/*
 * 04/13/2001 - 18:46:16
 *
 * TextUtilities.java - Utility functions used by the text area classes
 * Copyright (C) 1999, 2000 Slava Pestov
 *
 * 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.textarea;

import javax.swing.text.*;
import java.util.ArrayList;
import org.gjt.sp.jedit.syntax.*;

/**
 * Class with several utility functions used by the text area component.
 * This is a special version based on v 1.8 adapted by Matt Benson for Jext.
 * @author Slava Pestov
 * @author Matt Benson
 * @version $Id: TextUtilities.java,v 1.1.1.1 2001/08/20 22:32:16 gfx Exp $
 */
public class TextUtilities
{
	public static final String BRACKETS = "([{}])";

	public static final int FORWARD = 1;
	public static final int BACKWARD = -1;
	

/**
 * Returns an ArrayList filled with Tokens
 * linked to the argument token, in the order specified.
 * @param token   The initial Token that links to the others.
 * @param dir     The int representation of the ordering to be
 *                used when filling the ArrayList.
 */	
	private static ArrayList getTokenList(Token token, int dir)
	{
		ArrayList tokenList = new ArrayList();
		while (token != null)
		{
			if (token.id == Token.END)
			{
				token = null;
			}//end if token.id == Token.END
			else
			{
// The following is just a trick--size * 1 >= 0 but size * -1 <= 0
				tokenList.add(Math.max(0, (tokenList.size() * dir)), token);
				token = token.next;
			}//end else
		}//end while token != null
		return tokenList;
	}//end getTokenList

		
/**
 * Returns the offset of the bracket matching the one at the
 * specified offset of the document, or -1 if the bracket is
 * unmatched (or if the character is not a bracket).
 * @param doc The document
 * @param offset The offset
 * @exception BadLocationException If an out-of-bounds access
 * was attempted on the document text
 * @since jEdit 3.0pre1
 */
	public static int findMatchingBracket(SyntaxDocument doc, int offset)
	 throws BadLocationException
	{
		if (doc.getLength() == 0)
			return -1;

		Element map = doc.getDefaultRootElement();
		Element lineElement = doc.getParagraphElement(offset);
		Segment lineText = new Segment();
		int lineStart = lineElement.getStartOffset();
		int lineLength = lineElement.getEndOffset() - lineStart - 1;
		int line = map.getElementIndex(lineStart);
		doc.getText(lineStart, lineLength, lineText);
		offset-= lineStart;

		char c;
		try
		{
			c = lineText.array[lineText.offset + offset];//the character
		}//end try 
		catch(ArrayIndexOutOfBoundsException e)//for when cursor is positioned at offset 0.
		{
			c = (char)0;
		}//end catch ArrayIndexOutOfBoundsException
		
		int whichBracket = BRACKETS.indexOf(c);
		if (whichBracket == -1)
		{
			return whichBracket;
		}//end if whichBracket == -1
		char cprime = //corresponding character
		 BRACKETS.charAt(BRACKETS.length() - 1 - whichBracket);
		int direction = (whichBracket < BRACKETS.length() / 2) ? FORWARD : BACKWARD;
		
/* I didn't like the old switch statement.
 * Also I changed direction to an int which should be pos/neg 1 for ease in counting
 * with merged search logic as compared to SP versions which search bkwd & fwd separately.
 * Actually the merged search is pretty sloppy but Slava included the comment in an earlier
 * version that he was leaving the merge as an exercise to the reader, so I took him up on it.
 */
		TokenMarker tokenMarker = doc.getTokenMarker();
		
		if (tokenMarker == null)
		{
			return -1;
		}//end if tokenMarker == null
		
		ArrayList tokenList =
		 getTokenList(tokenMarker.markTokens(lineText, line), direction);
		
// Get the syntax token at 'offset'
// only tokens with the same type will be checked for
// the corresponding bracket
		byte idOfBracket = Token.INVALID;//default to invalid
		
		int tokenListOffset = 0;
		int tok = ((direction == FORWARD) ? 0 : tokenList.size() - 1);
		boolean foundBracket = false;
		do
		{
			Token testToken = null;
			try
			{
				testToken = (Token)tokenList.get(tok);
			}//end try 
			catch (IndexOutOfBoundsException oob)
			{
				return -1;
			}//end catch IndexOutOfBoundsException
			tokenListOffset+= testToken.length;
			if (tokenListOffset > offset)
			{
				idOfBracket = testToken.id;
				if (direction == FORWARD)
				{
					tokenListOffset-= testToken.length;
				}//end if FORWARD
				foundBracket = true;
			}//end if this Token
			else
			{
				tok+= direction;
			}//end else
		} while (!foundBracket);//end do while loop
		
		if (idOfBracket == Token.INVALID)
		{
			return -1;
		}//end if idOfBracket == Token.INVALID
		
		int count = 0;
		int repetitions =
		 ((direction == FORWARD) ? map.getElementCount() - line : line + 1);

		for (int i = 0; i < repetitions; i++)
		{
// get text
			int index = line + (i * direction);
			lineElement = map.getElement(index);
			lineStart = lineElement.getStartOffset();
			lineLength = lineElement.getEndOffset() - lineStart - 1;
			doc.getText(lineStart, lineLength, lineText);

			int scanStartOffset;
			if (index != line)
			{
				tokenList =
				 getTokenList(tokenMarker.markTokens(lineText, line), direction);
				tok = 0;
				if (direction == FORWARD)
				{
					scanStartOffset = tokenListOffset = 0;
				}//end if direction == FORWARD
				else
				{
					tokenListOffset = lineLength;
					scanStartOffset = tokenListOffset - 1;
				}//end else
				
