import {Component, EventEmitter, Output} from '@angular/core';
import {MatIconModule} from "@angular/material/icon";
import {MatButtonModule} from "@angular/material/button";
import {MatTreeFlatDataSource, MatTreeFlattener, MatTreeModule} from "@angular/material/tree";
import {FlatTreeControl} from "@angular/cdk/tree";
import {RecursiveTaskgroupInfo, TaskgroupService, TaskOverviewInfo, TaskShortInfo} from "../../../api";
import {TaskCreationEmitterInfo, TaskOverviewComponent} from "../task-overview/task-overview.component";


/** Flat node with expandable and level information */
interface ExampleFlatNode {
  expandable: boolean;
  level: number;
  name: string
  activeTasks: number;
  hasOverdueTask: boolean;
  tasks: TaskOverviewInfo[];
  taskgroupID: number
}

export interface TaskOverviewData {
  tasks: TaskOverviewInfo[],
  taskgroupID: number
}

@Component({
  selector: 'app-taskgroup-overview',
  templateUrl: './taskgroup-overview.component.html',
  styleUrls: ['./taskgroup-overview.component.css']
})
export class TaskgroupOverviewComponent {

  @Output('taskgroupSelected') taskgroupSelected: EventEmitter<TaskOverviewData> = new EventEmitter<TaskOverviewData>();
  private _transformer = (node: RecursiveTaskgroupInfo, level: number) => {
    return {
      expandable: !!node.childTaskgroups && node.childTaskgroups.length > 0,
      name: node.taskgroupName,
      level: level,
      activeTasks: node.amountActiveTasks,
      hasOverdueTask: node.hasOverdueTask,
      tasks: node.activeTasks,
      taskgroupID: node.taskgroupID
    };
  };

  treeControl = new FlatTreeControl<ExampleFlatNode>(
    node => node.level,
    node => node.expandable,
  );

  treeFlattener = new MatTreeFlattener(
    this._transformer,
    node => node.level,
    node => node.expandable,
    node => node.childTaskgroups,
  );

  dataSource = new MatTreeFlatDataSource(this.treeControl, this.treeFlattener);

  constructor(private taskgroupService: TaskgroupService) {

  }

  ngOnInit() {
    this.taskgroupService.taskgroupsTreeGet().subscribe({
      next: resp => {
        this.dataSource.data = resp;
      }
    })
  }

  hasChild = (_: number, node: ExampleFlatNode) => node.expandable;

  onSelectTaskgroup(tasks: TaskOverviewInfo[], taskgroupID: number) {
    this.taskgroupSelected.emit({
      tasks: tasks,
      taskgroupID:  taskgroupID
    })
  }

  finishTask(taskID: number) {
    let taskgroupQueue : RecursiveTaskgroupInfo[] = this.dataSource.data.slice();
    while(taskgroupQueue.length > 0) {
      const currentTaskgroup = taskgroupQueue.pop()!;
      const searchedTask = currentTaskgroup.activeTasks.find(searchedTask => searchedTask.taskID === taskID);
      if(searchedTask == undefined) {
        currentTaskgroup.childTaskgroups.forEach(childTask => {
          taskgroupQueue.push(childTask);
        })
      } else {
        currentTaskgroup.activeTasks = currentTaskgroup.activeTasks.filter(taskFilter => taskFilter.taskID !== searchedTask.taskID);
      }
    }
  }

  private findTaskgroup(taskgroupID: number) {
    let taskgroupQueue : RecursiveTaskgroupInfo[] = this.dataSource.data.slice();
    while(taskgroupQueue.length > 0) {
      const currentTaskgroup = taskgroupQueue.pop()!;
      if(currentTaskgroup.taskgroupID === taskgroupID) {
        return currentTaskgroup;
      } else {
        currentTaskgroup.childTaskgroups.forEach(childgroup => taskgroupQueue.push(childgroup));
      }
    }
    return undefined
  }

  onCreateTask(taskCreationInfo: TaskCreationEmitterInfo) {
    const taskgroup: RecursiveTaskgroupInfo | undefined = this.findTaskgroup(taskCreationInfo.taskgroupID);
    if(taskgroup != undefined) {
      taskgroup.activeTasks.push(taskCreationInfo.task);
    }
  }
}