export const worker = `(function metronomeWorkerSetup() {
  function ticker() {
    self.postMessage('tick');
  }
  self.onmessage = function (event) {
    const [data, time] = event.data;
    switch (data) {
      case 'start':
        setTimeout(ticker, time);
        break;
      default:
        break;
    }
  };
})()`;

/**
 * Delay for a @see ms amount of time
 * @param ms -- time in milliseconds
 */
export function sleep(ms: number): Promise<void> {
  if (ms < 0) {
    throw Error('`ms` should be a positive integer');
  }

  return new Promise(resolve => {
    setTimeout(resolve, ms);
  });
}

export function workerSleep(ms: number): Promise<void> {
  if (ms < 0) {
    throw Error('`ms` should be a positive integer');
  }
  if (typeof Worker === 'undefined') {
    return sleep(ms);
  }
  const WorkerThread = new Worker(URL.createObjectURL(new Blob([worker], { type: 'application/javascript' })));
  WorkerThread.postMessage(['start', ms]);
  return new Promise(resolve => {
    WorkerThread.onmessage = event => {
      if (event.data === 'tick') {
        resolve();
        WorkerThread.terminate();
      }
    };
  });
}

/**
 * Debounce Fn - Function to limit the number of executions of the passed in
 * function in a given time duration
 * @param fn Function to be called
 * @param delay time by which the function execution has to be delayed
 * @returns {void}
 */
export function debounce<T extends (...args: any) => any>(fn: T, delay = 300) {
  let timer: any | undefined;
  return function (...args: []) {
    clearTimeout(timer);
    timer = undefined;
    //@ts-ignore
    //eslint-disable-next-line
    const context = this;
    timer = setTimeout(() => {
      fn.apply(context, args);
    }, delay);
  };
}