/***
 * ASM: a very small and fast Java bytecode manipulation framework
 * Copyright (c) 2000-2011 INRIA, France Telecom
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the copyright holders nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 */
package org.apache.tapestry5.internal.plastic.asm.optimizer;

import java.util.ArrayList;
import java.util.List;

import org.apache.tapestry5.internal.plastic.asm.AnnotationVisitor;
import org.apache.tapestry5.internal.plastic.asm.Attribute;
import org.apache.tapestry5.internal.plastic.asm.ClassVisitor;
import org.apache.tapestry5.internal.plastic.asm.FieldVisitor;
import org.apache.tapestry5.internal.plastic.asm.Label;
import org.apache.tapestry5.internal.plastic.asm.MethodVisitor;
import org.apache.tapestry5.internal.plastic.asm.Opcodes;
import org.apache.tapestry5.internal.plastic.asm.TypePath;
import org.apache.tapestry5.internal.plastic.asm.commons.Remapper;
import org.apache.tapestry5.internal.plastic.asm.commons.RemappingClassAdapter;

/**
 * A {@link ClassVisitor} that renames fields and methods, and removes debug
 * info.
 * 
 * @author Eric Bruneton
 * @author Eugene Kuleshov
 */
public class ClassOptimizer extends RemappingClassAdapter {

    private String pkgName;
    String clsName;

    boolean isInterface = false;
    boolean hasClinitMethod = false;
    List<String> syntheticClassFields = new ArrayList<String>();

    public ClassOptimizer(final ClassVisitor cv, final Remapper remapper) {
        super(Opcodes.ASM5, cv, remapper);
    }

    FieldVisitor syntheticFieldVisitor(final int access, final String name,
            final String desc) {
        return super.visitField(access, name, desc, null, null);
    }

    // ------------------------------------------------------------------------
    // Overridden methods
    // ------------------------------------------------------------------------

    @Override
    public void visit(final int version, final int access, final String name,
            final String signature, final String superName,
            final String[] interfaces) {
        super.visit(Opcodes.V1_2, access, name, null, superName, interfaces);
        int index = name.lastIndexOf('/');
        if (index > 0) {
            pkgName = name.substring(0, index);
        } else {
            pkgName = "";
        }
        clsName = name;
        isInterface = (access & Opcodes.ACC_INTERFACE) != 0;
    }

    @Override
    public void visitSource(final String source, final String debug) {
        // remove debug info
    }

    @Override
    public void visitOuterClass(final String owner, final String name,
            final String desc) {
        // remove debug info
    }

    @Override
    public AnnotationVisitor visitAnnotation(final String desc,
            final boolean visible) {
        // remove annotations
        return null;
    }

    @Override
    public AnnotationVisitor visitTypeAnnotation(int typeRef,
            TypePath typePath, String desc, boolean visible) {
        // remove annotations
        return null;
    }

    @Override
    public void visitAttribute(final Attribute attr) {
        // remove non standard attributes
    }

    @Override
    public void visitInnerClass(final String name, final String outerName,
            final String innerName, final int access) {
        // remove debug info
    }

    @Override
    public FieldVisitor visitField(final int access, final String name,
            final String desc, final String signature, final Object value) {
        String s = remapper.mapFieldName(className, name, desc);
        if ("-".equals(s)) {
            return null;
        }
        if ((access & (Opcodes.ACC_PUBLIC | Opcodes.ACC_PROTECTED)) == 0) {
            if ((access & Opcodes.ACC_FINAL) != 0
                    && (access & Opcodes.ACC_STATIC) != 0 && desc.length() == 1) {
                return null;
            }
            if ("org/objectweb/asm".equals(pkgName) && s.equals(name)) {
                System.out.println("INFO: " + clsName + "." + s
                        + " could be renamed");
            }
            super.visitField(access, name, desc, null, value);
        } else {
            if (!s.equals(name)) {
                throw new RuntimeException("The public or protected field "
                        + className + '.' + name + " must not be renamed.");
            }
            super.visitField(access, name, desc, null, value);
        }
        return null; // remove debug info
    }

