/*
 * TokenMarker.java - Tokenizes lines of text
 * :tabSize=8:indentSize=8:noTabs=false:
 * :folding=explicit:collapseFolds=1:
 *
 * Copyright (C) 1998, 2003 Slava Pestov
 * Copyright (C) 1999, 2000 mike dillon
 *
 * 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
 * of the License, or 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; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */

package org.gjt.sp.jedit.syntax;

//{{{ Imports
import gnu.regexp.*;
import javax.swing.text.Segment;
import java.util.*;
import org.gjt.sp.jedit.*;
import org.gjt.sp.util.CharIndexedSegment;
import org.gjt.sp.util.Log;
//}}}

/**
 * A token marker splits lines of text into tokens. Each token carries
 * a length field and an identification tag that can be mapped to a color
 * or font style for painting that token.
 *
 * @author Slava Pestov, mike dillon
 * @version $Id: TokenMarker.java,v 1.62 2003/12/27 05:14:46 spestov Exp $
 *
 * @see org.gjt.sp.jedit.syntax.Token
 * @see org.gjt.sp.jedit.syntax.TokenHandler
 */
public class TokenMarker
{
	//{{{ TokenMarker constructor
	public TokenMarker()
	{
		ruleSets = new Hashtable(64);
	} //}}}

	//{{{ addRuleSet() method
	public void addRuleSet(ParserRuleSet rules)
	{
		ruleSets.put(rules.getSetName(), rules);

		if (rules.getSetName().equals("MAIN"))
			mainRuleSet = rules;
	} //}}}

	//{{{ getMainRuleSet() method
	public ParserRuleSet getMainRuleSet()
	{
		return mainRuleSet;
	} //}}}

	//{{{ getRuleSet() method
	public ParserRuleSet getRuleSet(String setName)
	{
		return (ParserRuleSet) ruleSets.get(setName);
	} //}}}

	//{{{ getRuleSets() method
	/**
	 * @since jEdit 4.2pre3
	 */
	public ParserRuleSet[] getRuleSets()
	{
		return (ParserRuleSet[])ruleSets.values().toArray(new ParserRuleSet[ruleSets.size()]);
	} //}}}

	//{{{ markTokens() method
	/**
	 * Do not call this method directly; call Buffer.markTokens() instead.
	 */
	public LineContext markTokens(LineContext prevContext,
		TokenHandler tokenHandler, Segment line)
	{
		//{{{ Set up some instance variables
		// this is to avoid having to pass around lots and lots of
		// parameters.
		this.tokenHandler = tokenHandler;
		this.line = line;

		lastOffset = line.offset;
		lineLength = line.count + line.offset;

		context = new LineContext();

		if(prevContext == null)
			context.rules = getMainRuleSet();
		else
		{
			context.parent = prevContext.parent;
			context.inRule = prevContext.inRule;
			context.rules = prevContext.rules;
			context.spanEndSubst = prevContext.spanEndSubst;
		}

		keywords = context.rules.getKeywords();
		escaped = false;

		seenWhitespaceEnd = false;
		whitespaceEnd = line.offset;
		//}}}

		//{{{ Main parser loop
		ParserRule rule;
		int terminateChar = context.rules.getTerminateChar();
		boolean terminated = false;

main_loop:	for(pos = line.offset; pos < lineLength; pos++)
		{
			//{{{ check if we have to stop parsing
			if(terminateChar >= 0 && pos - line.offset >= terminateChar
				&& !terminated)
			{
				terminated = true;
				context = new LineContext(ParserRuleSet
					.getStandardRuleSet(context.rules
					.getDefault()),context);
				keywords = context.rules.getKeywords();
			} //}}}

			//{{{ check for end of delegate
			if(context.parent != null)
			{
				rule = context.parent.inRule;
				if(rule != null)
				{
					if(checkDelegateEnd(rule))
					{
						seenWhitespaceEnd = true;
						continue main_loop;
					}
				}
			} //}}}

