java

@@ -0,0 +1,82 @@
+package com.stormtales.notevault.network.sync.models;
+
+import com.stormtales.notevault.data.entities.NoteSheet;
+import com.stormtales.notevault.data.entities.Song;
+
+import java.util.List;
+import java.util.stream.Collectors;
+
+public class SongModifyRequest {
+
+    private String serverID;
+    private String title;
+    private String composer;
+    private String genre;
+    private int year;
+    private List<NoteSheetModifyRequest> noteSheets;
+
+    public SongModifyRequest(String serverID, String title, String composer, String genre, int year) {
+        this.serverID = serverID;
+        this.title = title;
+        this.composer = composer;
+        this.genre = genre;
+        this.year = year;
+    }
+
+    public SongModifyRequest(Song song, List<NoteSheet> noteSheets) {
+        this.serverID = song.getServerID();
+        this.title = song.getTitle();
+        this.composer = song.getComposer();
+        this.genre = song.getGenre();
+        this.year = song.getYear();
+        this.noteSheets = noteSheets.stream().map(noteSheet -> new NoteSheetModifyRequest(noteSheet.getServerFileName(), noteSheet.getHash())).collect(Collectors.toList());
+    }
+
+    public String getServerID() {
+        return serverID;
+    }
+
+    public void setServerID(String serverID) {
+        this.serverID = serverID;
+    }
+
+    public String getTitle() {
+        return title;
+    }
+
+    public void setTitle(String title) {
+        this.title = title;
+    }
+
+    public String getComposer() {
+        return composer;
+    }
+
+    public void setComposer(String composer) {
+        this.composer = composer;
+    }
+
+    public String getGenre() {
+        return genre;
+    }
+
+    public void setGenre(String genre) {
+        this.genre = genre;
+    }
+
+    public int getYear() {
+        return year;
+    }
+
+    public void setYear(int year) {
+        this.year = year;
+    }
+
+    public List<NoteSheetModifyRequest> getNoteSheets() {
+        return noteSheets;
+    }
+
+    public void setNoteSheets(List<NoteSheetModifyRequest> noteSheets) {
+        this.noteSheets = noteSheets;
+    }
+}

app/src/main/java/com/stormtales/notevault/network/sync/models/SongModifyResponse.java

@@ -0,0 +1,25 @@
+package com.stormtales.notevault.network.sync.models;
+
+import java.util.List;
+
+public class SongModifyResponse {
+
+    private String serverID;
+    private List<String> outdated_note_sheets;
+
+    public List<String> getOutdated_note_sheets() {
+        return outdated_note_sheets;
+    }
+
+    public void setOutdated_note_sheets(List<String> outdated_note_sheets) {
+        this.outdated_note_sheets = outdated_note_sheets;
+    }
+
+    public String getServerID() {
+        return serverID;
+    }
+
+    public void setServerID(String serverID) {
+        this.serverID = serverID;
+    }
+}

app/src/main/java/com/stormtales/notevault/network/sync/models/UploadResponse.java

@@ -0,0 +1,31 @@
+package com.stormtales.notevault.network.sync.models;
+
+public class UploadResponse {
+    private String serverID;
+    private String localFile;
+    private String serverFile;
+
+    public String getServerID() {
+        return serverID;
+    }
+
+    public void setServerID(String serverID) {
+        this.serverID = serverID;
+    }
+
+    public String getLocalFile() {
+        return localFile;
+    }
+
+    public void setLocalFile(String localFile) {
+        this.localFile = localFile;
+    }
+
+    public String getServerFile() {
+        return serverFile;
+    }
+
+    public void setServerFile(String serverFile) {
+        this.serverFile = serverFile;
+    }
+}

app/src/main/java/com/stormtales/notevault/ui/gallery/GalleryFragment.java

@@ -0,0 +1,124 @@
+package com.stormtales.notevault.ui.gallery;
+
+import android.os.Bundle;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.Button;
+import android.widget.ProgressBar;
+import android.widget.TextView;
+import androidx.annotation.NonNull;
+import androidx.fragment.app.Fragment;
+import androidx.lifecycle.ViewModelProvider;
+import com.stormtales.notevault.data.repositories.SongRepository;
+import com.stormtales.notevault.databinding.FragmentGalleryBinding;
+import com.stormtales.notevault.network.sync.SongSyncModule;
+import com.stormtales.notevault.network.sync.SongSyncService;
+
+
+public class GalleryFragment extends Fragment {
+
+    GalleryViewModel galleryViewModel;
+    private FragmentGalleryBinding binding;
+    private ProgressBar progress_sync_created_songs;
+    private Button sync_created_songs_btn;
+    private ProgressBar progress_sync_modified_songs;
+    private Button sync_modified_songs_btn;
+    private ProgressBar progress_sync_deleted_songs;
+    private Button sync_deleted_songs_btn;
+
+    private ProgressBar progress_fetching_songs;
+    private Button sync_fetching_songs_btn;
+
+
+    public View onCreateView(@NonNull LayoutInflater inflater,
+                             ViewGroup container, Bundle savedInstanceState) {
+        galleryViewModel = new ViewModelProvider(this).get(GalleryViewModel.class);
+
+        binding = FragmentGalleryBinding.inflate(inflater, container, false);
+        View root = binding.getRoot();
+
+        progress_sync_created_songs = binding.progressSyncCreatedSongs;
+        sync_created_songs_btn = binding.syncCreatedBtn;
+        sync_created_songs_btn.setOnClickListener(v -> onSyncCreatedSongs());
+
+        progress_sync_modified_songs = binding.progressSyncModifiedSongs;
+        sync_modified_songs_btn = binding.syncModifiedBtn;
+        sync_modified_songs_btn.setOnClickListener(v -> onSyncModifiedSogs());
+
+        progress_sync_deleted_songs = binding.progressSyncDeletedSongs;
+        sync_deleted_songs_btn = binding.syncDeletedBtn;
+        sync_deleted_songs_btn.setOnClickListener(v -> onSyncDeletedSongs());
+
+        progress_fetching_songs = binding.progressFetchSongs;
+        sync_fetching_songs_btn = binding.fetchSongsBtn;
+        sync_fetching_songs_btn.setOnClickListener(v -> onFetchRemoteModifiedSongs());
+
+        galleryViewModel.setSongSyncModule(new SongSyncModule(getContext(), galleryViewModel));
+
+        galleryViewModel.getIsCreatedSongSyncing().observe(getViewLifecycleOwner(), isCreatedSyncinc -> {
+            if(isCreatedSyncinc) {
+                progress_sync_created_songs.setIndeterminate(true);
+                sync_created_songs_btn.setEnabled(false);
+            } else {
+                progress_sync_created_songs.setIndeterminate(false);
+                sync_created_songs_btn.setEnabled(true);
+            }
+        });
+
+        galleryViewModel.getIsModifiedSongSyncing().observe(getViewLifecycleOwner(), isModifiedSyncinc -> {
+            if(isModifiedSyncinc) {
+                progress_sync_modified_songs.setIndeterminate(true);
+                sync_modified_songs_btn.setEnabled(false);
+            } else {
+                progress_sync_modified_songs.setIndeterminate(false);
+                sync_modified_songs_btn.setEnabled(true);
+            }
+        });
+
+        galleryViewModel.getIsDeletedSongSyncing().observe(getViewLifecycleOwner(), isDeletedSyncinc -> {
+            if(isDeletedSyncinc) {
+                progress_sync_deleted_songs.setIndeterminate(true);
+                sync_deleted_songs_btn.setEnabled(false);
+            } else {
+                progress_sync_deleted_songs.setIndeterminate(false);
+                sync_deleted_songs_btn.setEnabled(true);
+            }
+        });
+
+        galleryViewModel.getIsFetchingActive().observe(getViewLifecycleOwner(), isFetchingActiveSyncinc -> {
+            if(isFetchingActiveSyncinc) {
+                progress_fetching_songs.setIndeterminate(true);
+                sync_fetching_songs_btn.setEnabled(false);
+            } else {
+                progress_fetching_songs.setIndeterminate(false);
+                sync_fetching_songs_btn.setEnabled(true);
+            }
+        });
+        return root;
+    }
+
+    private void onFetchRemoteModifiedSongs() {
+        galleryViewModel.startFetchingActive();
+    }
+
+    private void onSyncDeletedSongs() {
+        galleryViewModel.startDeletedSongSyncing();
+    }
+
+
+    @Override
+    public void onDestroyView() {
+        super.onDestroyView();
+        binding = null;
+    }
+
+    private void onSyncCreatedSongs() {
+        galleryViewModel.startCreateSongSyncing();
+    }
+
+
+    private void onSyncModifiedSogs() {
+        galleryViewModel.startModifiedSongSyncinc();
+    }
+}

app/src/main/java/com/stormtales/notevault/ui/gallery/GalleryViewModel.java

@@ -0,0 +1,92 @@
+package com.stormtales.notevault.ui.gallery;
+
+import androidx.lifecycle.LiveData;
+import androidx.lifecycle.MutableLiveData;
+import androidx.lifecycle.ViewModel;
+import com.stormtales.notevault.data.repositories.SongRepository;
+import com.stormtales.notevault.network.sync.SongSyncModule;
+
+public class GalleryViewModel extends ViewModel {
+
+    private final MutableLiveData<Boolean> isCreatedSongSyncing;
+    private final MutableLiveData<Boolean> isModifiedSongSyncing;
+    private final MutableLiveData<Boolean> isDeletedSongSyncing;
+    private final MutableLiveData<Boolean> isFetchingActive;
+    private SongSyncModule songSyncModule;
+
+    public GalleryViewModel() {
+
+        isCreatedSongSyncing = new MutableLiveData<>();
+        isCreatedSongSyncing.setValue(false);
+
+        isModifiedSongSyncing = new MutableLiveData<>();
+        isModifiedSongSyncing.setValue(false);
+
+        isDeletedSongSyncing = new MutableLiveData<>();
+        isDeletedSongSyncing.setValue(false);
+
+        isFetchingActive = new MutableLiveData<>();
+        isFetchingActive.setValue(false);
+    }
+
+    public MutableLiveData<Boolean> getIsCreatedSongSyncing() {
+        return isCreatedSongSyncing;
+    }
+
+    public void startCreateSongSyncing() {
+        if(this.songSyncModule == null) throw new RuntimeException("SongSyncModule is not initialized");
+        this.isCreatedSongSyncing.setValue(true);
+
+        this.songSyncModule.syncCreatedSongs();
+    }
+
+    public void finishCreateSongSyncing() {
+        this.isCreatedSongSyncing.setValue(false);
+    }
+
+    public void setSongSyncModule(SongSyncModule songSyncModule) {
+        this.songSyncModule = songSyncModule;
+    }
+
+    public void startModifiedSongSyncinc() {
+        if(this.songSyncModule == null) throw new RuntimeException("SongSyncModule is not initialized");
+        this.isModifiedSongSyncing.setValue(true);
+        this.songSyncModule.syncModifiedSongs();
+    }
+
+    public MutableLiveData<Boolean> getIsModifiedSongSyncing() {
+        return isModifiedSongSyncing;
+    }
+
+    public void finishModifiedSongSyncinc() {
+        this.isModifiedSongSyncing.setValue(false);
+    }
+
+    public MutableLiveData<Boolean> getIsDeletedSongSyncing() {
+        return isDeletedSongSyncing;
+    }
+
+    public void startDeletedSongSyncing() {
+        if(this.songSyncModule == null) throw new RuntimeException("SongSyncModule is not initialized");
+        this.isDeletedSongSyncing.setValue(true);
+        this.songSyncModule.syncDeletedSongs();
+    }
+
+    public void finishDeleteSongSyncinc() {
+        this.isDeletedSongSyncing.setValue(false);
+    }
+
+    public void startFetchingActive() {
+        if(this.songSyncModule == null) throw new RuntimeException("SongSyncModule is not initialized");
+        this.isFetchingActive.setValue(true);
+        this.songSyncModule.fetchRemoteModifiedSongs();
+    }
+
+    public void finishFetching() {
+        this.isFetchingActive.setValue(false);
+    }
+
+    public MutableLiveData<Boolean> getIsFetchingActive() {
+        return isFetchingActive;
+    }
+}

