// NOTE: x coords = top to bottom; y = left to right (from white player perspective)
class ChessRules
{
+ //////////////
+ // MISC UTILS
+
+ static get HasFlags() { return true; } //some variants don't have flags
+
+ static get HasEnpassant() { return true; } //some variants don't have ep.
+
// Path to pieces
static getPpath(b)
{
return b; //usual pieces in pieces/ folder
}
+
// Turn "wb" into "B" (for FEN)
static board2fen(b)
{
return b[0]=='w' ? b[1].toUpperCase() : b[1];
}
+
// Turn "p" into "bp" (for board)
static fen2board(f)
{
return f.charCodeAt()<=90 ? "w"+f.toLowerCase() : "b"+f;
}
- /////////////////
- // INITIALIZATION
-
- // fen == "position [flags [turn]]"
- constructor(fen, moves)
- {
- this.moves = moves;
- // Use fen string to initialize variables, flags, turn and board
- const fenParts = fen.split(" ");
- this.board = V.GetBoard(fenParts[0]);
- this.setFlags(fenParts[1]); //NOTE: fenParts[1] might be undefined
- this.setTurn(fenParts[2]); //Same note
- this.initVariables(fen);
- }
-
- // Some additional variables from FEN (variant dependant)
- initVariables(fen)
+ // Check if FEN describe a position
+ static IsGoodFen(fen)
{
- this.INIT_COL_KING = {'w':-1, 'b':-1};
- this.INIT_COL_ROOK = {'w':[-1,-1], 'b':[-1,-1]};
- this.kingPos = {'w':[-1,-1], 'b':[-1,-1]}; //squares of white and black king
- const fenParts = fen.split(" ");
- const position = fenParts[0].split("/");
- for (let i=0; i<position.length; i++)
+ const fenParsed = V.ParseFen(fen);
+ // 1) Check position
+ if (!V.IsGoodPosition(fenParsed.position))
+ return false;
+ // 2) Check turn
+ if (!fenParsed.turn || !["w","b"].includes(fenParsed.turn))
+ return false;
+ // 3) Check flags
+ if (V.HasFlags && (!fenParsed.flags || !V.IsGoodFlags(fenParsed.flags)))
+ return false;
+ // 4) Check enpassant
+ if (V.HasEnpassant)
{
- let k = 0; //column index on board
- for (let j=0; j<position[i].length; j++)
+ if (!fenParsed.enpassant)
+ return false;
+ if (fenParsed.enpassant != "-")
{
- switch (position[i].charAt(j))
- {
- case 'k':
- this.kingPos['b'] = [i,k];
- this.INIT_COL_KING['b'] = k;
- break;
- case 'K':
- this.kingPos['w'] = [i,k];
- this.INIT_COL_KING['w'] = k;
- break;
- case 'r':
- if (this.INIT_COL_ROOK['b'][0] < 0)
- this.INIT_COL_ROOK['b'][0] = k;
- else
- this.INIT_COL_ROOK['b'][1] = k;
- break;
- case 'R':
- if (this.INIT_COL_ROOK['w'][0] < 0)
- this.INIT_COL_ROOK['w'][0] = k;
- else
- this.INIT_COL_ROOK['w'][1] = k;
- break;
- default:
- const num = parseInt(position[i].charAt(j));
- if (!isNaN(num))
- k += (num-1);
- }
- k++;
+ const ep = V.SquareToCoords(fenParsed.enpassant);
+ if (ep.y < 0 || ep.y > V.size.y || isNaN(ep.x) || ep.x < 0 || ep.x > V.size.x)
+ return false;
}
}
- this.epSquares = [ this.getEpSquare(this.lastMove || fenParts[3]) ];
+ return true;
}
- // Check if FEN describe a position
- static IsGoodFen(fen)
+ // Is position part of the FEN a priori correct?