			}//end if not original line
			else
			{
				scanStartOffset = offset;
			}//end else 

			for (; tok < tokenList.size(); tok++)
			{
				Token currTok = (Token)(tokenList.get(tok));
				byte id = currTok.id;
				int len = currTok.length;
				
// only check tokens with id 'idOfBracket'
				if (id == idOfBracket)
				{
					char[] word = new char[len];
					int wordOffset = tokenListOffset +
						 ((direction == FORWARD) ? 0 : (direction * word.length));
					
					for (int j = 0; j < word.length; j++)
					{
						word[j] = lineText.array[lineText.offset + wordOffset + j];
					}//end for thru word
					
					int oppositeEnd = ((direction == FORWARD) ? 0 : word.length -1);
					int wordSearch = scanStartOffset - wordOffset - direction;
//set it 1 different than what we really want b/c we increment in the beginning of the loop
					do
					{
						wordSearch+= direction;
						char ch = word[wordSearch];
						if (ch == c)
						{
							count++;
						}//end if ch == c
							
						else if (ch == cprime)
						{
								if (--count == 0)
								{
									return lineStart + wordOffset + wordSearch;
								}
						}//end else
					} while ((wordSearch + oppositeEnd + 1) != word.length);
				}//end if id == idOfBracket

//the following skips to the next token offset by adding len of curr. token
					tokenListOffset+= (len * direction);
					scanStartOffset = tokenListOffset;
					if (direction == BACKWARD)
					{
						scanStartOffset--;
					}//end if 
			}//end for tok...
		}//end for i

// Nothing found
		return -1;
	}//end getMatchingBracket

	
/**
 * Locates the start of the word at the specified position.
 * @param line The text
 * @param pos The position
 * @param noWordSep Characters that are non-alphanumeric, but
 * should be treated as word characters anyway
 */
	public static int findWordStart(String line, int pos, String noWordSep)
	{
		char ch = line.charAt(pos);

		if (noWordSep == null)
			noWordSep = "";
		boolean selectNoLetter = (!Character.isLetterOrDigit(ch)
		 && noWordSep.indexOf(ch) == -1);

		int wordStart = 0;
		for(int i = pos; i >= 0; i--)
		{
			ch = line.charAt(i);
			if (selectNoLetter ^ (!Character.isLetterOrDigit(ch) &&
			 noWordSep.indexOf(ch) == -1))
			{
				wordStart = i + 1;
				break;
			}//end if 
		}//end for i

		return wordStart;
	}//end findWordStart

/**
* Locates the end of the word at the specified position.
* @param line The text
* @param pos The position
* @param noWordSep Characters that are non-alphanumeric, but
* should be treated as word characters anyway
*/
	public static int findWordEnd(String line, int pos, String noWordSep)
	{
		if (pos != 0)
		{
			pos--;
		}//end if pos != 0

		char ch = line.charAt(pos);

		if (noWordSep == null)
		{
			noWordSep = "";
		}//end if noWordSep == null
		boolean selectNoLetter = (!Character.isLetterOrDigit(ch)
			&& noWordSep.indexOf(ch) == -1);

		int wordEnd = line.length();
		for(int i = pos; i < line.length(); i++)
		{
			ch = line.charAt(i);
			if (selectNoLetter ^ (!Character.isLetterOrDigit(ch) &&
			 noWordSep.indexOf(ch) == -1))
			{
				wordEnd = i;
				break;
			}//end if
		}//end for i
		return wordEnd;
	}//end findWordEnd

	
/**
* Locates the next character type change searching in the specified direction.
* Included for use with Jext's CsWord Action.
* @param line        The text.
* @param pos         The position.
* @param direction   The direction in which the search should be made.
*/
	public static int findTypeChange(String line, int pos, int direction)
	{
		int type = Character.getType(line.charAt(pos));

		for (int i = pos + direction; ; i+= direction)
		{
			try
			{
				if (Character.getType(line.charAt(i)) != type)
				{
					return i;
				}//end if
			}//end try 
			catch(IndexOutOfBoundsException oobe)
			{
				return i - direction;
			}//end catch
		}//end for i
	}//end findWordEnd
	
}//end class TextUtilities

/*
 * ChangeLog:
 * $Log: TextUtilities.java,v $
 * Revision 1.1.1.1  2001/08/20 22:32:16  gfx
 * Jext 3.0pre5
 *
 * Revision 1.2  2001/04/13 16:55:20  gfx
 *
 * Bug fix by Matt. Benson
 *
 * Revision 1.8  2000/07/15 06:56:29  sp
 * bracket matching debugged
 *
 * Revision 1.7  2000/07/14 06:00:45  sp
 * bracket matching now takes syntax info into account
 *
 * Revision 1.6  2000/01/28 00:20:58  sp
 * Lots of stuff
 *
 * Revision 1.5  1999/12/19 11:14:29  sp
 * Static abbrev expansion started
 *
 * Revision 1.4  1999/12/13 03:40:30  sp
 * Bug fixes, syntax is now mostly GPL'd
 *
 * Revision 1.3  1999/11/21 03:40:18  sp
 * Parts of EditBus not used by core moved to EditBus.jar
 *
 * Revision 1.2  1999/07/16 23:45:49  sp
 * 1.7pre6 BugFree version
 *
 * Revision 1.1  1999/06/29 09:03:18  sp
 * oops, forgot to add TextUtilities.java
 *
 */