app/src/main/java/com/stormtales/notevault/ui/home/HomeFragment.java

@@ -0,0 +1,138 @@
+package com.stormtales.notevault.ui.home;
+
+import android.app.Activity;
+import android.content.Intent;
+import android.net.Uri;
+import android.os.Bundle;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.TextView;
+import android.widget.Toast;
+import androidx.activity.result.ActivityResult;
+import androidx.activity.result.ActivityResultCallback;
+import androidx.activity.result.ActivityResultLauncher;
+import androidx.activity.result.contract.ActivityResultContracts;
+import androidx.annotation.NonNull;
+import androidx.fragment.app.Fragment;
+import androidx.lifecycle.ViewModelProvider;
+import androidx.recyclerview.widget.DividerItemDecoration;
+import androidx.recyclerview.widget.LinearLayoutManager;
+import androidx.recyclerview.widget.RecyclerView;
+import com.google.android.material.floatingactionbutton.FloatingActionButton;
+import com.stormtales.notevault.R;
+import com.stormtales.notevault.data.entities.Song;
+import com.stormtales.notevault.data.repositories.SongRepository;
+import com.stormtales.notevault.databinding.FragmentHomeBinding;
+import com.stormtales.notevault.ui.sheetdisplay.NoteSheetDisplayActivity;
+import com.stormtales.notevault.ui.songeditor.SongEditorDialog;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class HomeFragment extends Fragment {
+
+    private FragmentHomeBinding binding;
+    private RecyclerView recyclerView;
+    private SongAdapter songAdapter;
+    private HomeViewModel homeViewModel;
+    private static final int PICK_FILE_REQUEST_CODE = 1;
+
+    public View onCreateView(@NonNull LayoutInflater inflater,
+                             ViewGroup container, Bundle savedInstanceState) {
+        homeViewModel = new ViewModelProvider(this).get(HomeViewModel.class);
+        homeViewModel.setSongRepository(new SongRepository(this.getContext()));
+
+        binding = FragmentHomeBinding.inflate(inflater, container, false);
+        View root = binding.getRoot();
+        recyclerView = root.findViewById(R.id.recycler_view_songs);
+
+        ActivityResultLauncher<Intent> launcher = registerForActivityResult(
+                new ActivityResultContracts.StartActivityForResult(),
+                activityResult -> {
+                    getActivity();
+                    if(activityResult.getResultCode() == Activity.RESULT_OK && activityResult.getData() != null) {
+                        if(activityResult.getData().getClipData() != null) {
+                            int fileNumber = activityResult.getData().getClipData().getItemCount();
+                            Uri[] files = new Uri[fileNumber];
+                            for(int i = 0; i < fileNumber; i++) {
+                                files[i] = activityResult.getData().getClipData().getItemAt(i).getUri();
+                                Toast.makeText(requireContext(), "Uri: " + files[i].toString(), Toast.LENGTH_SHORT).show();
+                            }
+                            handleSelectedNoteSheets(files);
+                        } else {
+                            Uri uri = activityResult.getData().getData();
+                            Toast.makeText(requireContext(), "Uri: " + uri.toString(), Toast.LENGTH_SHORT).show();
+                            handleSelectedNoteSheets(uri);
+                        }
+                    }
+                }
+        );
+
+        FloatingActionButton importBtn = root.findViewById(R.id.addSongBtn);
+        importBtn.setOnClickListener(v -> {
+            Intent intent = new Intent(Intent.ACTION_OPEN_DOCUMENT);
+            intent.setType("*/*"); // Alle Dateitypen
+
+            String[] mimeTypes = {"application/pdf", "image/png", "image/jpeg"};
+            intent.putExtra(Intent.EXTRA_MIME_TYPES, mimeTypes);
+            intent.putExtra(Intent.EXTRA_ALLOW_MULTIPLE, true);
+
+            intent.addCategory(Intent.CATEGORY_OPENABLE);
+
+
+            launcher.launch(intent);
+        });
+
+        // RecyclerView einrichten
+        songAdapter = new SongAdapter(new ArrayList<>(), this::onEditSong, this::onDeleteSong, this::onOpenSong);
+        recyclerView.setAdapter(songAdapter);
+        recyclerView.setLayoutManager(new LinearLayoutManager(getContext()));
+        DividerItemDecoration dividerItemDecoration = new DividerItemDecoration(recyclerView.getContext(), LinearLayoutManager.VERTICAL);
+        recyclerView.addItemDecoration(dividerItemDecoration);
+
+        // Beobachte Änderungen in der Song-Liste
+        homeViewModel.getAllSongsLive().observe(getViewLifecycleOwner(), songs -> {
+            songAdapter.updateData(songs);
+        });
+
+        return root;
+    }
+
+    @Override
+    public void onDestroyView() {
+        super.onDestroyView();
+        binding = null;
+    }
+
+    private void handleSelectedNoteSheets(Uri... files) {
+        SongEditorDialog songEditorDialog = new SongEditorDialog();
+        songEditorDialog.setNoteSheetFiles(files);
+        songEditorDialog.setHomeViewModel(homeViewModel);
+        songEditorDialog.show(getParentFragmentManager(), "songEditorDialog");
+    }
+
+    public void onEditSong(Song song) {
+        SongEditorDialog songEditorDialog = new SongEditorDialog();
+        songEditorDialog.setEditedSong(song);
+        songEditorDialog.setHomeViewModel(homeViewModel);
+        songEditorDialog.show(getParentFragmentManager(), "songEditorDialog");
+    }
+
+    public void onDeleteSong(Song song) {
+        this.homeViewModel.deleteSong(song);
+    }
+
+    public void onOpenSong(Song song) {
+        homeViewModel.getSongRepository().getNoteSheetFilesBySongID(song.getLocalID(), result -> {
+            String[] noteSheetFiles = new String[result.size()];
+            for(int i = 0; i < result.size(); i++) {
+                noteSheetFiles[i] = result.get(i);
+            }
+            Intent intent = new Intent(getContext(), NoteSheetDisplayActivity.class);
+            intent.putExtra("imageUris", noteSheetFiles);
+            getContext().startActivity(intent);
+
+        });
+    }
+}

app/src/main/java/com/stormtales/notevault/ui/home/HomeViewModel.java

@@ -0,0 +1,88 @@
+package com.stormtales.notevault.ui.home;
+
+import android.util.Log;
+import androidx.lifecycle.LiveData;
+import androidx.lifecycle.MutableLiveData;
+import androidx.lifecycle.ViewModel;
+import com.stormtales.notevault.data.entities.NoteSheet;
+import com.stormtales.notevault.data.entities.Song;
+import com.stormtales.notevault.data.repositories.SongRepository;
+import com.stormtales.notevault.data.sync.SyncStatus;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class HomeViewModel extends ViewModel {
+
+    private MutableLiveData<List<Song>> allSongs;
+    private SongRepository songRepository;
+
+    public HomeViewModel() {
+        List<Song> currentSongs = new ArrayList<>();
+        this.allSongs = new MutableLiveData<>(currentSongs);
+        /*this.allSongs.setValue(songRepository.getAllSongs());*/
+    }
+
+    public void addSong(Song song, List<NoteSheet> noteSheetList) {
+        songRepository.insert(song, internalSongID -> {
+            for(NoteSheet noteSheet : noteSheetList) {
+                noteSheet.setSongID(Math.toIntExact(internalSongID));
+            }
+            songRepository.insertNoteSheets(noteSheetList);
+        });
+
+
+        List<Song> currentSongs = allSongs.getValue();
+        if(currentSongs == null) {
+            currentSongs = new ArrayList<>();
+        }
+
+        // Neue Liste erstellen und den Song hinzufügen
+        List<Song> updatedSongs = new ArrayList<>(currentSongs);
+        updatedSongs.add(song);
+        // Neue Liste in MutableLiveData setzen
+        allSongs.setValue(updatedSongs);
+        Log.d("HomeViewModel", "Song added. Total songs: " + updatedSongs.size());
+    }
+
+    public LiveData<List<Song>> getAllSongsLive() {
+        return allSongs;
+    }
+
+    public void setSongRepository(SongRepository songRepository) {
+        this.songRepository = songRepository;
+        loadAllSongs();
+    }
+
+    public void loadAllSongs() {
+        songRepository.getAllSongs(songs->allSongs.setValue(songs));
+    }
+
+    public void deleteSong(Song song) {
+        songRepository.deleteSong(song);
+
+        List<Song> currentSongs = allSongs.getValue();
+        if(currentSongs != null) {
+            currentSongs.remove(song);
+            allSongs.setValue(currentSongs);
+        }
+    }
+
+    public void updateSong(Song editedSong) {
+        List<Song> currentSongs = allSongs.getValue();
+        if(currentSongs != null) {
+            for(int i = 0; i < currentSongs.size(); i++) {
+                if(currentSongs.get(i).getLocalID() == editedSong.getLocalID()) {
+                    currentSongs.set(i, editedSong);
+                    break;
+                }
+            }
+            songRepository.updateSong(editedSong);
+            allSongs.setValue(currentSongs);
+        }
+    }
+
+    public SongRepository getSongRepository() {
+        return songRepository;
+    }
+}

app/src/main/java/com/stormtales/notevault/ui/home/SongAdapter.java

@@ -0,0 +1,99 @@
+package com.stormtales.notevault.ui.home;
+
+import android.util.Log;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.ImageButton;
+import android.widget.TextView;
+import androidx.annotation.NonNull;
+import androidx.recyclerview.widget.RecyclerView;
+import com.stormtales.notevault.R;
+import com.stormtales.notevault.data.entities.Song;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class SongAdapter extends RecyclerView.Adapter<SongAdapter.SongViewHolder> {
+
+    private List<Song> songList;
+    private OnEditSongListener onEditSongListener;
+    private OnDeleteSongListener onDeleteSongListener;
+    private OnOpenSongListener onOpenSongListener;
+
+    public SongAdapter(List<Song> songList, OnEditSongListener onEditSongListener, OnDeleteSongListener onDeleteSongListener, OnOpenSongListener onOpenSongListener) {
+        this.songList = songList;
+        this.onEditSongListener = onEditSongListener;
+        this.onDeleteSongListener = onDeleteSongListener;
+        this.onOpenSongListener = onOpenSongListener;
+    }
+
+    public void updateData(List<Song> songs) {
+        if (songs == null) {
+            this.songList = new ArrayList<>();
+        } else {
+            this.songList = new ArrayList<>(songs);
+        }
+        notifyDataSetChanged();
+        Log.d("SongAdapter", "Data updated: " + this.songList.size());
+    }
+
+    public class SongViewHolder extends RecyclerView.ViewHolder {
+        TextView textYear, textComposition, textTitle;
+        ImageButton editButton, deleteButton;
+
+        public SongViewHolder(View itemView) {
+            super(itemView);
+            textYear = itemView.findViewById(R.id.text_year);
+            textComposition = itemView.findViewById(R.id.text_composition);
+            textTitle = itemView.findViewById(R.id.text_title);
+            editButton = itemView.findViewById(R.id.edit_song_button);
+            deleteButton = itemView.findViewById(R.id.delete_song_button);
+
+            textTitle.setOnClickListener(v -> {
+                int position = getAdapterPosition();
+                if (position != RecyclerView.NO_POSITION) {
+                    Song song = songList.get(position);
+                    onOpenSongListener.onOpenSong(song);
+                }
+            });
+        }
+    }
+
+    @NonNull
+    @Override
+    public @NotNull SongViewHolder onCreateViewHolder(@NonNull @NotNull ViewGroup parent, int i) {
+        View itemView = LayoutInflater.from(parent.getContext())
+                .inflate(R.layout.item_song, parent, false);
+        return new SongViewHolder(itemView);
+    }
+
+    @Override
+    public void onBindViewHolder(@NonNull @NotNull SongAdapter.SongViewHolder holder, int position) {
+        Song song = songList.get(position);
+        holder.textYear.setText(String.valueOf(song.getYear()));
+        holder.textComposition.setText(song.getComposer());
+        holder.textTitle.setText(song.getTitle());
+
+        holder.editButton.setOnClickListener(v -> onEditSongListener.onEditSong(song));
+        holder.deleteButton.setOnClickListener(v -> onDeleteSongListener.onDeleteSong(song));
+    }
+
+    @Override
+    public int getItemCount() {
+        return songList.size();
+    }
+
+    public interface OnEditSongListener {
+        void onEditSong(Song song);
+    }
+
+    public interface OnDeleteSongListener {
+        void onDeleteSong(Song song);
+    }
+
+    public interface OnOpenSongListener {
+        void onOpenSong(Song song);
+    }
+}

app/src/main/java/com/stormtales/notevault/ui/login/LoginDialog.java

@@ -0,0 +1,156 @@
+package com.stormtales.notevault.ui.login;
+
+import android.app.AlertDialog;
+import android.app.Dialog;
+import android.content.Context;
+import android.os.Bundle;
+import android.text.Editable;
+import android.text.TextWatcher;
+import android.util.Log;
+import android.view.KeyEvent;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.inputmethod.EditorInfo;
+import android.widget.*;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.fragment.app.DialogFragment;
+import androidx.lifecycle.Observer;
+import androidx.lifecycle.ViewModelProvider;
+import com.stormtales.notevault.R;
+import com.stormtales.notevault.network.APICallback;
+import com.stormtales.notevault.network.auth.AuthService;
+import org.jetbrains.annotations.NotNull;
+
+public class LoginDialog extends DialogFragment {
+
+    private LoginViewModel loginViewModel;
+    private boolean isLoginMode = true;
+    private Dialog dialog;
+
+    private Button loginButton;
+    private ProgressBar loadingProgressBar;
+    private EditText editTextUsername;
+    private EditText editTextPassword;
+    private EditText editTextEmail;
+    private TextView textViewTitle;
+    private TextView textViewSwitch;
+
+    @Override
+    public void onAttach(Context context) {
+        super.onAttach(context);
+
+    }
+
+    public LoginDialog(LoginViewModel loginViewModel) {
+        this.loginViewModel = loginViewModel;
+    }
+
+    @NonNull
+    @Override
+    public Dialog onCreateDialog(@Nullable Bundle savedInstanceState) {
+        AlertDialog.Builder builder = new AlertDialog.Builder(requireContext());
+        LayoutInflater inflater = requireActivity().getLayoutInflater();
+        View view = inflater.inflate(R.layout.fragment_login_dialog, null);
+
+        textViewTitle = view.findViewById(R.id.textViewTitle);
+        editTextUsername = view.findViewById(R.id.editTextUsername);
+        editTextEmail = view.findViewById(R.id.editTextEmail);
+        editTextPassword = view.findViewById(R.id.editTextPassword);
+        loginButton = view.findViewById(R.id.buttonAction);
+        textViewSwitch = view.findViewById(R.id.textViewSwitch);
+        loadingProgressBar = view.findViewById(R.id.loading);
+        // Handle action button click
+
+
+        // Toggle between Login and Registration
+        textViewSwitch.setOnClickListener(v -> {
+            isLoginMode = !isLoginMode;
+            textViewTitle.setText(isLoginMode ? "Login" : "Register");
+            editTextUsername.setVisibility(isLoginMode ? View.GONE : View.VISIBLE);
+            loginButton.setText(isLoginMode ? "Login" : "Register");
+            textViewSwitch.setText(isLoginMode ? "Don't have an account? Register" : "Already have an account? Login");
+        });
+
+        builder.setView(view);
+        dialog = builder.create();
+
+
+
+        TextWatcher afterTextChangedListener = new TextWatcher() {
+            @Override
+            public void beforeTextChanged(CharSequence s, int start, int count, int after) {
+
+            }
+
+            @Override
+            public void onTextChanged(CharSequence s, int start, int before, int count) {
+
+            }
+
+            @Override
+            public void afterTextChanged(Editable s) {
+                loginViewModel.updateLoginData(editTextUsername.getText().toString(), editTextPassword.getText().toString());
+            }
+        };
+
+        editTextUsername.addTextChangedListener(afterTextChangedListener);
+        editTextPassword.addTextChangedListener(afterTextChangedListener);
+        editTextPassword.setOnEditorActionListener(new TextView.OnEditorActionListener() {
+            @Override
+            public boolean onEditorAction(TextView v, int actionId, KeyEvent event) {
+                if(actionId == EditorInfo.IME_ACTION_DONE) {
+                    loginViewModel.performLogin(editTextUsername.getText().toString(), editTextPassword.getText().toString(), LoginDialog.this::onSuccessFullLogin);
+                }
+                return false;
+            }
+        });
+
+        loginButton.setOnClickListener(v -> {
+            loadingProgressBar.setVisibility(View.VISIBLE);
+            String email = editTextEmail.getText().toString();
+            String password = editTextPassword.getText().toString();
+            if (isLoginMode) {
+                // Handle login logic
+                this.loginViewModel.performLogin(email, password, this::onSuccessFullLogin);
+            } else {
+                // Handle registration logic
+                String username = editTextUsername.getText().toString();
+                this.loginViewModel.performRegistration(email, password, username, this::onSuccessFullRegistration);
+            }
+        });
+        return dialog;
+    }
+
+    private void onSuccessFullRegistration() {
+        Toast.makeText(getContext(), "Successfully registered", Toast.LENGTH_LONG).show();
+        this.isLoginMode = true;
+        textViewTitle.setText(isLoginMode ? "Login" : "Register");
+        editTextUsername.setVisibility(isLoginMode ? View.GONE : View.VISIBLE);
+        loginButton.setText(isLoginMode ? "Login" : "Register");
+        textViewSwitch.setText(isLoginMode ? "Don't have an account? Register" : "Already have an account? Login");
+    }
+
+    @Override
+    public void onViewCreated(@NonNull @NotNull View view, @Nullable @org.jetbrains.annotations.Nullable Bundle savedInstanceState) {
+        super.onViewCreated(view, savedInstanceState);
+        loginViewModel.getLoginFormState().observe(getViewLifecycleOwner(), new Observer<LoginFormState>() {
+            @Override
+            public void onChanged(LoginFormState loginFormState) {
+                if(loginFormState == null) return;
+                loginButton.setEnabled(loginFormState.isDataValid());
+                if(loginFormState.getUsernameError() != null) {
+                    editTextUsername.setError(getString(loginFormState.getUsernameError()));
+                }
+                if(loginFormState.getPasswordError() != null) {
+                    editTextPassword.setError(getString(loginFormState.getPasswordError()));
+                }
+            }
+        });
+    }
+
+    void onSuccessFullLogin() {
+        this.dialog.dismiss();
+    }
+
+}

