Scheduler.js

export default class Scheduler {
  constructor(ctx, period = 0.025, lookahead = 0.1) {
    this.queue = [];

    this.ctx = ctx;
    this.period = period;
    this.lookahead = lookahead;

    this.tick = this.tick.bind(this);
    // @todo - launch only if there is somthing to do
    this.tick();
  }

  tick() {
    if (!this.queue.length)
      return setTimeout(this.tick, this.period);

    const currentTime = this.ctx.currentTime;
    // time of the next event
    let nextTime = this.queue[0].time;

    while (nextTime < currentTime + this.lookahead) {
      const queued = this.queue[0];
      queued.time = queued.engine.advanceTime(nextTime);
      // reorder scheduler
      this.queue.sort((a, b) => a.time - b.time);
      // find next engine to be played
      nextTime = this.queue[0].time;
    }

    setTimeout(this.tick, this.period * 1000);
  }

  add(engine, time) {
    this.queue.push({ time, engine });
    this.queue.sort((a, b) => a.time - b.time);
  }

  reset(engine, time) {
    let queued = null;

    for (let i = 0; i < this.queue.length; i++) {
      queued = this.queue[i];

      if (queued.engine === engine)
        break;
    }

    if (queued) {
      queued.time = time;
      this.queue.sort((a, b) => a.time - b.time);
    }
  }
}