/**
 * lodash 4.1.0 (Custom Build) <https://lodash.com/>
 * Build: `lodash modularize exports="npm" -o ./`
 * Copyright 2012-2016 The Dojo Foundation <http://dojofoundation.org/>
 * Based on Underscore.js 1.8.3 <http://underscorejs.org/LICENSE>
 * Copyright 2009-2016 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
 * Available under MIT license <https://lodash.com/license>
 */
var unzip = require('lodash.unzip');

/**
 * A faster alternative to `Function#apply`, this function invokes `func`
 * with the `this` binding of `thisArg` and the arguments of `args`.
 *
 * @private
 * @param {Function} func The function to invoke.
 * @param {*} thisArg The `this` binding of `func`.
 * @param {Array} args The arguments to invoke `func` with.
 * @returns {*} Returns the result of `func`.
 */
function apply(func, thisArg, args) {
  var length = args.length;
  switch (length) {
    case 0: return func.call(thisArg);
    case 1: return func.call(thisArg, args[0]);
    case 2: return func.call(thisArg, args[0], args[1]);
    case 3: return func.call(thisArg, args[0], args[1], args[2]);
  }
  return func.apply(thisArg, args);
}

/**
 * A specialized version of `_.map` for arrays without support for iteratee
 * shorthands.
 *
 * @private
 * @param {Array} array The array to iterate over.
 * @param {Function} iteratee The function invoked per iteration.
 * @returns {Array} Returns the new mapped array.
 */
function arrayMap(array, iteratee) {
  var index = -1,
      length = array.length,
      result = Array(length);

  while (++index < length) {
    result[index] = iteratee(array[index], index, array);
  }
  return result;
}

/**
 * This method is like `_.unzip` except that it accepts `iteratee` to specify
 * how regrouped values should be combined. The iteratee is invoked with the
 * elements of each group: (...group).
 *
 * @static
 * @memberOf _
 * @since 3.8.0
 * @category Array
 * @param {Array} array The array of grouped elements to process.
 * @param {Function} [iteratee=_.identity] The function to combine
 *  regrouped values.
 * @returns {Array} Returns the new array of regrouped elements.
 * @example
 *
 * var zipped = _.zip([1, 2], [10, 20], [100, 200]);
 * // => [[1, 10, 100], [2, 20, 200]]
 *
 * _.unzipWith(zipped, _.add);
 * // => [3, 30, 300]
 */
function unzipWith(array, iteratee) {
  if (!(array && array.length)) {
    return [];
  }
  var result = unzip(array);
  if (iteratee == null) {
    return result;
  }
  return arrayMap(result, function(group) {
    return apply(iteratee, undefined, group);
  });
}

module.exports = unzipWith;