// Trollbot ICS

// Configuration:
// The name of the div where the chessboard will go
var gBoardDiv           = 'chessboard';

// The name of the div where the chess game attributes go
var gAttributesDiv      = 'attributes';

// The name of the div where the chess controls go
var gControlsDiv        = 'controls';

// The name of the div where the javascript check message goes
var gJavascriptCheckDiv = 'javascriptcheck';

// The name of the div where the moves are displayed
var gMovesDiv           = 'moves';

// Image path for pieces
var gImagePath          = './images/';

// Display the rank and file on the board
var gDisplayRankFile    = true;

// Don't modify these
var gCurMove             = 0;
var gCurSide             = 'white';
var gCurBoard            = false;
var gBoardStates         = false;
var gCurBoardTable       = false;
var gNumMoves            = 0;
var gStopped             = false;


function internalNotation(external)
{
	var retval = false;

	switch (external)
	{
		case '1':
		case 1:
			retval = 7;
			break;
		case '2':
		case 2:
			retval = 6;
			break;
		case '3':
		case 3:
			retval = 5;
			break;
		case '4':
		case 4:
			retval = 4;
			break;
		case '5':
		case 5:
			retval = 3;
			break;
		case '6':
		case 6:
			retval = 2;
			break;
		case '7':
		case 7:
			retval = 1;
			break;
		case '8':
		case 8:
			retval = 0;
			break;
		case 'a':
			retval = 0;
			break;
		case 'b':
			retval = 1;
			break;
		case 'c':
			retval = 2;
			break;
		case 'd':
			retval = 3;
			break;
		case 'e':
			retval = 4;
			break;
		case 'f':
			retval = 5;
			break;
		case 'g':
			retval = 6;
			break;
		case 'h':
			retval = 7;
			break;
	}

	return retval;

}

function externalFileNotation(internal)
{
	var retval = false;

	switch (internal)
	{
		case 0:
			retval = 8;
			break;
		case 1:
			retval = 7;
			break;
		case 2:
			retval = 6;
			break;
		case 3:
			retval = 5;
			break;
		case 4:
			retval = 4;
			break;
		case 5:
			retval = 3;
			break;
		case 6:
			retval = 2;
			break;
		case 7:
			retval = 1;
			break;
		case 8:
			retval = 0;
			break;
	}

	return retval;

}

function externalRankNotation(internal)
{
	var retval = false;

	switch (internal)
	{
		case 0:
			retval = 'a';
			break;
		case 1:
			retval = 'b';
			break;
		case 2:
			retval = 'c';
			break;
		case 3:
			retval = 'd';
			break;
		case 4:
			retval = 'e';
			break;
		case 5:
			retval = 'f';
			break;
		case 6:
			retval = 'g';
			break;
		case 7:
			retval = 'h';
			break;
	}

	return retval;
}


// This takes an existing board state, and calculates the PGN
// and returns the resulting board state
function pgnToInternalRepresentation(last_state, side, pgn)
{
	// Break the PGN format into the following
	var dst_rank     = false;
	var dst_file     = false;

	var src_rank     = false;
	var src_file     = false;
	var src_type     = false;

	var capture_flag = false;
	var check_flag   = false;
	var castle       = false;

	var dis_piece  = false;

	// Castle king's side
	if (pgn == 'O-O')
		return;

	// Castle queen's side
	if (pgn == 'O-O-O')
		return;

	// End game, white won
	if (pgn == '1-0')
		return;

	// End game, black won
	if (pgn == '0-1')
		return;

	// Stalemate/draw
	if (pgn == '1/2-1/2')
		return;

	if (pgn[pgn.length-1] == '+')
	{
		check_flag = true;
		pgn = pgn.substring(0, pgn.length-1);
	}

	dst_file = pgn[pgn.length-1];
	dst_rank = pgn[pgn.length-2];


	pgn = pgn.substring(0, pgn.length-2);

	// We have disambiguation data
	while (pgn.length > 0)
	{
		var dis_data = pgn[pgn.length-1];
		pgn = pgn.substring(0, pgn.length-1);	

		switch (dis_data)
		{
			case 'x':
				capture_flag = true;
				break;
			case 'a':
			case 'b':
			case 'c':
			case 'd':
			case 'e':
			case 'f':
			case 'g':
			case 'h':
				src_rank = dis_data;
				break;
			case '1':
			case '2':
			case '3':
			case '4':
			case '5':
			case '6':
			case '7':
			case '8':
				src_file = dis_data;
				break;
			case 'K':
			case 'k':
			case 'Q':
			case 'q':
			case 'R':
			case 'r':
			case 'B':
			case 'b':
			case 'P':
			case 'p':
			case 'N':
			case 'n':
				src_type = dis_data;
				break;
			default:
				alert('Unhandled PGN: ' + dis_data);
		}
	}
	
