/* StrongRenamer Copyright (C) 1999, 2000 Jochen Hoenicke.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; see the file COPYING.  If not, write to
 * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 * $Id$
 */

package jode.obfuscator.modules;
import jode.obfuscator.*;
///#def COLLECTIONS java.util
import java.util.Collection;
import java.util.Iterator;
///#enddef
///#def COLLECTIONEXTRA java.lang
import java.lang.UnsupportedOperationException;
///#enddef

public class StrongRenamer implements Renamer, OptionHandler {
    static String[] idents = {
	"Package", "Class", "Field", "Method", "Local"
    };
    static String[] parts = {
	"Start", "Part"
    };
    String charsets[][];

    String javaKeywords[] = {
	"abstract", "default", "if", "private", "throw", "boolean",
	"do", "implements", "protected", "throws", "break", "double",
	"import", "public", "transient", "byte", "else", "instanceof",
	"return", "try", "case", "extends", "int", "short", "void",
	"catch", "final", "interface", "static", "volatile", "char",
	"finally", "long", "super", "while", "class", "float",
	"native", "switch", "const", "for", "new", "synchronized",
	"continue", "goto", "package", "this", "strictfp", "null",
	"true", "false"
    };

    public StrongRenamer() {
	charsets = new String[idents.length][parts.length];
	for (int i=0; i< idents.length; i++)
	    for (int j=0; j< parts.length; j++)
		charsets[i][j] = "abcdefghijklmnopqrstuvwxyz";
    }

    public void setOption(String option, Collection values) {
	if (option.startsWith("charset")) {
	    Object value = values.iterator().next();
	    if (values.size() != 1 || !(value instanceof String))
		throw new IllegalArgumentException
		    ("Only string parameter are supported.");
	    String set = (String) value;
	    String remOpt = option.substring("charset".length());
	    int part = -1, ident = -1;
	    if (remOpt.length() > 0) {
		for (int i=0; i < idents.length; i++) {
		    if (remOpt.startsWith(idents[i])) {
			remOpt = remOpt.substring(idents[i].length());
			ident = i;
			break;
		    }
		}
	    }
	    if (remOpt.length() > 0) {
		for (int j=0; j < parts.length; j++) {
		    if (remOpt.startsWith(parts[j])) {
			remOpt = remOpt.substring(parts[j].length());
			part = j;
			break;
		    }
		}
	    }
	    if (remOpt.length() > 0)
		throw new IllegalArgumentException("Invalid charset `"
						   +option+"'");
	    for (int i = 0; i < idents.length; i++) {
		if (ident >= 0 && ident != i)
		    continue;
		for (int j = 0; j < parts.length; j++) {
		    if (part >= 0 && part != j)
			continue;
		    charsets[i][j] = set;
		}
	    }
	} else
	    throw new IllegalArgumentException("Invalid option `"
					       +option+"'");
    }

    public Iterator generateNames(Identifier ident) {
	int identType;
	if (ident instanceof PackageIdentifier)
	    identType = 0;
	else if (ident instanceof ClassIdentifier)
	    identType = 1;
	else if (ident instanceof FieldIdentifier)
	    identType = 2;
	else if (ident instanceof MethodIdentifier)
	    identType = 3;
	else if (ident instanceof LocalIdentifier)
	    identType = 4;
	else
	    throw new IllegalArgumentException(ident.getClass().getName());
	final String[] theCharset = charsets[identType];

	return new Iterator() {
	    char[] name = null;
	    int headIndex;

	    public boolean hasNext() {
		return true;
	    }
	    public Object next() {
		if (name == null) {
		    name = new char[] { theCharset[0].charAt(0) };
		    headIndex = 0;
		    return new String(name);
		}
	    next_name:
		while (true) {
		    if (++headIndex < theCharset[0].length()) {
			name[0] = theCharset[0].charAt(headIndex);
			return new String(name);
		    }
		    headIndex = 0;
		    name[0] = theCharset[0].charAt(0);
		    
		    String charset = theCharset[1];
		    for (int pos = 1; pos < name.length; pos++) {
			int index = charset.indexOf(name[pos]) + 1;
			if (index < charset.length()) {
			    name[pos] = charset.charAt(index);
			    return new String(name);
			}
			name[pos] = charset.charAt(0);
		    }
		
		    name = new char[name.length+1];
		    name[0] = theCharset[0].charAt(0);
		    char firstCont = theCharset[1].charAt(0);
		    for (int i=1; i <name.length; i++)
			name[i] = firstCont;
		    
		    String next = new String(name);
		    for (int i = 0; i < javaKeywords.length; i++) {
			if (next.equals(javaKeywords[i]))
			    continue next_name;
		    }
		    return next;
		}
	    }

	    public void remove() {
		throw new UnsupportedOperationException();
	    }
	};
    }
}