"use strict";
  
  const idlUtils = require("../generated/utils");
  const UIEventInit = require("../generated/UIEventInit");
  const EventImpl = require("./Event-impl").implementation;
  
  // Until webidl2js gains support for checking for Window, this would have to do.
  function isWindow(val) {
    if (typeof val !== "object") {
      return false;
    }
    const wrapper = idlUtils.wrapperForImpl(val);
    if (typeof wrapper === "object") {
      return wrapper === wrapper._globalProxy;
    }
  
    // `val` may be either impl or wrapper currently, because webidl2js currently unwraps Window objects (and their global
    // proxies) to their underlying EventTargetImpl during conversion, which is not what we want. But at the same time,
    // some internal usage call this constructor with the actual global proxy.
    return isWindow(idlUtils.implForWrapper(val));
  }
  
  class UIEventImpl extends EventImpl {
    constructor(globalObject, args, privateData) {
      const eventInitDict = args[1];
  
      // undefined check included so that we can omit the property in internal usage.
      if (eventInitDict && eventInitDict.view !== null && eventInitDict.view !== undefined) {
        if (!isWindow(eventInitDict.view)) {
          throw new TypeError(`Failed to construct '${new.target.name.replace(/Impl$/, "")}': member view is not of ` +
                              "type Window.");
        }
      }
  
      super(globalObject, args, privateData);
    }
  
    initUIEvent(type, bubbles, cancelable, view, detail) {
      if (view !== null) {
        if (!isWindow(view)) {
          throw new TypeError(`Failed to execute 'initUIEvent' on '${this.constructor.name.replace(/Impl$/, "")}': ` +
                              "parameter 4 is not of type 'Window'.");
        }
      }
  
      if (this._dispatchFlag) {
        return;
      }
  
      this.initEvent(type, bubbles, cancelable);
      this.view = view;
      this.detail = detail;
    }
  }
  UIEventImpl.defaultInit = UIEventInit.convert(undefined);
  
  module.exports = {
    implementation: UIEventImpl
  };