/**

  * Back 2 Browser Bytecode Translator

  * Copyright (C) 2012 Jaroslav Tulach <jaroslav.tulach@apidesign.org>

  *

  * This program is free software: you can redistribute it and/or modify

  * it under the terms of the GNU General Public License as published by

  * the Free Software Foundation, version 2 of the License.

  *

  * This program is distributed in the hope that it will be useful,

  * but WITHOUT ANY WARRANTY; without even the implied warranty of

  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

  * GNU General Public License for more details.

  *

  * You should have received a copy of the GNU General Public License

  * along with this program. Look for COPYING file in the top folder.

  * If not, see http://opensource.org/licenses/GPL-2.0.

  */

 package org.apidesign.bck2brwsr.launcher.fximpl;

 import java.net.URL;

 import java.util.ArrayList;

 import java.util.Collections;

 import java.util.Enumeration;

 import java.util.List;

 import java.util.TooManyListenersException;

 import javafx.beans.value.ChangeListener;

 import javafx.scene.web.WebEngine;

 import netscape.javascript.JSObject;

 /**

  *

  * @author Jaroslav Tulach <jtulach@netbeans.org>

  */

 public final class JVMBridge {

     private final WebEngine engine;

     private final WebClassLoader cl;

     private static ClassLoader[] ldrs;

     private static ChangeListener<Void> onBck2BrwsrLoad;

     JVMBridge(WebEngine eng) {

         this.engine = eng;

         this.cl = new WebClassLoader(JVMBridge.class.getClassLoader().getParent());

     }

     public static void registerClassLoaders(ClassLoader[] loaders) {

         ldrs = loaders.clone();

     }

     public static void addBck2BrwsrLoad(ChangeListener<Void> l) throws TooManyListenersException {

         if (onBck2BrwsrLoad != null) {

             throw new TooManyListenersException();

         }

         onBck2BrwsrLoad = l;

     }

     public static void onBck2BrwsrLoad() {

         ChangeListener<Void> l = onBck2BrwsrLoad;

         if (l != null) {

             l.changed(null, null, null);

         }

     }

     public Class<?> loadClass(String name) throws ClassNotFoundException {

         return Class.forName(name, true, cl);

     }

     private final class WebClassLoader extends JsClassLoader {

         public WebClassLoader(ClassLoader parent) {

             super(parent);

         }

         @Override

         protected URL findResource(String name) {

             if (ldrs != null) for (ClassLoader l : ldrs) {

                 URL u = l.getResource(name);

                 if (u != null) {

                     return u;

                 }

             }

             return null;

         }

         @Override

         protected Enumeration<URL> findResources(String name) {

             List<URL> arr = new ArrayList<URL>();

             if (ldrs != null) {

                 for (ClassLoader l : ldrs) {

                     URL u = l.getResource(name);

                     if (u != null) {

                         arr.add(u);

                     }

                 }

             }

             return Collections.enumeration(arr);

         }

         @Override

         protected Fn defineFn(String code, String... names) {

             StringBuilder sb = new StringBuilder();

             sb.append("(function() {");

             sb.append("  var x = {};");

             sb.append("  x.fn = function(");

             String sep = "";

             for (String n : names) {

                 sb.append(sep).append(n);

                 sep = ",";

             }

             sb.append(") {\n");

             sb.append(code);

             sb.append("};");

             sb.append("return x;");

             sb.append("})()");

             JSObject x = (JSObject) engine.executeScript(sb.toString());

             return new JSFn(x);

         }

     }

     private static final class JSFn extends Fn {

         private final JSObject fn;

         public JSFn(JSObject fn) {

             this.fn = fn;

         }

         @Override

         public Object invoke(Object thiz, Object... args) throws Exception {

             try {

                 return fn.call("fn", args); // NOI18N

             } catch (Error t) {

                 t.printStackTrace();

                 throw t;

             } catch (Exception t) {

                 t.printStackTrace();

                 throw t;

             }

         }

     }

 }