			//{{{ check every rule
			char ch = line.array[pos];

			rule = context.rules.getRules(ch);
			while(rule != null)
			{
				// stop checking rules if there was a match
				if (handleRule(rule,false))
				{
					seenWhitespaceEnd = true;
					continue main_loop;
				}

				rule = rule.next;
			} //}}}

			//{{{ check if current character is a word separator
			if(Character.isWhitespace(ch))
			{
				if(!seenWhitespaceEnd)
					whitespaceEnd = pos + 1;

				if(context.inRule != null)
					handleRule(context.inRule,true);

				handleNoWordBreak();

				markKeyword(false);

				if(lastOffset != pos)
				{
					tokenHandler.handleToken(line,
						context.rules.getDefault(),
						lastOffset - line.offset,
						pos - lastOffset,
						context);
				}

				tokenHandler.handleToken(line,
					context.rules.getDefault(),
					pos - line.offset,1,context);
				lastOffset = pos + 1;

				escaped = false;
			}
			else
			{
				if(keywords != null || context.rules.getRuleCount() != 0)
				{
					String noWordSep = context.rules.getNoWordSep();

					if(!Character.isLetterOrDigit(ch)
						&& noWordSep.indexOf(ch) == -1)
					{
						if(context.inRule != null)
							handleRule(context.inRule,true);

						handleNoWordBreak();

						markKeyword(true);

						tokenHandler.handleToken(line,
							context.rules.getDefault(),
							lastOffset - line.offset,1,
							context);
						lastOffset = pos + 1;
					}
				}

				seenWhitespaceEnd = true;
				escaped = false;
			} //}}}
		} //}}}

		//{{{ Mark all remaining characters
		pos = lineLength;

		if(context.inRule != null)
			handleRule(context.inRule,true);

		handleNoWordBreak();
		markKeyword(true);
		//}}}

		//{{{ Unwind any NO_LINE_BREAK parent delegates
unwind:		while(context.parent != null)
		{
			rule = context.parent.inRule;
			if((rule != null && (rule.action
				& ParserRule.NO_LINE_BREAK) == ParserRule.NO_LINE_BREAK)
				|| terminated)
			{
				context = context.parent;
				keywords = context.rules.getKeywords();
				context.inRule = null;
			}
			else
				break unwind;
		} //}}}

		tokenHandler.handleToken(line,Token.END,
			pos - line.offset,0,context);

		context = context.intern();
		tokenHandler.setLineContext(context);
		return context;
	} //}}}

	//{{{ Private members

	//{{{ Instance variables
	private Hashtable ruleSets;
	private ParserRuleSet mainRuleSet;

	// Instead of passing these around to each method, we just store them
	// as instance variables. Note that this is not thread-safe.
	private TokenHandler tokenHandler;
	private Segment line;
	private LineContext context;
	private KeywordMap keywords;
	private Segment pattern = new Segment();
	private int lastOffset;
	private int lineLength;
	private int pos;
	private boolean escaped;

	private int whitespaceEnd;
	private boolean seenWhitespaceEnd;
	//}}}

	//{{{ checkDelegateEnd() method
	private boolean checkDelegateEnd(ParserRule rule)
	{
		if(rule.end == null)
			return false;

		LineContext tempContext = context;
		context = context.parent;
		keywords = context.rules.getKeywords();
		boolean tempEscaped = escaped;
		boolean b = handleRule(rule,true);
		context = tempContext;
		keywords = context.rules.getKeywords();

		if(b && !tempEscaped)
		{
			if(context.inRule != null)
				handleRule(context.inRule,true);

			markKeyword(true);

			context = (LineContext)context.parent.clone();

			tokenHandler.handleToken(line,
				(context.inRule.action & ParserRule.EXCLUDE_MATCH)
				== ParserRule.EXCLUDE_MATCH
				? context.rules.getDefault()
				: context.inRule.token,
				pos - line.offset,pattern.count,context);

			keywords = context.rules.getKeywords();
			context.inRule = null;
			lastOffset = pos + pattern.count;

			// move pos to last character of match sequence
			pos += (pattern.count - 1);

			return true;
		}

		// check escape rule of parent
		if((rule.action & ParserRule.NO_ESCAPE) == 0)
		{
			ParserRule escape = context.parent.rules.getEscapeRule();
			if(escape != null && handleRule(escape,false))
				return true;
		}

		return false;
	} //}}}

	//{{{ handleRule() method
	/**
	 * Checks if the rule matches the line at the current position
	 * and handles the rule if it does match
	 */
	private boolean handleRule(ParserRule checkRule, boolean end)
	{
		//{{{ Some rules can only match in certain locations
		if(!end)
		{
			if(Character.toUpperCase(checkRule.hashChar)
				!= Character.toUpperCase(line.array[pos]))
			{
				return false;
			}
		}

		int offset = ((checkRule.action & ParserRule.MARK_PREVIOUS) != 0) ?
			lastOffset : pos;
		int posMatch = (end ? checkRule.endPosMatch : checkRule.startPosMatch);

		if((posMatch & ParserRule.AT_LINE_START)
			== ParserRule.AT_LINE_START)
		{
			if(offset != line.offset)
				return false;
		}
		else if((posMatch & ParserRule.AT_WHITESPACE_END)
			== ParserRule.AT_WHITESPACE_END)
		{
			if(offset != whitespaceEnd)
				return false;
		}
		else if((posMatch & ParserRule.AT_WORD_START)
			== ParserRule.AT_WORD_START)
		{
			if(offset != lastOffset)
				return false;
		} //}}}

		int matchedChars = 1;
		CharIndexedSegment charIndexed = null;
		REMatch match = null;

