More core audio work

src/app/services/audio.service.ts

@@ -1,30 +1,88 @@
-import {HttpClient} from '@angular/common/http';
+import {FileSystemFile, Track, TrackMeta, PlaylistItem} from '../models';
+import {Signal} from '@angular/core';
+import {IndexedArray} from '../lib';
 
 export class AudioService {
   protected context: AudioContext;
-  protected track?: MediaElementAudioSourceNode;
+  protected playlist: IndexedArray<PlaylistItem> = new IndexedArray();
+  public list: Signal<PlaylistItem[]> = this.playlist.playlist;
+  public current: Signal<PlaylistItem|null> = this.playlist.current;
+  public index: Signal<number> = this.playlist.index;
 
   constructor() {
     this.context = new AudioContext();
+
+    this.addItem(new Track(
+      new FileSystemFile('1.mp3', 'audio/1.mp3', 0),
+      new TrackMeta(),
+      0,
+      'mp3',
+      128
+    ));
+    this.addItem(new Track(
+      new FileSystemFile('2.mp3', 'audio/2.mp3', 0),
+      new TrackMeta(),
+      0,
+      'mp3',
+      128
+    ));
+    this.addItem(new Track(
+      new FileSystemFile('3.mp3', 'audio/3.mp3', 0),
+      new TrackMeta(),
+      0,
+      'mp3',
+      128
+    ));
   }
 
-  createElement(filename: string) {
-    const element = document.createElement('audio');
-    const source = document.createElement('source');
-    source.src = filename;
-    source.type = 'audio/mp3';
-    element.appendChild(source);
-    return element;
+  addItem(track: Track) {
+    this.playlist.add(new PlaylistItem(track, this.context));
+  }
+
+  removeItem(item: PlaylistItem) {
+    if (item.isPlaying() && item === this.current()) {
+      this.current()?.stop();
+      this.playlist.remove(item);
+      this.current()?.play();
+      return;
+    }
+
+    this.playlist.remove(item);
   }
 
   async play(): Promise<void> {
     if (this.context.state === 'suspended') {
       await this.context.resume();
     }
-    const element = this.createElement('audio/1.mp3');
-    this.track = this.context.createMediaElementSource(element);
-    this.track.connect(this.context.destination);
 
-    await element.play();
+    await this.current()?.play();
+  }
+
+  async stop(): Promise<void> {
+    await this.current()?.stop();
+  }
+
+  async next(): Promise<void> {
+    if (this.current()?.isPlaying()) {
+      await this.current()?.stop();
+      this.playlist.next();
+      await this.current()?.play();
+    } else {
+      this.playlist.next();
+    }
+  }
+
+  async prev(): Promise<void> {
+    if (this.current()?.isPlaying()) {
+      await this.current()?.stop();
+      this.playlist.prev();
+      await this.current()?.play();
+    } else {
+      this.playlist.prev();
+    }
+  }
+
+  async pause(): Promise<void> {
+    await this.current()?.pause();
   }
 }