window.onerror = function(){return true};


	/** /// Constants /// */
	var SUDOKU_SCRIPT     = "/script/getsudoku.php"; // where to get sudokus??

	var SUDOKU_PREFIX     = "_sudoku";	// div id prefix

	var DEFAULT_RATING    = "easy";		// default rating
	var WAIT_INTERVAL     = 100;		// time to wait for mutex in microseconds


	/** COLORS */
	var FIELD_SIZE	        		= 24;		// number fields will be FIELD_SIZE x FIELD_SIZE pixels

	var FIELD_COLOR       			= "#f0f0f0";  	// background color of fields without hints
	var FIELD_COLOR_FOCUS			= "#cccccc";

	var FIELD_COLOR_HINTS 			= "#9bd5e6"; 	// background color of fields with hints
	var FIELD_COLOR_HINTS_FOCUS     	= "#adc0f0";

	var FIELD_COLOR_ERROR 			= "#ff9999";	// background color of fields in errorzone
	var FIELD_COLOR_ERROR_FOCUS		= "#e87474";
	var FIELD_COLOR_ERROR_LOCKED    	= "#ff0000";	// background color of locked fields in errorzone
	var FIELD_COLOR_ERROR_LOCKED_FOCUS	= "#ea0000";



	var FONT_SIZE         = 17;        	// font size in fields
	var SECTION_SIZE      = 4;		// space between sections (3x3)

	var LOADING_TIMEOUT   = 10000;		// how long to wait before asuming timeout
	var LOADING_CODE      =			// code to display when loading sudoku
		'<table width="300" height="100%"><tr height="90%"><td align="center" width="300"><i>loading..</i><img src="../pics/loading.gif"></td></tr></table>';

		var ERROR_CODE        = 		// code to display when an error occures
		'<table width="310" height="310"><tr height="310"><td align="center" width="310"><i>an error occured!<br /><a href="http://www.sudokus2go.com/">click here to refresh the webpage.</a></i></td></tr></table>';
	var ERROR_AJAX	      = 		// no ajax! :(
		'<table width="310" height="310"><tr height="310"><td align="center" width="310"><i>Your browser is too old for this sudoku game :(<br />Please upgrade your browser and come back.</i></td></tr></table>';
	var ERROR_DB	      =
		'<table width="310" height="310"><tr height="310"><td align="center" width="310"><i>we are currently updating the sudoku database.. <br />please check back later :)</i></td></tr></table>';

	var RATING_EASY		  = 'Easy';
	var RATING_MEDIUM	  = 'Medium';
	var RATING_HARD		  = 'Hard';
	var RATING_EVIL		  = 'Evil';

	
	var ERROR_X = 0;
	var ERROR_Y = 1;
	var ERROR_B = 2;


	// MOVEMENT
	var KEY_UP    = 38;
	var KEY_DOWN  = 40;
	var KEY_LEFT  = 37;
	var KEY_RIGHT = 39;


	/** /// Globals /// */
	var hasBoard        = false;
	var boardHTML       = "";

	var isDownloading = false;
	var sudokuId      = "";
	var sudokuString  = "";
	var sudokuSolved  = "";
	var sudokuRating  = "";
	var sudokuPerm    = "";

	var sudokuBoard   = new Array(9);
	var sudokuLocked  = new Array(9);
	var sudokuBlock   = new Array(9);
	var sudokuError   = new Array(3);	// does the row, column or block contain an error?

	var ajaxLoading   = false;

	var CURRENT_X = -1;
	var CURRENT_Y = -1;


