/**
    *  MicroEmulator
    *  Copyright (C) 2006-2007 Bartek Teodorczyk <barteo@barteo.net>
    *  Copyright (C) 2006-2007 Vlad Skarzhevskyy
    *
    *  It is licensed under the following two licenses as alternatives:
    *    1. GNU Lesser General Public License (the "LGPL") version 2.1 or any newer version
    *    2. Apache License (the "AL") Version 2.0
    *
   *  You may not use this file except in compliance with at least one of
   *  the above two licenses.
   *
   *  You may obtain a copy of the LGPL at
   *      http://www.gnu.org/licenses/old-licenses/lgpl-2.1.txt
   *
   *  You may obtain a copy of the AL at
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   *  Unless required by applicable law or agreed to in writing, software
   *  distributed under the License is distributed on an "AS IS" BASIS,
   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   *  See the LGPL or the AL for the specific language governing permissions and
   *  limitations.
   *
   *  @version $Id: ChangeCallsMethodVisitor.java 1605 2008-02-25 21:07:14Z barteo $
   */
  package org.microemu.app.classloader;
  
  import java.util.HashMap;
  
  import org.microemu.Injected;
  import org.microemu.app.util.MIDletThread;
  import org.microemu.app.util.MIDletTimer;
  import org.objectweb.asm.Label;
  import org.objectweb.asm.MethodAdapter;
  import org.objectweb.asm.MethodVisitor;
  import org.objectweb.asm.Opcodes;
  
  /**
   * @author vlads
   *
   */
  public class ChangeCallsMethodVisitor extends MethodAdapter implements Opcodes {
  
  	private static final String INJECTED_CLASS = codeName(Injected.class);
  	
  	static String NEW_SYSTEM_OUT_CLASS = INJECTED_CLASS;
  	
  	static String NEW_SYSTEM_PROPERTIES_CLASS = INJECTED_CLASS;
  	
  	static String NEW_RESOURCE_LOADER_CLASS = INJECTED_CLASS;
  	
  	private HashMap catchInfo;
  	
  	private InstrumentationConfig config;
  	
  	private static class CatchInformation {
  		
  		Label label; 
  		
  		String type;
  
  		public CatchInformation(String type) {
  			this.label = new Label();
  			this.type = type;
  		}
  	}
  	
  	public ChangeCallsMethodVisitor(MethodVisitor mv, InstrumentationConfig config) {
  		super(mv);
  		this.config = config;
  	}
  
  	public static String codeName(Class klass) {
  		return klass.getName().replace('.', '/');
  	}
  
      public void visitFieldInsn(final int opcode, final String owner, final String name, final String desc) {
  		switch (opcode) {
  		case GETSTATIC:
  			if ((name.equals("out")) && (owner.equals("java/lang/System"))) {
  				//System.out.println("owner " + owner + " name " + name + " desc " + desc);
  				// GETSTATIC System.out : PrintStream
  				mv.visitFieldInsn(opcode, NEW_SYSTEM_OUT_CLASS, name, desc);
  				return;
  			}
  			if ((name.equals("err")) && (owner.equals("java/lang/System"))) {
  				//System.out.println("owner " + owner + " name " + name + " desc " + desc);
  				// GETSTATIC System.out : PrintStream
  				mv.visitFieldInsn(opcode, NEW_SYSTEM_OUT_CLASS, name, desc);
  				return;
  			}
  			break;
  
  		}
  		mv.visitFieldInsn(opcode, owner, name, desc);
  	}
      
  	public void visitMethodInsn(int opcode, String owner, String name, String desc) {
 		switch (opcode) {
 		case INVOKESTATIC:
 			//System.out.println("Method owner " + owner + " name " + name + " desc " + desc);
 			if ((name.equals("getProperty")) && (owner.equals("java/lang/System"))) {
 				// INVOKESTATIC
                 // java/lang/System.getProperty(Ljava/lang/String;)Ljava/lang/String;
 				mv.visitMethodInsn(opcode, NEW_SYSTEM_PROPERTIES_CLASS, name, desc);
 				return;
 			}
 			break;
 		case INVOKEVIRTUAL:
 			if ((name.equals("getResourceAsStream")) && (owner.equals("java/lang/Class"))) {
 				// INVOKEVIRTUAL
 		        // java/lang/Class.getResourceAsStream(Ljava/lang/String;)Ljava/io/InputStream;
 				// "org/microemu/ResourceLoader", "getResourceAsStream", "(Ljava/lang/Class;Ljava/lang/String;)Ljava/io/InputStream;");
 				mv.visitMethodInsn(INVOKESTATIC, NEW_RESOURCE_LOADER_CLASS, name, "(Ljava/lang/Class;Ljava/lang/String;)Ljava/io/InputStream;");
 				return;
 			} else if ((name.equals("printStackTrace")) && (owner.equals("java/lang/Throwable"))) {
 				// INVOKEVIRTUAL java/lang/Throwable.printStackTrace()V
 				mv.visitMethodInsn(INVOKESTATIC, INJECTED_CLASS, name, "(Ljava/lang/Throwable;)V");
 				return;
 			}
 			break;
 		case INVOKESPECIAL:
 			if  ((config.isEnhanceThreadCreation()) && (name.equals("<init>"))) {
 				if (owner.equals("java/util/Timer")) {
 					owner = codeName(MIDletTimer.class);
 				} else if (owner.equals("java/lang/Thread")) {
 					owner = codeName(MIDletThread.class);
 				}
 			}
 			break;
 		}
 
 		mv.visitMethodInsn(opcode, owner, name, desc);
 	}
 	
     public void visitTypeInsn(final int opcode, String desc) {
     	if ((opcode == NEW) && (config.isEnhanceThreadCreation())) {
     		if ("java/util/Timer".equals(desc)) {
     			desc = codeName(MIDletTimer.class);
     		} else if ("java/lang/Thread".equals(desc)) {
     			desc = codeName(MIDletThread.class);
     		}
     	} 
     	mv.visitTypeInsn(opcode, desc);
     }
     
     public void visitTryCatchBlock(final Label start, final Label end, final Label handler, final String type) {
     	if (config.isEnhanceCatchBlock() && type != null) {
     		if (catchInfo == null) {
     			catchInfo = new HashMap(); 
     		}
     		CatchInformation newHandler = (CatchInformation)catchInfo.get(handler);
     		if (newHandler == null) {
     			newHandler = new CatchInformation(type);
     			catchInfo.put(handler, newHandler);
     		}
     		mv.visitTryCatchBlock(start, end, newHandler.label, type);
     	} else {
     		mv.visitTryCatchBlock(start, end, handler, type);
     	}
 	}
     
     //TODO make this work for gMaps case
     public void visitLabel(Label label) {
     	if (config.isEnhanceCatchBlock() && catchInfo != null) {
     		CatchInformation newHandler = (CatchInformation)catchInfo.get(label);
     		if (newHandler != null) {
     			mv.visitLabel(newHandler.label);
     			// no push, just use current Throwable in stack
     			mv.visitMethodInsn(INVOKESTATIC, INJECTED_CLASS, "handleCatchThrowable", "(Ljava/lang/Throwable;)Ljava/lang/Throwable;");
     			// stack contains Throwable, just verify that it is right type for this handler
         		mv.visitTypeInsn(CHECKCAST, newHandler.type);
     		}	
     	}
     	mv.visitLabel(label);
     }
 	
 }