	// Translate crap into our notation
	if (dst_file)
	{
		dst_file = internalNotation(dst_file);
	}

	if (dst_rank)
	{
		dst_rank = internalNotation(dst_rank);
	}

	if (src_file)
	{
		src_file = internalNotation(src_file);
	}

	if (src_rank)
	{
		src_rank = internalNotation(src_rank);
	}


	switch (src_type)
	{
		// Brute force it
		case false:
			// Try and find pawn first
			// go through list of other pieces which have a possible move to dst_rank, dst_file
			var pawn_match = false;

			if (capture_flag == true)
			{
				// can split two ways
				if ((dst_rank - 1) > 0 && (dst_file + (1 * ((side == 'white') ? -1 : 1))) > 0)
				{
					if (last_state[dst_rank-1][dst_file+(1 * ((side == 'white') ? -1 : 1))])
					{
						alert('pawn_match');
						pawn_match = true;
						break;
					}
				}
				else if ((dst_rank + 1) > 0 && (dst_file + (1 * ((side == 'white') ? -1 : 1))) > 0)
				{
					if (last_state[dst_rank+(1 * ((side == 'white') ? -1 : 1))][dst_file+1])
					{
						src_rank = dst_rank+(1 * ((side == 'white') ? -1 : 1));
						pawn_match = true;
						break;
					}
				}
			}
			else
			{
				if ((dst_file + (1 * ((side == 'white') ? 1 : -1))) >= 0 && (dst_file + (1 * ((side == 'white') ? 1 : -1))) < 8)
				{
					if (last_state[(dst_file + (1 * ((side == 'white') ? 1 : -1)))][dst_rank] == (((side == 'white') ? 'w' : 'b') + 'p'))
					{
						src_rank = externalRankNotation(dst_rank);
						src_file = externalFileNotation((dst_file + (1 * ((side == 'white') ? 1 : -1)))); 
						
						var newstate = last_state.slice();
						newstate[internalNotation(src_file)][internalNotation(src_rank)] = 't';
				
						newstate[dst_file][dst_rank] = ((side == 'white') ? 'wp' : 'bp');
						return newstate;
					}

					if ((dst_file + (2 * ((side == 'white') ? 1 : -1))) >= 0 && (dst_file + (2 * ((side == 'white') ? 1 : -1))) < 8)
					{
						if (last_state[(dst_file + (2 * ((side == 'white') ? 1 : -1)))][dst_rank] == (((side == 'white') ? 'w' : 'b') + 'p'))
						{
							src_rank = externalRankNotation(dst_rank);
							src_file = externalFileNotation((dst_file + (2 * ((side == 'white') ? 1 : -1)))); 

							var newstate = last_state.slice();
							newstate[internalNotation(src_file)][internalNotation(src_rank)] = 't';

							newstate[dst_file][dst_rank] = ((side == 'white') ? 'wp' : 'bp');
							return newstate;
						}
					}

					return false;
				}
			}
			break;
		case 'K':
		case 'k':
			// it was a king move, find within 1 of dst_file, dst_rank
			//      \ | /
			// 	    - K -
			// 	    / | \
			break;
		case 'Q':
		case 'q':
			// it was a queen move, find within +-8 of dst_file, dst_rank
			//      \ | /
			// 	    - Q -
			// 	    / | \
			for (var i = 0; i < 8; i++)
			{
				for (var j = 0; j < 8; j++)
				{
					// Diagonal left
					//	if (dst_rank + (i - i <= 0 && 
				}
			}
			break;
		case 'b':
		case 'B':
			// it was a bishop move, find within +-8 of dst_file, dst_rank
			//      \   /
			// 	      B  
			// 	    /   \
			break;
		case 'R':
		case 'r':
			// it was a rook move, find within +-8 of dst_file, dst_rank
			//        |  
			// 	    - R -
			// 	      |  
			break;
		case 'N':
		case 'n':
			// It was a knight's move, find within +- 2 dst_rank, +- 1 dst_file
			
