w: ['b', 'q'],
x: ['b', 'k'],
y: ['q', 'q'],
- z: ['q', 'k']
+ z: ['q', 'k'],
+ '_': ['k', 'k']
};
}
if (position.length == 0) return false;
const rows = position.split("/");
if (rows.length != V.size.x) return false;
- let kingSymb = ['k', 'g', 'm', 'u', 'x'];
+ let kingSymb = ['k', 'g', 'm', 'u', 'x', '_'];
let kings = { 'k': 0, 'K': 0 };
for (let row of rows) {
let sumElts = 0;
for (let i = 0; i < row.length; i++) {
const lowR = row[i].toLowerCase
- if (!!(row[i].toLowerCase().match(/[a-z]/))) {
+ if (!!(row[i].toLowerCase().match(/[a-z_]/))) {
sumElts++;
if (kingSymb.includes(row[i])) kings['k']++;
- else if (kingSymb.some(s => row[i] == s.toUpperCase())) kings['K']++;
+ // Not "else if", if two kings dancing together
+ if (kingSymb.some(s => row[i] == s.toUpperCase())) kings['K']++;
}
else {
const num = parseInt(row[i], 10);
this.kingPos = { w: [-1, -1], b: [-1, -1] };
const fenRows = V.ParseFen(fen).position.split("/");
const startRow = { 'w': V.size.x - 1, 'b': 0 };
- const kingSymb = ['k', 'g', 'm', 'u', 'x'];
+ const kingSymb = ['k', 'g', 'm', 'u', 'x', '_'];
for (let i = 0; i < fenRows.length; i++) {
let k = 0;
for (let j = 0; j < fenRows[i].length; j++) {
const c = fenRows[i].charAt(j);
- if (kingSymb.includes(c))
- this.kingPos["b"] = [i, k];
- else if (kingSymb.some(s => c == s.toUpperCase()))
- this.kingPos["w"] = [i, k];
+ if (!!(c.toLowerCase().match(/[a-z_]/))) {
+ if (kingSymb.includes(c))
+ this.kingPos["b"] = [i, k];
+ // Not "else if", in case of two kings dancing together
+ if (kingSymb.some(s => c == s.toUpperCase()))
+ this.kingPos["w"] = [i, k];
+ }
else {
const num = parseInt(fenRows[i].charAt(j), 10);
if (!isNaN(num)) k += num - 1;
return true;
}
+ static IsGoodFlags(flags) {
+ // 4 for castle + 16 for pawns
+ return !!flags.match(/^[a-z]{4,4}[01]{16,16}$/);
+ }
+
+ setFlags(fenflags) {
+ super.setFlags(fenflags); //castleFlags
+ this.pawnFlags = {
+ w: [...Array(8)], //pawns can move 2 squares?
+ b: [...Array(8)]
+ };
+ const flags = fenflags.substr(4); //skip first 4 letters, for castle
+ for (let c of ["w", "b"]) {
+ for (let i = 0; i < 8; i++)
+ this.pawnFlags[c][i] = flags.charAt((c == "w" ? 0 : 8) + i) == "1";
+ }
+ }
+
+ aggregateFlags() {
+ return [this.castleFlags, this.pawnFlags];
+ }
+
+ disaggregateFlags(flags) {
+ this.castleFlags = flags[0];
+ this.pawnFlags = flags[1];
+ }
+
getUmove(move) {
if (
move.vanish.length == 1 &&
}
static GenRandInitFen(randomness) {
- // Add empty umove
- return ChessRules.GenRandInitFen(randomness) + " -";
+ // Add 16 pawns flags + empty umove:
+ return ChessRules.GenRandInitFen(randomness)
+ .slice(0, -2) + "1111111111111111 - -";
+ }
+
+ getFlagsFen() {
+ let fen = super.getFlagsFen();
+ // Add pawns flags
+ for (let c of ["w", "b"])
+ for (let i = 0; i < 8; i++) fen += (this.pawnFlags[c][i] ? "1" : "0");
+ return fen;
}
getUmoveFen() {
this.board[x][y] = this.turn + piece;
}
let baseMoves = [];
+ const c = this.turn;
switch (piece || this.getPiece(x, y)) {
- case V.PAWN:
- baseMoves = this.getPotentialPawnMoves([x, y]);
+ case V.PAWN: {
+ const firstRank = (c == 'w' ? 7 : 0);
+ baseMoves = this.getPotentialPawnMoves([x, y]).filter(m => {
+ // Skip forbidden 2-squares jumps (except from first rank)
+ // Also skip unions capturing en-passant (not allowed).
