/***
 * ASM: a very small and fast Java bytecode manipulation framework
 * Copyright (c) 2000-2005 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.mvel2.asm.util;

import org.mvel2.asm.*;
import org.mvel2.asm.signature.SignatureReader;

import java.util.HashMap;

/**
 * A {@link MethodVisitor} that prints a disassembled view of the methods it
 * visits.
 *
 * @author Eric Bruneton
 */
public class TraceMethodVisitor extends TraceAbstractVisitor implements
    MethodVisitor {

  /**
   * The {@link MethodVisitor} to which this visitor delegates calls. May be
   * <tt>null</tt>.
   */
  protected MethodVisitor mv;

  /**
   * Tab for bytecode instructions.
   */
  protected String tab2 = "    ";

  /**
   * Tab for table and lookup switch instructions.
   */
  protected String tab3 = "      ";

  /**
   * Tab for labels.
   */
  protected String ltab = "   ";

  /**
   * The label names. This map associate String values to Label keys.
   */
  protected final HashMap labelNames;

  /**
   * Constructs a new {@link TraceMethodVisitor}.
   */
  public TraceMethodVisitor() {
    this(null);
  }

  /**
   * Constructs a new {@link TraceMethodVisitor}.
   *
   * @param mv the {@link MethodVisitor} to which this visitor delegates
   *           calls. May be <tt>null</tt>.
   */
  public TraceMethodVisitor(final MethodVisitor mv) {
    this.labelNames = new HashMap();
    this.mv = mv;
  }

  // ------------------------------------------------------------------------
  // Implementation of the MethodVisitor interface
  // ------------------------------------------------------------------------

  public AnnotationVisitor visitAnnotation(
      final String desc,
      final boolean visible) {
    AnnotationVisitor av = super.visitAnnotation(desc, visible);
    if (mv != null) {
      ((TraceAnnotationVisitor) av).av = mv.visitAnnotation(desc, visible);
    }
    return av;
  }

  public void visitAttribute(final Attribute attr) {
    buf.setLength(0);
    buf.append(tab).append("ATTRIBUTE ");
    appendDescriptor(-1, attr.type);

    if (attr instanceof Traceable) {
      ((Traceable) attr).trace(buf, labelNames);
    }
    else {
      buf.append(" : unknown\n");
    }

    text.add(buf.toString());
    if (mv != null) {
      mv.visitAttribute(attr);
    }
  }

  public AnnotationVisitor visitAnnotationDefault() {
    text.add(tab2 + "default=");
    TraceAnnotationVisitor tav = createTraceAnnotationVisitor();
    text.add(tav.getText());
    text.add("\n");
    if (mv != null) {
      tav.av = mv.visitAnnotationDefault();
    }
    return tav;
  }

  public AnnotationVisitor visitParameterAnnotation(
      final int parameter,
      final String desc,
      final boolean visible) {
    buf.setLength(0);
    buf.append(tab2).append('@');
    appendDescriptor(FIELD_DESCRIPTOR, desc);
    buf.append('(');
    text.add(buf.toString());
    TraceAnnotationVisitor tav = createTraceAnnotationVisitor();
    text.add(tav.getText());
    text.add(visible ? ") // parameter " : ") // invisible, parameter ");
    text.add(new Integer(parameter));
    text.add("\n");
    if (mv != null) {
      tav.av = mv.visitParameterAnnotation(parameter, desc, visible);
    }
    return tav;
  }

  public void visitCode() {
    if (mv != null) {
      mv.visitCode();
    }
  }

  public void visitFrame(
      final int type,
      final int nLocal,
      final Object[] local,
      final int nStack,
      final Object[] stack) {
    buf.setLength(0);
    buf.append(ltab);
    buf.append("FRAME ");
    switch (type) {
      case Opcodes.F_NEW:
      case Opcodes.F_FULL:
        buf.append("FULL [");
        appendFrameTypes(nLocal, local);
        buf.append("] [");
        appendFrameTypes(nStack, stack);
        buf.append("]");
        break;
      case Opcodes.F_APPEND:
        buf.append("APPEND [");
        appendFrameTypes(nLocal, local);
        buf.append("]");
        break;
      case Opcodes.F_CHOP:
        buf.append("CHOP ").append(nLocal);
        break;
      case Opcodes.F_SAME:
        buf.append("SAME");
        break;
      case Opcodes.F_SAME1:
        buf.append("SAME1 ");
        appendFrameTypes(1, stack);
        break;
    }
    buf.append("\n");
    text.add(buf.toString());

    if (mv != null) {
      mv.visitFrame(type, nLocal, local, nStack, stack);
    }
  }

  public void visitInsn(final int opcode) {
    buf.setLength(0);
    buf.append(tab2).append(OPCODES[opcode]).append('\n');
    text.add(buf.toString());

    if (mv != null) {
      mv.visitInsn(opcode);
    }
  }

  public void visitIntInsn(final int opcode, final int operand) {
    buf.setLength(0);
    buf.append(tab2)
        .append(OPCODES[opcode])
        .append(' ')
        .append(opcode == Opcodes.NEWARRAY
            ? TYPES[operand]
            : Integer.toString(operand))
        .append('\n');
    text.add(buf.toString());

    if (mv != null) {
      mv.visitIntInsn(opcode, operand);
    }
  }

  public void visitVarInsn(final int opcode, final int var) {
    buf.setLength(0);
    buf.append(tab2)
        .append(OPCODES[opcode])
        .append(' ')
        .append(var)
        .append('\n');
    text.add(buf.toString());

    if (mv != null) {
      mv.visitVarInsn(opcode, var);
    }
  }

  public void visitTypeInsn(final int opcode, final String desc) {
    buf.setLength(0);
    buf.append(tab2).append(OPCODES[opcode]).append(' ');
    if (desc.startsWith("[")) {
      appendDescriptor(FIELD_DESCRIPTOR, desc);
    }
    else {
      appendDescriptor(INTERNAL_NAME, desc);
    }
    buf.append('\n');
    text.add(buf.toString());

    if (mv != null) {
      mv.visitTypeInsn(opcode, desc);
    }
  }

  public void visitFieldInsn(
      final int opcode,
      final String owner,
      final String name,
      final String desc) {
    buf.setLength(0);
    buf.append(tab2).append(OPCODES[opcode]).append(' ');
    appendDescriptor(INTERNAL_NAME, owner);
    buf.append('.').append(name).append(" : ");
    appendDescriptor(FIELD_DESCRIPTOR, desc);
    buf.append('\n');
    text.add(buf.toString());

    if (mv != null) {
      mv.visitFieldInsn(opcode, owner, name, desc);
    }
  }

  public void visitMethodInsn(
      final int opcode,
      final String owner,
      final String name,
      final String desc) {
    buf.setLength(0);
    buf.append(tab2).append(OPCODES[opcode]).append(' ');
    appendDescriptor(INTERNAL_NAME, owner);
    buf.append('.').append(name).append(' ');
    appendDescriptor(METHOD_DESCRIPTOR, desc);
    buf.append('\n');
    text.add(buf.toString());

    if (mv != null) {
      mv.visitMethodInsn(opcode, owner, name, desc);
    }
  }

  public void visitJumpInsn(final int opcode, final Label label) {
    buf.setLength(0);
    buf.append(tab2).append(OPCODES[opcode]).append(' ');
    appendLabel(label);
    buf.append('\n');
    text.add(buf.toString());

    if (mv != null) {
      mv.visitJumpInsn(opcode, label);
    }
  }

  public void visitLabel(final Label label) {
    buf.setLength(0);
    buf.append(ltab);
    appendLabel(label);
    buf.append('\n');
    text.add(buf.toString());

    if (mv != null) {
      mv.visitLabel(label);
    }
  }

  public void visitLdcInsn(final Object cst) {
    buf.setLength(0);
    buf.append(tab2).append("LDC ");
    if (cst instanceof String) {
      AbstractVisitor.appendString(buf, (String) cst);
    }
    else if (cst instanceof Type) {
      buf.append(((Type) cst).getDescriptor() + ".class");
    }
    else {
      buf.append(cst);
    }
    buf.append('\n');
    text.add(buf.toString());

    if (mv != null) {
      mv.visitLdcInsn(cst);
    }
  }

  public void visitIincInsn(final int var, final int increment) {
    buf.setLength(0);
    buf.append(tab2)
        .append("IINC ")
        .append(var)
        .append(' ')
        .append(increment)
        .append('\n');
    text.add(buf.toString());

    if (mv != null) {
      mv.visitIincInsn(var, increment);
    }
  }

  public void visitTableSwitchInsn(
      final int min,
      final int max,
      final Label dflt,
      final Label labels[]) {
    buf.setLength(0);
    buf.append(tab2).append("TABLESWITCH\n");
    for (int i = 0; i < labels.length; ++i) {
      buf.append(tab3).append(min + i).append(": ");
      appendLabel(labels[i]);
      buf.append('\n');
    }
    buf.append(tab3).append("default: ");
    appendLabel(dflt);
    buf.append('\n');
    text.add(buf.toString());

    if (mv != null) {
      mv.visitTableSwitchInsn(min, max, dflt, labels);
    }
  }

  public void visitLookupSwitchInsn(
      final Label dflt,
      final int keys[],
      final Label labels[]) {
    buf.setLength(0);
    buf.append(tab2).append("LOOKUPSWITCH\n");
    for (int i = 0; i < labels.length; ++i) {
      buf.append(tab3).append(keys[i]).append(": ");
      appendLabel(labels[i]);
      buf.append('\n');
    }
    buf.append(tab3).append("default: ");
    appendLabel(dflt);
    buf.append('\n');
    text.add(buf.toString());

    if (mv != null) {
      mv.visitLookupSwitchInsn(dflt, keys, labels);
    }
  }

  public void visitMultiANewArrayInsn(final String desc, final int dims) {
    buf.setLength(0);
    buf.append(tab2).append("MULTIANEWARRAY ");
    appendDescriptor(FIELD_DESCRIPTOR, desc);
    buf.append(' ').append(dims).append('\n');
    text.add(buf.toString());

    if (mv != null) {
      mv.visitMultiANewArrayInsn(desc, dims);
    }
  }

  public void visitTryCatchBlock(
      final Label start,
      final Label end,
      final Label handler,
      final String type) {
    buf.setLength(0);
    buf.append(tab2).append("TRYCATCHBLOCK ");
    appendLabel(start);
    buf.append(' ');
    appendLabel(end);
    buf.append(' ');
    appendLabel(handler);
    buf.append(' ');
    appendDescriptor(INTERNAL_NAME, type);
    buf.append('\n');
    text.add(buf.toString());

    if (mv != null) {
      mv.visitTryCatchBlock(start, end, handler, type);
    }
  }

  public void visitLocalVariable(
      final String name,
      final String desc,
      final String signature,
      final Label start,
      final Label end,
      final int index) {
    buf.setLength(0);
    buf.append(tab2).append("LOCALVARIABLE ").append(name).append(' ');
    appendDescriptor(FIELD_DESCRIPTOR, desc);
    buf.append(' ');
    appendLabel(start);
    buf.append(' ');
    appendLabel(end);
    buf.append(' ').append(index).append('\n');

    if (signature != null) {
      buf.append(tab2);
      appendDescriptor(FIELD_SIGNATURE, signature);

      TraceSignatureVisitor sv = new TraceSignatureVisitor(0);
      SignatureReader r = new SignatureReader(signature);
      r.acceptType(sv);
      buf.append(tab2)
          .append("// declaration: ")
          .append(sv.getDeclaration())
          .append('\n');
    }
    text.add(buf.toString());

    if (mv != null) {
      mv.visitLocalVariable(name, desc, signature, start, end, index);
    }
  }

  public void visitLineNumber(final int line, final Label start) {
    buf.setLength(0);
    buf.append(tab2).append("LINENUMBER ").append(line).append(' ');
    appendLabel(start);
    buf.append('\n');
    text.add(buf.toString());

    if (mv != null) {
      mv.visitLineNumber(line, start);
    }
  }

  public void visitMaxs(final int maxStack, final int maxLocals) {
    buf.setLength(0);
    buf.append(tab2).append("MAXSTACK = ").append(maxStack).append('\n');
    text.add(buf.toString());

    buf.setLength(0);
    buf.append(tab2).append("MAXLOCALS = ").append(maxLocals).append('\n');
    text.add(buf.toString());

    if (mv != null) {
      mv.visitMaxs(maxStack, maxLocals);
    }
  }

  public void visitEnd() {
    super.visitEnd();

    if (mv != null) {
      mv.visitEnd();
    }
  }

  // ------------------------------------------------------------------------
  // Utility methods
  // ------------------------------------------------------------------------

  private void appendFrameTypes(final int n, final Object[] o) {
    for (int i = 0; i < n; ++i) {
      if (i > 0) {
        buf.append(' ');
      }
      if (o[i] instanceof String) {
        String desc = (String) o[i];
        if (desc.startsWith("[")) {
          appendDescriptor(FIELD_DESCRIPTOR, desc);
        }
        else {
          appendDescriptor(INTERNAL_NAME, desc);
        }
      }
      else if (o[i] instanceof Integer) {
        switch (((Integer) o[i]).intValue()) {
          case 0:
            appendDescriptor(FIELD_DESCRIPTOR, "T");
            break;
          case 1:
            appendDescriptor(FIELD_DESCRIPTOR, "I");
            break;
          case 2:
            appendDescriptor(FIELD_DESCRIPTOR, "F");
            break;
          case 3:
            appendDescriptor(FIELD_DESCRIPTOR, "D");
            break;
          case 4:
            appendDescriptor(FIELD_DESCRIPTOR, "J");
            break;
          case 5:
            appendDescriptor(FIELD_DESCRIPTOR, "N");
            break;
          case 6:
            appendDescriptor(FIELD_DESCRIPTOR, "U");
            break;
        }
      }
      else {
        appendLabel((Label) o[i]);
      }
    }
  }

  /**
   * Appends the name of the given label to {@link #buf buf}. Creates a new
   * label name if the given label does not yet have one.
   *
   * @param l a label.
   */
  protected void appendLabel(final Label l) {
    String name = (String) labelNames.get(l);
    if (name == null) {
      name = "L" + labelNames.size();
      labelNames.put(l, name);
    }
    buf.append(name);
  }
}
