/**
 * Lo-Dash 2.4.1 (Custom Build) <http://lodash.com/>
 * Build: `lodash modularize modern exports="node" -o ./modern/`
 * Copyright 2012-2013 The Dojo Foundation <http://dojofoundation.org/>
 * Based on Underscore.js 1.5.2 <http://underscorejs.org/LICENSE>
 * Copyright 2009-2013 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
 * Available under MIT license <http://lodash.com/license>
 */
var baseFlatten = require('../internals/baseFlatten'),
    createCallback = require('../functions/createCallback'),
    forIn = require('./forIn'),
    isObject = require('./isObject');

/**
 * Creates a shallow clone of `object` composed of the specified properties.
 * Property names may be specified as individual arguments or as arrays of
 * property names. If a callback is provided it will be executed for each
 * property of `object` picking the properties the callback returns truey
 * for. The callback is bound to `thisArg` and invoked with three arguments;
 * (value, key, object).
 *
 * @static
 * @memberOf _
 * @category Objects
 * @param {Object} object The source object.
 * @param {Function|...string|string[]} [callback] The function called per
 *  iteration or property names to pick, specified as individual property
 *  names or arrays of property names.
 * @param {*} [thisArg] The `this` binding of `callback`.
 * @returns {Object} Returns an object composed of the picked properties.
 * @example
 *
 * _.pick({ 'name': 'fred', '_userid': 'fred1' }, 'name');
 * // => { 'name': 'fred' }
 *
 * _.pick({ 'name': 'fred', '_userid': 'fred1' }, function(value, key) {
 *   return key.charAt(0) != '_';
 * });
 * // => { 'name': 'fred' }
 */
function pick(object, callback, thisArg) {
  var result = {};
  if (typeof callback != 'function') {
    var index = -1,
        props = baseFlatten(arguments, true, false, 1),
        length = isObject(object) ? props.length : 0;

    while (++index < length) {
      var key = props[index];
      if (key in object) {
        result[key] = object[key];
      }
    }
  } else {
    callback = createCallback(callback, thisArg, 3);
    forIn(object, function(value, key, object) {
      if (callback(value, key, object)) {
        result[key] = value;
      }
    });
  }
  return result;
}

module.exports = pick;
