audiobookshelf/server/objects/TrackProgressMonitor.js

89 lines
3.0 KiB
JavaScript

class TrackProgressMonitor {
/**
* @callback TrackStartedCallback
* @param {number} trackIndex - The index of the track that started.
*/
/**
* @callback ProgressCallback
* @param {number} trackIndex - The index of the current track.
* @param {number} progressInTrack - The current track progress 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(totalProgress) {
const progressInTrack = (this.currentTrackProgress / this.currentTrackPercentage) * 100
this.progressCallback(this.currentTrackIndex, progressInTrack, totalProgress)
}
#trackFinished() {
this.trackFinishedCallback(this.currentTrackIndex)
}
/**
* Updates the track progress based on the total progress.
* @param {number} totalProgress - The total progress in percent.
*/
update(totalProgress) {
while (this.#outsideCurrentTrack(totalProgress) && !this.allTracksFinished) this.#moveToNextTrack()
if (!this.allTracksFinished) this.#progressUpdated(totalProgress)
}
/**
* Finish the track progress monitoring.
* Forces all remaining tracks to finish.
*/
finish() {
this.update(101)
}
}
module.exports = TrackProgressMonitor