+ static IsGoodPosition(position)
{
- const fenParts = fen.split(" ");
- if (fenParts.length== 0)
+ if (position.length == 0)
return false;
- // 1) Check position
- const position = fenParts[0];
const rows = position.split("/");
if (rows.length != V.size.x)
return false;
if (sumElts != V.size.y)
return false;
}
- // 2) Check flags (if present)
- if (fenParts.length >= 2)
- {
- if (!V.IsGoodFlags(fenParts[1]))
- return false;
- }
- // 3) Check turn (if present)
- if (fenParts.length >= 3)
- {
- if (!["w","b"].includes(fenParts[2]))
- return false;
- }
return true;
}
return !!flags.match(/^[01]{4,4}$/);
}
- // Turn diagram fen into double array ["wb","wp","bk",...]
- static GetBoard(fen)
+ // 3 --> d (column letter from number)
+ static GetColumn(colnum)
+ {
+ return String.fromCharCode(97 + colnum);
+ }
+
+ // a4 --> {x:3,y:0}
+ static SquareToCoords(sq)
+ {
+ return {
+ x: V.size.x - parseInt(sq.substr(1)),
+ y: sq[0].charCodeAt() - 97
+ };
+ }
+
+ // {x:0,y:4} --> e8
+ static CoordsToSquare(coords)
+ {
+ return V.GetColumn(coords.y) + (V.size.x - coords.x);
+ }
+
+ // Aggregates flags into one object
+ aggregateFlags()
+ {
+ return this.castleFlags;
+ }
+
+ // Reverse operation
+ disaggregateFlags(flags)
+ {
+ this.castleFlags = flags;
+ }
+
+ // En-passant square, if any
+ getEpSquare(moveOrSquare)
+ {
+ if (!moveOrSquare)
+ return undefined;
+ if (typeof moveOrSquare === "string")
+ {
+ const square = moveOrSquare;
+ if (square == "-")
+ return undefined;
+ return V.SquareToCoords(square);
+ }
+ // Argument is a move:
+ const move = moveOrSquare;
+ const [sx,sy,ex] = [move.start.x,move.start.y,move.end.x];
+ if (this.getPiece(sx,sy) == V.PAWN && Math.abs(sx - ex) == 2)
+ {
+ return {
+ x: (sx + ex)/2,
+ y: sy
+ };
+ }
+ return undefined; //default
+ }
+
+ // Can thing on square1 take thing on square2
+ canTake([x1,y1], [x2,y2])
+ {
+ return this.getColor(x1,y1) !== this.getColor(x2,y2);
+ }
+
+ // Is (x,y) on the chessboard?
+ static OnBoard(x,y)
{
- const rows = fen.split(" ")[0].split("/");
+ return (x>=0 && x<V.size.x && y>=0 && y<V.size.y);
+ }
+
+ // Used in interface: 'side' arg == player color
+ canIplay(side, [x,y])
+ {
+ return (this.turn == side && this.getColor(x,y) == side);
+ }
+
+ // On which squares is opponent under check after our move ? (for interface)
+ getCheckSquares(move)
+ {
+ this.play(move);
+ const color = this.turn; //opponent
+ let res = this.isAttacked(this.kingPos[color], [this.getOppCol(color)])
+ ? [JSON.parse(JSON.stringify(this.kingPos[color]))] //need to duplicate!
