/**

 * 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.InputStream;

import java.lang.invoke.CallSite;

import java.lang.invoke.MethodHandles;

import java.lang.invoke.MethodType;

import java.lang.reflect.Method;

import org.objectweb.asm.ClassReader;

import org.objectweb.asm.ClassVisitor;

import org.objectweb.asm.ClassWriter;

import org.objectweb.asm.Handle;

import org.objectweb.asm.MethodVisitor;

import org.objectweb.asm.Opcodes;

import static org.objectweb.asm.Opcodes.ASM4;

import static org.objectweb.asm.Opcodes.INVOKESTATIC;

import static org.testng.Assert.*;

import org.testng.annotations.BeforeClass;

import org.testng.annotations.Test;

/**

 *

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

 */

public class InvokeDynamicTest {

    private static Class<?> invokeDynamicClass;

    @Test public void simpleDynamicInJava() throws Exception {

        Method m = invokeDynamicClass.getMethod("dynamicSay");

        Object ret = m.invoke(m);

        assertEquals(ret, "Hello from Dynamic!");

    }

/*    

    private static TestVM code;

    @BeforeClass

    public void compileTheCode() throws Exception {

        code = TestVM.compileClass(InvokeDynamic.class.getName());

    }

    @AfterClass

    public static void releaseTheCode() {

        code = null;

    }

    private void assertExec(

            String msg, Class clazz, String method, Object expRes, Object... args

    ) throws Exception {

        code.assertExec(msg, clazz, method, expRes, args);

    }

 */

    //

    // the following code is inspired by 

    // https://code.google.com/p/indy-maven-plugin/

    // which I don't want to use, as it is not in a public repository

    //

    @BeforeClass 

    public static void prepareClass() throws Exception {

        InputStream input = InvokeDynamic.class.getResourceAsStream("InvokeDynamic.class");

        assertNotNull(input, "Class found");

        ClassReader reader = new ClassReader(input);

        ClassWriter writer = new ClassWriter(reader, 0);

        reader.accept(

                new ClassVisitor(ASM4, writer) {

                    @Override

                    public MethodVisitor visitMethod(int access, String name, String desc, String signature, String[] exceptions

                    ) {

                        MethodVisitor mv = super.visitMethod(access, name, desc, signature, exceptions);

                        return new InvokeDynamicProcessor(mv);

                    }

                },

                0);

        input.close();

        final byte[] invokeDynamicBytes = writer.toByteArray();

        ClassLoader l = new ClassLoader() {

            @Override

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

                if (name.equals(InvokeDynamic.class.getName())) {

                    return defineClass(name, invokeDynamicBytes, 0, invokeDynamicBytes.length);

                }

                return super.loadClass(name);

            }

        };

        invokeDynamicClass = l.loadClass(InvokeDynamic.class.getName());

    }

    private static class InvokeDynamicProcessor extends MethodVisitor {

        InvokeDynamicProcessor(MethodVisitor mv) {

            super(ASM4, mv);

        }

        @Override

        public void visitMethodInsn(int opcode, String owner, String name, String desc) {

            if (opcode == INVOKESTATIC) {

                if (name.startsWith("TEST_dynamic_")) {

                    final String shortName = name.substring(13);

                    Handle mh = new Handle(

                        Opcodes.H_INVOKESTATIC, owner, shortName,

                        MethodType.methodType(

                            CallSite.class,

                            MethodHandles.Lookup.class,

                            String.class, 

                            MethodType.class

                        ).toMethodDescriptorString()

                    );

                    super.visitInvokeDynamicInsn(shortName, desc, mh);

                    return;

                }

            }

            super.visitMethodInsn(opcode, owner, name, desc);

        }

    }

}