/*
    * Copyright (c) 2002-2026 Gargoyle Software Inc.
    *
    * Licensed under the Apache License, Version 2.0 (the "License");
    * you may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    * https://www.apache.org/licenses/LICENSE-2.0
    *
    * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package org.htmlunit.javascript.host;
  
  import java.net.URL;
  
  import org.htmlunit.Page;
  import org.htmlunit.WebWindow;
  import org.htmlunit.corejs.javascript.Function;
  import org.htmlunit.javascript.AbstractJavaScriptEngine;
  import org.htmlunit.javascript.HtmlUnitContextFactory;
  import org.htmlunit.javascript.PostponedAction;
  import org.htmlunit.javascript.configuration.JsxClass;
  import org.htmlunit.javascript.configuration.JsxConstructor;
  import org.htmlunit.javascript.configuration.JsxFunction;
  import org.htmlunit.javascript.configuration.JsxGetter;
  import org.htmlunit.javascript.configuration.JsxSetter;
  import org.htmlunit.javascript.host.event.Event;
  import org.htmlunit.javascript.host.event.EventTarget;
  import org.htmlunit.javascript.host.event.MessageEvent;
  
  /**
   * JavaScript host object for {@code MessagePort}.
   *
   * @author Ahmed Ashour
   * @author Ronald Brill
   *
   * @see <a href="https://developer.mozilla.org/en-US/docs/Web/API/MessagePort">MDN Documentation</a>
   */
  @JsxClass
  public class MessagePort extends EventTarget {
  
      private MessagePort port_;
  
      /**
       * Default constructor.
       */
      public MessagePort() {
          super();
      }
  
      /**
       * Creates an instance of this object.
       */
      @Override
      @JsxConstructor
      public void jsConstructor() {
          super.jsConstructor();
      }
  
      /**
       * Creates an instance connected to the specified port.
       *
       * @param port the port to connect to
       */
      public MessagePort(final MessagePort port) {
          super();
          port_ = port;
      }
  
      /**
       * Returns the {@code onmessage} event handler.
       *
       * @return the {@code onmessage} event handler
       */
      @JsxGetter
      public Function getOnmessage() {
          return getHandlerForJavaScript(Event.TYPE_MESSAGE);
      }
  
      /**
       * Sets the {@code onmessage} event handler.
       *
       * @param onmessage the {@code onmessage} event handler
       */
      @JsxSetter
      public void setOnmessage(final Object onmessage) {
          setHandlerForJavaScript(Event.TYPE_MESSAGE, onmessage);
      }
  
      private Function getHandlerForJavaScript(final String eventName) {
          return getEventListenersContainer().getEventHandler(eventName);
      }
  
      private void setHandlerForJavaScript(final String eventName, final Object handler) {
          getEventListenersContainer().setEventHandler(eventName, handler);
      }
 
     /**
      * Posts a message to the connected port.
      *
      * @param message the object to post
      * @param transfer an optional sequence of transferable objects
      * @see <a href="https://developer.mozilla.org/en-US/docs/Web/API/MessagePort/postMessage">MDN Documentation</a>
      */
     @JsxFunction
     public void postMessage(final String message, final Object transfer) {
         if (port_ != null) {
             final Window w = getWindow();
             final WebWindow webWindow = w.getWebWindow();
             final Page page = webWindow.getEnclosedPage();
 
             final MessageEvent event = new MessageEvent();
             final URL currentURL = page.getUrl();
             final String origin = currentURL.getProtocol() + "://" + currentURL.getHost() + ':' + currentURL.getPort();
             event.initMessageEvent(Event.TYPE_MESSAGE, false, false, message, origin, "", w, transfer);
             event.setParentScope(getParentScope());
             event.setPrototype(getPrototype(event.getClass()));
 
             final AbstractJavaScriptEngine<?> jsEngine = webWindow.getWebClient().getJavaScriptEngine();
             final PostponedAction action = new PostponedAction(page, "MessagePort.postMessage") {
                 @Override
                 public void execute() {
                     final HtmlUnitContextFactory cf = jsEngine.getContextFactory();
                     cf.call(cx -> port_.dispatchEvent(event));
                 }
             };
             jsEngine.addPostponedAction(action);
         }
     }
 
     /**
      * Starts the sending of messages queued on the port.
      * Only needed when using {@code EventTarget.addEventListener}; it is implied when using {@code onmessage}.
      *
      * @see <a href="https://developer.mozilla.org/en-US/docs/Web/API/MessagePort/start">MDN Documentation</a>
      */
     @JsxFunction
     public void start() {
         // dummy for the moment
     }
 
     /**
      * Disconnects the port so it is no longer active.
      *
      * @see <a href="https://developer.mozilla.org/en-US/docs/Web/API/MessagePort/close">MDN Documentation</a>
      */
     @JsxFunction
     public void close() {
         // dummy for the moment
     }
 }