var debounce = require('./debounce'),
      isObject = require('./isObject');
  
  /** Error message constants. */
  var FUNC_ERROR_TEXT = 'Expected a function';
  
  /**
   * Creates a throttled function that only invokes `func` at most once per
   * every `wait` milliseconds. The throttled function comes with a `cancel`
   * method to cancel delayed `func` invocations and a `flush` method to
   * immediately invoke them. Provide `options` to indicate whether `func`
   * should be invoked on the leading and/or trailing edge of the `wait`
   * timeout. The `func` is invoked with the last arguments provided to the
   * throttled function. Subsequent calls to the throttled function return the
   * result of the last `func` invocation.
   *
   * **Note:** If `leading` and `trailing` options are `true`, `func` is
   * invoked on the trailing edge of the timeout only if the throttled function
   * is invoked more than once during the `wait` timeout.
   *
   * If `wait` is `0` and `leading` is `false`, `func` invocation is deferred
   * until to the next tick, similar to `setTimeout` with a timeout of `0`.
   *
   * See [David Corbacho's article](https://css-tricks.com/debouncing-throttling-explained-examples/)
   * for details over the differences between `_.throttle` and `_.debounce`.
   *
   * @static
   * @memberOf _
   * @since 0.1.0
   * @category Function
   * @param {Function} func The function to throttle.
   * @param {number} [wait=0] The number of milliseconds to throttle invocations to.
   * @param {Object} [options={}] The options object.
   * @param {boolean} [options.leading=true]
   *  Specify invoking on the leading edge of the timeout.
   * @param {boolean} [options.trailing=true]
   *  Specify invoking on the trailing edge of the timeout.
   * @returns {Function} Returns the new throttled function.
   * @example
   *
   * // Avoid excessively updating the position while scrolling.
   * jQuery(window).on('scroll', _.throttle(updatePosition, 100));
   *
   * // Invoke `renewToken` when the click event is fired, but not more than once every 5 minutes.
   * var throttled = _.throttle(renewToken, 300000, { 'trailing': false });
   * jQuery(element).on('click', throttled);
   *
   * // Cancel the trailing throttled invocation.
   * jQuery(window).on('popstate', throttled.cancel);
   */
  function throttle(func, wait, options) {
    var leading = true,
        trailing = true;
  
    if (typeof func != 'function') {
      throw new TypeError(FUNC_ERROR_TEXT);
    }
    if (isObject(options)) {
      leading = 'leading' in options ? !!options.leading : leading;
      trailing = 'trailing' in options ? !!options.trailing : trailing;
    }
    return debounce(func, wait, {
      'leading': leading,
      'maxWait': wait,
      'trailing': trailing
    });
  }
  
  module.exports = throttle;