/**

 * 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>

 */

class VMLazy extends ByteCodeToJavaScript {

    private final Object loader;

    private VMLazy(Object loader, Appendable out) {

        super(out);

        this.loader = loader;

    }

    static void init() {

    }

    @JavaScriptBody(args={"res", "args" }, body = "return args[0](res.toString());")

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

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

    throws IOException, ClassNotFoundException {

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

        byte[] arr = read(res, arguments);

        if (arr == null) {

            throw new ClassNotFoundException(name);

        }

        String code = toJavaScript(loader, arr);

        return applyCode(loader, name, code);

    }

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

        "try {\n" +

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

        "} catch (ex) {\n" +

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

        "}\n" +

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

    )

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

    private static String toJavaScript(Object loader, byte[] is) throws IOException {

        StringBuilder sb = new StringBuilder();

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

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

        new VMLazy(loader, sb).compile(new ByteArrayInputStream(is));

        return sb.toString().toString();

    }

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

        body=

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

        + "var loader = self.fld_loader;"

        + "var vm = loader.vm;"

        + "if (vm[cls]) return false;"

        + "vm[cls] = function() {"

        + "  return loader.loadClass(n,cls);"

        + "};"

        + "return 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;

    }

}