+ : [];
+ this.undo(move);
+ return res;
+ }
+
+ /////////////
+ // FEN UTILS
+
+ // Setup the initial random (assymetric) position
+ static GenRandInitFen()
+ {
+ let pieces = { "w": new Array(8), "b": new Array(8) };
+ // Shuffle pieces on first and last rank
+ for (let c of ["w","b"])
+ {
+ let positions = _.range(8);
+
+ // Get random squares for bishops
+ let randIndex = 2 * _.random(3);
+ let bishop1Pos = positions[randIndex];
+ // The second bishop must be on a square of different color
+ let randIndex_tmp = 2 * _.random(3) + 1;
+ let bishop2Pos = positions[randIndex_tmp];
+ // Remove chosen squares
+ positions.splice(Math.max(randIndex,randIndex_tmp), 1);
+ positions.splice(Math.min(randIndex,randIndex_tmp), 1);
+
+ // Get random squares for knights
+ randIndex = _.random(5);
+ let knight1Pos = positions[randIndex];
+ positions.splice(randIndex, 1);
+ randIndex = _.random(4);
+ let knight2Pos = positions[randIndex];
+ positions.splice(randIndex, 1);
+
+ // Get random square for queen
+ randIndex = _.random(3);
+ let queenPos = positions[randIndex];
+ positions.splice(randIndex, 1);
+
+ // Rooks and king positions are now fixed, because of the ordering rook-king-rook
+ let rook1Pos = positions[0];
+ let kingPos = positions[1];
+ let rook2Pos = positions[2];
+
+ // Finally put the shuffled pieces in the board array
+ pieces[c][rook1Pos] = 'r';
+ pieces[c][knight1Pos] = 'n';
+ pieces[c][bishop1Pos] = 'b';
+ pieces[c][queenPos] = 'q';
+ pieces[c][kingPos] = 'k';
+ pieces[c][bishop2Pos] = 'b';
+ pieces[c][knight2Pos] = 'n';
+ pieces[c][rook2Pos] = 'r';
+ }
+ return pieces["b"].join("") +
+ "/pppppppp/8/8/8/8/PPPPPPPP/" +
+ pieces["w"].join("").toUpperCase() +
+ " w 1111 -"; //add turn + flags + enpassant
+ }
+
+ // "Parse" FEN: just return untransformed string data
+ static ParseFen(fen)
+ {
+ const fenParts = fen.split(" ");
+ let res =
+ {
+ position: fenParts[0],
+ turn: fenParts[1],
+ };
+ let nextIdx = 2;
+ if (V.HasFlags)
+ Object.assign(res, {flags: fenParts[nextIdx++]});
+ if (V.HasEnpassant)
+ Object.assign(res, {enpassant: fenParts[nextIdx]});
+ return res;
+ }
+
+ // Return current fen (game state)
+ getFen()
+ {
+ return this.getBaseFen() + " " + this.turn +
+ (V.HasFlags ? (" " + this.getFlagsFen()) : "") +
+ (V.HasEnpassant ? (" " + this.getEnpassantFen()) : "");
+ }
+
+ // Position part of the FEN string
+ getBaseFen()
+ {
+ let position = "";
+ for (let i=0; i<V.size.x; i++)
+ {
+ let emptyCount = 0;
+ for (let j=0; j<V.size.y; j++)
+ {
+ if (this.board[i][j] == V.EMPTY)
+ emptyCount++;
+ else
+ {
+ if (emptyCount > 0)
+ {
+ // Add empty squares in-between
+ position += emptyCount;
+ emptyCount = 0;
+ }
+ position += V.board2fen(this.board[i][j]);
+ }
+ }
+ if (emptyCount > 0)
+ {
+ // "Flush remainder"
+ position += emptyCount;
+ }
+ if (i < V.size.x - 1)
+ position += "/"; //separate rows
+ }
+ return position;
+ }
+
+ // Flags part of the FEN string
+ getFlagsFen()
+ {
+ let flags = "";
+ // Add castling flags
+ for (let i of ['w','b'])
+ {
+ for (let j=0; j<2; j++)
+ flags += (this.castleFlags[i][j] ? '1' : '0');
+ }
+ return flags;
+ }
+
+ // Enpassant part of the FEN string
+ getEnpassantFen()
+ {
+ const L = this.epSquares.length;
+ if (!this.epSquares[L-1])
+ return "-"; //no en-passant
+ return V.CoordsToSquare(this.epSquares[L-1]);
+ }
+
+ // Turn position fen into double array ["wb","wp","bk",...]