app/src/main/java/com/stormtales/notevault/ui/login/LoginFormState.java

@@ -0,0 +1,37 @@
+package com.stormtales.notevault.ui.login;
+
+import androidx.annotation.Nullable;
+
+public class LoginFormState {
+    @Nullable
+    private Integer usernameError;
+    @Nullable
+    private Integer passwordError;
+    private boolean isDataValid;
+
+    LoginFormState(@Nullable Integer usernameError, @Nullable Integer passwordError) {
+        this.usernameError = usernameError;
+        this.passwordError = passwordError;
+        this.isDataValid = false;
+    }
+
+    LoginFormState(boolean isDataValid) {
+        this.usernameError = null;
+        this.passwordError = null;
+        this.isDataValid = isDataValid;
+    }
+
+    @Nullable
+    Integer getUsernameError() {
+        return usernameError;
+    }
+
+    @Nullable
+    Integer getPasswordError() {
+        return passwordError;
+    }
+
+    boolean isDataValid() {
+        return isDataValid;
+    }
+}

app/src/main/java/com/stormtales/notevault/ui/login/LoginViewModel.java

@@ -0,0 +1,116 @@
+package com.stormtales.notevault.ui.login;
+
+import android.util.Log;
+import android.util.Patterns;
+import android.widget.Toast;
+import androidx.lifecycle.MutableLiveData;
+import androidx.lifecycle.ViewModel;
+import com.stormtales.notevault.R;
+import com.stormtales.notevault.network.APICallback;
+import com.stormtales.notevault.network.auth.AuthService;
+import com.stormtales.notevault.network.auth.LoginResponse;
+
+public class LoginViewModel extends ViewModel {
+
+    private final MutableLiveData<String> username;
+    private final MutableLiveData<Boolean> isLoggedIn;
+    private MutableLiveData<LoginFormState> loginFormState = new MutableLiveData<>();
+    private AuthService authService;
+
+    public LoginViewModel() {
+        username = new MutableLiveData<>("Not Logged In");
+        isLoggedIn = new MutableLiveData<>(false);
+    }
+
+    public void performLogin(String email, String password, SuccessFullLoginCallback successFullLoginCallback) {
+        if(authService != null) {
+            authService.performLogin(email, password, new LoginCallBackImpl(successFullLoginCallback));
+        } else {
+            throw new RuntimeException("AuthService is not provided to LoginViewModel");
+        }
+    }
+
+    public void performRegistration(String email, String password, String username, SuccessFullLoginCallback successFullLoginCallback) {
+        if(authService != null) {
+            authService.performRegistration(email, username, password, new APICallback() {
+                @Override
+                public void onSuccess() {
+                    successFullLoginCallback.onSuccess();
+                }
+
+                @Override
+                public void onError(String error) {
+                    Log.d("LoginService", error);
+                }
+            });
+        }
+    }
+
+    public void setAuthService(AuthService authService) {
+        this.authService = authService;
+    }
+
+    public MutableLiveData<Boolean> getIsLoggedIn() {
+        return isLoggedIn;
+    }
+
+    public MutableLiveData<String> getUsername() {
+        return username;
+    }
+
+    public void updateLoginData(String username, String password) {
+        if(!isUserNameValid(username)) {
+            loginFormState.setValue(new LoginFormState(R.string.invalid_username, null));
+        } else if(!isPasswordValid(password)) {
+            loginFormState.setValue(new LoginFormState(null, R.string.invalid_password));
+        } else {
+            loginFormState.setValue(new LoginFormState(true));
+        }
+    }
+
+    public class LoginCallBackImpl implements AuthService.LoginCallback {
+
+        private final SuccessFullLoginCallback successFullLoginCallback;
+
+        public LoginCallBackImpl(SuccessFullLoginCallback successFullLoginCallback) {
+            this.successFullLoginCallback = successFullLoginCallback;
+        }
+
+        @Override
+        public void onSuccess(LoginResponse loginResponse) {
+            username.setValue(loginResponse.getUsername());
+            isLoggedIn.setValue(true);
+            successFullLoginCallback.onSuccess();
+        }
+
+        @Override
+        public void onError(String error) {
+            Log.d("LoginService", error);
+        }
+    }
+
+    public interface SuccessFullLoginCallback {
+        void onSuccess();
+    }
+
+    public MutableLiveData<LoginFormState> getLoginFormState() {
+        return loginFormState;
+    }
+
+    // A placeholder username validation check
+    private boolean isUserNameValid(String username) {
+        if (username == null) {
+            return false;
+        }
+        if (username.contains("@")) {
+            return Patterns.EMAIL_ADDRESS.matcher(username).matches();
+        } else {
+            return !username.trim().isEmpty();
+        }
+    }
+
+    // A placeholder password validation check
+    private boolean isPasswordValid(String password) {
+        return password != null && password.trim().length() > 5;
+    }
+}

app/src/main/java/com/stormtales/notevault/ui/sheetdisplay/ImagePagerAdapter.java

@@ -1,4 +1,5 @@
-package core.notevault.ui.noteviewer;
+package com.stormtales.notevault.ui.sheetdisplay;
+
 
 import android.content.Context;
 import android.net.Uri;
@@ -8,7 +9,7 @@ import android.view.ViewGroup;
 import androidx.annotation.NonNull;
 import androidx.recyclerview.widget.RecyclerView;
 import com.github.chrisbanes.photoview.PhotoView;
-import core.notevault.R;
+import com.stormtales.notevault.R;
 
 import java.util.List;
 

app/src/main/java/com/stormtales/notevault/ui/sheetdisplay/NoteSheetDisplayActivity.java

@@ -1,25 +1,26 @@
-package core.notevault.ui.home;
+package com.stormtales.notevault.ui.sheetdisplay;
 
 import android.content.Intent;
-import android.net.Uri;
 import android.os.Bundle;
-import android.widget.ImageView;
 import androidx.appcompat.app.AppCompatActivity;
 import androidx.viewpager2.widget.ViewPager2;
-import core.notevault.R;
+import com.google.android.material.tabs.TabLayout;
-import core.notevault.ui.noteviewer.ImagePagerAdapter;
+import com.google.android.material.tabs.TabLayoutMediator;
+import com.stormtales.notevault.R;
 
 import java.util.Arrays;
 import java.util.List;
 
-public class FullScreenImageActivity extends AppCompatActivity {
+public class NoteSheetDisplayActivity extends AppCompatActivity {
-
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
-        setContentView(R.layout.activity_fullscreen_image); // Erstelle eine Layout-Datei
+        setContentView(R.layout.activity_note_sheet_viewer); // Erstelle eine Layout-Datei
 
         ViewPager2 imageView = findViewById(R.id.viewPager); // Angenommen, du hast ein ImageView
+        TabLayout tabLayout = findViewById(R.id.tabLayout);
+
+
 
         // Die URI aus dem Intent erhalten
         Intent intent = getIntent();
@@ -28,6 +29,10 @@ public class FullScreenImageActivity extends AppCompatActivity {
             List<String> uriList = Arrays.asList(imageUris);
             ImagePagerAdapter adapter = new ImagePagerAdapter(this, uriList);
             imageView.setAdapter(adapter); // Setze die URI in das ImageView
+
+            new TabLayoutMediator(tabLayout, imageView,
+                    (tab, position) -> tab.setText("Sheet " + (position + 1)) // Hier kannst du auch andere Labels verwenden
+            ).attach();
         } else {
             throw new NullPointerException();
         }

app/src/main/java/com/stormtales/notevault/ui/slideshow/SlideshowFragment.java

@@ -1,4 +1,4 @@
-package core.notevault.ui.slideshow;
+package com.stormtales.notevault.ui.slideshow;
 
 import android.os.Bundle;
 import android.view.LayoutInflater;
@@ -8,7 +8,7 @@ import android.widget.TextView;
 import androidx.annotation.NonNull;
 import androidx.fragment.app.Fragment;
 import androidx.lifecycle.ViewModelProvider;
-import core.notevault.databinding.FragmentSlideshowBinding;
+import com.stormtales.notevault.databinding.FragmentSlideshowBinding;
 
 public class SlideshowFragment extends Fragment {
 

app/src/main/java/com/stormtales/notevault/ui/slideshow/SlideshowViewModel.java

@@ -1,4 +1,4 @@
-package core.notevault.ui.slideshow;
+package com.stormtales.notevault.ui.slideshow;
 
 import androidx.lifecycle.LiveData;
 import androidx.lifecycle.MutableLiveData;

app/src/main/java/com/stormtales/notevault/ui/songeditor/SongEditorDialog.java

@@ -0,0 +1,193 @@
+package com.stormtales.notevault.ui.songeditor;
+
+import android.app.AlertDialog;
+import android.app.Dialog;
+import android.content.Context;
+import android.net.Uri;
+import android.os.Bundle;
+import android.text.Layout;
+import android.util.Log;
+import android.widget.Button;
+import android.widget.EditText;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.fragment.app.DialogFragment;
+import androidx.fragment.app.Fragment;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import androidx.lifecycle.ViewModelProvider;
+import com.stormtales.notevault.R;
+import com.stormtales.notevault.data.entities.NoteSheet;
+import com.stormtales.notevault.data.entities.Song;
+import com.stormtales.notevault.data.sync.SyncStatus;
+import com.stormtales.notevault.network.sync.SongSyncService;
+import com.stormtales.notevault.network.sync.models.AIRecognizedSong;
+import com.stormtales.notevault.ui.home.HomeViewModel;
+import com.stormtales.notevault.utils.NoteSheetsUtil;
+import com.stormtales.notevault.utils.Tupel;
+import org.jetbrains.annotations.NotNull;
+
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.util.ArrayList;
+import java.util.List;
+
+
+public class SongEditorDialog extends DialogFragment {
+
+    Dialog dialog;
+    private Uri[] noteSheetFiles;
+    private HomeViewModel homeViewModel;
+
+    private Song editedSong;
+    private SongSyncService songSyncService;
+
+    private View progressbar;
+    public SongEditorDialog() {
+        // Required empty public constructor
+        this.songSyncService = new SongSyncService(this.getContext());
+    }
+
+
+    @NonNull
+    @Override
+    public @NotNull Dialog onCreateDialog(@Nullable @org.jetbrains.annotations.Nullable Bundle savedInstanceState) {
+        LayoutInflater inflater = LayoutInflater.from(getContext());
+        View dialogView = inflater.inflate(R.layout.fragment_song_editor_dialog, null);
+
+
+        dialogView.findViewById(R.id.btnCancel).setOnClickListener(v-> onCancel());
+        dialogView.findViewById(R.id.btnSave).setOnClickListener(v -> onSave());
+
+        if(this.noteSheetFiles == null || noteSheetFiles.length == 0) {
+            dialogView.findViewById(R.id.btnAutoDetect).setEnabled(false);
+        } else {
+            progressbar = dialogView.findViewById(R.id.spinnerAutoDetect);
+
+        }
+
+        dialogView.findViewById(R.id.btnAutoDetect).setOnClickListener(v -> {
+            progressbar.setVisibility(ViewGroup.VISIBLE);
+            extractTitleFromFirstPage();
+        });
+
+        AlertDialog.Builder builder = new AlertDialog.Builder(getContext());
+        builder.setCancelable(false);
+        builder.setView(dialogView);
+
+        dialog = builder.create();
+        dialog.setCanceledOnTouchOutside(false);
+        return dialog;
+    }
+
+    private File createTemporaryFileForRecognition(Uri noteSheetUri) {
+        try {
+            // Hole den InputStream des Bildes
+            InputStream inputStream = getContext().getContentResolver().openInputStream(noteSheetUri);
+            if (inputStream != null) {
+                // Erstelle eine temporäre Datei
+                File tempFile = File.createTempFile("temp_note_sheet", ".jpg", getContext().getCacheDir());
+
+                // Inhalt des InputStreams in die temporäre Datei schreiben
+                try (OutputStream outputStream = new FileOutputStream(tempFile)) {
+                    byte[] buffer = new byte[8192];
+                    int bytesRead;
+                    while ((bytesRead = inputStream.read(buffer)) != -1) {
+                        outputStream.write(buffer, 0, bytesRead);
+                    }
+                }
+
+                // Schließe den InputStream
+                inputStream.close();
+
+                return tempFile;
+            }
+        } catch (Exception e) {
+            Log.e("SongEditorDialog", "Fehler beim Erstellen der temporären Datei: " + e.getMessage());
+        }
+
+        return null;
+    }
+    private void extractTitleFromFirstPage() {
+        if(noteSheetFiles != null && noteSheetFiles.length > 0) {
+            Uri firstPageUri = noteSheetFiles[0];
+
+            // Temporäre Datei erstellen
+            File tempFile = createTemporaryFileForRecognition(firstPageUri);
+            if(tempFile != null) {
+                songSyncService.recognizeTitle(tempFile.getAbsolutePath(), new SongSyncService.RecognizedSongCallback() {
+                    @Override
+                    public void onRecognizedSong(AIRecognizedSong aiRecognizedSong) {
+                        progressbar.setVisibility(ViewGroup.GONE);
+                        ((EditText) dialog.findViewById(R.id.etTitle)).setText(aiRecognizedSong.getTitle());
+                        ((EditText) dialog.findViewById(R.id.etComposer)).setText(aiRecognizedSong.getComposer());
+                        ((EditText) dialog.findViewById(R.id.etYear)).setText(String.valueOf(aiRecognizedSong.getYear()));
+                        ((EditText) dialog.findViewById(R.id.etGenre)).setText(aiRecognizedSong.getDescription());
+                    }
+                });
+            }
+        }
+    }
+
+    @Override
+    public void onStart() {
+        super.onStart();
+        if(editedSong != null) {
+            ((EditText) dialog.findViewById(R.id.etTitle)).setText(editedSong.getTitle());
+            ((EditText) dialog.findViewById(R.id.etComposer)).setText(editedSong.getComposer());
+            ((EditText) dialog.findViewById(R.id.etGenre)).setText(editedSong.getGenre());
+            ((EditText) dialog.findViewById(R.id.etYear)).setText(String.valueOf(editedSong.getYear()));
+        }
+    }
+
+    private void onCancel() {
+        dialog.dismiss();
+    }
+
+    private void onSave() {
+        String title = ((EditText) dialog.findViewById(R.id.etTitle)).getText().toString();
+        String composer = ((EditText) dialog.findViewById(R.id.etComposer)).getText().toString();
+
+        String year_string = ((EditText) dialog.findViewById(R.id.etYear)).getText().toString();
+        int releaseYear = year_string.isBlank()? 0 : Integer.parseInt(year_string);
+        String genre = ((EditText) dialog.findViewById(R.id.etGenre)).getText().toString();
+
+        if(editedSong != null) {
+            editedSong.setTitle(title);
+            editedSong.setComposer(composer);
+            editedSong.setYear(releaseYear);
+            editedSong.setGenre(genre);
+            editedSong.setSyncStatus(SyncStatus.MODIFIED);
+            homeViewModel.updateSong(editedSong);
+        } else {
+            Song song = new Song(title, composer, genre, releaseYear);
+
+            Context context = this.getContext();
+            List<NoteSheet> noteSheetList = new ArrayList<>();
+            for(Uri uri : noteSheetFiles) {
+                Tupel<String, String> result = NoteSheetsUtil.saveImageInternally(context.getContentResolver(), uri, context.getFilesDir());
+                noteSheetList.add(new NoteSheet(result.getValue00(), result.getValue01()));
+            }
+            homeViewModel.addSong(song, noteSheetList);
+        }
+
+
+        dialog.dismiss();
+
+    }
+
+    public void setNoteSheetFiles(Uri[] noteSheetFiles) {
+        this.noteSheetFiles = noteSheetFiles;
+    }
+
+    public void setHomeViewModel(HomeViewModel homeViewModel) {
+        this.homeViewModel = homeViewModel;
+    }
+
+    public void setEditedSong(Song editedSong) {
+        this.editedSong = editedSong;
+    }
+}

