backend/src/main/java/core/api/controller/TaskController.java

@@ -164,4 +164,20 @@ public class TaskController {
         taskService.finishTask(taskPermissionResult.getResult());
         return ResponseEntity.ok(new SimpleStatusResponse("success"));
     }
+
+    @PutMapping("/tasks/{taskID}/createSubtask")
+    public ResponseEntity<?> onCreateSubTask(@PathVariable long taskID, @Valid @RequestBody TaskFieldInfo taskFieldInfo) {
+        var taskPermissionResult = taskService.getTaskPermissions(taskID, SecurityContextHolder.getContext().getAuthentication().getName());
+        if(taskPermissionResult.hasIssue()) {
+            return taskPermissionResult.mapToResponseEntity();
+        }
+
+        var serviceResult = taskService.createSubTask(taskPermissionResult.getResult(), taskFieldInfo);
+        if(serviceResult.hasIssue()) {
+            return serviceResult.mapToResponseEntity();
+        } else {
+            return ResponseEntity.ok(new TaskEntityInfo(serviceResult.getResult()));
+        }
+
+    }
 }

backend/src/main/java/core/entities/timemanager/Task.java

@@ -33,7 +33,7 @@ public class Task {
     @OneToOne(mappedBy = "task", cascade = CascadeType.ALL, orphanRemoval = true)
     private TaskSerieItem taskSerieItem;
 
-    @OneToMany(mappedBy = "parent", cascade = CascadeType.ALL, orphanRemoval = true)
+    @OneToMany(mappedBy = "parent", cascade = CascadeType.ALL, orphanRemoval = true, fetch = FetchType.EAGER)
     private Set<Task> subtasks;
 
     @ManyToOne

frontend/src/api/api/task.service.ts

@@ -153,6 +153,76 @@ export class TaskService {
         );
     }
 
+    /**
+     * Creates Subtask
+     * Create Subtask
+     * @param taskID internal id of task
+     * @param taskFieldInfo 
+     * @param observe set whether or not to return the data Observable as the body, response or events. defaults to returning the body.
+     * @param reportProgress flag to report request and response progress.
+     */
+    public tasksTaskIDCreateSubtaskPut(taskID: number, taskFieldInfo?: TaskFieldInfo, observe?: 'body', reportProgress?: boolean, options?: {httpHeaderAccept?: 'application/json', context?: HttpContext}): Observable<TaskEntityInfo>;
+    public tasksTaskIDCreateSubtaskPut(taskID: number, taskFieldInfo?: TaskFieldInfo, observe?: 'response', reportProgress?: boolean, options?: {httpHeaderAccept?: 'application/json', context?: HttpContext}): Observable<HttpResponse<TaskEntityInfo>>;
+    public tasksTaskIDCreateSubtaskPut(taskID: number, taskFieldInfo?: TaskFieldInfo, observe?: 'events', reportProgress?: boolean, options?: {httpHeaderAccept?: 'application/json', context?: HttpContext}): Observable<HttpEvent<TaskEntityInfo>>;
+    public tasksTaskIDCreateSubtaskPut(taskID: number, taskFieldInfo?: TaskFieldInfo, observe: any = 'body', reportProgress: boolean = false, options?: {httpHeaderAccept?: 'application/json', context?: HttpContext}): Observable<any> {
+        if (taskID === null || taskID === undefined) {
+            throw new Error('Required parameter taskID was null or undefined when calling tasksTaskIDCreateSubtaskPut.');
+        }
+
+        let localVarHeaders = this.defaultHeaders;
+
+        let localVarCredential: string | undefined;
+        // authentication (API_TOKEN) required
+        localVarCredential = this.configuration.lookupCredential('API_TOKEN');
+        if (localVarCredential) {
+            localVarHeaders = localVarHeaders.set('Authorization', 'Bearer ' + localVarCredential);
+        }
+
+        let localVarHttpHeaderAcceptSelected: string | undefined = options && options.httpHeaderAccept;
+        if (localVarHttpHeaderAcceptSelected === undefined) {
+            // to determine the Accept header
+            const httpHeaderAccepts: string[] = [
+                'application/json'
+            ];
+            localVarHttpHeaderAcceptSelected = this.configuration.selectHeaderAccept(httpHeaderAccepts);
+        }
+        if (localVarHttpHeaderAcceptSelected !== undefined) {
+            localVarHeaders = localVarHeaders.set('Accept', localVarHttpHeaderAcceptSelected);
+        }
+
+        let localVarHttpContext: HttpContext | undefined = options && options.context;
+        if (localVarHttpContext === undefined) {
+            localVarHttpContext = new HttpContext();
+        }
+
+
+        // to determine the Content-Type header
+        const consumes: string[] = [
+            'application/json'
+        ];
+        const httpContentTypeSelected: string | undefined = this.configuration.selectHeaderContentType(consumes);
+        if (httpContentTypeSelected !== undefined) {
+            localVarHeaders = localVarHeaders.set('Content-Type', httpContentTypeSelected);
+        }
+
+        let responseType_: 'text' | 'json' = 'json';
+        if(localVarHttpHeaderAcceptSelected && localVarHttpHeaderAcceptSelected.startsWith('text')) {
+            responseType_ = 'text';
+        }
+
+        return this.httpClient.put<TaskEntityInfo>(`${this.configuration.basePath}/tasks/${encodeURIComponent(String(taskID))}/createSubtask`,
+            taskFieldInfo,
+            {
+                context: localVarHttpContext,
+                responseType: <any>responseType_,
+                withCredentials: this.configuration.withCredentials,
+                headers: localVarHeaders,
+                observe: observe,
+                reportProgress: reportProgress
+            }
+        );
+    }
+
     /**
      * edits an existing task
      * edits an existing task