			// Checks for movement right 2, forward +1
			var v = (dst_file + (1 * ((side == 'white') ? 1 : -1)));
			var h = (dst_rank - (2 * ((side == 'white') ? 1 : -1)));

			if (v >= 0 && v < 8 && h >= 0 && h < 8)
			{
				if (last_state[v][h] == ((side == 'white') ? "wn" : "bn"))
				{
					src_rank = externalRankNotation(h);
					src_file = externalFileNotation(v); 

					var newstate = last_state.slice();
					newstate[v][h] = 't';

					newstate[dst_file][dst_rank] = ((side == 'white') ? 'wn' : 'bn');
					return newstate;
				}
			}

			// Checks for movement left 2, forward 1
			v = (dst_file - (1 * ((side == 'white') ? 1 : -1)));
			h = (dst_rank - (2 * ((side == 'white') ? 1 : -1)));

			if (v >= 0 && v < 8 && h >= 0 && h < 8)
			{
				if (last_state[v][h] == ((side == 'white') ? "wn" : "bn"))
				{
					src_rank = externalRankNotation(h);
					src_file = externalFileNotation(v); 

					var newstate = last_state.slice();
					newstate[v][h] = 't';

					newstate[dst_file][dst_rank] = ((side == 'white') ? 'wn' : 'bn');
					return newstate;
				}
			}

/*
			// Checks for movement left 2, forward 1
			v = (dst_file - (2 * ((side == 'white') ? 1 : -1)));
			h = (dst_rank - (1 * ((side == 'white') ? 1 : -1)));

			if (v >= 0 && v < 8 && h >= 0 && h < 8)
			{
				alert('duh' + h + v);
				alert(dst_file);
				if (last_state[v][h] == ((side == 'white') ? "wn" : "bn"))
				{
					src_rank = externalRankNotation(h);
					src_file = externalFileNotation(v); 

					var newstate = last_state.slice();
					newstate[v][h] = 't';

					newstate[dst_file][dst_rank] = ((side == 'white') ? 'wn' : 'bn');
					return newstate;
				}
			}
*/

			// Checks for movement left 2, back 1
			v = (dst_file - (1 * ((side == 'white') ? 1 : -1)));
			h = (dst_rank + (2 * ((side == 'white') ? 1 : -1)));

			if (v >= 0 && v < 8 && h >= 0 && h < 8)
			{
				if (last_state[v][h] == ((side == 'white') ? "wn" : "bn"))
				{
					src_rank = externalRankNotation(h);
					src_file = externalFileNotation(v); 

					var newstate = last_state.slice();
					newstate[v][h] = 't';

					newstate[dst_file][dst_rank] = ((side == 'white') ? 'wn' : 'bn');
					return newstate;
				}
			}
			
			if (((dst_file + (2 * ((side == 'white') ? 1 : -1))) >= 0) || ((dst_file + (2 * ((side == 'white') ? 1 : -1))) >= 0))
			{
				if (last_state[(dst_file + (2 * ((side == 'white') ? 1 : -1)))][dst_rank-1] == ((side == 'white') ? 'wn' : 'bn'))
				{
					src_rank = externalRankNotation(dst_rank-1);
					src_file = externalFileNotation((dst_file + (2 * ((side == 'white') ? 1 : -1)))); 

					var newstate = last_state.slice();
					newstate[internalNotation(src_file)][internalNotation(src_rank)] = 't';

					newstate[dst_file][dst_rank] = ((side == 'white') ? 'wn' : 'bn');
					return newstate;
				}
				else if (last_state[(dst_file + (2 * ((side == 'white') ? 1 : -1)))][dst_rank+1] == ((side == 'white') ? 'wn' : 'bn'))
				{
					src_rank = externalRankNotation(dst_rank+1);
					src_file = externalFileNotation((dst_file + (2 * ((side == 'white') ? 1 : -1)))); 

					var newstate = last_state.slice();
					newstate[internalNotation(src_file)][internalNotation(src_rank)] = 't';

					newstate[dst_file][dst_rank] = ((side == 'white') ? 'wn' : 'bn');
					return newstate;
				}
			}

			
			alert('We got to the end of the list without handling anything');
			gStopped = true;
			break;
	}

	return false;
}

function prepareBoardStates()
{
	if (gStopped == true)
		return;

	// Get number of moves
	gNumMoves = gChessBoard.total_moves;
	
