Fixes + add progress to m4b and embed tools

server/objects/TrackProgressMonitor.js

@@ -0,0 +1,88 @@
+class TrackProgressMonitor {
+  /**
+   * @callback TrackStartedCallback
+   * @param {number} trackIndex - The index of the track that started.
+   */
+
+  /**
+   * @callback ProgressCallback
+   * @param {number} trackIndex - The index of the track that is being updated.
+   * @param {number} progressInTrack - The progress of the track in percent.
+   * @param {number} totalProgress - The total progress in percent.
+   */
+
+  /**
+   * @callback TrackFinishedCallback
+   * @param {number} trackIndex - The index of the track that finished.
+   */
+
+  /**
+   * Creates a new TrackProgressMonitor.
+   * @constructor
+   * @param {number[]} trackDurations - The durations of the tracks in seconds.
+   * @param {TrackStartedCallback} trackStartedCallback - The callback to call when a track starts.
+   * @param {ProgressCallback} progressCallback - The callback to call when progress is updated.
+   * @param {TrackFinishedCallback} trackFinishedCallback - The callback to call when a track finishes.
+   */
+  constructor(trackDurations, trackStartedCallback, progressCallback, trackFinishedCallback) {
+    this.trackDurations = trackDurations
+    this.totalDuration = trackDurations.reduce((total, duration) => total + duration, 0)
+    this.trackStartedCallback = trackStartedCallback
+    this.progressCallback = progressCallback
+    this.trackFinishedCallback = trackFinishedCallback
+    this.currentTrackIndex = -1
+    this.cummulativeProgress = 0
+    this.currentTrackPercentage = 0
+    this.numTracks = this.trackDurations.length
+    this.allTracksFinished = false
+    this.#moveToNextTrack()
+  }
+
+  #outsideCurrentTrack(progress) {
+    this.currentTrackProgress = progress - this.cummulativeProgress
+    return this.currentTrackProgress >= this.currentTrackPercentage
+  }
+
+  #moveToNextTrack() {
+    if (this.currentTrackIndex >= 0) this.#trackFinished()
+    this.currentTrackIndex++
+    this.cummulativeProgress += this.currentTrackPercentage
+    if (this.currentTrackIndex >= this.numTracks) {
+      this.allTracksFinished = true
+      return
+    }
+    this.currentTrackPercentage = (this.trackDurations[this.currentTrackIndex] / this.totalDuration) * 100
+    this.#trackStarted()
+  }
+
+  #trackStarted() {
+    this.trackStartedCallback(this.currentTrackIndex)
+  }
+
+  #progressUpdated(progress) {
+    const progressInTrack = (this.currentTrackProgress / this.currentTrackPercentage) * 100
+    this.progressCallback(this.currentTrackIndex, progressInTrack, progress)
+  }
+
+  #trackFinished() {
+    this.trackFinishedCallback(this.currentTrackIndex)
+  }
+
+  /**
+   * Updates the progress of the track.
+   * @param {number} progress - The progress of the track in percent.
+   */
+  update(progress) {
+    while (this.#outsideCurrentTrack(progress) && !this.allTracksFinished) this.#moveToNextTrack()
+    if (!this.allTracksFinished) this.#progressUpdated(progress)
+  }
+
+  /**
+   * Finish the track progress monitoring.
+   * Forces all remaining tracks to finish.
+   */
+  finish() {
+    this.update(101)
+  }
+}
+module.exports = TrackProgressMonitor