diff src/app/services/audio-player.service.ts @ 31:f6ea31a3b1a3

Encapsulate audio playing and decoding logic in a ng2 service, provided by the root module.

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/app/services/audio-player.service.ts	Wed Nov 30 10:21:27 2016 +0000
@@ -0,0 +1,51 @@
+import {Injectable, Inject} from '@angular/core';
+
+@Injectable()
+export class AudioPlayerService {
+
+  constructor(@Inject(HTMLAudioElement) private audioElement: HTMLAudioElement /* TODO probably shouldn't play audio this way */,
+              @Inject('AudioContext') private audioContext: AudioContext) {
+  }
+
+  getCurrentTime(): number {
+    return this.audioElement.currentTime;
+  }
+
+  isPlaying(): boolean {
+    return !this.audioElement.paused;
+  }
+
+  decodeAudioData(buffer: ArrayBuffer): Promise<AudioBuffer> {
+    return new Promise((res, rej) => this.audioContext.decodeAudioData(buffer, res, rej));
+  }
+
+  loadAudioFromUrl(url: string): void {
+    this.audioElement.pause();
+    this.audioElement.src = url;
+  }
+
+  togglePlaying(): void {
+    this.isPlaying() ? this.audioElement.pause() : this.audioElement.play();
+  }
+
+  setVolume(value: number): void {
+    this.audioElement.volume = value; // TODO check bounds?
+  }
+
+  seekBy(seconds: number): void {
+    // TODO some kind of error handling?
+    this.audioElement.currentTime += seconds;
+  }
+
+  seekToStart(): void {
+    this.audioElement.currentTime = 0;
+  }
+
+  seekToEnd(): void {
+    this.audioElement.currentTime = this.getDuration();
+  }
+
+  getDuration(): number {
+    return this.audioElement.duration;
+  }
+}