		//{{{ See if the rule's start or end sequence matches here
		if(!end || (checkRule.action & ParserRule.MARK_FOLLOWING) == 0)
		{
			// the end cannot be a regular expression
			if((checkRule.action & ParserRule.REGEXP) == 0 || end)
			{
				if(end)
				{
					if(context.spanEndSubst != null)
						pattern.array = context.spanEndSubst;
					else
						pattern.array = checkRule.end;
				}
				else
					pattern.array = checkRule.start;
				pattern.offset = 0;
				pattern.count = pattern.array.length;
				matchedChars = pattern.count;

				if(!SyntaxUtilities.regionMatches(context.rules
					.getIgnoreCase(),line,pos,pattern.array))
				{
					return false;
				}
			}
			else
			{
				// note that all regexps start with \A so they only
				// match the start of the string
				int matchStart = pos - line.offset;
				charIndexed = new CharIndexedSegment(line,matchStart);
				match = checkRule.startRegexp.getMatch(
					charIndexed,0,RE.REG_ANCHORINDEX);
				if(match == null)
					return false;
				else if(match.getStartIndex() != 0)
					throw new InternalError("Can't happen");
				else
				{
					matchedChars = match.getEndIndex();
					/* workaround for hang if match was
					 * zero-width. not sure if there is
					 * a better way to handle this */
					if(matchedChars == 0)
						matchedChars = 1;
				}
			}
		} //}}}

		//{{{ Check for an escape sequence
		if((checkRule.action & ParserRule.IS_ESCAPE) == ParserRule.IS_ESCAPE)
		{
			if(context.inRule != null)
				handleRule(context.inRule,true);

			escaped = !escaped;
			pos += pattern.count - 1;
		}
		else if(escaped)
		{
			escaped = false;
			pos += pattern.count - 1;
		} //}}}
		//{{{ Handle start of rule
		else if(!end)
		{
			if(context.inRule != null)
				handleRule(context.inRule,true);

			markKeyword((checkRule.action & ParserRule.MARK_PREVIOUS)
				!= ParserRule.MARK_PREVIOUS);

			switch(checkRule.action & ParserRule.MAJOR_ACTIONS)
			{
			//{{{ SEQ
			case ParserRule.SEQ:
				context.spanEndSubst = null;

				if((checkRule.action & ParserRule.REGEXP) != 0)
				{
					handleTokenWithSpaces(tokenHandler,
						checkRule.token,
						pos - line.offset,
						matchedChars,
						context);
				}
				else
				{
					tokenHandler.handleToken(line,
						checkRule.token,
						pos - line.offset,
						matchedChars,context);
				}

				// a DELEGATE attribute on a SEQ changes the
				// ruleset from the end of the SEQ onwards
				if(checkRule.delegate != null)
				{
					context = new LineContext(
						checkRule.delegate,
						context.parent);
					keywords = context.rules.getKeywords();
				}
				break;
			//}}}
			//{{{ SPAN, EOL_SPAN
			case ParserRule.SPAN:
			case ParserRule.EOL_SPAN:
				context.inRule = checkRule;

				byte tokenType = ((checkRule.action & ParserRule.EXCLUDE_MATCH)
					== ParserRule.EXCLUDE_MATCH
					? context.rules.getDefault() : checkRule.token);

				if((checkRule.action & ParserRule.REGEXP) != 0)
				{
					handleTokenWithSpaces(tokenHandler,
						tokenType,
						pos - line.offset,
						matchedChars,
						context);
				}
				else
				{
					tokenHandler.handleToken(line,tokenType,
						pos - line.offset,
						matchedChars,context);
				}

				char[] spanEndSubst = null;
				/* substitute result of matching the rule start
				 * into the end string.
				 *
				 * eg, in shell script mode, <<\s*(\w+) is
				 * matched into \<$1\> to construct rules for
				 * highlighting read-ins like this <