var arrayFilter = require('../internal/arrayFilter'),
    baseCallback = require('../internal/baseCallback'),
    baseFilter = require('../internal/baseFilter'),
    isArray = require('../lang/isArray');

/**
 * Iterates over elements of `collection`, returning an array of all elements
 * `predicate` returns truthy for. The predicate is bound to `thisArg` and
 * invoked with three arguments; (value, index|key, collection).
 *
 * If a property name is provided for `predicate` the created "_.property"
 * style callback returns the property value of the given element.
 *
 * If an object is provided for `predicate` the created "_.matches" style
 * callback returns `true` for elements that have the properties of the given
 * object, else `false`.
 *
 * @static
 * @memberOf _
 * @alias select
 * @category Collection
 * @param {Array|Object|string} collection The collection to iterate over.
 * @param {Function|Object|string} [predicate=_.identity] The function invoked
 *  per iteration. If a property name or object is provided it is used to
 *  create a "_.property" or "_.matches" style callback respectively.
 * @param {*} [thisArg] The `this` binding of `predicate`.
 * @returns {Array} Returns the new filtered array.
 * @example
 *
 * var evens = _.filter([1, 2, 3, 4], function(n) { return n % 2 == 0; });
 * // => [2, 4]
 *
 * var users = [
 *   { 'user': 'barney', 'age': 36, 'active': false },
 *   { 'user': 'fred',   'age': 40, 'active': true }
 * ];
 *
 * // using the "_.property" callback shorthand
 * _.pluck(_.filter(users, 'active'), 'user');
 * // => ['fred']
 *
 * // using the "_.matches" callback shorthand
 * _.pluck(_.filter(users, { 'age': 36 }), 'user');
 * // => ['barney']
 */
function filter(collection, predicate, thisArg) {
  var func = isArray(collection) ? arrayFilter : baseFilter;
  predicate = baseCallback(predicate, thisArg, 3);
  return func(collection, predicate);
}

module.exports = filter;