	/** /// Convenient Functions /// */
	function CurrencyFormatted(amount)
	{
		var i = parseInt(amount);
    	t = ''+amount;
		output = (t.substr(t.length-3));
		i = Math.floor(i/1000);

		while(i > 1000) {
      		t = ''+i;
			output = (t.substr(t.length-3)) + '.' + output;
			i = Math.floor(i/1000);
		}
		if (i > 0) {
			output = i + '.' + output;
		}
		return output;
	}
	function getElement(id)
	{
		return document.getElementById(id);
	}
	function setElement(id, str)
	{
		getElement(id).innerHTML = str;
	}
	function setValue(id, val)
	{
		getElement(id).value = val;
	}

	function checkLock(elem)
	{
		var v = elem.id;
		var x = v.charAt(7);
		var y = v.charAt(8);

		if (sudokuLocked[x][y])
		{
			elem.blur();
		}
	}

	/** extern */
	function openwindow()
	{
		window.open("http://sudokus2go.com/showsudoku.php?id=" + sudokuId, "_sudoku");
	}
	function printsudoku()
	{
		window.open("http://sudokus2go.com/printsudoku.php?id=" + sudokuId, "_printsudoku");
	}


	/** check for sudoku logic */
	function checkLogic(checkx, checky)
	{

		/** check x */
		var solved = true;
		var error = false;
		var numbers = new Array(9);
		for (var x = 0; x < 10; x++)
		{
			numbers[x] = false;
		}
		for (var x = 0; x < 9; x++)
		{
			var n = sudokuBoard[x][checky];
			if (n > 0)
			{
				if (numbers[n])
				{
					error = true;
					break;
				}
				numbers[n] = true;


				if (!(sudokuError[ERROR_B][ sudokuBlock[x][checky] ] ||
				      sudokuError[ERROR_Y][ x ]))
				{
					if (sudokuLocked[x][checky])
					{
						getElement(SUDOKU_PREFIX + x + checky).style.background = FIELD_COLOR_HINTS;
					}
					else
					{
						getElement(SUDOKU_PREFIX + x + checky).style.background = FIELD_COLOR;
					}
				}

			}
			else
			{
				solved = false;
				if (!sudokuError[ERROR_B][ sudokuBlock[x][checky] ] &&
				    !sudokuError[ERROR_Y][ x ])
				{
					getElement(SUDOKU_PREFIX + x + checky).style.background = FIELD_COLOR;
				}
			}
		}
		sudokuError[ERROR_X][checky] = error;
		if (error)
		{
			solved = false;
			for (var x = 0; x < 9; x++)
			{
				if (sudokuLocked[x][checky])
				{
					getElement(SUDOKU_PREFIX + x + checky).style.background = FIELD_COLOR_ERROR_LOCKED;
				}
				else
				{
					getElement(SUDOKU_PREFIX + x + checky).style.background = FIELD_COLOR_ERROR;
				}
			}
		}



		/** check y */
		error = false;
		for (var y = 0; y < 10; y++)
		{
			numbers[y] = false;
		}
		for (var y = 0; y < 9; y++)
		{
			var n = sudokuBoard[checkx][y];
			if (n > 0)
			{
				if (numbers[n])
				{
					error = true;
					break;
				}
				numbers[n] = true;


				if (!(sudokuError[ERROR_B][ sudokuBlock[checkx][y] ] ||
				      sudokuError[ERROR_X][ y ]))
				{
					if (sudokuLocked[checkx][y])
					{
						getElement(SUDOKU_PREFIX + checkx + y).style.background = FIELD_COLOR_HINTS;
					}
					else
					{
						getElement(SUDOKU_PREFIX + checkx + y).style.background = FIELD_COLOR;
					}
				}
			}
			else
			{
				solved = false;
				if (!(sudokuError[ERROR_B][ sudokuBlock[checkx][y] ] ||
				      sudokuError[ERROR_X][ y ]))
				{
					getElement(SUDOKU_PREFIX + checkx + y).style.background = FIELD_COLOR;
				}
			}
		}
		sudokuError[ERROR_Y][checkx] = error;
		if (error)
		{
			solved = false;
			for (var y = 0; y < 9; y++)
			{
				if (sudokuLocked[checkx][y])
				{
					getElement(SUDOKU_PREFIX + checkx + y).style.background = FIELD_COLOR_ERROR_LOCKED;
				}
				else
				{
					getElement(SUDOKU_PREFIX + checkx + y).style.background = FIELD_COLOR_ERROR;
				}
			}
		}