+ static GetBoard(position)
+ {
+ const rows = position.split("/");
let board = doubleArray(V.size.x, V.size.y, "");
for (let i=0; i<rows.length; i++)
{
this.castleFlags[i < 2 ? 'w' : 'b'][i%2] = (fenflags.charAt(i) == '1');
}
- // Initialize turn (white or black)
- setTurn(turnflag)
+ //////////////////
+ // INITIALIZATION
+
+ // Fen string fully describes the game state
+ constructor(fen, moves)
+ {
+ this.moves = moves;
+ const fenParsed = V.ParseFen(fen);
+ this.board = V.GetBoard(fenParsed.position);
+ this.turn = (fenParsed.turn || "w");
+ this.setOtherVariables(fen);
+ }
+
+ // Scan board for kings and rooks positions
+ scanKingsRooks(fen)
{
- this.turn = turnflag || "w";
+ this.INIT_COL_KING = {'w':-1, 'b':-1};
+ this.INIT_COL_ROOK = {'w':[-1,-1], 'b':[-1,-1]};
+ this.kingPos = {'w':[-1,-1], 'b':[-1,-1]}; //squares of white and black king
+ const fenRows = V.ParseFen(fen).position.split("/");
+ for (let i=0; i<fenRows.length; i++)
+ {
+ let k = 0; //column index on board
+ for (let j=0; j<fenRows[i].length; j++)
+ {
+ switch (fenRows[i].charAt(j))
+ {
+ case 'k':
+ this.kingPos['b'] = [i,k];
+ this.INIT_COL_KING['b'] = k;
+ break;
+ case 'K':
+ this.kingPos['w'] = [i,k];
+ this.INIT_COL_KING['w'] = k;
+ break;
+ case 'r':
+ if (this.INIT_COL_ROOK['b'][0] < 0)
+ this.INIT_COL_ROOK['b'][0] = k;
+ else
+ this.INIT_COL_ROOK['b'][1] = k;
+ break;
+ case 'R':
+ if (this.INIT_COL_ROOK['w'][0] < 0)
+ this.INIT_COL_ROOK['w'][0] = k;
+ else
+ this.INIT_COL_ROOK['w'][1] = k;
+ break;
+ default:
+ const num = parseInt(fenRows[i].charAt(j));
+ if (!isNaN(num))
+ k += (num-1);
+ }
+ k++;
+ }
+ }
}
- ///////////////////
- // GETTERS, SETTERS
+ // Some additional variables from FEN (variant dependant)
+ setOtherVariables(fen)
+ {
+ // Set flags and enpassant:
+ const parsedFen = V.ParseFen(fen);
+ if (V.HasFlags)
+ this.setFlags(parsedFen.flags);
+ if (V.HasEnpassant)
+ {
+ const epSq = parsedFen.enpassant != "-"
+ ? V.SquareToCoords(parsedFen.enpassant)
+ : undefined;
+ this.epSquares = [ epSq ];
+ }
+ // Search for king and rooks positions:
+ this.scanKingsRooks(fen);
+ }
- static get size() { return {x:8, y:8}; }
+ /////////////////////
+ // GETTERS & SETTERS
- // Two next functions return 'undefined' if called on empty square
- getColor(i,j) { return this.board[i][j].charAt(0); }
- getPiece(i,j) { return this.board[i][j].charAt(1); }
+ static get size()
+ {
+ return {x:8, y:8};
+ }
- // Color
- getOppCol(color) { return (color=="w" ? "b" : "w"); }
+ // Color of thing on suqare (i,j). 'undefined' if square is empty
+ getColor(i,j)
+ {
+ return this.board[i][j].charAt(0);
+ }
- get lastMove() {
+ // Piece type on square (i,j). 'undefined' if square is empty
+ getPiece(i,j)
+ {
+ return this.board[i][j].charAt(1);
+ }
+
+ // Get opponent color
+ getOppCol(color)
+ {
+ return (color=="w" ? "b" : "w");
+ }
+
+ get lastMove()
+ {
const L = this.moves.length;
return (L>0 ? this.moves[L-1] : null);
}
- // Pieces codes
+ // Pieces codes (for a clearer code)
static get PAWN() { return 'p'; }
static get ROOK() { return 'r'; }