    @Override
    public MethodVisitor visitMethod(final int access, final String name,
            final String desc, final String signature, final String[] exceptions) {
        String s = remapper.mapMethodName(className, name, desc);
        if ("-".equals(s)) {
            return null;
        }
        if (name.equals("<clinit>") && !isInterface) {
            hasClinitMethod = true;
            MethodVisitor mv = super.visitMethod(access, name, desc, null,
                    exceptions);
            return new MethodVisitor(Opcodes.ASM5, mv) {
                @Override
                public void visitCode() {
                    super.visitCode();
                    mv.visitMethodInsn(Opcodes.INVOKESTATIC, clsName,
                            "_clinit_", "()V", false);
                }
            };
        }

        if ((access & (Opcodes.ACC_PUBLIC | Opcodes.ACC_PROTECTED)) == 0) {
            if ("org/objectweb/asm".equals(pkgName) && !name.startsWith("<")
                    && s.equals(name)) {
                System.out.println("INFO: " + clsName + "." + s
                        + " could be renamed");
            }
            return super.visitMethod(access, name, desc, null, exceptions);
        } else {
            if (!s.equals(name)) {
                throw new RuntimeException("The public or protected method "
                        + className + '.' + name + desc
                        + " must not be renamed.");
            }
            return super.visitMethod(access, name, desc, null, exceptions);
        }
    }

    @Override
    protected MethodVisitor createRemappingMethodAdapter(int access,
            String newDesc, MethodVisitor mv) {
        return new MethodOptimizer(this, access, newDesc, mv, remapper);
    }

    @Override
    public void visitEnd() {
        if (syntheticClassFields.isEmpty()) {
            if (hasClinitMethod) {
                MethodVisitor mv = cv.visitMethod(Opcodes.ACC_STATIC
                        | Opcodes.ACC_SYNTHETIC, "_clinit_", "()V", null, null);
                mv.visitCode();
                mv.visitInsn(Opcodes.RETURN);
                mv.visitMaxs(0, 0);
                mv.visitEnd();
            }
        } else {
            MethodVisitor mv = cv.visitMethod(Opcodes.ACC_STATIC
                    | Opcodes.ACC_SYNTHETIC, "class$",
                    "(Ljava/lang/String;)Ljava/lang/Class;", null, null);
            mv.visitCode();
            Label l0 = new Label();
            Label l1 = new Label();
            Label l2 = new Label();
            mv.visitTryCatchBlock(l0, l1, l2,
                    "java/lang/ClassNotFoundException");
            mv.visitLabel(l0);
            mv.visitVarInsn(Opcodes.ALOAD, 0);
            mv.visitMethodInsn(Opcodes.INVOKESTATIC, "java/lang/Class",
                    "forName", "(Ljava/lang/String;)Ljava/lang/Class;", false);
            mv.visitLabel(l1);
            mv.visitInsn(Opcodes.ARETURN);
            mv.visitLabel(l2);
            mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL,
                    "java/lang/ClassNotFoundException", "getMessage",
                    "()Ljava/lang/String;", false);
            mv.visitVarInsn(Opcodes.ASTORE, 1);
            mv.visitTypeInsn(Opcodes.NEW, "java/lang/NoClassDefFoundError");
            mv.visitInsn(Opcodes.DUP);
            mv.visitVarInsn(Opcodes.ALOAD, 1);
            mv.visitMethodInsn(Opcodes.INVOKESPECIAL,
                    "java/lang/NoClassDefFoundError", "<init>",
                    "(Ljava/lang/String;)V", false);
            mv.visitInsn(Opcodes.ATHROW);
            mv.visitMaxs(3, 2);
            mv.visitEnd();

            if (hasClinitMethod) {
                mv = cv.visitMethod(Opcodes.ACC_STATIC | Opcodes.ACC_PRIVATE,
                        "_clinit_", "()V", null, null);
            } else {
                mv = cv.visitMethod(Opcodes.ACC_STATIC, "<clinit>", "()V",
                        null, null);
            }
            for (String ldcName : syntheticClassFields) {
                String fieldName = "class$" + ldcName.replace('/', '$');
                mv.visitLdcInsn(ldcName.replace('/', '.'));
                mv.visitMethodInsn(Opcodes.INVOKESTATIC, clsName, "class$",
                        "(Ljava/lang/String;)Ljava/lang/Class;", false);
                mv.visitFieldInsn(Opcodes.PUTSTATIC, clsName, fieldName,
                        "Ljava/lang/Class;");
            }
            mv.visitInsn(Opcodes.RETURN);
            mv.visitMaxs(1, 0);
            mv.visitEnd();
        }
        super.visitEnd();
    }
}