package com.de22.javabytecode.code;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;

import com.common.debug.Debug;
import com.common.io.ByteArrayInputStream;
import com.common.io.ByteArrayOutputStream;
import com.common.io.ObjectInputStream;
import com.common.io.ObjectOutputStream;
import com.de22.javabytecode.Type;

/**
 * Copyright Declarative Engineering LLC 2007<p>
 * A simple test class that reads in a class file and then writes it out without any modifications.
 * This class tests the ability to read and write a class file without introducing errors.
 */
public class Test {
/**
 * Reverse engineers a class file and writes it back out to 'output.class'.
 * @param args The array of initialization parameters.
 * 	args[0] = The path and file name of the class to reverse engineer.
 *  args[1] = The path (must exist) where the output.class file will be stored.  If the file exists it will be over written.
 */
public static void main(String[] args) {
	String debugText = null;
	long t = System.currentTimeMillis();
	
	try {
		File file = new File(args[0]);
		File path = args.length > 1 ? new File(args[1]) : null;
		
		if(path != null && (path.isFile() || (!path.exists() && !path.mkdirs()))) {
			path = null;
		}//if//
		
		if(file.getName().endsWith(".class")) {
			debugText = file.getPath();
			processClassFile(file, new File(path, "output.class"));
			compareClassFiles(file, new File(path, "output.class"));
		}//if//
	}//try//
	catch(Throwable e) {
		Debug.log(e, "Caught while processing the class file: " + debugText);
	}//catch//
	
	Debug.log("Total time (milliseconds): " + (System.currentTimeMillis() - t));
	
	System.exit(0);
}//main()//
/**
 * Writes a file.
 * @param file The file to write.
 * @param bytes The bytes to place in the file.
 */
public static void writeFile(File file, byte[] bytes) {
	FileOutputStream fout = null;
	
	try {
		fout = new FileOutputStream(file);
		fout.write(bytes);
	}//try//
	catch(Throwable e) {
		e.printStackTrace();
	}//catch//
	finally {
		if(fout != null) {
			try {
				fout.close();
			}//try//
			catch(Throwable e) {
			}//catch//
		}//if//
	}//finally//
}//writeFile()//
/**
 * Reads a file and returns the bytes contained there in.
 * @param file The file to read.
 * @return The bytes contained in the file.
 */
public static byte[] readFile(File file) {
	FileInputStream fin = null;
	byte[] bytes = null;
	int counter = 0;
	
	try {
		fin = new FileInputStream(file);
		bytes = new byte[fin.available()];
		
		while(counter < bytes.length) {
			counter += fin.read(bytes, counter, bytes.length - counter);
		}//while//
		
		fin.close();
	}//try//
	catch(Throwable e) {
		e.printStackTrace();
	}//catch//
	finally {
		if(fin != null) {
			try {
				fin.close();
			}//try//
			catch(Throwable e) {
			}//catch//
		}//if//
	}//finally//
	
	return bytes;
}//readFile()//
/**
 * Processes a class file and writes out the byte codes in a semi-readable form.
 * @param bytesIn The input stream containing the bytes codes.  This stream will always be closed by this method.
 * @param outputPath The optional path where the class output should be written to (under its packaging of course).  The console will be used otherwise.
 */
private static void processClassFile(File inputFile, File outputFile) throws Throwable {
	ByteArrayInputStream bin = null;
	ObjectInputStream in = null;
	Type type = null;
	ByteArrayOutputStream bout = null;
	ObjectOutputStream out = null;
	
	try {
		bin = new ByteArrayInputStream(readFile(inputFile));
		in = new ObjectInputStream(bin, null, null);

		type = new Type();
		type.readExternal(in);
		
		bout = new ByteArrayOutputStream(100000, false);
		out = new ObjectOutputStream(bout, null);
		type.writeExternal(out);
		out.flush();
		writeFile(outputFile, bout.toByteArray());
	}//try//
	catch(Throwable e) {
		e.printStackTrace();
		throw e;
	}//catch//
}//processClassFile()//
/**
 * Processes a class file and writes out the byte codes in a semi-readable form.
 * @param bytesIn The input stream containing the bytes codes.  This stream will always be closed by this method.
 * @param outputPath The optional path where the class output should be written to (under its packaging of course).  The console will be used otherwise.
 */
private static void compareClassFiles(File inputFile, File outputFile) throws Throwable {
	byte[] originalBytes;
	byte[] modifiedBytes;
	int byteLength;
	
	originalBytes = readFile(inputFile);
	modifiedBytes = readFile(outputFile);
	byteLength = Math.min(originalBytes.length, modifiedBytes.length);
	
	for(int index = 0; index < byteLength; index++) {
		if(originalBytes[index] != modifiedBytes[index]) {
			Debug.log("Files diverge at index " + index);
			return;
		}//if//
	}//for//
	
	if(originalBytes.length != modifiedBytes.length) {
		Debug.log("One file has more bytes than the other.");
	}//if//
	else {
		Debug.log("Files are exactly the same.");
	}//else//
}//processClassFile()//
}//Test//