audiojs/audio

/**
 * Extend audio with playback functionality
 *
 * @module  audio/src/playback
 */

'use strict'

const isPromise = require('is-promise')
const play = require('audio-play')
const nidx = require('negative-index')
let Audio = require('../')
let { parseArgs } = require('./util')


//preview the sound
Audio.prototype.play = function (time, duration, opts, onend) {
    opts = parseArgs(this, time, duration, opts)

    if (!this.playback) {
        let buf = this.buffer.copy(opts.start, opts.end)
        this.playback = play(buf, {}, () => {
            this.stop();
            onend && onend();
        });
    }
    else this.playback.play();

    return this;
}

//pause playback
Audio.prototype.pause = function () {
    if (this.playback) {
        this.playback.pause();
        this.emit('pause');
    }

    return this;
}

//reset playback
Audio.prototype.stop = function () {
    if (this.playback) this.playback.pause();
    this.playback = null;

    return this;
}


//regulate volume of playback/output/read etc
Audio.prototype.volume = function volume (start, end) {
    if (arguments.length < 2) {
        duration = start;
        start = 0;
    }
    if (duration == null) duration = .5;

    start = Math.floor(nidx(start, this.buffer.length))
    start = nidx(start, duration);

    return this;
};


module.exports = Audio;