app/src/main/java/com/stormtales/notevault/utils/NoteSheetsUtil.java

@@ -0,0 +1,117 @@
+package com.stormtales.notevault.utils;
+
+import android.content.ContentResolver;
+import android.content.Context;
+import android.media.ExifInterface;
+import android.net.Uri;
+import okhttp3.ResponseBody;
+
+import java.io.*;
+import java.nio.file.Files;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+import java.text.ParseException;
+import java.text.SimpleDateFormat;
+import java.util.*;
+
+public class NoteSheetsUtil {
+    private static long getImageTimestamp(Context context, Uri imageUri) {
+        try  {
+            InputStream inputStream = context.getContentResolver().openInputStream(imageUri);
+            ExifInterface exif = new ExifInterface(inputStream);
+
+            String dateTime = exif.getAttribute(ExifInterface.TAG_DATETIME);
+            if(dateTime != null) {
+                SimpleDateFormat format = new SimpleDateFormat("yyyy:MM:dd HH:mm:ss", Locale.getDefault());
+                Date date = format.parse(dateTime);
+                return date != null ? date.getTime() : 0;
+            } else {
+                File file = new File(imageUri.getPath());
+                return file.lastModified();
+            }
+        } catch (IOException | ParseException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    public static void sortNoteSheetsByTimestamp(Context context, Uri[] uris) {
+        ArrayList<UriTimestamp> uriTimestamps = new ArrayList<>();
+
+        for(Uri uri : uris) {
+            long timestamp = getImageTimestamp(context, uri);
+            uriTimestamps.add(new UriTimestamp(uri, timestamp));
+        }
+
+        Collections.sort(uriTimestamps, Comparator.comparingLong(UriTimestamp::getTimestamp));
+
+        for(int i=0; i<uriTimestamps.size(); i++) {
+            uris[i] = uriTimestamps.get(i).getUri();
+        }
+    }
+
+    public static Tupel<String, String> saveImageInternally(ContentResolver contentResolver, Uri uri, File filesDir) {
+        try (InputStream inputStream = contentResolver.openInputStream(uri)) {
+            // Datei erstellen
+            File imageFile = new File(filesDir, "saved_image_" + System.currentTimeMillis() + ".jpg");
+            try (OutputStream outputStream = Files.newOutputStream(imageFile.toPath())) {
+                // SHA-256 Hash-Funktion initialisieren
+                MessageDigest digest = MessageDigest.getInstance("SHA-256");
+
+                // Daten blockweise lesen und gleichzeitig schreiben und hashen
+                byte[] buffer = new byte[4096];
+                int bytesRead;
+                while ((bytesRead = inputStream.read(buffer)) != -1) {
+                    outputStream.write(buffer, 0, bytesRead);
+                    digest.update(buffer, 0, bytesRead); // Hash aktualisieren
+                }
+
+                // Hash berechnen
+                byte[] hashBytes = digest.digest();
+                StringBuilder hashString = new StringBuilder();
+                for (byte b : hashBytes) {
+                    hashString.append(String.format("%02x", b)); // Bytes in Hexadezimal umwandeln
+                }
+
+                // Hashwert zurückgeben (kann auch zusammen mit dem Pfad gespeichert werden)
+                return new Tupel<>(imageFile.getAbsolutePath(), hashString.toString());
+            } catch (NoSuchAlgorithmException e) {
+                throw new RuntimeException(e);
+            }
+        } catch (IOException e) {
+            e.printStackTrace();
+            return null;
+        }
+    }
+
+    public static Tupel<String, String> saveImageFromServer(ResponseBody body, File filesDir) {
+        File imageFile = new File(filesDir, "saved_image_" + System.currentTimeMillis() + ".jpg");
+        try (InputStream inputStream = body.byteStream();
+             FileOutputStream outputStream = new FileOutputStream(imageFile)) {
+            MessageDigest digest = MessageDigest.getInstance("SHA-256");
+
+            // Daten blockweise lesen und gleichzeitig schreiben und hashen
+            byte[] buffer = new byte[4096];
+            int bytesRead;
+            while ((bytesRead = inputStream.read(buffer)) != -1) {
+                outputStream.write(buffer, 0, bytesRead);
+                digest.update(buffer, 0, bytesRead); // Hash aktualisieren
+            }
+
+            // Hash berechnen
+            byte[] hashBytes = digest.digest();
+            StringBuilder hashString = new StringBuilder();
+            for (byte b : hashBytes) {
+                hashString.append(String.format("%02x", b)); // Bytes in Hexadezimal umwandeln
+            }
+
+            // Hashwert zurückgeben (kann auch zusammen mit dem Pfad gespeichert werden)
+            return new Tupel<>(imageFile.getAbsolutePath(), hashString.toString());
+        } catch (IOException | NoSuchAlgorithmException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    public static void deleteNoteSheet(String filePath) throws IOException {
+        Files.delete(new File(filePath).toPath());
+    }
+}

app/src/main/java/com/stormtales/notevault/utils/Tupel.java

@@ -0,0 +1,33 @@
+package com.stormtales.notevault.utils;
+
+import java.util.Objects;
+
+public class Tupel<A,B> {
+    private final A value00;
+    private final B value01;
+
+    public Tupel(A value00, B value01) {
+        this.value00 = value00;
+        this.value01 = value01;
+    }
+
+    public A getValue00() {
+        return value00;
+    }
+
+    public B getValue01() {
+        return value01;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (o == null || getClass() != o.getClass()) return false;
+        Tupel<?, ?> tupel = (Tupel<?, ?>) o;
+        return Objects.equals(value00, tupel.value00) && Objects.equals(value01, tupel.value01);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(value00, value01);
+    }
+}

app/src/main/java/com/stormtales/notevault/utils/UriTimestamp.java

@@ -1,4 +1,4 @@
-package core.notevault.util;
+package com.stormtales.notevault.utils;
 
 import android.net.Uri;
 

app/src/main/java/core/notevault/MainActivity.java

@@ -1,308 +0,0 @@
-package core.notevault;
-
-import android.content.Intent;
-import android.net.Uri;
-import android.os.Bundle;
-import android.text.TextUtils;
-import android.util.Log;
-import android.view.MenuItem;
-import android.view.View;
-import android.view.Menu;
-import android.widget.Toast;
-import androidx.fragment.app.Fragment;
-import androidx.fragment.app.FragmentManager;
-import androidx.navigation.fragment.NavHostFragment;
-import androidx.work.OneTimeWorkRequest;
-import androidx.work.WorkManager;
-import com.google.android.material.snackbar.Snackbar;
-import com.google.android.material.navigation.NavigationView;
-import androidx.navigation.NavController;
-import androidx.navigation.Navigation;
-import androidx.navigation.ui.AppBarConfiguration;
-import androidx.navigation.ui.NavigationUI;
-import androidx.drawerlayout.widget.DrawerLayout;
-import androidx.appcompat.app.AppCompatActivity;
-import core.notevault.data.*;
-import core.notevault.databinding.ActivityMainBinding;
-import core.notevault.sync.SyncWorker;
-import core.notevault.sync.auth.AuthRepository;
-import core.notevault.sync.auth.LoginCallback;
-import core.notevault.ui.gallery.GalleryFragment;
-import core.notevault.ui.gallery.detail.ConcertSongSelector;
-import core.notevault.ui.gallery.editor.ConcertEditorDialog;
-import core.notevault.ui.home.HomeFragment;
-import core.notevault.ui.login.LoginCallBackImpl;
-import core.notevault.ui.login.LoginDialogFragment;
-import core.notevault.ui.login.RegisterCallback;
-import core.notevault.ui.metadatadialog.MetaDataDialog;
-import core.notevault.ui.metadatadialog.SongEditDialog;
-import core.notevault.util.NoteSheetsUtil;
-
-import java.io.*;
-import java.nio.file.Files;
-import java.util.ArrayList;
-import java.util.Calendar;
-import java.util.Date;
-import java.util.List;
-import java.util.concurrent.TimeUnit;
-
-public class MainActivity extends AppCompatActivity implements MetaDataDialog.OnMetadataListener,
-        ConcertEditorDialog.OnConcertEditorListener, ConcertSongSelector.OnSongSelectedListener, LoginCallback, SongEditDialog.SongEditorListener {
-
-    private AppBarConfiguration mAppBarConfiguration;
-    private ActivityMainBinding binding;
-
-    private MusicDatabase musicDB;
-
-    @Override
-    protected void onCreate(Bundle savedInstanceState) {
-        super.onCreate(savedInstanceState);
-
-        binding = ActivityMainBinding.inflate(getLayoutInflater());
-        setContentView(binding.getRoot());
-
-        setSupportActionBar(binding.appBarMain.toolbar);
-        DrawerLayout drawer = binding.drawerLayout;
-        NavigationView navigationView = binding.navView;
-        // Passing each menu ID as a set of Ids because each
-        // menu should be considered as top level destinations.
-        mAppBarConfiguration = new AppBarConfiguration.Builder(
-                R.id.nav_home, R.id.nav_gallery, R.id.nav_slideshow)
-                .setOpenableLayout(drawer)
-                .build();
-        NavController navController = Navigation.findNavController(this, R.id.nav_host_fragment_content_main);
-        NavigationUI.setupActionBarWithNavController(this, navController, mAppBarConfiguration);
-        NavigationUI.setupWithNavController(navigationView, navController);
-
-        setupLoginButton();
-        musicDB = MusicDatabase.getDatabase(this);
-        scheduleSync();
-    }
-
-    public void scheduleSync() {
-        // Setze eine Uhrzeit für die Synchronisation
-        Calendar calendar = Calendar.getInstance();
-        calendar.set(Calendar.HOUR_OF_DAY,11);
-        calendar.set(Calendar.MINUTE, 32);
-        calendar.set(Calendar.SECOND, 0);
-
-        long triggerTime = calendar.getTimeInMillis(); // Zeitstempel für den Trigger
-
-        // Erstelle die OneTimeWorkRequest für den SyncWorker
-        OneTimeWorkRequest syncRequest = new OneTimeWorkRequest.Builder(SyncWorker.class)
-                .setInitialDelay(triggerTime - System.currentTimeMillis(), TimeUnit.MILLISECONDS) // Verzögerung bis zur Ausführung
-                .build();
-
-        // Planen des Workers mit WorkManager
-        WorkManager.getInstance(getBaseContext()).enqueue(syncRequest);
-    }
-
-    @Override
-    public boolean onPrepareOptionsMenu(Menu menu) {
-        MenuItem loginItem = menu.findItem(R.id.action_login);
-        if (isLoggedIn()) {
-            loginItem.setIcon(R.drawable.logout); // Setze das Logout-Symbol
-        } else {
-            loginItem.setIcon(R.drawable.login); // Setze das Login-Symbol
-        }
-        return super.onPrepareOptionsMenu(menu);
-    }
-
-    public void updateLoginButton() {
-        invalidateOptionsMenu(); // Menü neu zeichnen
-    }
-
-    private void setupLoginButton() {
-        binding.appBarMain.toolbar.setOnMenuItemClickListener(item -> {
-            if (item.getItemId() == R.id.action_login) {
-                if (isLoggedIn()) {
-                    performLogout(); // Logout-Logik aufrufen
-                } else {
-                    showLoginDialog(); // Zeige das Login-Fenster an
-                }
-                return true;
-            }
-            return false;
-        });
-    }
-
-    private boolean isLoggedIn() {
-        AuthRepository authRepository = new AuthRepository(this);
-        return !TextUtils.isEmpty(authRepository.getToken());
-    }
-
-    private void showLoginDialog() {
-        LoginDialogFragment loginDialogFragment = LoginDialogFragment.newInstance(new LoginCallBackImpl(this), new RegisterCallback(this));
-        loginDialogFragment.show(getSupportFragmentManager(), "login");
-    }
-
-    private void performLogout() {
-        // Füge hier deine Logout-Logik hinzu
-        AuthRepository authRepository = new AuthRepository(this);
-
-        authRepository.logout(); // Implementiere die Token-Löschung
-        updateLoginButton();
-    }
-
-
-
-    @Override
-    public boolean onCreateOptionsMenu(Menu menu) {
-        // Inflate the menu; this adds items to the action bar if it is present.
-        getMenuInflater().inflate(R.menu.main, menu);
-        return true;
-    }
-
-    @Override
-    public boolean onOptionsItemSelected(MenuItem item) {
-        int id = item.getItemId();
-        if(id == R.id.action_login) {
-            openLoginDialog();
-            return true;
-        }
-        return super.onOptionsItemSelected(item);
-    }
-
-    private void openLoginDialog() {
-        LoginDialogFragment loginDialogFragment = new LoginDialogFragment();
-        loginDialogFragment.show(getSupportFragmentManager(), "LOGIN_TAG");
-    }
-
-    @Override
-    public boolean onSupportNavigateUp() {
-        NavController navController = Navigation.findNavController(this, R.id.nav_host_fragment_content_main);
-        return NavigationUI.navigateUp(navController, mAppBarConfiguration)
-                || super.onSupportNavigateUp();
-    }
-
-    @Override
-    public void onMetadataEntered(Uri[] uris, String title, String composer, int year, String genre) {
-        new Thread(() -> {
-            MusicNote musicNote = new MusicNote(title, composer, year, genre);
-            long musicNoteID = musicDB.musicNoteDao().insert(musicNote);
-            musicNote.setMusicNoteId(musicNoteID);
-
-            Log.d("MainActivity", "MusicNoteID of inserted song: " + musicNoteID);
-            Log.d("MainActivity", "MusicNoteID of referenced song: " + musicNote.getMusicNoteId());
-            for(Uri uri: uris) {
-                String filePath = saveImageInternally(uri);
-                NoteSheet noteSheet = new NoteSheet(musicNoteID, filePath);
-                musicDB.musicNoteDao().insertNoteSheet(noteSheet);
-            }
-
-            runOnUiThread(() -> {
-                NavHostFragment navHostFragment = (NavHostFragment) getSupportFragmentManager().findFragmentById(R.id.nav_host_fragment_content_main);
-                Fragment currentFragment = navHostFragment != null ? navHostFragment.getChildFragmentManager().getFragments().get(0) : null;
-
-                if(currentFragment instanceof HomeFragment) {
-                    HomeFragment homeFragment = (HomeFragment) currentFragment;
-                    homeFragment.addSong(musicNote);
-                }
-            });
-        }).start();
-    }
-
-    // Speichere eine Kopie des Bilds im internen Speicher
-    private String saveImageInternally(Uri uri) {
-        try (InputStream inputStream = getContentResolver().openInputStream(uri)) {
-            File imageFile = new File(getFilesDir(), "saved_image_" + System.currentTimeMillis() + ".jpg");
-            try (OutputStream outputStream = Files.newOutputStream(imageFile.toPath())) {
-                byte[] buffer = new byte[4096];
-                int bytesRead;
-                while ((bytesRead = inputStream.read(buffer)) != -1) {
-                    outputStream.write(buffer, 0, bytesRead);
-                }
-            }
-            return imageFile.getAbsolutePath(); // Pfad speichern, um später darauf zuzugreifen
-        } catch (IOException e) {
-            e.printStackTrace();
-            return null;
-        }
-    }
-
-    @Override
-    public void onConcertEditorClosed(String concertTitle, String concertDate, int concertID) {
-        new Thread(() -> {
-            if(concertID < 0) {
-                Concert concert = new Concert(concertTitle, concertDate);
-                Log.d("ConcertEditor", "Saved Concert: " + concertTitle + " on " + concertDate);
-                musicDB.musicNoteDao().insertConcert(concert);
-
-                runOnUiThread(() -> {
-                    NavHostFragment navHostFragment = (NavHostFragment) getSupportFragmentManager().findFragmentById(R.id.nav_host_fragment_content_main);
-                    Fragment currentFragment = navHostFragment != null ? navHostFragment.getChildFragmentManager().getFragments().get(0) : null;
-
-                    Log.d("MainActivity", "Test for GalleryFragment");
-                    Log.d("MainActivity", "Current Fragment: " + currentFragment.getClass().getSimpleName());
-                    if(currentFragment instanceof GalleryFragment) {
-                        Log.d("MainActivity", "GalleryFragment Found");
-                        GalleryFragment galleryFragment = (GalleryFragment) currentFragment;
-                        galleryFragment.addConcert(concert);
-                    } else {
-                        Log.d("MainActivity", "GalleryFragment Not Found");
-                    }
-                });
-            } else {
-                Concert concert = new Concert(concertID, concertTitle, concertDate);
-                musicDB.musicNoteDao().updateConcert(concert);
-                runOnUiThread(() -> {
-                    NavHostFragment navHostFragment = (NavHostFragment) getSupportFragmentManager().findFragmentById(R.id.nav_host_fragment_content_main);
-                    Fragment currentFragment = navHostFragment != null ? navHostFragment.getChildFragmentManager().getFragments().get(0) : null;
-
-                    Log.d("MainActivity", "Test for GalleryFragment");
-                    Log.d("MainActivity", "Current Fragment: " + currentFragment.getClass().getSimpleName());
-                    if(currentFragment instanceof GalleryFragment) {
-                        Log.d("MainActivity", "GalleryFragment Found");
-                        GalleryFragment galleryFragment = (GalleryFragment) currentFragment;
-                        galleryFragment.updateConcert(concert);
-                    } else {
-                        Log.d("MainActivity", "GalleryFragment Not Found");
-                    }
-                });
-            }
-
-        }).start();
-    }
-
-    @Override
-    public void onSongsSelected(List<MusicNote> songs, int concertID) {
-        Log.d("MainActivity", "Inserted Songs: " + songs.size());
-        new Thread(() -> {
-            for(MusicNote musicNote : songs) {
-                ConcertSong concertSong = new ConcertSong(musicNote.getMusicNoteId(), concertID);
-                musicDB.musicNoteDao().insertConcertSong(concertSong);
-                Log.d("MainActivity", "Insert Song: " + musicNote.getTitle());
-            }
-        }).start();
-    }
-
-
-    @Override
-    public void onSuccess() {
-        updateLoginButton();
-    }
-
-    @Override
-    public void onError(String error) {
-        Toast.makeText(this, error, Toast.LENGTH_LONG).show();
-        Log.d("LoginError", error);
-    }
-
-    @Override
-    public void onSongEdited(MusicNote updatedSong) {
-        new Thread(() -> {
-            musicDB.musicNoteDao().updateSong(updatedSong);
-            Log.d("MainActivity", "Updated Song: " + updatedSong.getTitle());
-        }).start();
-        NavHostFragment navHostFragment = (NavHostFragment) getSupportFragmentManager().findFragmentById(R.id.nav_host_fragment_content_main);
-        Fragment currentFragment = navHostFragment != null ? navHostFragment.getChildFragmentManager().getFragments().get(0) : null;
-
-        if(currentFragment instanceof HomeFragment) {
-            HomeFragment homeFragment = (HomeFragment) currentFragment;
-            homeFragment.updateSong(updatedSong);
-        } else if(currentFragment instanceof GalleryFragment) {
-            GalleryFragment galleryFragment = (GalleryFragment) currentFragment;
-
-        }
-    }
-}

