var createWrapper = require('./_createWrapper'),
    getPlaceholder = require('./_getPlaceholder'),
    replaceHolders = require('./_replaceHolders'),
    rest = require('./rest');

/** Used to compose bitmasks for wrapper metadata. */
var PARTIAL_RIGHT_FLAG = 64;

/**
 * This method is like `_.partial` except that partially applied arguments
 * are appended to those provided to the new function.
 *
 * The `_.partialRight.placeholder` value, which defaults to `_` in monolithic
 * builds, may be used as a placeholder for partially applied arguments.
 *
 * **Note:** This method doesn't set the "length" property of partially
 * applied functions.
 *
 * @static
 * @memberOf _
 * @category Function
 * @param {Function} func The function to partially apply arguments to.
 * @param {...*} [partials] The arguments to be partially applied.
 * @returns {Function} Returns the new partially applied function.
 * @example
 *
 * var greet = function(greeting, name) {
 *   return greeting + ' ' + name;
 * };
 *
 * var greetFred = _.partialRight(greet, 'fred');
 * greetFred('hi');
 * // => 'hi fred'
 *
 * // Partially applied with placeholders.
 * var sayHelloTo = _.partialRight(greet, 'hello', _);
 * sayHelloTo('fred');
 * // => 'hello fred'
 */
var partialRight = rest(function(func, partials) {
  var holders = replaceHolders(partials, getPlaceholder(partialRight));
  return createWrapper(func, PARTIAL_RIGHT_FLAG, undefined, partials, holders);
});

// Assign default placeholders.
partialRight.placeholder = {};

module.exports = partialRight;