+ return (
+ (
+ m.start.x == firstRank ||
+ Math.abs(m.end.x - m.start.x) == 1 ||
+ this.pawnFlags[c][m.start.y]
+ )
+ &&
+ (
+ this.board[x][y].charAt(1) == V.PAWN ||
+ m.start.y == m.end.y
+ )
+ );
+ });
break;
+ }
case V.ROOK:
baseMoves = this.getPotentialRookMoves([x, y]);
break;
// When a pawn in an union reaches final rank with a non-standard
// promotion move: apply promotion anyway
let moves = [];
- const c = this.turn;
const oppCol = V.GetOppCol(c);
const oppLastRank = (c == 'w' ? 7 : 0);
baseMoves.forEach(m => {
!!m1 &&
!(ChessRules.PIECES.includes(m2.appear[0].p)) &&
m2.vanish.length == 1 &&
+ !m2.released &&
m1.start.x == m2.end.x &&
m1.end.x == m2.start.x &&
m1.start.y == m2.end.y &&
);
}
- // Do not consider checks for now (TODO)
- underCheck() {
+ getCastleMoves([x, y]) {
+ const c = this.getColor(x, y);
+ const oppCol = V.GetOppCol(c);
+ let moves = [];
+ const finalSquares = [ [2, 3], [6, 5] ];
+ castlingCheck: for (let castleSide = 0; castleSide < 2; castleSide++) {
+ if (this.castleFlags[c][castleSide] >= 8) continue;
+ const rookPos = this.castleFlags[c][castleSide];
+ const castlingColor = this.board[x][rookPos].charAt(0);
+ const castlingPiece = this.board[x][rookPos].charAt(1);
+
+ // Nothing on the path of the king ?
+ const finDist = finalSquares[castleSide][0] - y;
+ let step = finDist / Math.max(1, Math.abs(finDist));
+ let i = y;
+ let kingSquares = [y];
+ do {
+ if (
+ (
+ this.board[x][i] != V.EMPTY &&
+ (this.getColor(x, i) != c || ![y, rookPos].includes(i))
+ )
+ ) {
+ continue castlingCheck;
+ }
+ i += step;
+ kingSquares.push(i);
+ } while (i != finalSquares[castleSide][0]);
+ // No checks on the path of the king ?
+ if (this.isAttacked(kingSquares, oppCol)) continue castlingCheck;
+
+ // Nothing on the path to the rook?
+ step = castleSide == 0 ? -1 : 1;
+ for (i = y + step; i != rookPos; i += step) {
+ if (this.board[x][i] != V.EMPTY) continue castlingCheck;
+ }
+
+ // Nothing on final squares, except maybe king and castling rook?
+ for (i = 0; i < 2; i++) {
+ if (
+ finalSquares[castleSide][i] != rookPos &&
+ this.board[x][finalSquares[castleSide][i]] != V.EMPTY &&
+ (
+ finalSquares[castleSide][i] != y ||
+ this.getColor(x, finalSquares[castleSide][i]) != c
+ )
+ ) {
+ continue castlingCheck;
+ }
+ }
+
+ moves.push(
+ new Move({
+ appear: [
+ new PiPo({
+ x: x,
+ y: finalSquares[castleSide][0],
+ p: V.KING,
+ c: c
+ }),
+ new PiPo({
+ x: x,
+ y: finalSquares[castleSide][1],
+ p: castlingPiece,
+ c: castlingColor
+ })
+ ],
+ vanish: [
+ // King might be initially disguised (Titan...)
+ new PiPo({ x: x, y: y, p: V.KING, c: c }),
+ new PiPo({ x: x, y: rookPos, p: castlingPiece, c: castlingColor })
+ ],
+ end:
+ Math.abs(y - rookPos) <= 2
+ ? { x: x, y: rookPos }
+ : { x: x, y: y + 2 * (castleSide == 0 ? -1 : 1) }
+ })
+ );
+ }
+
+ return moves;
+ }
+
+ getEnpassantCaptures(sq, shiftX) {
+ // HACK: when artificially change turn, do not consider en-passant
+ const mcMod2 = this.movesCount % 2;
+ const c = this.turn;
+ if ((c == 'w' && mcMod2 == 1) || (c == 'b' && mcMod2 == 0)) return [];
+ return super.getEnpassantCaptures(sq, shiftX);
+ }
+
+ isAttacked_aux(files, color, positions, fromSquare, released) {
+ // "positions" = array of FENs to detect infinite loops. Example:
+ // r1q1k2r/p1Pb1ppp/5n2/1f1p4/AV5P/P1eDP3/3B1PP1/R3K1NR,
+ // Bxd2 Bxc3 Bxb4 Bxc3 Bxb4 etc.