	// Create tables of pieces for each move, for each side
	gBoardStates = new Array();

	gBoardStates[0] = {};
	gBoardStates[0].white = gCurBoard.slice();
	gBoardStates[0].black = gCurBoard.slice();

	var toggle = false;
	
	for (var i = 1; i <= gNumMoves; i++)
	{
		gBoardStates[i] = new Array();
		alert(gBoardStates[0].white);
		gBoardStates[i].white = pgnToInternalRepresentation(gBoardStates[i-1].black, 'white', gChessBoard.moves[i].white);
		gBoardStates[i].black = pgnToInternalRepresentation(gBoardStates[i-1].white, 'black', gChessBoard.moves[i].black);
	}
}

function resetBoard()
{
	gCurMove  = 0;
	gCurSide  = 'white';
	gCurBoard = new Array(8);

	for (var y = 0; y < 8; y++)
	{
		gCurBoard[y]      = new Array(8);

		for (var x = 0; x < 8; x++)
		{
			switch (y)
			{
				case 0:
					switch (x)
					{
						case 0:
						case 7:
							gCurBoard[y][x] = "br";
							break;
						case 1:
						case 6:
							gCurBoard[y][x] = "bn";
							break;
						case 2:
						case 5:
							gCurBoard[y][x] = "bb";
							break;
						case 3:
							gCurBoard[y][x] = "bq";
							break;
						case 4:
							gCurBoard[y][x] = "bk";
							break;
					}
					break;
				case 1:
					gCurBoard[y][x] = "bp";
					break;
				case 6:
					gCurBoard[y][x] = "wp";
					break;
				case 7:
					switch (x)
					{
						case 0:
						case 7:
							gCurBoard[y][x] = "wr";
							break;
						case 1:
						case 6:
							gCurBoard[y][x] = "wn";
							break;
						case 2:
						case 5:
							gCurBoard[y][x] = "wb";
							break;
						case 3:
							gCurBoard[y][x] = "wq";
							break;
						case 4:
							gCurBoard[y][x] = "wk";
							break;
					}
					break;
				default:
					gCurBoard[y][x] = "t";
					break;
			}
		}
	}		
}

function goBeginningChessBoard()
{
	resetBoard();
	reDrawBoard();
}

function goEndChessBoard()
{
}

function goForwardChessBoard()
{
	if (gStopped == true)
		return;

	if (gCurMove == 0 || gCurSide == 'black')
	{
		gCurMove++;
		gCurSide = 'white';
	}
	else
	{
		gCurSide = 'black';
	}

	if (gCurSide == 'white')
		gCurBoard = gBoardStates[gCurMove-1].white;
	else
		gCurBoard = gBoardStates[gCurMove-1].black;

//	gCurBoard = pgnToInternalRepresentation(gCurBoard, gCurSide, gChessBoard.moves[gCurMove][gCurSide]);

	if (gCurBoard != false && gStopped != true)
		reDrawBoard();
}

function goBackChessBoard()
{
	if (gCurMove == 0 || gCurMove == 1)
		return;

	if (gCurSide == 'white')
	{
		gCurMove--;
		gCurSide = 'black';
	}
	else
	{
		gCurSide = 'white';
	}

//alert(gChessBoard.moves[gCurMove][gCurSide]);
//	reDrawBoard();
}

function buildMoves()
{
	var lDiv = document.getElementById(gMovesDiv);

	if (lDiv == false)
		return;

	var lTable = document.createElement('table');
	lTable.border = '1';

	var lTr = document.createElement('tr');

	var lTh = document.createElement('th');

	lTh.innerHTML = 'Move #';
	lTr.appendChild(lTh);

	lTh = document.createElement('th');

	lTh.innerHTML = 'White';
	lTr.appendChild(lTh);

	lTh = document.createElement('th');

	lTh.innerHTML = 'Black';
	lTr.appendChild(lTh);

	lTable.appendChild(lTr);
	
	for (var key in gChessBoard.moves)
	{
		lTr = document.createElement('tr');
		
		var lTd = document.createElement('td');
		
		lTd.innerHTML = key;

		lTr.appendChild(lTd);

		lTd = document.createElement('td');

		lTd.innerHTML = gChessBoard.moves[key].white;
	
		lTr.appendChild(lTd);

		lTd = document.createElement('td');

		lTd.innerHTML = gChessBoard.moves[key].black;
	
		lTr.appendChild(lTd);


		lTable.appendChild(lTr);
	}	

	lDiv.appendChild(lTable);
}

function buildControls()
{
	var lDiv = document.getElementById(gControlsDiv);
	
