var baseSlice = require('./_baseSlice'),
    toInteger = require('./toInteger');

/* Built-in method references for those with the same name as other `lodash` methods. */
var nativeCeil = Math.ceil,
    nativeMax = Math.max;

/**
 * Creates an array of elements split into groups the length of `size`.
 * If `array` can't be split evenly, the final chunk will be the remaining
 * elements.
 *
 * @static
 * @memberOf _
 * @category Array
 * @param {Array} array The array to process.
 * @param {number} [size=0] The length of each chunk.
 * @returns {Array} Returns the new array containing chunks.
 * @example
 *
 * _.chunk(['a', 'b', 'c', 'd'], 2);
 * // => [['a', 'b'], ['c', 'd']]
 *
 * _.chunk(['a', 'b', 'c', 'd'], 3);
 * // => [['a', 'b', 'c'], ['d']]
 */
function chunk(array, size) {
  size = nativeMax(toInteger(size), 0);

  var length = array ? array.length : 0;
  if (!length || size < 1) {
    return [];
  }
  var index = 0,
      resIndex = -1,
      result = Array(nativeCeil(length / size));

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

module.exports = chunk;