+ const newPos = { fen: super.getBaseFen(), piece: released };
+ if (positions.some(p => p.piece == newPos.piece && p.fen == newPos.fen))
+ // Start of an infinite loop: exit
+ return false;
+ positions.push(newPos);
+ const rank = (color == 'w' ? 0 : 7);
+ const moves = this.getPotentialMovesFrom(fromSquare);
+ if (moves.some(m => m.end.x == rank && files.includes(m.end.y)))
+ // Found an attack!
+ return true;
+ for (let m of moves) {
+ if (!!m.released) {
+ // Turn won't change since !!m.released
+ this.play(m);
+ const res = this.isAttacked_aux(
+ files, color, positions, [m.end.x, m.end.y], m.released);
+ this.undo(m);
+ if (res) return true;
+ }
+ }
return false;
}
+
+ isAttacked(files, color) {
+ const rank = (color == 'w' ? 0 : 7);
+ // Since it's too difficult (impossible?) to search from the square itself,
+ // let's adopt a suboptimal but working strategy: find all attacks.
+ const c = this.turn;
+ // Artificial turn change is required:
+ this.turn = color;
+ let res = false;
+ outerLoop: for (let i=0; i<8; i++) {
+ for (let j=0; j<8; j++) {
+ // Attacks must start from a normal piece, not an union.
+ // Therefore, the following test is correct.
+ if (
+ this.board[i][j] != V.EMPTY &&
+ // Do not start with king (irrelevant, and lead to infinite calls)
+ [V.PAWN, V.ROOK, V.KNIGHT, V.BISHOP, V.QUEEN].includes(
+ this.board[i][j].charAt(1)) &&
+ this.board[i][j].charAt(0) == color
+ ) {
+ // Try from here.
+ const moves = this.getPotentialMovesFrom([i, j]);
+ if (moves.some(m => m.end.x == rank && files.includes(m.end.y))) {
+ res = true;
+ break outerLoop;
+ }
+ for (let m of moves) {
+ if (!!m.released) {
+ // Turn won't change since !!m.released
+ this.play(m);
+ let positions = [];
+ res = this.isAttacked_aux(
+ files, color, positions, [m.end.x, m.end.y], m.released);
+ this.undo(m);
+ if (res) break outerLoop;
+ }
+ }
+ }
+ }
+ }
+ this.turn = c;
+ return res;
+ }
+
+ // Do not consider checks, except to forbid castling
getCheckSquares() {
return [];
}
}
play(move) {
+ move.flags = JSON.stringify(this.aggregateFlags());
this.epSquares.push(this.getEpSquare(move));
// Check if the move is the last of the turn: all cases except releases
if (!move.released) {
this.postPlay(move);
}
+ updateCastleFlags(move, piece) {
+ const c = V.GetOppCol(this.turn);
+ const firstRank = (c == "w" ? 7 : 0);
+ const oppCol = this.turn;
+ const oppFirstRank = 7 - firstRank;
+ if (piece == V.KING && move.appear.length > 0)
+ this.castleFlags[c] = [V.size.y, V.size.y];
+ else if (
+ move.start.x == firstRank &&
+ this.castleFlags[c].includes(move.start.y)
+ ) {
+ const flagIdx = (move.start.y == this.castleFlags[c][0] ? 0 : 1);
+ this.castleFlags[c][flagIdx] = V.size.y;
+ }
+ // No more checking: a rook in union can take part in castling.
+ }
+
postPlay(move) {
if (move.vanish.length == 0)
- // A piece released just moved. Cannot be the king.
+ // A released piece just moved. Cannot be the king.
return;
const c = move.vanish[0].c;
const piece = move.vanish[0].p;
if (piece == V.KING)
this.kingPos[c] = [move.appear[0].x, move.appear[0].y];
this.updateCastleFlags(move, piece);
+ if (
+ [1, 6].includes(move.start.x) &&
+ move.vanish.length >= 1 &&
+ move.appear.length == 1
+ ) {
+ // Does this move turn off a 2-squares pawn flag?
+ if (
+ move.vanish[0].p == V.PAWN ||
+ (
+ !(ChessRules.PIECES.includes(move.vanish[0].p)) &&
+ this.getUnionPieces(move.vanish[0].c, move.vanish[0].p)[c] == V.PAWN
+ )
+ ) {
+ this.pawnFlags[move.start.x == 6 ? "w" : "b"][move.start.y] = false;
+ }
+ }
}
undo(move) {
this.epSquares.pop();
+ this.disaggregateFlags(JSON.parse(move.flags));
V.UndoOnBoard(this.board, move);
this.lastMoveEnd.pop();
if (!move.released) {
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