		/** check block */
		error = false;
		var blockx = Math.floor(checkx / 3) * 3;
		var blocky = Math.floor(checky / 3) * 3;
		var breaking = false;

		for (var y = 0; y < 10; y++)
		{
			numbers[y] = false;
		}
		for (var y = 0; y < 3; y++)
		{
			var thisy = blocky + y;
			for (var x = 0; x < 3; x++)
			{
				var thisx = blockx + x;
				var n = sudokuBoard[thisx][thisy];
				if (n > 0)
				{
					if (numbers[n])
					{
						error = true;
						breaking = true;
						break;
					}
					numbers[n] = true;


					if (!(sudokuError[ERROR_X][ thisy ] ||
					      sudokuError[ERROR_Y][ thisx ]))
					{
						if (sudokuLocked[thisx][thisy])
						{
							getElement(SUDOKU_PREFIX + thisx + thisy).style.background = FIELD_COLOR_HINTS;
						}
						else
						{
							getElement(SUDOKU_PREFIX + thisx + thisy).style.background = FIELD_COLOR;
						}
					}
				}
				else
				{
					solved = false;
					if (!(sudokuError[ERROR_X][ thisy ] ||
						sudokuError[ERROR_Y][ thisx ]))
					{
						getElement(SUDOKU_PREFIX + thisx + thisy).style.background = FIELD_COLOR;
					}
				}

			}
			if (breaking)
			{
				break;
			}
		}
		var blockn = sudokuBlock[blockx][blocky];
		sudokuError[ERROR_B][blockn] = error;
		if (error)
		{
			solved = false;
			for (var y = 0; y < 3; y++)
			{
				var thisy = blocky + y;
				for (var x = 0; x < 3; x++)
				{
					var thisx = blockx + x;

					if (sudokuLocked[thisx][thisy])
					{
						getElement(SUDOKU_PREFIX + thisx + thisy).style.background = FIELD_COLOR_ERROR_LOCKED;
					}
					else
					{
						getElement(SUDOKU_PREFIX + thisx + thisy).style.background = FIELD_COLOR_ERROR;
					}
				}
			}
		}

		if (solved) {
			var really_solved = true;
			for(var x = 0; x < 9; x++) {
				for(var y = 0; y < 9; y++) {
					if(sudokuBoard[x][y] == 0) {
						really_solved = false;
						break;
					}
				}
			}
			if(really_solved) {
				alert('Congratulations! You solved the Sudoku! :)');
			}
		}

	}


	/** /// Sudoku Functions /// */
	/** get sudoku */
	function loadSudokuRandomExt(rating, symmetric)
	{
		if (rating == null)
		{
			rating = DEFAULT_RATING;
		}
		if (symmetric == null)
		{
			symmetric = (Math.random() * 2 < 1) ? "true" : "false";
		}

		sudokuRating = rating;

		setElement("sudokuBoard", LOADING_CODE);
		sudokuId     = "";
		sudokuString = "";
		sudokuSolved = "";

		ajaxLoading = true;
		downloadSudoku(null, rating, symmetric, loadSudokuRandomExtCallback);
	}
	function loadSudokuById(sid)
	{
		if (sid == null)
		{
			sid = 0;
		}

		setElement("sudokuBoard", LOADING_CODE);
		sudokuId     = "";
		sudokuString = "";
		sudokuSolved = "";