static get KNIGHT() { return 'n'; }
static get KING() { return 'k'; }
// For FEN checking:
- static get PIECES() {
+ static get PIECES()
+ {
return [V.PAWN,V.ROOK,V.KNIGHT,V.BISHOP,V.QUEEN,V.KING];
}
// Empty square
- static get EMPTY() { return ''; }
+ static get EMPTY() { return ""; }
// Some pieces movements
- static get steps() {
+ static get steps()
+ {
return {
'r': [ [-1,0],[1,0],[0,-1],[0,1] ],
'n': [ [-1,-2],[-1,2],[1,-2],[1,2],[-2,-1],[-2,1],[2,-1],[2,1] ],
};
}
- // Aggregates flags into one object
- get flags() {
- return this.castleFlags;
- }
-
- // Reverse operation
- parseFlags(flags)
- {
- this.castleFlags = flags;
- }
-
- // En-passant square, if any
- getEpSquare(moveOrSquare)
- {
- if (typeof moveOrSquare === "string")
- {
- const square = moveOrSquare;
- if (square == "-")
- return undefined;
- return {
- x: square[0].charCodeAt()-97,
- y: V.size.x-parseInt(square[1])
- };
- }
- // Argument is a move:
- const move = moveOrSquare;
- const [sx,sy,ex] = [move.start.x,move.start.y,move.end.x];
- if (this.getPiece(sx,sy) == V.PAWN && Math.abs(sx - ex) == 2)
- {
- return {
- x: (sx + ex)/2,
- y: sy
- };
- }
- return undefined; //default
- }
-
- // Can thing on square1 take thing on square2
- canTake([x1,y1], [x2,y2])
- {
- return this.getColor(x1,y1) !== this.getColor(x2,y2);
- }
-
- ///////////////////
+ ////////////////////
// MOVES GENERATION
// All possible moves from selected square (assumption: color is OK)
return mv;
}
- // Is (x,y) on the chessboard?
- static OnBoard(x,y)
- {
- return (x>=0 && x<V.size.x && y>=0 && y<V.size.y);
- }
-
// Generic method to find possible moves of non-pawn pieces ("sliding or jumping")
getSlideNJumpMoves([x,y], steps, oneStep)
{
// En passant
const Lep = this.epSquares.length;
- const epSquare = (Lep>0 ? this.epSquares[Lep-1] : undefined);
+ const epSquare = this.epSquares[Lep-1]; //always at least one element
if (!!epSquare && epSquare.x == x+shift && Math.abs(epSquare.y - y) == 1)
{
const epStep = epSquare.y - y;
return moves;
}
- ///////////////////
+ ////////////////////
// MOVES VALIDATION
- canIplay(side, [x,y])
- {
- return (this.turn == side && this.getColor(x,y) == side);
- }
-
getPossibleMovesFrom(sq)
{
// Assuming color is right (already checked)
return false;
}
- // Check if pieces of color in array 'colors' are attacking square x,y
+ // Check if pieces of color in array 'colors' are attacking (king) on square x,y
isAttacked(sq, colors)
{
return (this.isAttackedByPawn(sq, colors)
return res;
}
- // On which squares is opponent under check after our move ?
- getCheckSquares(move)
- {
- this.play(move);
- const color = this.turn; //opponent
- let res = this.isAttacked(this.kingPos[color], [this.getOppCol(color)])
- ? [ JSON.parse(JSON.stringify(this.kingPos[color])) ] //need to duplicate!
- : [ ];
- this.undo(move);
- return res;
- }
+ /////////////////
+ // MOVES PLAYING
// Apply a move on board
static PlayOnBoard(board, move)
}
}
- // After move is undo-ed, un-update variables (flags are reset)
- // TODO: more symmetry, by storing flags increment in move...
