- getCastleMoves([x, y]) {
- const c = this.getColor(x, y);
- if (x != (c == "w" ? V.size.x - 1 : 0) || y != this.INIT_COL_KING[c])
- return []; //x isn't first rank, or king has moved (shortcut)
-
- // Castling ?
- const oppCol = V.GetOppCol(c);
- let moves = [];
- let i = 0;
- // King, then rook:
- const finalSquares = [
- [2, 3],
- [V.size.y - 2, V.size.y - 3]
- ];
- castlingCheck: for (
- let castleSide = 0;
- castleSide < 2;
- castleSide++ //large, then small
- ) {
- if (!this.castleFlags[c][castleSide]) continue;
- // If this code is reached, rooks and king are on initial position
-
- // Nothing on the path of the king ? (and no checks)
- const finDist = finalSquares[castleSide][0] - y;
- let step = finDist / Math.max(1, Math.abs(finDist));
- for (let i = y; i != finalSquares[castleSide][0]; i += step) {
- if (
- this.board[x][i] != V.EMPTY &&
- // NOTE: next check is enough, because of chessboard constraints
- (this.getColor(x, i) != c ||
- ![V.KING, V.ROOK].includes(this.getPiece(x, i)))
- ) {
- continue castlingCheck;
- }
- }
-
- // Nothing on the path to the rook?
- step = castleSide == 0 ? -1 : 1;
- for (i = y + step; i != this.INIT_COL_ROOK[c][castleSide]; i += step) {
- if (this.board[x][i] != V.EMPTY) continue castlingCheck;
- }
- const rookPos = this.INIT_COL_ROOK[c][castleSide];
-
- // Nothing on final squares, except maybe king and castling rook?
- for (i = 0; i < 2; i++) {
- if (
- this.board[x][finalSquares[castleSide][i]] != V.EMPTY &&
- this.getPiece(x, finalSquares[castleSide][i]) != V.KING &&
- finalSquares[castleSide][i] != rookPos
- ) {
- 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: V.ROOK, c: c })
- ],
- vanish: [
- new PiPo({ x: x, y: y, p: V.KING, c: c }),
- new PiPo({ x: x, y: rookPos, p: V.ROOK, c: c })
- ],
- end:
- Math.abs(y - rookPos) <= 2
- ? { x: x, y: rookPos }
- : { x: x, y: y + 2 * (castleSide == 0 ? -1 : 1) }
- })
- );
- }
-
- return moves;