		ajaxLoading = true;
		downloadSudoku(sid, null, null, loadSudokuRandomExtCallback);
	}
	function loadSudokuRandom()
	{
		loadSudokuRandomExt(null, null);
	}
	function loadSudokuRandomExtCallback(responseText)
	{
		if (responseText)
		{
			ajaxLoading = false;
			sudokuString = responseText.substring(0,81);
			sudokuSolved = responseText.substring(81);
			sudokuPerm   = responseText.substring(162,171);
			sudokuId     = responseText.substring(171);
			setElement("sudokuLink", "open sudoku #"+CurrencyFormatted(sudokuId)+" in a new window");

			if (!parseSudoku())
			{
				getElement("sudokuBoard").innerHTML = ERROR_DB;
				return false;
			}
			showSudoku(false);

			if (getElement("rating"))
			{
				switch(sudokuRating)
				{
					case "easy":
						getElement("rating").innerHTML = RATING_EASY;
						break;
					case "medium":
						getElement("rating").innerHTML = RATING_MEDIUM;
						break;
					case "hard":
						getElement("rating").innerHTML = RATING_HARD;
						break;
					case "evil":
						getElement("rating").innerHTML = RATING_EVIL;
						break;
				}
			}
		}
		else
		{
			ajaxLoading = false;
			setElement("sudokuBoard", ERROR_CODE);
		}
	}

	/** download sudoku */
	function downloadSudoku(sid, rating, symmetric, callback)
	{
		isDownloading = true;

		if (sid == null)
		{
			sudokuString = xml_request(SUDOKU_SCRIPT + "?rating=" + rating + "&symmetric=" + symmetric, callback);
		}
		else
		{
			sudokuString = xml_request(SUDOKU_SCRIPT + "?id=" + sid, callback);
		}

		isDownloading = false;

	}


	/** convert sudoku string to array */
	function parseSudoku(isResetting)
	{
		var sudokuSolvedPerm = "";

		var i = 0;
		var zero = "0".charCodeAt(0);
		for (var y = 0; y < 9; y++)
		{
			for (var x = 0; x < 9; x++)
			{
				var c = sudokuString.charCodeAt(i) - zero;
				if (c < 10 && c > 0)
				{
					sudokuBoard[x][y] = sudokuPerm.charAt(c-1);
					sudokuSolvedPerm += sudokuPerm.charAt(c-1);
				}
				else if(c == 0)
				{
					sudokuBoard[x][y] = 0;

					var sc = sudokuSolved.charCodeAt(i) - zero;
					sudokuSolvedPerm += sudokuPerm[sc-1];
				}
				else
				{
					return false;
				}

				++i;
			}
		}
		sudokuSolved = isResetting ? sudokuSolved : sudokuSolvedPerm;
		return true;
	}

	/** generate HTML code for sudoku */
	function showSudoku(isResetting)
	{
		/** check if html code for sudokuBoard has already been generated */
		if (hasBoard)
		{
			setElement("sudokuBoard", boardHTML);
			for (var y = 0; y < 9; y++)
			{
				for (var x = 0; x < 9; x++)
				{
					if(sudokuBoard[x][y] > 0)
					{
						var elem = getElement(SUDOKU_PREFIX + x + y);
						elem.value = sudokuBoard[x][y];
						elem.style.background = FIELD_COLOR_HINTS;
						sudokuLocked[x][y] = true;
					}
					else
					{
						var elem = getElement(SUDOKU_PREFIX + x + y);
						elem.value = "";
						elem.style.background = FIELD_COLOR;
						sudokuLocked[x][y] = false;
					}
				}
			}
			boardHTML = getElement("sudokuBoard").innerHTML;
			getElement(SUDOKU_PREFIX + "44").focus();
		}
		else
		{
			var FORMAT = "border: 1px solid #000000; text-align: center; font-size: " + FONT_SIZE + "px; width: " + FIELD_SIZE + "px; height: " + FIELD_SIZE + "px;";
			var PREFIX = '<td><input id="_sudoku';
			var MIDDLE = '" onfocus="_focus(this)" onblur="_blur(this)" onKeyDown="return _keydown(event, this)" value="';

