var baseFlatten = require('../internal/baseFlatten'),
    createWrapper = require('../internal/createWrapper'),
    functions = require('../object/functions'),
    restParam = require('./restParam');

/** Used to compose bitmasks for wrapper metadata. */
var BIND_FLAG = 1;

/**
 * Binds methods of an object to the object itself, overwriting the existing
 * method. Method names may be specified as individual arguments or as arrays
 * of method names. If no method names are provided all enumerable function
 * properties, own and inherited, of `object` are bound.
 *
 * **Note:** This method does not set the "length" property of bound functions.
 *
 * @static
 * @memberOf _
 * @category Function
 * @param {Object} object The object to bind and assign the bound methods to.
 * @param {...(string|string[])} [methodNames] The object method names to bind,
 *  specified as individual method names or arrays of method names.
 * @returns {Object} Returns `object`.
 * @example
 *
 * var view = {
 *   'label': 'docs',
 *   'onClick': function() {
 *     console.log('clicked ' + this.label);
 *   }
 * };
 *
 * _.bindAll(view);
 * jQuery('#docs').on('click', view.onClick);
 * // => logs 'clicked docs' when the element is clicked
 */
var bindAll = restParam(function(object, methodNames) {
  methodNames = methodNames.length ? baseFlatten(methodNames) : functions(object);

  var index = -1,
      length = methodNames.length;

  while (++index < length) {
    var key = methodNames[index];
    object[key] = createWrapper(object[key], BIND_FLAG, object);
  }
  return object;
});

module.exports = bindAll;