- castlingCheck: for (
- let castleSide = 0;
- castleSide < 2;
- castleSide++ //large, then small
- ) {
- if (this.castleFlags[c][castleSide] >= V.size.y) continue;
- // If this code is reached, rook and king are on initial position
-
- // NOTE: in some variants this is not a rook
- const rookPos = this.castleFlags[c][castleSide];
- if (this.board[x][rookPos] == V.EMPTY || this.getColor(x, rookPos) != c)
- // Rook is not here, or changed color (see Benedict)
- continue;
-
- // Nothing on the path of the king ? (and no checks)
- const castlingPiece = this.getPiece(x, rookPos);
- const finDist = finalSquares[castleSide][0] - y;
- let step = finDist / Math.max(1, Math.abs(finDist));
- i = y;
- do {
- if (
- (!castleInCheck && this.isAttacked([x, i], oppCol)) ||
- (this.board[x][i] != V.EMPTY &&
- // NOTE: next check is enough, because of chessboard constraints
- (this.getColor(x, i) != c ||
- ![V.KING, castlingPiece].includes(this.getPiece(x, i))))
- ) {
- continue castlingCheck;
- }
- i += step;
- } while (i != finalSquares[castleSide][0]);
-
- // 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 &&
- (
- this.getPiece(x, finalSquares[castleSide][i]) != V.KING ||
- this.getColor(x, finalSquares[castleSide][i]) != c
- )
- ) {
- continue castlingCheck;
- }
- }
-
- // If this code is reached, castle is valid
- 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: c
- })
- ],
- vanish: [
- new PiPo({ x: x, y: y, p: V.KING, c: c }),
- new PiPo({ x: x, y: rookPos, p: castlingPiece, c: c })
- ],
- end:
- Math.abs(y - rookPos) <= 2
- ? { x: x, y: rookPos }
- : { x: x, y: y + 2 * (castleSide == 0 ? -1 : 1) }
- })
- );
- }
-
- return moves;