			var STYLE0 = '" maxlength="1" style="' + FORMAT + " background: " + FIELD_COLOR_HINTS + ";" + '"';
			var STYLE1 = '" maxlength="1" style="' + FORMAT + " background: " + FIELD_COLOR + ";" + '"';

			var SUFFIX = '></input></td>';

			var TRSPACE = '<tr style="height: ' + SECTION_SIZE + 'px;"><td><img src="/pics/spacer.gif"></td></tr>';
			var TDSPACE = '<td style="width: ' + SECTION_SIZE + 'px;"><img src="/pics/spacer.gif"></td>';

			var html = '<table cellpadding="0" cellpadding="0">';
			for (var y = 0; y < 9; y++)
			{

				/** space */
				if (y % 3 == 0 && y != 0)
				{
					html = html + TRSPACE;
				}

				html = html + '<tr>';
				for (var x = 0; x < 9; x++)
				{

					if (x % 3 == 0 && x != 0)
					{
						html = html + TDSPACE;
					}

					if (sudokuBoard[x][y] > 0)
					{
						html = html + PREFIX + x + y
							    + MIDDLE + sudokuBoard[x][y]
							    + STYLE0
							    + SUFFIX;
						sudokuLocked[x][y] = true;
					}
					else
					{
						html = html + PREFIX + x + y
							    + MIDDLE
							    + STYLE1
							    + SUFFIX;
						sudokuLocked[x][y] = false;
					}
				}
				html = html + '</tr>';
			}
			html = html + '</table>';

			boardHTML = html;
			setElement("sudokuBoard", html);

			hasBoard = true;

		}

	}

	/** hint */
	/** hint */
	function getHint()
	{
		var sx = 0;
		var sy = 0;
		if (CURRENT_X != -1 && CURRENT_Y != -1 && sudokuBoard[CURRENT_X][CURRENT_Y] == 0) {
			sx = CURRENT_X;
			sy = CURRENT_Y;
		} else {
			sx = Math.floor(Math.random()*9);
			sy = Math.floor(Math.random()*9);
		}

		var x;
		var y;
		if (sudokuBoard[sx][sy] > 0)
		{

			x = (sx == 8) ? 0 : sx + 1;
			y = (sy == 8) ? 0 : sy + 1;

			while (x != sx || y != sy)
			{

				if (sudokuBoard[x][y] == 0) {
					break;
				}

				x++;
				if (x == 9) {
					x = 0;
					y = (y == 8) ? 0 : y + 1;
				}
			}
		}
		else
		{
			x = sx;
			y = sy;
		}

		if (sudokuBoard[x][y] == 0)
		{
			var n = sudokuSolved.charAt(x*1 + y*9);

			sudokuBoard[x][y] = n;
			getElement(SUDOKU_PREFIX + x + y).value = n;
			checkLogic(x, y);
		}

	}

	/** reset */
	function reset()
	{

		var agree = confirm("Reset Sudoku??");
		if (agree)
		{

			for (var i = 0; i < 3; i++)
			{
				for (var j = 0; j < 9; j++)
				{
					sudokuError[i][j] = false;
				}
			}

			parseSudoku();
			showSudoku(true);

		}
	}



	/** /// EVENTS /// */
	function _focus(elem)
	{
		var v = elem.id;
		var checkx = v.charAt(7);
		var checky = v.charAt(8);