+ // After move is undo-ed *and flags resetted*, un-update other variables
+ // TODO: more symmetry, by storing flags increment in move (?!)
unupdateVariables(move)
{
// (Potentially) Reset king position
this.kingPos[c] = [move.start.x, move.start.y];
}
- // Hash of position+flags+turn after a move is played (to detect repetitions)
- getHashState()
- {
- return hex_md5(this.getFen());
- }
-
play(move, ingame)
{
// DEBUG:
// if (!this.states) this.states = [];
-// if (!ingame) this.states.push(JSON.stringify(this.board));
+// if (!ingame) this.states.push(this.getFen());
if (!!ingame)
move.notation = [this.getNotation(move), this.getLongNotation(move)];
- move.flags = JSON.stringify(this.flags); //save flags (for undo)
+ if (V.HasFlags)
+ move.flags = JSON.stringify(this.aggregateFlags()); //save flags (for undo)
this.updateVariables(move);
this.moves.push(move);
- this.epSquares.push( this.getEpSquare(move) );
+ if (V.HasEnpassant)
+ this.epSquares.push( this.getEpSquare(move) );
this.turn = this.getOppCol(this.turn);
V.PlayOnBoard(this.board, move);
if (!!ingame)
- move.hash = this.getHashState();
+ {
+ // Hash of current game state *after move*, to detect repetitions
+ move.hash = hex_md5(this.getFen());
+ }
}
undo(move)
{
V.UndoOnBoard(this.board, move);
this.turn = this.getOppCol(this.turn);
- this.epSquares.pop();
+ if (V.HasEnpassant)
+ this.epSquares.pop();
this.moves.pop();
this.unupdateVariables(move);
- this.parseFlags(JSON.parse(move.flags));
+ if (V.HasFlags)
+ this.disaggregateFlags(JSON.parse(move.flags));
// DEBUG:
-// if (JSON.stringify(this.board) != this.states[this.states.length-1])
+// if (this.getFen() != this.states[this.states.length-1])
// debugger;
// this.states.pop();
}
- //////////////
+ ///////////////
// END OF GAME
// Check for 3 repetitions (position + flags + turn)
return color == "w" ? "0-1" : "1-0";
}
- ////////
- //ENGINE
+ ///////////////
+ // ENGINE PLAY
// Pieces values
- static get VALUES() {
+ static get VALUES()
+ {
return {
'p': 1,
'r': 5,
};
}
- static get INFINITY() {
- return 9999; //"checkmate" (unreachable eval)
- }
+ // "Checkmate" (unreachable eval)
+ static get INFINITY() { return 9999; }
- static get THRESHOLD_MATE() {
- // At this value or above, the game is over
- return V.INFINITY;
- }
+ // At this value or above, the game is over
+ static get THRESHOLD_MATE() { return V.INFINITY; }
- static get SEARCH_DEPTH() {
- return 3; //2 for high branching factor, 4 for small (Loser chess)
- }
+ // Search depth: 2 for high branching factor, 4 for small (Loser chess, eg.)
+ static get SEARCH_DEPTH() { return 3; }
// Assumption: at least one legal move
// NOTE: works also for extinction chess because depth is 3...
let finish = (Math.abs(this.evalPosition()) >= V.THRESHOLD_MATE);
if (!finish && !this.atLeastOneMove())
{
- // Try mate (for other variants)
+ // Test mate (for other variants)
const score = this.checkGameEnd();
if (score != "1/2")
finish = true;
evalPos = this.evalPosition()
else
{
- // Work with scores for Loser variant
+ // Working with scores is more accurate (necessary for Loser variant)
const score = this.checkGameEnd();
evalPos = (score=="1/2" ? 0 : (score=="1-0" ? 1 : -1) * maxeval);
}
this.undo(moves1[i]);
}
moves1.sort( (a,b) => { return (color=="w" ? 1 : -1) * (b.eval - a.eval); });
- //console.log(moves1.map(m => { return [this.getNotation(m), m.eval]; }));
let candidates = [0]; //indices of candidates moves
for (let j=1; j<moves1.length && moves1[j].eval == moves1[0].eval; j++)
return evaluation;
}
- ////////////