	if (lDiv == false)
		return;

	var lInput = document.createElement('input');
	lInput.type    = 'button';
	lInput.onclick = goBeginningChessBoard;
	lInput.value   = '<<';
	
	lDiv.appendChild(lInput);

	lInput = document.createElement('input');
	lInput.type    = 'button';
	lInput.onclick = goBackChessBoard;
	lInput.value   = '<';

	lDiv.appendChild(lInput);

	lInput = document.createElement('input');
	lInput.type    = 'button';
	lInput.onclick = goForwardChessBoard;
	lInput.value   = '>';

	lDiv.appendChild(lInput);

	lInput = document.createElement('input');
	lInput.type    = 'button';
	lInput.onclick = goEndChessBoard;
	lInput.value   = '>>';

	lDiv.appendChild(lInput);
}

function buildAttributes()
{
	var lDiv   = document.getElementById(gAttributesDiv);

	if (lDiv == false)
		return;

	var lTable = document.createElement('table');
	lTable.border = '1';
	
	for (var key in gChessBoard.attributes)
	{
		var lTr = document.createElement('tr');
		
		var lTd = document.createElement('th');
		
		lTd.innerHTML = key + ':';

		lTr.appendChild(lTd);

		lTd = document.createElement('td');

		lTd.innerHTML = gChessBoard.attributes[key];
	
		lTr.appendChild(lTd);

		lTable.appendChild(lTr);
	}	

	lDiv.appendChild(lTable);
}

function doJavascriptCheck()
{
	var lDiv = document.getElementById(gJavascriptCheckDiv);

	if (lDiv == false)
		return;

	lDiv.innerHTML = '';
}

function startItUp()
{
	resetBoard();
	doJavascriptCheck();
	drawBoard();
	buildAttributes();
	buildControls();
	buildMoves();
	prepareBoardStates();
	resetBoard();
	gStopped = false;
}

function reDrawBoard()
{
	var lDiv = document.getElementById(gBoardDiv);

	if (lDiv == false)
		return;

  for (var j = 0; j < 8; j++)
  {
    for (var i = 0; i < 8; i++)
    {
			gCurBoardTable[j][i].src =  gImagePath + gCurBoard[j][i] + '.gif';
		}
	}

}

function drawBoard()
{
	//SetImagePath("alpha30/");//use this function when your images are in another directory
	var lDiv = document.getElementById(gBoardDiv);

	if (lDiv == false)
		return;

	var lTable = document.createElement('table');
	lTable.cellPadding = '1';
	lTable.cellSpacing = '0';

	gCurBoardTable = new Array(8);

  for (var j = 0; j < 8; j++)
  {
		gCurBoardTable[j] = new Array(8);

		var lTr = document.createElement('tr');
		
    for (var i = 0; i < 8; i++)
    {
			var lTd = document.createElement('td');
			//lTd.style.backgroundColor = (((i % 2 == 1) ^ (j % 2 == 1)) ? "white" : "black");
			
			lTd.style.backgroundImage= "url('" + gImagePath + (((i % 2 == 1) ^ (j % 2 == 1)) ? "w" : "b") + '.gif' + "')";	
			
			var lSquare = document.createElement('img');
			
			lSquare.src = gImagePath + gCurBoard[j][i] + '.gif';
			lSquare.id  = (8*j)+i;
			gCurBoardTable[j][i] = lSquare;

			lTd.appendChild(lSquare);
			lTr.appendChild(lTd);
    }

		if (gDisplayRankFile == true)
		{
			lTd = document.createElement('td');

			lTd.style.textAlign = 'center';

			lTd.innerHTML = externalFileNotation(j);

			lTr.appendChild(lTd);
		}


		lTable.appendChild(lTr);
  }

	// Append an extra tr with tds with rank a-h
	if (gDisplayRankFile == true)
	{
		lTr = document.createElement('tr');
		
		for (i = 0; i < 8; i++)
		{
			lTd = document.createElement('td');
			lTd.style.textAlign = 'center';
			lTd.innerHTML = externalRankNotation(i);
			lTr.appendChild(lTd);
		}
		
		
		lTd = document.createElement('td');
		lTd.style.textAlign = 'center';
		lTd.innerHTML = '#';
		lTr.appendChild(lTd);

		lTable.appendChild(lTr);
	}

	lDiv.appendChild(lTable);
}