		CURRENT_X = parseInt(checkx);
		CURRENT_Y = parseInt(checky);

		var error =	sudokuError[ERROR_X][ checky ] ||
				sudokuError[ERROR_Y][ checkx ] ||
				sudokuError[ERROR_B][ sudokuBlock[checkx][checky] ];

		if (sudokuLocked[checkx][checky])
		{
			getElement(v).style.background =
				(error) ? FIELD_COLOR_ERROR_LOCKED_FOCUS : FIELD_COLOR_HINTS_FOCUS;
		}
		else
		{
			getElement(v).style.background =
				(error) ? FIELD_COLOR_ERROR_FOCUS : FIELD_COLOR_FOCUS;
		}

		return true;
	}

	function _blur(elem)
	{
		var v = elem.id;
		var checkx = v.charAt(7);
		var checky = v.charAt(8);

		var error =	sudokuError[ERROR_X][ checky ] ||
				sudokuError[ERROR_Y][ checkx ] ||
				sudokuError[ERROR_B][ sudokuBlock[checkx][checky] ];

		if (sudokuLocked[checkx][checky])
		{
			getElement(v).style.background =
				(error) ? FIELD_COLOR_ERROR_LOCKED : FIELD_COLOR_HINTS;
		}
		else
		{
			getElement(v).style.background =
				(error) ? FIELD_COLOR_ERROR : FIELD_COLOR;
		}
		return true;
	}

	function _keydown(event, elem)
	{

		var v = elem.id;
		var checkx = v.charAt(7);
		var checky = v.charAt(8);

		var n = event.keyCode ? event.keyCode : event.charCode; //sudokuBoard[checkx][checky];

		if (n >= 49 && n <= 57)
		{
			if (!sudokuLocked[checkx][checky])
			{
				var v = n - 48;
				sudokuBoard[checkx][checky] = v;
				checkLogic(checkx, checky);
				elem.value = v;
			}
			getElement(SUDOKU_PREFIX + checkx + checky).blur();
			getElement(SUDOKU_PREFIX + checkx + checky).focus();
			return false;
		}
		else if (n >= 97 && n <= 105)
		{
			if (!sudokuLocked[checkx][checky])
			{
				var v = n - 96;
				sudokuBoard[checkx][checky] = v;
				checkLogic(checkx, checky);
				elem.value = v;
			}
			getElement(SUDOKU_PREFIX + checkx + checky).blur();
			getElement(SUDOKU_PREFIX + checkx + checky).focus();
			return false;
		}
		else if (n >= KEY_LEFT && n <= KEY_DOWN)
		{
			switch (n)
			{
				case KEY_UP:
					checky = (checky > 0) ? checky - 1 : 8;
					break;
				case KEY_DOWN:
					checky = (checky < 8) ? checky - 0 + 1 : 0;
					break;
				case KEY_LEFT:
					checkx = (checkx > 0) ? checkx - 1 : 8;
					break;
				case KEY_RIGHT:
					checkx = (checkx < 8) ? checkx - 0 + 1 : 0;
					break;
			}
			getElement(SUDOKU_PREFIX + checkx + checky).blur();
			getElement(SUDOKU_PREFIX + checkx + checky).focus();
			return false;
		}
		else if (n == 48 || n == 96 || n == 32 || n == 13 || n == 8 || n == 46 || n == 12)
		{
			if (!sudokuLocked[checkx][checky])
			{
				sudokuBoard[checkx][checky] = 0;
				checkLogic(checkx, checky);
				elem.value = "";
				elem.focus();
			}
			getElement(SUDOKU_PREFIX + checkx + checky).blur();
			getElement(SUDOKU_PREFIX + checkx + checky).focus();
			return false;
		}
		else
		{
			getElement(SUDOKU_PREFIX + checkx + checky).blur();
			elem.focus();
			return false;
		}

	}


	/** /// INIT /// */
	for (var i = 0; i < 9; i++)
	{
		sudokuBoard[i]  = new Array(9);
		sudokuLocked[i] = new Array(9);
		sudokuBlock[i]  = new Array(9);
		for (var j = 0; j < 9; j++)
		{
			sudokuBlock[i][j] = Math.floor(i / 3) + Math.floor(j / 3) * 3;
		}
	}
	for (var i = 0; i < 3; i++)
	{
		sudokuError[i] = new Array(9);
		for (var j = 0; j < 9; j++)
		{
			sudokuError[i][j] = false;
		}
	}