- // FEN utils
-
- // Setup the initial random (assymetric) position
- static GenRandInitFen()
- {
- let pieces = { "w": new Array(8), "b": new Array(8) };
- // Shuffle pieces on first and last rank
- for (let c of ["w","b"])
- {
- let positions = _.range(8);
-
- // Get random squares for bishops
- let randIndex = 2 * _.random(3);
- let bishop1Pos = positions[randIndex];
- // The second bishop must be on a square of different color
- let randIndex_tmp = 2 * _.random(3) + 1;
- let bishop2Pos = positions[randIndex_tmp];
- // Remove chosen squares
- positions.splice(Math.max(randIndex,randIndex_tmp), 1);
- positions.splice(Math.min(randIndex,randIndex_tmp), 1);
-
- // Get random squares for knights
- randIndex = _.random(5);
- let knight1Pos = positions[randIndex];
- positions.splice(randIndex, 1);
- randIndex = _.random(4);
- let knight2Pos = positions[randIndex];
- positions.splice(randIndex, 1);
-
- // Get random square for queen
- randIndex = _.random(3);
- let queenPos = positions[randIndex];
- positions.splice(randIndex, 1);
-
- // Rooks and king positions are now fixed, because of the ordering rook-king-rook
- let rook1Pos = positions[0];
- let kingPos = positions[1];
- let rook2Pos = positions[2];
-
- // Finally put the shuffled pieces in the board array
- pieces[c][rook1Pos] = 'r';
- pieces[c][knight1Pos] = 'n';
- pieces[c][bishop1Pos] = 'b';
- pieces[c][queenPos] = 'q';
- pieces[c][kingPos] = 'k';
- pieces[c][bishop2Pos] = 'b';
- pieces[c][knight2Pos] = 'n';
- pieces[c][rook2Pos] = 'r';
- }
- return pieces["b"].join("") +
- "/pppppppp/8/8/8/8/PPPPPPPP/" +
- pieces["w"].join("").toUpperCase() +
- " 1111 w"; //add flags + turn
- }
-
- // Return current fen according to pieces+colors state
- getFen()
- {
- return this.getBaseFen() + " " + this.getFlagsFen() + " " + this.turn;
- }
-
- // Position part of the FEN string
- getBaseFen()
- {
- let fen = "";
- for (let i=0; i<V.size.x; i++)
- {
- let emptyCount = 0;
- for (let j=0; j<V.size.y; j++)
- {
- if (this.board[i][j] == V.EMPTY)
- emptyCount++;
- else
- {
- if (emptyCount > 0)
- {
- // Add empty squares in-between
- fen += emptyCount;
- emptyCount = 0;
- }
- fen += V.board2fen(this.board[i][j]);
- }
- }
- if (emptyCount > 0)
- {
- // "Flush remainder"
- fen += emptyCount;
- }
- if (i < V.size.x - 1)
- fen += "/"; //separate rows
- }
- return fen;
- }
-
- // Flags part of the FEN string
- getFlagsFen()
- {
- let fen = "";
- // Add castling flags
- for (let i of ['w','b'])
- {
- for (let j=0; j<2; j++)
- fen += (this.castleFlags[i][j] ? '1' : '0');
- }
- return fen;
- }
+ /////////////////////////
+ // MOVES + GAME NOTATION
+ /////////////////////////
// Context: just before move is played, turn hasn't changed
getNotation(move)
return (move.end.y < move.start.y ? "0-0-0" : "0-0");
// Translate final square
- const finalSquare = String.fromCharCode(97 + move.end.y) + (V.size.x-move.end.x);
+ const finalSquare = V.CoordsToSquare(move.end);
const piece = this.getPiece(move.start.x, move.start.y);
if (piece == V.PAWN)
// Complete the usual notation, may be required for de-ambiguification
getLongNotation(move)
{
- const startSquare =
- String.fromCharCode(97 + move.start.y) + (V.size.x-move.start.x);
- const finalSquare = String.fromCharCode(97 + move.end.y) + (V.size.x-move.end.x);
- return startSquare + finalSquare; //not encoding move. But short+long is enough
+ // Not encoding move. But short+long is enough
+ return V.CoordsToSquare(move.start) + V.CoordsToSquare(move.end);
}
// The score is already computed when calling this function