dev@37: import {Injectable, Inject} from '@angular/core';
dev@236: import {Subject} from 'rxjs/Subject';
dev@236: import {Observable} from 'rxjs/Observable';
dev@346: import {ReplaySubject} from 'rxjs/ReplaySubject';
dev@497: import {UrlResourceLifetimeManager} from '../File';
dev@191: 
dev@192: export type ResourceReader = (resource: File | Blob) => Promise<ArrayBuffer>;
dev@193: 
dev@193: export interface AudioResource {
dev@193:   samples: AudioBuffer;
dev@193:   url: string;
dev@193:   mimeType: string;
dev@193: }
dev@193: 
dev@193: export interface AudioResourceError {
dev@193:   message: string;
dev@193: }
dev@193: 
dev@193: export type AudioLoadResponse = AudioResource | AudioResourceError;
dev@193: 
dev@37: @Injectable()
dev@37: export class AudioPlayerService {
dev@37: 
dev@52:   private currentObjectUrl: string;
dev@52:   private playingStateChange: Subject<boolean>;
dev@52:   playingStateChange$: Observable<boolean>;
dev@52:   private seeked: Subject<number>;
dev@52:   seeked$: Observable<number>;
dev@193:   private audioLoaded: Subject<AudioLoadResponse>;
dev@193:   audioLoaded$: Observable<AudioLoadResponse>;
dev@52: 
dev@37:   constructor(@Inject(HTMLAudioElement) private audioElement: HTMLAudioElement /* TODO probably shouldn't play audio this way */,
dev@191:               @Inject('AudioContext') private audioContext: AudioContext,
dev@192:               @Inject('ResourceReader') private readResource: ResourceReader,
dev@191:               @Inject(
dev@191:                 'UrlResourceLifetimeManager'
dev@191:               ) private resourceManager: UrlResourceLifetimeManager) {
dev@52:     this.currentObjectUrl = '';
dev@346:     this.playingStateChange = new ReplaySubject<boolean>(1);
dev@346:     this.playingStateChange$ = this.playingStateChange
dev@346:       .asObservable();
dev@346: 
dev@52:     this.seeked = new Subject<number>();
dev@52:     this.seeked$ = this.seeked.asObservable();
dev@52:     this.audioElement.addEventListener('ended', () => {
dev@52:       this.playingStateChange.next(this.isPlaying());
dev@52:     });
dev@52:     this.audioElement.addEventListener('seeked', () => {
dev@52:       this.seeked.next(this.audioElement.currentTime);
dev@52:     });
dev@193:     this.audioLoaded = new Subject<AudioLoadResponse>();
dev@193:     this.audioLoaded$ = this.audioLoaded.asObservable();
dev@37:   }
dev@37: 
dev@37:   getCurrentTime(): number {
dev@37:     return this.audioElement.currentTime;
dev@37:   }
dev@37: 
dev@37:   isPlaying(): boolean {
dev@37:     return !this.audioElement.paused;
dev@37:   }
dev@37: 
dev@458:   loadAudioFromUri(uri: string): void {
dev@458:     this.currentObjectUrl = uri;
dev@458:     this.audioElement.pause();
dev@458:     this.audioElement.src = uri;
dev@458:     this.audioElement.load();
dev@458:   }
dev@37: 
dev@199:   loadAudio(resource: File | Blob): string {
dev@193:     const url: string = this.resourceManager.createUrlToResource(resource);
dev@458:     this.loadAudioFromUri(url);
dev@193: 
dev@193:     const decode: (buffer: ArrayBuffer) => Promise<AudioBuffer> = buffer => {
dev@207:       try {
dev@207:         return this.audioContext.decodeAudioData(buffer) as Promise<AudioBuffer>;
dev@207:       } catch (e) {
dev@207:         console.warn('Falling back to callback style decodeAudioData');
dev@207:         return new Promise(
dev@207:           (res, rej) => this.audioContext.decodeAudioData(buffer, res, rej)
dev@207:         );
dev@207:       }
dev@193:     };
dev@193: 
dev@193:     this.readResource(resource)
dev@193:       .then(decode)
dev@193:       .then(val => {
dev@193:         this.audioLoaded.next({
dev@193:           samples: val,
dev@193:           url: url,
dev@193:           mimeType: resource.type
dev@193:         });
dev@193:       })
dev@193:       .catch(err => {
dev@236:         const message = err && err.message ? err.message : 'Read error';
dev@193:         this.audioLoaded.next({
dev@207:           message: message
dev@193:         });
dev@193:       });
dev@199:     return url;
dev@37:   }
dev@37: 
dev@457:   unload(): void {
dev@458:     this.loadAudioFromUri('');
dev@457:   }
dev@457: 
dev@37:   togglePlaying(): void {
dev@57:     if (this.audioElement.readyState >= 2) {
dev@57:       this.isPlaying() ? this.audioElement.pause() : this.audioElement.play();
dev@57:       this.playingStateChange.next(this.isPlaying());
dev@57:     }
dev@37:   }
dev@37: 
dev@37:   setVolume(value: number): void {
dev@37:     this.audioElement.volume = value; // TODO check bounds?
dev@37:   }
dev@37: 
dev@82:   seekTo(seconds: number): void {
dev@82:     if (seconds < 0) {
dev@82:       this.audioElement.currentTime = 0;
dev@82:     } else if (seconds < this.getDuration()) {
dev@82:       this.audioElement.currentTime = seconds;
dev@82:     } else {
dev@82:       this.audioElement.currentTime = this.getDuration();
dev@82:     }
dev@82:   }
dev@82: 
dev@37:   seekBy(seconds: number): void {
dev@37:     // TODO some kind of error handling?
dev@37:     this.audioElement.currentTime += seconds;
dev@37:   }
dev@37: 
dev@37:   seekToStart(): void {
dev@37:     this.audioElement.currentTime = 0;
dev@37:   }
dev@37: 
dev@37:   seekToEnd(): void {
dev@37:     this.audioElement.currentTime = this.getDuration();
dev@37:   }
dev@37: 
dev@37:   getDuration(): number {
dev@153:     return this.audioElement.duration || 0;
dev@37:   }
dev@37: }