app/src/main/java/core/notevault/data/Concert.java

@@ -1,90 +0,0 @@
-package core.notevault.data;
-
-import androidx.room.*;
-import core.notevault.data.sync.SyncStatus;
-import core.notevault.data.sync.SyncStatusConverter;
-
-import java.text.SimpleDateFormat;
-import java.time.LocalDateTime;
-import java.util.Date;
-import java.util.Locale;
-
-@Entity(tableName = "concerts")
-@TypeConverters(SyncStatusConverter.class)
-public class Concert {
-
-    @PrimaryKey(autoGenerate = true)
-    private int id;
-
-    private String serverSpecificConcertID;
-    private String title;
-    private String concertDate;
-    private SyncStatus syncStatus;
-
-    private LocalDateTime lastModified;
-
-    @Ignore
-    public Concert(String title, String concertDate) {
-        this.title = title;
-        this.concertDate = concertDate;
-        this.lastModified = LocalDateTime.now();
-    }
-
-    public Concert() {
-    }
-
-    @Ignore
-    public Concert(int id, String title, String concertDate) {
-        this.id = id;
-        this.title = title;
-        this.concertDate = concertDate;
-    }
-
-    public int getId() {
-        return id;
-    }
-
-    public void setId(int id) {
-        this.id = id;
-    }
-
-    public String getTitle() {
-        return title;
-    }
-
-    public void setTitle(String title) {
-        this.title = title;
-    }
-
-    public String getConcertDate() {
-        return concertDate;
-    }
-
-    public void setConcertDate(String concertDate) {
-        this.concertDate = concertDate;
-    }
-
-    public String getServerSpecificConcertID() {
-        return serverSpecificConcertID;
-    }
-
-    public void setServerSpecificConcertID(String serverSpecificConcertID) {
-        this.serverSpecificConcertID = serverSpecificConcertID;
-    }
-
-    public SyncStatus getSyncStatus() {
-        return syncStatus;
-    }
-
-    public void setSyncStatus(SyncStatus syncStatus) {
-        this.syncStatus = syncStatus;
-    }
-
-    public LocalDateTime getLastModified() {
-        return lastModified;
-    }
-
-    public void setLastModified(LocalDateTime lastModified) {
-        this.lastModified = lastModified;
-    }
-}

app/src/main/java/core/notevault/data/ConcertSong.java

@@ -1,55 +0,0 @@
-package core.notevault.data;
-
-import androidx.room.Entity;
-import androidx.room.Ignore;
-import androidx.room.PrimaryKey;
-
-@Entity(tableName = "concert_songs")
-public class ConcertSong {
-
-    @PrimaryKey(autoGenerate = true)
-    private int id;
-
-    private long musicNoteID;
-    private int concertID;
-
-    @Ignore
-    public ConcertSong(long musicNoteID, int concertID) {
-        this.musicNoteID = musicNoteID;
-        this.concertID = concertID;
-    }
-
-    @Ignore
-    public ConcertSong(int id, long musicNoteID, int concertID) {
-        this.id = id;
-        this.musicNoteID = musicNoteID;
-        this.concertID = concertID;
-    }
-
-    public ConcertSong() {
-    }
-
-    public int getId() {
-        return id;
-    }
-
-    public void setId(int id) {
-        this.id = id;
-    }
-
-    public long getMusicNoteID() {
-        return musicNoteID;
-    }
-
-    public void setMusicNoteID(long musicNoteID) {
-        this.musicNoteID = musicNoteID;
-    }
-
-    public int getConcertID() {
-        return concertID;
-    }
-
-    public void setConcertID(int concertID) {
-        this.concertID = concertID;
-    }
-}

app/src/main/java/core/notevault/data/MusicDatabase.java

@@ -1,27 +0,0 @@
-package core.notevault.data;
-
-import android.content.Context;
-import androidx.room.*;
-import core.notevault.data.sync.SyncDataObject;
-import core.notevault.data.sync.SyncStatusConverter;
-
-@Database(entities = {MusicNote.class, NoteSheet.class, Concert.class, ConcertSong.class, SyncDataObject.class}, version = 2, exportSchema = false)
-@TypeConverters(DateConverter.class)
-public abstract class MusicDatabase extends RoomDatabase {
-    public abstract MusicNoteDAO musicNoteDao();
-
-    private static MusicDatabase INSTANCE;
-
-    public static MusicDatabase getDatabase(final Context context) {
-        if (INSTANCE == null) {
-            synchronized (MusicDatabase.class) {
-                if (INSTANCE == null) {
-                    INSTANCE = Room.databaseBuilder(context.getApplicationContext(),
-                                    MusicDatabase.class, "music_database")
-                            .build();
-                }
-            }
-        }
-        return INSTANCE;
-    }
-}

app/src/main/java/core/notevault/data/MusicNote.java

@@ -1,107 +0,0 @@
-package core.notevault.data;
-
-import androidx.room.Entity;
-import androidx.room.Ignore;
-import androidx.room.PrimaryKey;
-import core.notevault.data.sync.SyncStatus;
-
-import java.time.LocalDateTime;
-
-@Entity(tableName = "music_notes")
-public class MusicNote {
-
-    @PrimaryKey(autoGenerate = true)
-    private long musicNoteId;
-    private String serverID;
-    private SyncStatus syncStatus;
-    private LocalDateTime last_sync;
-
-    private String title;
-    private String composer;
-    private int year;
-    private String genre;
-
-    @Ignore
-    public MusicNote(String title,  String composer, int year, String genre) {
-        this.title = title;
-        this.composer = composer;
-        this.year = year;
-        this.genre = genre;
-        this.syncStatus = SyncStatus.CREATED;
-    }
-
-    public MusicNote(long musicNoteId, String title) {
-        this.musicNoteId = musicNoteId;
-        this.title = title;
-        this.syncStatus = SyncStatus.CREATED;
-    }
-
-    @Ignore
-    public MusicNote() {
-    }
-
-    public long getMusicNoteId() {
-        return musicNoteId;
-    }
-
-    public void setMusicNoteId(long musicNoteId) {
-        this.musicNoteId = musicNoteId;
-    }
-
-    public String getTitle() {
-        return title;
-    }
-
-    public void setTitle(String title) {
-        this.title = title;
-    }
-
-    public String getComposer() {
-        return composer;
-    }
-
-    public void setComposer(String composer) {
-        this.composer = composer;
-    }
-
-    public String getGenre() {
-        return genre;
-    }
-
-    public void setGenre(String genre) {
-        this.genre = genre;
-    }
-
-    public int getYear() {
-        return year;
-    }
-
-    public void setYear(int year) {
-        this.year = year;
-    }
-
-    public String getServerID() {
-        return serverID;
-    }
-
-    public void setServerID(String serverID) {
-        this.serverID = serverID;
-    }
-
-    public SyncStatus getSyncStatus() {
-        return syncStatus;
-    }
-
-    public void setSyncStatus(SyncStatus syncStatus) {
-        this.syncStatus = syncStatus;
-    }
-
-    public LocalDateTime getLast_sync() {
-
-        return last_sync;
-    }
-
-    public void setLast_sync(LocalDateTime last_sync) {
-        this.last_sync = last_sync;
-    }
-}

app/src/main/java/core/notevault/data/MusicNoteDAO.java

@@ -1,89 +0,0 @@
-package core.notevault.data;
-
-import androidx.room.*;
-
-import core.notevault.data.sync.SyncDataObject;
-import core.notevault.data.sync.SyncStatus;
-import core.notevault.sync.synchronisation.songs.creation.SongCreationResponse;
-
-import java.time.LocalDateTime;
-import java.util.List;
-import java.util.Optional;
-
-@Dao
-public interface MusicNoteDAO {
-
-    @Insert
-    long insert(MusicNote musicNote);
-
-    @Insert
-    void insertNoteSheet(NoteSheet noteSheet);
-
-    @Query("SELECT * FROM music_notes WHERE syncStatus != 'DELETED'")
-    List<MusicNote> getAllNotes();
-
-    @Query("SELECT * FROM note_sheets WHERE musicNoteId = :musicNoteId")
-    List<NoteSheet> getNoteSheetsForMusicSong(long musicNoteId);
-
-    @Query("SELECT * FROM concerts WHERE syncStatus = :status")
-    List<Concert> getConcertsWithSyncStatus(SyncStatus status);
-
-    @Query("SELECT * FROM music_notes WHERE syncStatus = :status")
-    List<MusicNote> getSongsWithSyncStatus(SyncStatus status);
-
-    @Insert
-    void insertConcert(Concert concert);
-
-    @Query("SELECT * FROM concerts")
-    List<Concert> getAllConcerts();
-
-    @Delete
-    void deleteConcert(Concert concert);
-
-    @Update
-    void updateConcert(Concert concert);
-
-    @Delete
-    void deleteSong(MusicNote musicNote);
-
-    @Insert
-    void insertConcertSong(ConcertSong concertSong);
-
-    @Query("SELECT m.* FROM music_notes m JOIN concert_songs cs ON m.musicNoteId = cs.musicNoteID WHERE cs.id = :concertID")
-    List<MusicNote> getAllMusicNotesOfConcert(long concertID);
-
-    @Query("DELETE FROM concert_songs WHERE concertID = :concertID AND musicNoteID = :songID")
-    void deleteConcertSong(long songID, int concertID);
-
-    @Transaction
-    default void storeSongSyncResponses(List<SongCreationResponse> songCreationResponses) {
-        for (SongCreationResponse response : songCreationResponses) {
-            storeSongSyncResponse(response.getLocalID(), SyncStatus.SYNCED, response.getServerID());
-        }
-    }
-
-    @Query("UPDATE music_notes SET syncStatus = :status, serverID = :serverID WHERE musicNoteId = :localID")
-    void storeSongSyncResponse(long localID, SyncStatus status, String serverID);
-
-    @Query("UPDATE music_notes SET syncStatus = :status, last_sync = :currentTime WHERE serverID IN (:serverIDs)")
-    void storeSongSyncModifyResponses(List<String> serverIDs, SyncStatus status, LocalDateTime currentTime);
-
-    @Update
-    void updateSong(MusicNote musicNote);
-
-    @Query("DELETE FROM music_notes WHERE serverID IN (:serverIDs)")
-    void deleteSongs(List<String> serverIDs);
-
-    @Query("SELECT * FROM note_sheets ns WHERE ns.syncStatus = :status")
-    List<NoteSheet> getNoteSheetsWithStatus(SyncStatus status);
-
-    @Query("SELECT mn.serverID FROM music_notes mn WHERE mn.musicNoteId =:musicNoteId")
-    Optional<String> getMusicNoteByLocalID(long musicNoteId);
-
-    @Update
-    void updateNoteSheet(NoteSheet noteSheet);
-
-    @Transaction
-    @Insert(onConflict = OnConflictStrategy.REPLACE) // oder andere Strategie je nach Bedarf
-    void insertSyncDataObjects(List<SyncDataObject> syncDataObjects);
-}

app/src/main/java/core/notevault/data/NoteSheet.java

@@ -1,56 +0,0 @@
-package core.notevault.data;
-
-import androidx.room.Entity;
-import androidx.room.PrimaryKey;
-import core.notevault.data.sync.SyncStatus;
-
-@Entity(tableName = "note_sheets")
-public class NoteSheet {
-
-    @PrimaryKey(autoGenerate = true)
-    private int id;
-    private SyncStatus syncStatus;
-    private long musicNoteId;
-    private String filePath;
-
-    public NoteSheet(long musicNoteID, String filePath) {
-        this.musicNoteId = musicNoteID;
-        this.filePath = filePath;
-        this.syncStatus = SyncStatus.CREATED;
-    }
-
-    public NoteSheet() {
-    }
-
-    public int getId() {
-        return id;
-    }
-
-    public void setId(int id) {
-        this.id = id;
-    }
-
-    public long getMusicNoteId() {
-        return musicNoteId;
-    }
-
-    public void setMusicNoteId(long musicNoteId) {
-        this.musicNoteId = musicNoteId;
-    }
-
-    public String getFilePath() {
-        return filePath;
-    }
-
-    public void setFilePath(String filePath) {
-        this.filePath = filePath;
-    }
-
-    public SyncStatus getSyncStatus() {
-        return syncStatus;
-    }
-
-    public void setSyncStatus(SyncStatus syncStatus) {
-        this.syncStatus = syncStatus;
-    }
-}

app/src/main/java/core/notevault/data/sync/SyncDataObject.java

@@ -1,49 +0,0 @@
-package core.notevault.data.sync;
-
-import androidx.room.Entity;
-import androidx.room.Ignore;
-import androidx.room.PrimaryKey;
-import androidx.room.TypeConverters;
-
-@Entity(tableName = "sync_data_objects")
-@TypeConverters(SyncDataObjectTypeConverter.class)
-public class SyncDataObject {
-    @PrimaryKey(autoGenerate = true)
-    private int id;
-
-    private String serverID;
-    private SyncDataObjectType type;
-
-    @Ignore
-    public SyncDataObject(String serverID, SyncDataObjectType type) {
-        this.serverID = serverID;
-        this.type = type;
-    }
-
-    public SyncDataObject() {
-    }
-
-    public int getId() {
-        return id;
-    }
-
-    public void setId(int id) {
-        this.id = id;
-    }
-
-    public String getServerID() {
-        return serverID;
-    }
-
-    public void setServerID(String serverID) {
-        this.serverID = serverID;
-    }
-
-    public SyncDataObjectType getType() {
-        return type;
-    }
-
-    public void setType(SyncDataObjectType type) {
-        this.type = type;
-    }
-}

app/src/main/java/core/notevault/data/sync/SyncDataObjectType.java

@@ -1,5 +0,0 @@
-package core.notevault.data.sync;
-
-public enum SyncDataObjectType {
-    MUSIC_NOTE
-}

app/src/main/java/core/notevault/data/sync/SyncDataObjectTypeConverter.java

@@ -1,15 +0,0 @@
-package core.notevault.data.sync;
-
-import androidx.room.TypeConverter;
-
-public class SyncDataObjectTypeConverter {
-    @TypeConverter
-    public static SyncDataObjectType fromInt(int value) {
-        return SyncDataObjectType.values()[value];
-    }
-
-    @TypeConverter
-    public static int toInt(SyncDataObjectType objectType) {
-        return objectType.ordinal();
-    }
-}

app/src/main/java/core/notevault/sync/SyncWorker.java

@@ -1,38 +0,0 @@
-package core.notevault.sync;
-import android.content.Context;
-import androidx.annotation.NonNull;
-import androidx.work.Worker;
-import androidx.work.WorkerParameters;
-import core.notevault.data.MusicDatabase;
-
-import core.notevault.sync.synchronisation.*;
-import core.notevault.sync.synchronisation.songs.SongSyncWorker;
-
-
-public class SyncWorker extends Worker{
-    private SongSyncWorker songSyncWorker;
-    public SyncWorker(@NonNull Context context, @NonNull WorkerParameters workerParams) {
-        super(context, workerParams);
-        SyncService syncService = ApiClient.getRetrofitInstance(context).create(SyncService.class);
-        MusicDatabase musicDatabase = MusicDatabase.getDatabase(context);
-        this.songSyncWorker = new SongSyncWorker(syncService, musicDatabase.musicNoteDao(), context);
-    }
-
-    @NonNull
-    @Override
-    public Result doWork() {
-        try {
-            songSyncWorker.syncSongCreations();
-            songSyncWorker.syncSongModifications();
-            songSyncWorker.syncSongDeletions();
-            songSyncWorker.uploadNoteSheets();
-            songSyncWorker.fetchModifiedSongs();
-            return Result.success();
-        } catch (Exception e) {
-            e.printStackTrace();
-            return Result.failure();
-        }
-    }
-
-
-}

app/src/main/java/core/notevault/sync/auth/LoginCallback.java

@@ -1,7 +0,0 @@
-package core.notevault.sync.auth;
-
-public interface LoginCallback {
-
-    void onSuccess();
-    void onError(String error);
-}

app/src/main/java/core/notevault/sync/auth/apimodel/RegisterResponse.java

@@ -1,31 +0,0 @@
-package core.notevault.sync.auth.apimodel;
-
-public class RegisterResponse {
-
-    private String username;
-    private String email;
-
-    public RegisterResponse(String username, String email) {
-        this.username = username;
-        this.email = email;
-    }
-
-    public RegisterResponse() {
-    }
-
-    public String getUsername() {
-        return username;
-    }
-
-    public void setUsername(String username) {
-        this.username = username;
-    }
-
-    public String getEmail() {
-        return email;
-    }
-
-    public void setEmail(String email) {
-        this.email = email;
-    }
-}

app/src/main/java/core/notevault/sync/synchronisation/FetchRequest.java

@@ -1,19 +0,0 @@
-package core.notevault.sync.synchronisation;
-
-import java.time.LocalDateTime;
-
-public class FetchRequest {
-    private LocalDateTime client_last_sync;
-
-    public FetchRequest(LocalDateTime client_last_sync) {
-        this.client_last_sync = client_last_sync;
-    }
-
-    public LocalDateTime getClient_last_sync() {
-        return client_last_sync;
-    }
-
-    public void setClient_last_sync(LocalDateTime client_last_sync) {
-        this.client_last_sync = client_last_sync;
-    }
-}

app/src/main/java/core/notevault/sync/synchronisation/SyncService.java

@@ -1,36 +0,0 @@
-package core.notevault.sync.synchronisation;
-
-
-import core.notevault.sync.synchronisation.songs.creation.SongCreationBatchRequest;
-import core.notevault.sync.synchronisation.songs.creation.SongCreationBatchResponse;
-import core.notevault.sync.synchronisation.songs.deletion.SongDeletionBatchRequest;
-import core.notevault.sync.synchronisation.songs.deletion.SongDeletionBatchResponse;
-import core.notevault.sync.synchronisation.songs.modification.SongModificationBatchRequest;
-import core.notevault.sync.synchronisation.songs.modification.SongModificationBatchResponse;
-import core.notevault.sync.synchronisation.songs.notesheets.UploadResponse;
-import okhttp3.MultipartBody;
-import okhttp3.RequestBody;
-import retrofit2.Call;
-import retrofit2.http.*;
-
-import java.time.LocalDateTime;
-
-public interface SyncService {
-
-    @POST("/sync/songs/create")
-    Call<SongCreationBatchResponse> performSongCreation(@Body SongCreationBatchRequest syncRequest);
-
-    @POST("/sync/songs/modify")
-    Call<SongModificationBatchResponse> performSongModification(@Body SongModificationBatchRequest syncRequest);
-
-    @POST("/sync/songs/delete")
-    Call<SongDeletionBatchResponse> performSongDeletion(@Body SongDeletionBatchRequest syncRequest);
-
-    @Multipart
-    @POST("/sync/songs/note_sheet/upload")
-    Call<UploadResponse> uploadNoteSheet(@Part("serverID") RequestBody serverID, @Part("fileName") RequestBody fileName,
-                                         @Part MultipartBody.Part image);
-
-    @GET("/sync/songs/fetch")
-    Call<FetchResponse> fetchModifiedSongs(@Query("last_client_sync") LocalDateTime last_client_sync);
-}

app/src/main/java/core/notevault/sync/synchronisation/songs/SongSyncWorker.java

@@ -1,199 +0,0 @@
-package core.notevault.sync.synchronisation.songs;
-
-import android.content.Context;
-import android.os.AsyncTask;
-import android.widget.Toast;
-import core.notevault.data.MusicNote;
-import core.notevault.data.MusicNoteDAO;
-import core.notevault.data.NoteSheet;
-import core.notevault.data.sync.SyncDataObject;
-import core.notevault.data.sync.SyncDataObjectType;
-import core.notevault.data.sync.SyncStatus;
-import core.notevault.sync.synchronisation.FetchRequest;
-import core.notevault.sync.synchronisation.FetchResponse;
-import core.notevault.sync.synchronisation.SyncService;
-import core.notevault.sync.synchronisation.songs.creation.SongCreationBatchRequest;
-import core.notevault.sync.synchronisation.songs.creation.SongCreationBatchResponse;
-import core.notevault.sync.synchronisation.songs.creation.SongCreationRequest;
-import core.notevault.sync.synchronisation.songs.deletion.SongDeletionBatchRequest;
-import core.notevault.sync.synchronisation.songs.deletion.SongDeletionBatchResponse;
-import core.notevault.sync.synchronisation.songs.modification.SongModificationBatchRequest;
-import core.notevault.sync.synchronisation.songs.modification.SongModificationBatchResponse;
-import core.notevault.sync.synchronisation.songs.modification.SongModificationRequest;
-import core.notevault.sync.synchronisation.songs.notesheets.UploadResponse;
-import okhttp3.MediaType;
-import okhttp3.MultipartBody;
-import okhttp3.RequestBody;
-import retrofit2.Call;
-import retrofit2.Callback;
-import retrofit2.Response;
-
-import java.io.File;
-import java.time.LocalDateTime;
-import java.util.ArrayList;
-import java.util.List;
-import java.util.Optional;
-import java.util.concurrent.ExecutorService;
-import java.util.concurrent.Executors;
-import java.util.stream.Collectors;
-
-public class SongSyncWorker {
-    private SyncService syncService;
-    private MusicNoteDAO database;
-    private Context context;
-    private ExecutorService executorService = Executors.newSingleThreadExecutor();
-
-    public SongSyncWorker(SyncService syncService, MusicNoteDAO database, Context context) {
-        this.syncService = syncService;
-        this.database = database;
-        this.context = context;
-    }
-
-    private SongCreationBatchRequest buildCreationRequest() {
-        List<MusicNote> created_songs = database.getSongsWithSyncStatus(SyncStatus.CREATED);
-        List<SongCreationRequest> songCreationRequests = new ArrayList<>();
-        for(MusicNote musicNote : created_songs) {
-            songCreationRequests.add(new SongCreationRequest(musicNote.getMusicNoteId(), musicNote.getTitle(), musicNote.getComposer(), musicNote.getGenre(), musicNote.getYear()));
-        }
-        return new SongCreationBatchRequest(songCreationRequests);
-    }
-
-    public void syncSongCreations() {
-        SongCreationBatchRequest request = buildCreationRequest();
-        syncService.performSongCreation(request).enqueue(new Callback<SongCreationBatchResponse>() {
-            @Override
-            public void onResponse(Call<SongCreationBatchResponse> call, Response<SongCreationBatchResponse> response) {
-                if(response.isSuccessful() && response.body() != null) {
-                    executorService.execute(() -> {
-                        database.storeSongSyncResponses(response.body().getSongs());
-                    });
-                } else {
-                    Toast.makeText(context, "Song creation failed", Toast.LENGTH_LONG).show();
-                }
-            }
-
-            @Override
-            public void onFailure(Call<SongCreationBatchResponse> call, Throwable throwable) {
-                Toast.makeText(context, "Song creation failed", Toast.LENGTH_LONG).show();
-            }
-        });
-    }
-
-    private SongModificationBatchRequest buildModificationRequest() {
-        List<MusicNote> modified_songs = database.getSongsWithSyncStatus(SyncStatus.MODIFIED);
-        List<SongModificationRequest> songModificationRequests = new ArrayList<>();
-        for(MusicNote musicNote : modified_songs) {
-            songModificationRequests.add(new SongModificationRequest(musicNote.getServerID(), musicNote.getTitle(), musicNote.getComposer(), musicNote.getGenre(), musicNote.getYear()));
-        }
-        return new SongModificationBatchRequest(songModificationRequests);
-    }
-
-    public void syncSongModifications() {
-        SongModificationBatchRequest request = buildModificationRequest();
-        syncService.performSongModification(request).enqueue(new Callback<SongModificationBatchResponse>() {
-            @Override
-            public void onResponse(Call<SongModificationBatchResponse> call, Response<SongModificationBatchResponse> response) {
-                executorService.execute(() -> {
-                    database.storeSongSyncModifyResponses(response.body().getUpdated_songs(), SyncStatus.SYNCED, LocalDateTime.now());
-                });
-            }
-
-            @Override
-            public void onFailure(Call<SongModificationBatchResponse> call, Throwable throwable) {
-                Toast.makeText(context, "Sync of Modified Songs failed", Toast.LENGTH_LONG).show();
-            }
-        });
-    }
-
-    private SongDeletionBatchRequest buildDeletionBatchRequest() {
-        List<MusicNote> deleted_songs = database.getSongsWithSyncStatus(SyncStatus.DELETED);
-        List<String> deleted_song_ids = deleted_songs.stream().map(MusicNote::getServerID).collect(Collectors.toList());
-        return new SongDeletionBatchRequest(deleted_song_ids);
-    }
-
-    public void syncSongDeletions() {
-        SongDeletionBatchRequest request = buildDeletionBatchRequest();
-        syncService.performSongDeletion(request).enqueue(new Callback<SongDeletionBatchResponse>() {
-            @Override
-            public void onResponse(Call<SongDeletionBatchResponse> call, Response<SongDeletionBatchResponse> response) {
-                if(response.isSuccessful() && response.body() != null) {
-                    executorService.execute(() -> {
-                        database.deleteSongs(response.body().getDeletedSongs());
-                    });
-                }
-            }
-
-            @Override
-            public void onFailure(Call<SongDeletionBatchResponse> call, Throwable throwable) {
-                Toast.makeText(context, "Sync of Deleted Songs failed", Toast.LENGTH_LONG).show();
-            }
-        });
-    }
-
-    public void uploadNoteSheets() {
-        List<NoteSheet> noteSheets = database.getNoteSheetsWithStatus(SyncStatus.CREATED);
-        for(NoteSheet noteSheet : noteSheets) {
-            Optional<String> serverID = database.getMusicNoteByLocalID(noteSheet.getMusicNoteId());
-
-            if(serverID.isPresent()) {
-                File imageFile = new File(noteSheet.getFilePath());
-                // Erstelle Request-Bodies für serverID und fileName
-                RequestBody serverIDBody = RequestBody.create(MediaType.parse("text/plain"), serverID.get());
-                RequestBody fileNameBody = RequestBody.create(MediaType.parse("text/plain"), imageFile.getName());
-
-                // Erstelle den Multipart-Body für die Bilddatei
-                RequestBody imageRequestBody = RequestBody.create(MediaType.parse("image/*"), imageFile);
-                MultipartBody.Part imagePart = MultipartBody.Part.createFormData("image", imageFile.getName(), imageRequestBody);
-
-                syncService.uploadNoteSheet(serverIDBody, fileNameBody, imagePart).enqueue(new Callback<UploadResponse>() {
-                    @Override
-                    public void onResponse(Call<UploadResponse> call, Response<UploadResponse> response) {
-                        if (response.isSuccessful() && response.body() != null) {
-                            // Erfolg: Antwort verarbeiten
-                            Toast.makeText(context, "Upload erfolgreich", Toast.LENGTH_LONG).show();
-                            executorService.execute(() -> {
-                                noteSheet.setSyncStatus(SyncStatus.SYNCED);
-                                database.updateNoteSheet(noteSheet);
-                            });
-                        } else {
-                            // Fehler: Antwort prüfen
-                            Toast.makeText(context, "Fehler beim Upload: " + response.code(), Toast.LENGTH_LONG).show();
-                        }
-
-                    }
-
-                    @Override
-                    public void onFailure(Call<UploadResponse> call, Throwable throwable) {
-                        Toast.makeText(context, "Fehler beim Upload: " + throwable.toString(), Toast.LENGTH_LONG).show();
-                    }
-                });
-            }
-        }
-    }
-
-    public void fetchModifiedSongs() {
-        FetchRequest request = new FetchRequest(LocalDateTime.MIN);
-
-        syncService.fetchModifiedSongs(LocalDateTime.MIN).enqueue(new Callback<FetchResponse>() {
-            @Override
-            public void onResponse(Call<FetchResponse> call, Response<FetchResponse> response) {
-                if(response.isSuccessful() && response.body() != null) {
-                    executorService.execute(() -> {
-                        List<SyncDataObject> syncDataObjects = new ArrayList<>();
-                        for(String serverID: response.body().getServerIDs()) {
-                            syncDataObjects.add(new SyncDataObject(serverID, SyncDataObjectType.MUSIC_NOTE));
-                        }
-                        database.insertSyncDataObjects(syncDataObjects);
-                    });
-                } else {
-                    Toast.makeText(context, "Fehler beim Fetch: " + response.code(), Toast.LENGTH_LONG).show();
-                }
-            }
-
-            @Override
-            public void onFailure(Call<FetchResponse> call, Throwable throwable) {
-                Toast.makeText(context, "Fehler beim Fetch: " + throwable.getMessage(), Toast.LENGTH_LONG).show();
-            }
-        });
-    }
-}

