/**

  * 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.vm4brwsr;

 import java.io.ByteArrayInputStream;

 import java.io.IOException;

 import org.apidesign.bck2brwsr.core.JavaScriptBody;

 /**

  *

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

  */

 final class VMLazy {

     private final Object loader;

     private final Object[] args;

     private VMLazy(Object loader, Object[] args) {

         this.loader = loader;

         this.args = args;

     }

     static void init() {

     }

     @JavaScriptBody(args={"l", "res", "args" }, body = ""

         + "\ntry {"

         + "\n  return args[0](res.toString());"

         + "\n} catch (x) {"

         + "\n  throw Object.getOwnPropertyNames(l.vm).toString() + x.toString();"

         + "\n}")

     private static native byte[] read(Object l, String res, Object[] args);

     static Object load(Object loader, String name, Object[] arguments) 

     throws IOException, ClassNotFoundException {

         return new VMLazy(loader, arguments).load(name);

     }

     private Object load(String name)

     throws IOException, ClassNotFoundException {

         String res = name.replace('.', '/') + ".class";

         byte[] arr = read(loader, res, args);

         if (arr == null) {

             throw new ClassNotFoundException(name);

         }

 //        beingDefined(loader, name);

         StringBuilder out = new StringBuilder();

         out.append("var loader = arguments[0];\n");

         out.append("var vm = loader.vm;\n");

         new Gen(this, out).compile(new ByteArrayInputStream(arr));

         String code = out.toString().toString();

         String under = name.replace('.', '_');

         return applyCode(loader, under, code);

     }

 /* possibly not needed:

     @JavaScriptBody(args = {"loader", "n" }, body =

         "var cls = n.replace__Ljava_lang_String_2CC(n, '.','_').toString();" +

         "loader.vm[cls] = true;\n"

     )

     private static native void beingDefined(Object loader, String name);

 */

     @JavaScriptBody(args = {"loader", "name", "script" }, body =

         "try {\n" +

         "  new Function(script)(loader, name);\n" +

         "} catch (ex) {\n" +

         "  throw 'Cannot compile ' + ex + ' line: ' + ex.lineNumber + ' script:\\n' + script;\n" +

         "}\n" +

         "return vm[name](false);\n"

     )

     private static native Object applyCode(Object loader, String name, String script);

     private static final class Gen extends ByteCodeToJavaScript {

         private final VMLazy lazy;

         public Gen(VMLazy vm, Appendable out) {

             super(out);

             this.lazy = vm;

         }

         @JavaScriptBody(args = {"self", "n"},

         body =

         "var cls = n.replace__Ljava_lang_String_2CC(n, '/','_').toString();"

         + "\nvar dot = n.replace__Ljava_lang_String_2CC(n,'/','.').toString();"

         + "\nvar lazy = self.fld_lazy;"

         + "\nvar loader = lazy.fld_loader;"

         + "\nvar vm = loader.vm;"

         + "\nif (vm[cls]) return false;"

         + "\nvm[cls] = function() {"

         + "\n  return lazy.load__Ljava_lang_Object_2Ljava_lang_String_2(lazy, dot);"

         + "\n};"

         + "\nreturn true;")

         @Override

         protected boolean requireReference(String internalClassName) {

             throw new UnsupportedOperationException();

         }

         @Override

         protected void requireScript(String resourcePath) {

         }

         @Override

         String assignClass(String className) {

             return "vm[arguments[1]]=";

         }

         @Override

         String accessClass(String classOperation) {

             return "vm." + classOperation;

         }

     }

 }