/**
 * Copyright (c) 2015-present, Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under the BSD-style license found in the
 * LICENSE file in the root directory of this source tree. An additional grant
 * of patent rights can be found in the PATENTS file in the same directory.
 *
 * @providesModule TimerMixin
 * @flow
 */
'use strict';

var setImmediate = require('setImmediate');
var clearImmediate = require('clearImmediate');

/**
 * Using bare setTimeout, setInterval, setImmediate and
 * requestAnimationFrame calls is very dangerous because if you forget to cancel
 * the request before the component is unmounted, you risk the callback throwing
 * an exception.
 *
 * If you include TimerMixin, then you can replace your calls
 *   to `setTimeout(fn, 500)`
 * with `this.setTimeout(fn, 500)` (just prepend `this.`)
 * and everything will be properly cleaned up for you.
 *
 * Example:
 *
 *   var Component = React.createClass({
 *     mixins: [TimerMixin],
 *     componentDidMount: function() {
 *       this.setTimeout(
 *         () => { console.log('I do not leak!'); },
 *         500
 *       );
 *     }
 *   });
 */

 var setter = function(setter, clearer, array) {
   return function(
     callback: () => void,
     delta: number
   ): number {
     var id = setter(() => {
       clearer.call(this, id);
       callback.apply(this, arguments);
     }, delta);

     if (!this[array]) {
       this[array] = [id];
     } else {
       this[array].push(id);
     }
     return id;
   };
 };

 var clearer = function(clearer, array) {
   return function(id: number) {
     if (this[array]) {
       var index = this[array].indexOf(id);
       if (index !== -1) {
         this[array].splice(index, 1);
       }
     }
     clearer(id);
   };
 };

 var _timeouts = 'TimerMixin_timeouts';
 var _clearTimeout = clearer(clearTimeout, _timeouts);
 var _setTimeout = setter(setTimeout, _clearTimeout, _timeouts);

 var _intervals = 'TimerMixin_intervals';
 var _clearInterval = clearer(clearInterval, _intervals);
 var _setInterval = setter(setInterval, () => {/* noop */}, _intervals);

 var _immediates = 'TimerMixin_immediates';
 var _clearImmediate = clearer(clearImmediate, _immediates);
 var _setImmediate = setter(setImmediate, _clearImmediate, _immediates);

 var _rafs = 'TimerMixin_rafs';
 var _cancelAnimationFrame = clearer(window.cancelAnimationFrame, _rafs);
 var _requestAnimationFrame = setter(window.requestAnimationFrame, _cancelAnimationFrame, _rafs);

var TimerMixin = {
  componentWillUnmount: function() {
    this[_timeouts] && this[_timeouts].forEach(this.clearTimeout);
    this[_intervals] && this[_intervals].forEach(this.clearInterval);
    this[_immediates] && this[_immediates].forEach(this.clearImmediate);
    this[_rafs] && this[_rafs].forEach(this.cancelAnimationFrame);
  },

  setTimeout: _setTimeout,
  clearTimeout: _clearTimeout,

  setInterval: _setInterval,
  clearInterval: _clearInterval,

  setImmediate: _setImmediate,
  clearImmediate: _clearImmediate,

  requestAnimationFrame: _requestAnimationFrame,
  cancelAnimationFrame: _cancelAnimationFrame,
};

module.exports = TimerMixin;