dev@397: /**
dev@397:  * Created by lucast on 02/06/2017.
dev@397:  */
dev@397: import {Injectable, NgZone} from '@angular/core';
dev@397: import {AudioPlayerService} from '../audio-player/audio-player.service';
dev@397: import {Subscription} from 'rxjs/Subscription';
dev@397: import {OnSeekHandler} from '../../playhead/PlayHeadHelpers';
dev@397: 
dev@400: export type TaskRemover = () => void;
dev@400: type TaskId = number;
dev@400: 
dev@397: @Injectable()
dev@397: export class RenderLoopService {
dev@397:   private playingStateSubscription: Subscription;
dev@397:   private seekedSubscription: Subscription;
dev@400:   private tasks: Map<TaskId, OnSeekHandler>;
dev@400:   private countingId: TaskId;
dev@397: 
dev@397:   constructor(private player: AudioPlayerService,
dev@397:               private zone: NgZone) {
dev@400:     this.countingId = 0;
dev@400:     this.tasks = new Map();
dev@397:     this.seekedSubscription = this.player.seeked$.subscribe(() => {
dev@397:       if (!this.player.isPlaying()) {
dev@397:         this.zone.runOutsideAngular(() => {
dev@397:           this.runTasks();
dev@397:         });
dev@397:       }
dev@397:     });
dev@397:     this.playingStateSubscription = this.player.playingStateChange$.subscribe(
dev@397:       isPlaying => {
dev@397:         if (isPlaying) {
dev@397:           this.animate();
dev@397:         }
dev@397:       });
dev@397:   }
dev@397: 
dev@400:   addPlayingTask(task: OnSeekHandler): TaskRemover {
dev@400:     const id = this.countingId++;
dev@400:     this.tasks.set(id, task);
dev@400:     return () => {
dev@400:       this.tasks.delete(id);
dev@400:     };
dev@397:   }
dev@397: 
dev@397:   private animate(): void {
dev@397:     this.zone.runOutsideAngular(() => {
dev@397:       const animateNextFrame = () => {
dev@397:         if (this.player.isPlaying()) {
dev@397:           this.runTasks();
dev@397:           requestAnimationFrame(animateNextFrame);
dev@397:         }
dev@397:       };
dev@397:       requestAnimationFrame(animateNextFrame);
dev@397:     });
dev@397:   }
dev@397: 
dev@397:   private runTasks(): void {
dev@397:     const currentTime = this.player.getCurrentTime();
dev@400:     for (const task of this.tasks.values()) {
dev@397:       task(currentTime);
dev@397:     }
dev@397:   }
dev@397: }