frontend/src/app/active-task-overview/active-task-overview.component.ts

@@ -93,7 +93,8 @@ export class ActiveTaskOverviewComponent implements OnInit{
   editTask(editedTask: TaskTaskgroupInfo) {
     const taskEditorInfo: TaskEditorData = {
       task: editedTask,
-      taskgroupID: editedTask.taskgroups[editedTask.taskgroups.length-1].taskgroupID
+      taskgroupID: editedTask.taskgroups[editedTask.taskgroups.length-1].taskgroupID,
+      parentTask: undefined
     };
     this.dialog.open(TaskEditorComponent, {data: taskEditorInfo, width: "600px"})
   }

frontend/src/app/dashboard/task-overview/task-overview.component.ts

@@ -75,7 +75,8 @@ export class TaskOverviewComponent {
   openTaskCreation() {
     const editorData: TaskEditorData = {
       task: undefined,
-      taskgroupID: this.taskgroupID!
+      taskgroupID: this.taskgroupID!,
+      parentTask: undefined
     }
     const dialogRef = this.dialog.open(TaskEditorComponent, {data: editorData, width: "600px"})
     dialogRef.afterClosed().subscribe(res => {

frontend/src/app/taskgroups/taskgroup-dashboard/taskgroup-dashboard.component.ts

@@ -104,7 +104,8 @@ export class TaskgroupDashboardComponent implements OnInit {
   openTaskCreation() {
     const editorData: TaskEditorData = {
       task: undefined,
-      taskgroupID: this.taskgroupID
+      taskgroupID: this.taskgroupID,
+      parentTask: undefined
     }
     const dialogRef = this.dialog.open(TaskEditorComponent, {data: editorData, width: "600px"})
     dialogRef.afterClosed().subscribe(res => {

frontend/src/app/tasks/task-dashboard/task-dashboard.component.ts

@@ -97,7 +97,8 @@ export class TaskDashboardComponent implements OnChanges{
   editTask(task: TaskEntityInfo) {
     const taskEditorInfo: TaskEditorData = {
       task: task,
-      taskgroupID: this.taskgroupID!
+      taskgroupID: this.taskgroupID!,
+      parentTask: undefined
     };
     const dialogRef = this.dialog.open(TaskEditorComponent, {data: taskEditorInfo, minWidth: "400px"})
   }

frontend/src/app/tasks/task-detail-overview/task-detail-overview.component.html

@@ -7,7 +7,7 @@
           <div class="left">
             <div>{{taskStatus + " " + task!.taskName}}</div>
           </div>
-          <button class="right lightBlueBtn" mat-raised-button style="margin-left: auto">Add Subtask</button>
+          <button class="right lightBlueBtn" mat-raised-button style="margin-left: auto" (click)="addSubtask()">Add Subtask</button>
         </div>
       </mat-card-title>
 

frontend/src/app/tasks/task-detail-overview/task-detail-overview.component.ts

@@ -135,7 +135,8 @@ export class TaskDetailOverviewComponent implements OnInit {
     if(this.task != undefined) {
       const taskEditorInfo: TaskEditorData = {
         task: this.task!,
-        taskgroupID: this.taskgroupID!
+        taskgroupID: this.taskgroupID!,
+        parentTask: undefined
       };
       this.dialog.open(TaskEditorComponent, {data: taskEditorInfo, width: "600px"})
     }
@@ -166,4 +167,16 @@ export class TaskDetailOverviewComponent implements OnInit {
       minWidth: "400px"
     })
   }
+
+  addSubtask() {
+    const editorData: TaskEditorData = {
+      task: undefined,
+      taskgroupID: this.taskgroupID,
+      parentTask: this.task
+    }
+    const dialogRef = this.dialog.open(TaskEditorComponent, {
+      data: editorData,
+      minWidth: "400px"
+    })
+  }
 }

