/**
 * Delay.js
 *
 * Released under LGPL License.
 * Copyright (c) 1999-2017 Ephox Corp. All rights reserved
 *
 * License: http://www.tinymce.com/license
 * Contributing: http://www.tinymce.com/contributing
 */

import Promise from './Promise';

/**
 * Utility class for working with delayed actions like setTimeout.
 *
 * @class tinymce.util.Delay
 */

let requestAnimationFramePromise;

const requestAnimationFrame = function (callback, element?) {
  let i, requestAnimationFrameFunc: any = window.requestAnimationFrame;
  const vendors = ['ms', 'moz', 'webkit'];

  const featurefill = function (callback) {
    window.setTimeout(callback, 0);
  };

  for (i = 0; i < vendors.length && !requestAnimationFrameFunc; i++) {
    requestAnimationFrameFunc = window[vendors[i] + 'RequestAnimationFrame'];
  }

  if (!requestAnimationFrameFunc) {
    requestAnimationFrameFunc = featurefill;
  }

  requestAnimationFrameFunc(callback, element);
};

const wrappedSetTimeout = function (callback, time?) {
  if (typeof time !== 'number') {
    time = 0;
  }

  return setTimeout(callback, time);
};

const wrappedSetInterval = function (callback, time?) {
  if (typeof time !== 'number') {
    time = 1; // IE 8 needs it to be > 0
  }

  return setInterval(callback, time);
};

const wrappedClearTimeout = function (id) {
  return clearTimeout(id);
};

const wrappedClearInterval = function (id) {
  return clearInterval(id);
};

const debounce = function (callback, time?) {
  let timer, func;

  func = function () {
    const args = arguments;

    clearTimeout(timer);

    timer = wrappedSetTimeout(function () {
      callback.apply(this, args);
    }, time);
  };

  func.stop = function () {
    clearTimeout(timer);
  };

  return func;
};

export default {
  /**
   * Requests an animation frame and fallbacks to a timeout on older browsers.
   *
   * @method requestAnimationFrame
   * @param {function} callback Callback to execute when a new frame is available.
   * @param {DOMElement} element Optional element to scope it to.
   */
  requestAnimationFrame (callback, element?) {
    if (requestAnimationFramePromise) {
      requestAnimationFramePromise.then(callback);
      return;
    }

    requestAnimationFramePromise = new Promise(function (resolve) {
      if (!element) {
        element = document.body;
      }

      requestAnimationFrame(resolve, element);
    }).then(callback);
  },

  /**
   * Sets a timer in ms and executes the specified callback when the timer runs out.
   *
   * @method setTimeout
   * @param {function} callback Callback to execute when timer runs out.
   * @param {Number} time Optional time to wait before the callback is executed, defaults to 0.
   * @return {Number} Timeout id number.
   */
  setTimeout: wrappedSetTimeout,

  /**
   * Sets an interval timer in ms and executes the specified callback at every interval of that time.
   *
   * @method setInterval
   * @param {function} callback Callback to execute when interval time runs out.
   * @param {Number} time Optional time to wait before the callback is executed, defaults to 0.
   * @return {Number} Timeout id number.
   */
  setInterval: wrappedSetInterval,

  /**
   * Sets an editor timeout it's similar to setTimeout except that it checks if the editor instance is
   * still alive when the callback gets executed.
   *
   * @method setEditorTimeout
   * @param {tinymce.Editor} editor Editor instance to check the removed state on.
   * @param {function} callback Callback to execute when timer runs out.
   * @param {Number} time Optional time to wait before the callback is executed, defaults to 0.
   * @return {Number} Timeout id number.
   */
  setEditorTimeout (editor, callback, time?) {
    return wrappedSetTimeout(function () {
      if (!editor.removed) {
        callback();
      }
    }, time);
  },

  /**
   * Sets an interval timer it's similar to setInterval except that it checks if the editor instance is
   * still alive when the callback gets executed.
   *
   * @method setEditorInterval
   * @param {function} callback Callback to execute when interval time runs out.
   * @param {Number} time Optional time to wait before the callback is executed, defaults to 0.
   * @return {Number} Timeout id number.
   */
  setEditorInterval (editor, callback, time?) {
    let timer;

    timer = wrappedSetInterval(function () {
      if (!editor.removed) {
        callback();
      } else {
        clearInterval(timer);
      }
    }, time);

    return timer;
  },

  /**
   * Creates debounced callback function that only gets executed once within the specified time.
   *
   * @method debounce
   * @param {function} callback Callback to execute when timer finishes.
   * @param {Number} time Optional time to wait before the callback is executed, defaults to 0.
   * @return {Function} debounced function callback.
   */
  debounce,

  // Throttle needs to be debounce due to backwards compatibility.
  throttle: debounce,

  /**
   * Clears an interval timer so it won't execute.
   *
   * @method clearInterval
   * @param {Number} Interval timer id number.
   */
  clearInterval: wrappedClearInterval,

  /**
   * Clears an timeout timer so it won't execute.
   *
   * @method clearTimeout
   * @param {Number} Timeout timer id number.
   */
  clearTimeout: wrappedClearTimeout
};