app/src/main/java/core/notevault/sync/synchronisation/songs/creation/SongCreationBatchRequest.java

@@ -1,11 +0,0 @@
-package core.notevault.sync.synchronisation.songs.creation;
-
-import java.util.List;
-
-public class SongCreationBatchRequest {
-    private List<SongCreationRequest> songs;
-
-    public SongCreationBatchRequest(List<SongCreationRequest> songs) {
-        this.songs = songs;
-    }
-}

app/src/main/java/core/notevault/sync/synchronisation/songs/creation/SongCreationBatchResponse.java

@@ -1,19 +0,0 @@
-package core.notevault.sync.synchronisation.songs.creation;
-
-import java.util.List;
-
-public class SongCreationBatchResponse {
-    private List<SongCreationResponse> songs;
-
-    public SongCreationBatchResponse(List<SongCreationResponse> songs) {
-        this.songs = songs;
-    }
-
-    public List<SongCreationResponse> getSongs() {
-        return songs;
-    }
-
-    public void setSongs(List<SongCreationResponse> songs) {
-        this.songs = songs;
-    }
-}

app/src/main/java/core/notevault/sync/synchronisation/songs/creation/SongCreationRequest.java

@@ -1,17 +0,0 @@
-package core.notevault.sync.synchronisation.songs.creation;
-
-public class SongCreationRequest {
-    private long localID;
-    private String title;
-    private String composer;
-    private String genre;
-    private int year;
-
-    public SongCreationRequest(long localID, String title, String composer, String genre, int year) {
-        this.localID = localID;
-        this.title = title;
-        this.composer = composer;
-        this.genre = genre;
-        this.year = year;
-    }
-}

app/src/main/java/core/notevault/sync/synchronisation/songs/deletion/SongDeletionBatchResponse.java

@@ -1,19 +0,0 @@
-package core.notevault.sync.synchronisation.songs.deletion;
-
-import java.util.List;
-
-public class SongDeletionBatchResponse {
-    private List<String> deletedSongs;
-
-    public SongDeletionBatchResponse(List<String> deletedSongs) {
-        this.deletedSongs = deletedSongs;
-    }
-
-    public List<String> getDeletedSongs() {
-        return deletedSongs;
-    }
-
-    public void setDeletedSongs(List<String> deletedSongs) {
-        this.deletedSongs = deletedSongs;
-    }
-}

app/src/main/java/core/notevault/sync/synchronisation/songs/modification/SongModificationBatchRequest.java

@@ -1,11 +0,0 @@
-package core.notevault.sync.synchronisation.songs.modification;
-
-import java.util.List;
-
-public class SongModificationBatchRequest {
-    private List<SongModificationRequest> songs;
-
-    public SongModificationBatchRequest(List<SongModificationRequest> songs) {
-        this.songs = songs;
-    }
-}

app/src/main/java/core/notevault/sync/synchronisation/songs/modification/SongModificationBatchResponse.java

@@ -1,19 +0,0 @@
-package core.notevault.sync.synchronisation.songs.modification;
-
-import java.util.List;
-
-public class SongModificationBatchResponse {
-    private List<String> songs;
-
-    public SongModificationBatchResponse(List<String> songs) {
-        this.songs = songs;
-    }
-
-    public List<String> getUpdated_songs() {
-        return songs;
-    }
-
-    public void setUpdated_songs(List<String> updated_songs) {
-        this.songs = updated_songs;
-    }
-}

app/src/main/java/core/notevault/sync/synchronisation/songs/notesheets/UploadResponse.java

@@ -1,5 +0,0 @@
-package core.notevault.sync.synchronisation.songs.notesheets;
-
-public class UploadResponse {
-    private String serverID;
-}

app/src/main/java/core/notevault/ui/gallery/ConcertAdapter.java

@@ -1,86 +0,0 @@
-package core.notevault.ui.gallery;
-
-import android.util.Log;
-import android.view.LayoutInflater;
-import android.view.View;
-import android.view.ViewGroup;
-import android.widget.ImageButton;
-import android.widget.TextView;
-import androidx.annotation.NonNull;
-import androidx.recyclerview.widget.RecyclerView;
-import core.notevault.R;
-import core.notevault.data.Concert;
-import core.notevault.ui.home.NoteSongAdapter;
-import org.jetbrains.annotations.NotNull;
-
-import java.util.ArrayList;
-import java.util.List;
-
-public class ConcertAdapter extends RecyclerView.Adapter<ConcertAdapter.ConcertViewHolder> {
-
-    private final List<Concert> concertList;
-    private final OnConcertClickListener concertClickListener;
-
-    public interface OnConcertClickListener {
-        void onDeleteConcert(Concert concert);
-        void onOpenConcertEditor(Concert concert);
-        void onConcertClick(Concert concert);
-    }
-
-
-    public ConcertAdapter(List<Concert> concertList, OnConcertClickListener concertClickListener) {
-        this.concertList = concertList;
-        this.concertClickListener = concertClickListener;
-    }
-
-    public ConcertAdapter(OnConcertClickListener onConcertClickListener) {
-        this.concertClickListener = onConcertClickListener;
-        this.concertList = new ArrayList<>();
-    }
-
-    @Override
-    public void onBindViewHolder(@NonNull ConcertViewHolder holder, int position) {
-        holder.concertTitleView.setText(concertList.get(position).getTitle());
-        holder.dateHolder.setText(concertList.get(position).getConcertDate());
-
-        holder.deleteButton.setOnClickListener(v -> concertClickListener.onDeleteConcert(concertList.get(position)));
-        holder.editButton.setOnClickListener(v -> concertClickListener.onOpenConcertEditor(concertList.get(position)));
-        holder.itemView.setOnClickListener(v -> concertClickListener.onConcertClick(concertList.get(position)));
-    }
-
-    @Override
-    public int getItemCount() {
-        return concertList.size();
-    }
-
-    @NonNull
-    @Override
-    public ConcertViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
-        View view = LayoutInflater.from(parent.getContext())
-                .inflate(R.layout.concert_item, parent, false);
-        return new ConcertViewHolder(view);
-    }
-
-    public void updateConcerts(List<Concert> concerts) {
-        Log.d("ConcertAdapter", "Update Concerts: " + this.concertList.size() + "vs new: " + concerts.size());
-        this.concertList.clear();
-        this.concertList.addAll(concerts);
-        notifyDataSetChanged();
-    }
-
-    public class ConcertViewHolder extends RecyclerView.ViewHolder {
-        TextView concertTitleView;
-        TextView dateHolder;
-
-        ImageButton deleteButton;
-        ImageButton editButton;
-
-        public ConcertViewHolder(@NonNull @NotNull View itemView) {
-            super(itemView);
-            concertTitleView = itemView.findViewById(R.id.concert_title);
-            dateHolder = itemView.findViewById(R.id.concert_date);
-            deleteButton = itemView.findViewById(R.id.delete_concert_button);
-            editButton = itemView.findViewById(R.id.edit_concert_button);
-        }
-    }
-}

app/src/main/java/core/notevault/ui/gallery/GalleryFragment.java

@@ -1,153 +0,0 @@
-package core.notevault.ui.gallery;
-
-import android.os.AsyncTask;
-import android.os.Bundle;
-import android.os.Handler;
-import android.os.Looper;
-import android.util.Log;
-import android.view.LayoutInflater;
-import android.view.View;
-import android.view.ViewGroup;
-import android.widget.TextView;
-import androidx.annotation.NonNull;
-import androidx.fragment.app.Fragment;
-import androidx.lifecycle.ViewModelProvider;
-import androidx.navigation.NavController;
-import androidx.navigation.NavDirections;
-import androidx.navigation.Navigation;
-import androidx.recyclerview.widget.DividerItemDecoration;
-import androidx.recyclerview.widget.LinearLayoutManager;
-import androidx.recyclerview.widget.RecyclerView;
-import com.google.android.material.floatingactionbutton.FloatingActionButton;
-import core.notevault.R;
-import core.notevault.data.Concert;
-import core.notevault.data.MusicDatabase;
-import core.notevault.data.MusicNote;
-import core.notevault.data.MusicNoteDAO;
-import core.notevault.databinding.FragmentGalleryBinding;
-import core.notevault.ui.gallery.editor.ConcertEditorDialog;
-
-import java.util.List;
-
-public class GalleryFragment extends Fragment {
-
-    private FragmentGalleryBinding binding;
-    private ConcertAdapter concertAdapter;
-    private GalleryViewModel galleryViewModel;
-
-    public View onCreateView(@NonNull LayoutInflater inflater,
-                             ViewGroup container, Bundle savedInstanceState) {
-        galleryViewModel =
-                new ViewModelProvider(this).get(GalleryViewModel.class);
-
-        binding = FragmentGalleryBinding.inflate(inflater, container, false);
-        View root = binding.getRoot();
-
-        RecyclerView recyclerView = root.findViewById(R.id.concert_recycler_view);
-        concertAdapter = new ConcertAdapter(new ConcertAdapter.OnConcertClickListener() {
-            @Override
-            public void onDeleteConcert(Concert concert) {
-                deleteConcert(concert);
-            }
-
-            @Override
-            public void onOpenConcertEditor(Concert concert) {
-                editConcert(concert);
-            }
-
-            @Override
-            public void onConcertClick(Concert concert) {
-                Log.d("GalleryFragment", "Clicked on Concert: " + concert.getTitle());
-                Bundle bundle = new Bundle();
-                bundle.putInt("concertID", concert.getId());
-                bundle.putString("concertTitle", concert.getTitle());
-                bundle.putString("concertDate", concert.getConcertDate());
-
-                NavController navController = Navigation.findNavController(getActivity(), R.id.nav_host_fragment_content_main);
-                navController.navigate(R.id.concertDetailFragment, bundle);
-            }
-        });
-        recyclerView.setAdapter(concertAdapter);
-        recyclerView.setLayoutManager(new LinearLayoutManager(getContext()));
-
-        DividerItemDecoration dividerItemDecoration = new DividerItemDecoration(recyclerView.getContext(), LinearLayoutManager.VERTICAL);
-        recyclerView.addItemDecoration(dividerItemDecoration);
-
-
-        FloatingActionButton addConcertBtn = root.findViewById(R.id.add_concert_btn);
-        addConcertBtn.setOnClickListener(v -> onCreateNewConcert());
-
-        galleryViewModel.getConcerts().observe(getViewLifecycleOwner(), newConcerts -> {
-            concertAdapter.updateConcerts(newConcerts);
-        });
-
-        new LoadConcerts().execute();
-        return root;
-    }
-
-    public void deleteConcert(Concert concert) {
-        Log.d("GalleryFragment", "Delete Concert");
-        new Thread(() -> {
-            MusicDatabase musicDatabase = MusicDatabase.getDatabase(this.getContext());
-            MusicNoteDAO musicNoteDAO = musicDatabase.musicNoteDao();
-            musicNoteDAO.deleteConcert(concert);
-
-            new Handler(Looper.getMainLooper()).post(() -> {
-                galleryViewModel.deleteConcert(concert);
-                Log.d("GalleryFragment", "Concert deleted successfully and ViewModel updated");
-            });
-        }).start();
-    }
-
-    public void editConcert(Concert concert) {
-        ConcertEditorDialog concertEditorDialog = new ConcertEditorDialog();
-
-        Bundle args = new Bundle();
-        args.putString("concert_title", concert.getTitle());
-        args.putString("concert_date", concert.getConcertDate());
-        args.putInt("concertID", concert.getId());
-
-        concertEditorDialog.setArguments(args);
-
-        concertEditorDialog.show(getParentFragmentManager(), ConcertEditorDialog.TAG);
-    }
-
-    public void updateConcert(Concert concert) {
-        galleryViewModel.updateConcert(concert);
-    }
-
-    private class LoadConcerts extends AsyncTask<Void, Void, List<Concert>> {
-
-        @Override
-        protected List<Concert> doInBackground(Void... voids) {
-            MusicDatabase db = MusicDatabase.getDatabase(getContext());
-            MusicNoteDAO musicNoteDAO = db.musicNoteDao();
-            List<Concert> concerts =  musicNoteDAO.getAllConcerts();
-            Log.d("GalleryFragment", "Fetching concerts: " + concerts.size());
-            return concerts;
-
-        }
-
-        @Override
-        protected void onPostExecute(List<Concert> concerts) {
-            Log.d("GalleryFragment", "Concerts size in onPostExecute: " + concerts.size());
-            // concertAdapter.updateConcerts(concerts); // Aktualisiere den Adapter mit den Titeln
-            galleryViewModel.setConcerts(concerts);
-        }
-    }
-
-    public void onCreateNewConcert() {
-        ConcertEditorDialog concertEditorDialog = new ConcertEditorDialog();
-        concertEditorDialog.show(getParentFragmentManager(), ConcertEditorDialog.TAG);
-    }
-
-    public void addConcert(Concert concert) {
-        this.galleryViewModel.addConcert(concert);
-    }
-
-    @Override
-    public void onDestroyView() {
-        super.onDestroyView();
-        binding = null;
-    }
-}

app/src/main/java/core/notevault/ui/gallery/GalleryViewModel.java

@@ -1,58 +0,0 @@
-package core.notevault.ui.gallery;
-
-import android.util.Log;
-import androidx.lifecycle.LiveData;
-import androidx.lifecycle.MutableLiveData;
-import androidx.lifecycle.ViewModel;
-import core.notevault.data.Concert;
-
-import java.util.List;
-
-public class GalleryViewModel extends ViewModel {
-
-    private final MutableLiveData<List<Concert>> concerts;
-
-    public GalleryViewModel() {
-       this.concerts = new MutableLiveData<>();
-    }
-
-
-    public LiveData<List<Concert>> getConcerts() {
-        return concerts;
-    }
-
-    public void setConcerts(List<Concert> concerts) {
-        this.concerts.setValue(concerts);
-    }
-
-    public void addConcert(Concert concert) {
-        List<Concert> currentConcerts = this.concerts.getValue();
-        Log.d("GalleryViewModel", "Add Concert");
-        if(currentConcerts != null) {
-            currentConcerts.add(concert);
-            concerts.setValue(currentConcerts);
-        }
-    }
-
-    public void deleteConcert(Concert concert) {
-        List<Concert> currentConcerts = concerts.getValue();
-        if(currentConcerts != null) {
-            currentConcerts.remove(concert);
-            concerts.setValue(currentConcerts);
-        }
-    }
-
-    public void updateConcert(Concert concert) {
-        List<Concert> currentConcerts = concerts.getValue();
-        if(currentConcerts != null) {
-            for(int i = 0; i < currentConcerts.size(); i++) {
-                if(currentConcerts.get(i).getId() == concert.getId()) {
-                    currentConcerts.get(i).setTitle(concert.getTitle());
-                    currentConcerts.get(i).setConcertDate(concert.getConcertDate());
-                    break;
-                }
-            }
-            concerts.setValue(currentConcerts);
-        }
-    }
-}

app/src/main/java/core/notevault/ui/gallery/detail/ConcertDetailFragment.java

@@ -1,119 +0,0 @@
-package core.notevault.ui.gallery.detail;
-
-import android.os.AsyncTask;
-import android.os.Bundle;
-import android.util.Log;
-import android.view.LayoutInflater;
-import android.view.View;
-import android.view.ViewGroup;
-import androidx.fragment.app.Fragment;
-import androidx.lifecycle.ViewModelProvider;
-import androidx.recyclerview.widget.DividerItemDecoration;
-import androidx.recyclerview.widget.LinearLayoutManager;
-import androidx.recyclerview.widget.RecyclerView;
-import androidx.room.util.ViewInfo;
-import com.google.android.material.floatingactionbutton.FloatingActionButton;
-import core.notevault.data.Concert;
-import core.notevault.data.MusicDatabase;
-import core.notevault.data.MusicNote;
-import core.notevault.data.MusicNoteDAO;
-import core.notevault.databinding.FragmentConcertDetailBinding;
-import core.notevault.ui.home.NoteSongAdapter;
-import core.notevault.ui.metadatadialog.SongEditDialog;
-
-import java.util.Collections;
-import java.util.List;
-
-public class ConcertDetailFragment extends Fragment {
-
-    public interface OnConcertSongsLoadedListener {
-        void onSongsLoaded(List<MusicNote> songs);
-    }
-
-    private FragmentConcertDetailBinding binding;
-    private Concert concert;
-    private ConcertDetailViewModel concertDetailViewModel;
-    private NoteSongAdapter noteSongAdapter;
-
-    @Override
-    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
-        concertDetailViewModel = new ViewModelProvider(this).get(ConcertDetailViewModel.class);
-
-        binding = FragmentConcertDetailBinding.inflate(inflater, container, false);
-        int concertId = getArguments().getInt("concertID");
-        String concertTitle = getArguments().getString("concertTitle");
-        String concertDate = getArguments().getString("concertDate");
-        concert = new Concert(concertId, concertTitle, concertDate);
-
-        binding.textConcertDetailsTitle.setText(concertTitle);
-        binding.textConcertDetailsDate.setText(concertDate);
-
-        RecyclerView recyclerView = binding.noteRecyclerView;
-        noteSongAdapter = new NoteSongAdapter(this::deleteSongFromConcert, this::editSongFromConcert);
-        recyclerView.setAdapter(noteSongAdapter);
-        recyclerView.setLayoutManager(new LinearLayoutManager(getContext()));
-
-        DividerItemDecoration dividerItemDecoration = new DividerItemDecoration(recyclerView.getContext(), LinearLayoutManager.VERTICAL);
-        recyclerView.addItemDecoration(dividerItemDecoration);
-
-        FloatingActionButton fab = binding.addSongConcert;
-        fab.setOnClickListener(view -> {
-            ConcertSongSelector concertSongSelector = new ConcertSongSelector();
-
-            Bundle bundle = new Bundle();
-            bundle.putString("concertTitle", concertTitle);
-            bundle.putString("concertDate", concertDate);
-            bundle.putInt("concertID", concertId);
-
-            concertSongSelector.setArguments(bundle);
-
-            concertSongSelector.show(getParentFragmentManager(), ConcertSongSelector.TAG);
-        });
-
-        concertDetailViewModel.getConcertSongs().observe(getViewLifecycleOwner(), songs -> {
-            noteSongAdapter.updateSongTitles(songs);
-        });
-
-        new LoadConcertSongsTask(concertId, songs -> {
-            this.concertDetailViewModel.setConcertSongs(songs);
-        }).execute();
-
-        return binding.getRoot();
-    }
-
-    private void deleteSongFromConcert(MusicNote musicNote) {
-        this.concertDetailViewModel.deleteConcertSong(musicNote);
-        new Thread(() -> {
-            MusicNoteDAO musicNoteDAO = MusicDatabase.getDatabase(getContext()).musicNoteDao();
-            musicNoteDAO.deleteConcertSong(musicNote.getMusicNoteId(), concert.getId());
-        }).start();
-    }
-
-    private void editSongFromConcert(MusicNote musicNote) {
-        SongEditDialog songEditDialog = new SongEditDialog();
-        songEditDialog.setSong(musicNote);
-        songEditDialog.show(getParentFragmentManager(), SongEditDialog.TAG);
-    }
-
-    private class LoadConcertSongsTask extends AsyncTask<Void, Void, List<MusicNote>> {
-        private final int concertID;
-        private final OnConcertSongsLoadedListener listener;
-
-        public LoadConcertSongsTask(int concertID, OnConcertSongsLoadedListener listener) {
-            this.concertID = concertID;
-            this.listener = listener;
-        }
-
-        @Override
-        protected List<MusicNote> doInBackground(Void... voids) {
-            MusicDatabase db = MusicDatabase.getDatabase(getContext());
-            return db.musicNoteDao().getAllMusicNotesOfConcert(concertID);
-        }
-
-        @Override
-        protected void onPostExecute(List<MusicNote> songs) {
-            Log.d("ConcertDetailFragment", "Loaded Concertsongs: " + songs.size());
-            listener.onSongsLoaded(songs);
-        }
-    }
-}

app/src/main/java/core/notevault/ui/gallery/detail/ConcertDetailViewModel.java

@@ -1,41 +0,0 @@
-package core.notevault.ui.gallery.detail;
-
-import androidx.lifecycle.LiveData;
-import androidx.lifecycle.MutableLiveData;
-import androidx.lifecycle.ViewModel;
-import core.notevault.data.MusicNote;
-
-import java.util.ArrayList;
-import java.util.List;
-
-public class ConcertDetailViewModel extends ViewModel {
-    private final MutableLiveData<List<MusicNote>> concertSongs;
-
-    public ConcertDetailViewModel() {
-        this.concertSongs = new MutableLiveData<>(new ArrayList<>());
-    }
-
-    public LiveData<List<MusicNote>> getConcertSongs() {
-        return concertSongs;
-    }
-
-    public void setConcertSongs(List<MusicNote> concertSongs) {
-       this.concertSongs.setValue(concertSongs);
-    }
-
-    public void deleteConcertSong(MusicNote note) {
-        List<MusicNote> currentConcertSongs = concertSongs.getValue();
-        if(currentConcertSongs != null) {
-            currentConcertSongs.remove(note);
-            this.concertSongs.setValue(currentConcertSongs);
-        }
-    }
-
-    public void addConcertSongs(List<MusicNote> concertSongs) {
-        List<MusicNote> currentConcertSongs = this.concertSongs.getValue();
-        if(currentConcertSongs != null) {
-            currentConcertSongs.addAll(concertSongs);
-            this.concertSongs.setValue(currentConcertSongs);
-        }
-    }
-}

app/src/main/java/core/notevault/ui/gallery/detail/ConcertSongSelector.java

@@ -1,116 +0,0 @@
-package core.notevault.ui.gallery.detail;
-
-import android.app.AlertDialog;
-import android.app.Dialog;
-import android.content.Context;
-import android.os.AsyncTask;
-import android.os.Bundle;
-import android.util.Log;
-import android.view.LayoutInflater;
-import android.view.View;
-import android.widget.SearchView;
-import android.widget.TextView;
-import androidx.annotation.NonNull;
-import androidx.fragment.app.DialogFragment;
-import androidx.recyclerview.widget.LinearLayoutManager;
-import androidx.recyclerview.widget.RecyclerView;
-import core.notevault.R;
-import core.notevault.data.ConcertSong;
-import core.notevault.data.MusicDatabase;
-import core.notevault.data.MusicNote;
-import core.notevault.data.MusicNoteDAO;
-import core.notevault.ui.metadatadialog.MetaDataDialog;
-
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.List;
-
-public class ConcertSongSelector extends DialogFragment {
-
-    private ConcertSongSelectorAdapter adapter;
-    private OnSongSelectedListener listener;
-    private int concertID;
-
-    public interface OnSongSelectedListener {
-        void onSongsSelected(List<MusicNote> songs, int concertID);
-    }
-
-    @NonNull
-    @Override
-    public Dialog onCreateDialog(Bundle savedInstanceState) {
-        LayoutInflater inflater = getActivity().getLayoutInflater();
-        View dialogView = inflater.inflate(R.layout.dialog_concert_song_selector, null);
-
-        String concertTitle = getArguments().getString("concertTitle");
-        String concertDate = getArguments().getString("concertDate");
-        concertID = getArguments().getInt("concertID");
-
-        TextView dialogTitle = dialogView.findViewById(R.id.dialog_title_concert_song_selector);
-        dialogTitle.setText("Wähle Stücke für das Konzert '" + concertTitle + "' am " + concertDate + " aus");
-
-        RecyclerView recyclerView = dialogView.findViewById(R.id.concert_song_selector_recycler);
-        recyclerView.setLayoutManager(new LinearLayoutManager(getContext()));
-
-
-        adapter = new ConcertSongSelectorAdapter(new ArrayList<>());
-        recyclerView.setAdapter(adapter);
-
-        SearchView searchView = dialogView.findViewById(R.id.search_view);
-        searchView.setOnQueryTextListener(new SearchView.OnQueryTextListener() {
-            @Override
-            public boolean onQueryTextSubmit(String s) {
-                return false;
-            }
-
-            @Override
-            public boolean onQueryTextChange(String s) {
-                adapter.filter(s);
-                return true;
-            }
-        });
-
-        fetchAllSongs();
-
-        return new AlertDialog.Builder(requireContext())
-                .setView(dialogView)
-                .setPositiveButton("Speichern", (dialog, which) -> {
-                    List<MusicNote> selectedSongs = adapter.getSelectedSongs();
-                    listener.onSongsSelected(selectedSongs, concertID);
-                })
-                .setNegativeButton("Abbrechen", (dialog, which) -> {} )
-                .create();
-    }
-
-    @Override
-    public void onAttach(@NonNull Context context) {
-        super.onAttach(context);
-        if (context instanceof ConcertSongSelector.OnSongSelectedListener) {
-            listener = (ConcertSongSelector.OnSongSelectedListener) context;
-        } else {
-            throw new RuntimeException(context.toString()
-                    + " must implement OnMetadataListener");
-        }
-    }
-
-    private void fetchAllSongs() {
-        // Ersetze dies durch das Laden der Songs aus der Datenbank oder einer anderen Quelle
-        new LoadSongTitlesTask().execute();
-    }
-
-    private class LoadSongTitlesTask extends AsyncTask<Void, Void, List<MusicNote>> {
-
-        @Override
-        protected List<MusicNote> doInBackground(Void... voids) {
-            MusicDatabase db = MusicDatabase.getDatabase(getContext());
-            MusicNoteDAO musicNoteDAO = db.musicNoteDao();
-            return musicNoteDAO.getAllNotes();
-        }
-
-        @Override
-        protected void onPostExecute(List<MusicNote> songs) {
-            adapter.setSongs(songs);
-        }
-    }
-
-    public static String TAG = "ConcertSongSelector";
-}