frontend/src/app/tasks/task-editor/TaskEditorData.ts

@@ -3,4 +3,5 @@ import {TaskEntityInfo, TaskTaskgroupInfo} from "../../../api";
 export interface TaskEditorData {
   taskgroupID: number;
   task: TaskTaskgroupInfo | TaskEntityInfo | undefined
+  parentTask: TaskEntityInfo | undefined
 }

frontend/src/app/tasks/task-editor/task-editor.component.html

@@ -1,6 +1,7 @@
 <h1 mat-dialog-title *ngIf="editorData.task != undefined">Edit Task ({{editorData.task!.taskName}})</h1>
-<h1 mat-dialog-title *ngIf="editorData.task == undefined">Create New Task</h1>
+<h1 mat-dialog-title *ngIf="editorData.task == undefined">Create New {{editorData.parentTask != undefined? 'Sub-':''}}Task</h1>
 <div mat-dialog-content>
+  <p *ngIf="editorData.parentTask != undefined">Create a new Subtask for the Task <i>{{editorData.parentTask!.taskName}}</i></p>
   <mat-form-field appearance="outline" class="long-form">
     <mat-label>Name</mat-label>
     <input matInput [formControl]="nameCtrl">

frontend/src/app/tasks/task-editor/task-editor.component.ts

@@ -61,6 +61,9 @@ export class TaskEditorComponent implements OnInit {
       startDate_formatted = moment(this.startDate.value).format('YYYY-MM-DDTHH:mm:ss.SSSZ');
     }
 
+    if(this.editorData.parentTask != undefined) {
+      this.createSubTask(startDate_formatted, endDate_formatted);
+    } else {
       this.taskService.tasksTaskgroupIDPut(this.editorData.taskgroupID, {
         taskName: this.nameCtrl.value,
         eta: this.etaCtrl.value,
@@ -84,6 +87,34 @@ export class TaskEditorComponent implements OnInit {
         }
       })
     }
+  }
+
+  createSubTask(startDate_formatted: string|undefined, endDate_formatted: string|undefined) {
+    this.taskService.tasksTaskIDCreateSubtaskPut(this.editorData.parentTask!.taskID, {
+      taskName: this.nameCtrl.value,
+      eta: this.etaCtrl.value,
+      startDate: startDate_formatted,
+      deadline: endDate_formatted,
+      finishable: this.finishable,
+    }).subscribe({
+      next: resp => {
+        this.dialog.close(resp);
+      },
+      error: err => {
+        if(err.status == 403) {
+          this.snackbar.open("No permission", "", {duration: 2000});
+        } else if(err.status == 404) {
+          this.snackbar.open("Taskgroup not found", "", {duration: 2000});
+        } else if(err.status == 409) {
+          this.snackbar.open("Task already exists", "", {duration: 2000});
+        } else if(err.status == 400) {
+          this.snackbar.open("Invalid Dates", "", {duration: 2000})
+        } else {
+          this.snackbar.open("Unexpected error", "", {duration: 3000});
+        }
+      }
+    })
+  }
 
   editTask() {
     let endDate_formatted: string|undefined = undefined;
@@ -123,4 +154,6 @@ export class TaskEditorComponent implements OnInit {
       }
     })
   }
+
+  protected readonly parent = parent;
 }

frontend/src/app/upcoming-task-overview/upcoming-task-overview.component.ts

@@ -59,7 +59,8 @@ export class UpcomingTaskOverviewComponent implements OnInit{
   editTask(editedTask: TaskTaskgroupInfo) {
     const taskEditorInfo: TaskEditorData = {
       task: editedTask,
-      taskgroupID: editedTask.taskgroups[editedTask.taskgroups.length-1].taskgroupID
+      taskgroupID: editedTask.taskgroups[editedTask.taskgroups.length-1].taskgroupID,
+      parentTask: undefined
     };
     this.dialog.open(TaskEditorComponent, {data: taskEditorInfo, width: "600px"})
   }

openapi.yaml

@@ -1269,6 +1269,53 @@ paths:
               schema:
                 type: object
                 $ref: "#/components/schemas/SimpleStatusResponse"
+  /tasks/{taskID}/createSubtask:
+    put:
+      security:
+        - API_TOKEN: []
+      tags:
+        - task
+      description: Create Subtask
+      summary: Creates Subtask
+      parameters:
+        - name: taskID
+          in: path
+          description: internal id of task
+          required: true
+          schema:
+            type: number
+            example: 1
+      requestBody:
+        content:
+          application/json:
+            schema:
+              $ref: '#/components/schemas/TaskFieldInfo'
+      responses:
+        200:
+          description: Operation successfull
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/TaskEntityInfo'
+        403:
+          description: No permission
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/SimpleStatusResponse'
+        404:
+          description: Task not found
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/SimpleStatusResponse'
+        400:
+          description: Invalid start/end date
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/SimpleStatusResponse'
+      
   /schedules:
     get:
       security: