/***
 * ASM: a very small and fast Java bytecode manipulation framework
 * Copyright (c) 2000-2007 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 alterrs.asm.util;

import java.util.HashMap;
import java.util.Map;

import alterrs.asm.AnnotationVisitor;
import alterrs.asm.Attribute;
import alterrs.asm.Label;
import alterrs.asm.MethodVisitor;
import alterrs.asm.Opcodes;
import alterrs.asm.Type;
import alterrs.asm.signature.SignatureReader;

/**
 * A {@link alterrs.asm.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 Map 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 type) {
		buf.setLength(0);
		buf.append(tab2).append(OPCODES[opcode]).append(' ');
		appendDescriptor(INTERNAL_NAME, type);
		buf.append('\n');
		text.add(buf.toString());

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

	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) {
			appendString(buf, (String) cst);
		} else if (cst instanceof Type) {
			buf.append(((Type) cst).getDescriptor()).append(".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);
	}
}
