var createCtor = require('./_createCtor'),
      root = require('./_root');
  
  /** Used to compose bitmasks for function metadata. */
  var WRAP_BIND_FLAG = 1;
  
  /**
   * Creates a function that wraps `func` to invoke it with the optional `this`
   * binding of `thisArg`.
   *
   * @private
   * @param {Function} func The function to wrap.
   * @param {number} bitmask The bitmask flags. See `createWrap` for more details.
   * @param {*} [thisArg] The `this` binding of `func`.
   * @returns {Function} Returns the new wrapped function.
   */
  function createBind(func, bitmask, thisArg) {
    var isBind = bitmask & WRAP_BIND_FLAG,
        Ctor = createCtor(func);
  
    function wrapper() {
      var fn = (this && this !== root && this instanceof wrapper) ? Ctor : func;
      return fn.apply(isBind ? thisArg : this, arguments);
    }
    return wrapper;
  }
  
  module.exports = createBind;