/*
 * Created on Dec 5, 2004
 *
 */
package fr.lifl.stc.stan.tools;

import java.io.IOException;

import org.apache.bcel.classfile.Attribute;
import org.apache.bcel.classfile.ClassParser;
import org.apache.bcel.classfile.EscapeAttribute;
import org.apache.bcel.classfile.JavaClass;
import org.apache.bcel.classfile.Method;

/**
 * @author yann
 *
 */
public class Diff {
	
	private static JavaClass[] classes;
	
	private static String diff(short[] s1, short[] s2) {
		String res = "";
		for(int i = 0; i < s2.length; i++) {
			int j = 0;
			while(j < s1.length) {
				if(s2[i] == s1[j])
					break;
				j++;
			}
			if(j == s1.length)
				res += s2[i] + " ";
		}
		return res;
	}
	
	private static void compare(EscapeAttribute a1, EscapeAttribute a2) {		
		if(a1 == null && a2 == null) {
			return;
		} else if (a1 == null) {
			short[] s = a2.getOffsets();
			String res = "";
			for(int i = 0; i < s.length; i++) {
				res += s[i] + " ";
			}
			System.out.println("+ " + res);
		} else if (a2 == null) {
			short[] s = a1.getOffsets();
			String res = "";
			for(int i = 0; i < s.length; i++) {
				res += s[i] + " ";
			}
			System.out.println("- " + res);
		} else {
			String splus = diff(a1.getOffsets(),a2.getOffsets());
			String sminus = diff(a2.getOffsets(),a1.getOffsets());
			if(!splus.equals(""))
				System.out.println("+ " + splus);
			if(!sminus.equals(""))
				System.out.println("- " + sminus);
		}
	}
	
	private static EscapeAttribute findEscapeAttr(Attribute[] a) {
		EscapeAttribute res = null;
		
		for(int i = 0; i < a.length; i++) {
			if(a[i] instanceof EscapeAttribute) {
				res = (EscapeAttribute)a[i];
				break;
			}
		}
		
		return res;
	}
	
	private static void compare(JavaClass c1, JavaClass c2) {
		if(!c1.getClassName().equals(c2.getClassName())) {
			System.err.println("Trying to compare different classes");
			System.exit(1);
		}
		
		Method[] m1 = c1.getMethods();
		Method[] m2 = c2.getMethods();
		
		for(int i = 0; i < m1.length; i++) {
			System.out.println("Method: " + m1[i]);
			if(m1[i].getCode() != null) {
				Attribute[] a1 = m1[i].getCode().getAttributes();
				Attribute[] a2 = m2[i].getCode().getAttributes();
				
				compare(findEscapeAttr(a1),findEscapeAttr(a2));
			}
		}
	}
	
	public static void main(String[] args) {
		if(args.length != 2) {
			System.err.println("You must give exactly 2 arguments");
			System.exit(1);
		}
		
		int i = 0;
		try
		{
			classes = new JavaClass[args.length];
			while (i < args.length) {
				classes[i] = (new ClassParser(args[i])).parse();
				i++;
			}
			
			compare(classes[0], classes[1]);
			
		} catch (IOException e) {
			System.err.println("E: File " + args[i]
			                                     + " does not exist or you don't have permission on it.");
			System.exit(1);
		}
	}
}