/* ScriptParser Copyright (C) 1999 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;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.Reader;

import @COLLECTIONS@.Collection;
import @COLLECTIONS@.LinkedList;

public class ScriptParser {
    static int NO_TOKEN         = -2;
    static int EOF_TOKEN        = -1;
    static int STRING_TOKEN     = 0;
    static int NEW_TOKEN        = 1;
    static int EQUALS_TOKEN     = 2;
    static int COMMA_TOKEN      = 3;
    static int OPENBRACE_TOKEN  = 4;
    static int CLOSEBRACE_TOKEN = 5;
    static int IDENTIFIER_TOKEN = 6;
    static int NUMBER_TOKEN     = 7;    
    Scanner scanner;

    class Scanner {
	BufferedReader input;
	String value;
	String line;
	int column;
	int linenr;
	int pushback = NO_TOKEN;
	
	public Scanner(Reader i) {
	    input = new BufferedReader(i);
	}

	public void readString() throws ParseException {
	    StringBuffer val = new StringBuffer();
	    while (column < line.length()) {
		char c = line.charAt(column++);
		if (c == '"') {
		    value = val.toString();
		    return;
		}
		if (c == '\\') {
		    c = line.charAt(column++);
		    switch (c) {
		    case 'n':
			val.append('\n');
			break;
		    case 't':
			val.append('\t');
			break;
		    case 'r':
			val.append('\r');
			break;
		    case 'u':
			if (column+4 <= line.length()) {
			    try {
				char uni = (char) Integer.parseInt
				    (line.substring(column, column+4), 16);
				column += 4;
				val.append(uni);
			    } catch (NumberFormatException ex) {
				throw new ParseException
				    (linenr,
				     "Invalid unicode escape character");
			    }
			} else
			    throw new ParseException
				(linenr,
				 "Invalid unicode escape character");
			break;
		    default:
			val.append(c);
		    }
		} else 
		    val.append(c);
	    }
	    throw new ParseException(linenr, 
				     "String spans over multiple lines");
	}
	public void readIdentifier() {
	    int start = column-1;
	    while (column < line.length()
		   && Character.isUnicodeIdentifierPart(line.charAt(column)))
		column++;
	    value = line.substring(start, column);
	}

	public void readNumber() {
	    boolean hex = false;
	    int start = column-1;
	    /* special case for hex numbers */
	    if (line.charAt(start) == '0' && line.charAt(column) == 'x') {
		column++;
		hex = true;
	    }
	    while (column < line.length()) {
		char c = line.charAt(column);
		if (!Character.isDigit(c)) {
		    if (!hex)
		        break;
		    if ((c < 'A' || c > 'F') && (c < 'a' || c > 'f'))
			break;
		}
		column++;
	    }
	    value = line.substring(start, column);
	}

	public void pushbackToken(int token) {
	    if (pushback != NO_TOKEN)
		throw new IllegalStateException
		    ("Can only handle one pushback");
	    pushback = token;
	}

	public int getToken() throws ParseException, IOException {
	    if (pushback != NO_TOKEN) {
		int result = pushback;
		pushback = NO_TOKEN;
		return result;
	    }
	    value = null;
	    while (true) {
		if (line == null) {
		    line = input.readLine();
		    if (line == null)
			return EOF_TOKEN;
		    linenr++;
		    column = 0;
		}
		while (column < line.length()) {
		    char c = line.charAt(column++);
		    if (Character.isWhitespace(c))
			continue;
		    if (c == '#')
			// this is a comment, skip this line
			break;
		    if (c == '=')
			return EQUALS_TOKEN;
		    if (c == ',')
			return COMMA_TOKEN;
		    if (c == '{')
			return OPENBRACE_TOKEN;
		    if (c == '}')
			return CLOSEBRACE_TOKEN;
		    if (c == '"') {
			readString();
			return STRING_TOKEN;
		    }
		    if (Character.isDigit(c) || c == '+' || c == '-') {
			readNumber();
			return NUMBER_TOKEN;
		    }
		    if (Character.isUnicodeIdentifierStart(c)) {
			readIdentifier();
			if (value.equals("new"))
			    return NEW_TOKEN;
			return IDENTIFIER_TOKEN;
		    }
		    throw new ParseException 
			(linenr, "Illegal character `"+c+"'");
		}
		line = null;
	    }
	}
	    
	public String getValue() {
	    return value;
	}
	
	public int getLineNr() {
	    return linenr;
	}
    }
	
    public ScriptParser(Reader reader) {
	this.scanner = new Scanner(reader);
    }

    public Object parseClass() throws ParseException, IOException {
	int linenr = scanner.getLineNr();
	int token = scanner.getToken();
	if (token != IDENTIFIER_TOKEN)
	    throw new ParseException(linenr, "Class name expected");
	Object instance;
	try {
	    Class clazz = Class.forName("jode.obfuscator."+scanner.getValue());
	    instance = clazz.newInstance();
	} catch (ClassNotFoundException ex) {
	    throw new ParseException(scanner.getLineNr(), 
				     "Class `"+scanner.getValue()
				     +"' not found");
	} catch (Exception ex) {
	    throw new ParseException(scanner.getLineNr(), 
				     "Class `"+scanner.getValue()
				     +"' not valid: "+ex.getMessage());
	}

	token = scanner.getToken();
	if (token == OPENBRACE_TOKEN) {
	    if (!(instance instanceof OptionHandler))
		throw new ParseException
		    (scanner.getLineNr(), 
		     "Class `"+instance.getClass().getName()
		     +"' doesn't handle options.");
	    parseOptions((OptionHandler) instance);
	    if (scanner.getToken() != CLOSEBRACE_TOKEN)
		throw new ParseException(scanner.getLineNr(), "`}' expected");
	} else
	    scanner.pushbackToken(token);
	return instance;
    }

    public void parseOptions(OptionHandler optionHandler) 
	throws ParseException, IOException
    {
	int token = scanner.getToken();
	while (true) {
	    if (token == EOF_TOKEN || token == CLOSEBRACE_TOKEN) {
		scanner.pushbackToken(token);
		return;
	    }
	    if (token != IDENTIFIER_TOKEN)
		throw new ParseException(scanner.getLineNr(), 
					 "identifier expected");
	    String ident = scanner.getValue();
	    if (scanner.getToken() != EQUALS_TOKEN)
		throw new ParseException(scanner.getLineNr(), 
					 "equal sign expected");

	    int linenr = scanner.getLineNr();
	    Collection values = new LinkedList();
	    do {
		token = scanner.getToken();
		if (token == NEW_TOKEN) {
		    values.add(parseClass());
		} else if (token == STRING_TOKEN) {
		    values.add(scanner.getValue());
		} else if (token == NUMBER_TOKEN) {
		    values.add(new Integer(scanner.getValue()));
		}
		token = scanner.getToken();
	    } while (token == COMMA_TOKEN);
	    try {
		optionHandler.setOption(ident, values);
	    } catch (IllegalArgumentException ex) {
		throw new ParseException(linenr, 
					 optionHandler.getClass().getName()
					 +": "+ex.getMessage());
	    } catch (RuntimeException ex) {
		throw new ParseException(linenr, 
					 optionHandler.getClass().getName()
					 +": Illegal value: "
					 +ex.getClass().getName()
					 +": "+ex.getMessage());
	    }
	}
    }
}