--- /dev/null
+import { ChessRules } from "@/base_rules";
+
+export class CopycatRules extends ChessRules {
+
+ getPotentialMovesFrom([x, y]) {
+ let moves = super.getPotentialMovesFrom([x, y]);
+ // Expand potential moves if attacking friendly pieces.
+ const piece = this.getPiece(x,y);
+ if ([V.PAWN, V.KING].includes(piece)) return moves;
+ const color = this.turn;
+ const oneStep = (piece == V.PAWN);
+ let movements = {},
+ steps = [];
+ if (piece == V.QUEEN) steps = V.steps[V.ROOK].concat(V.steps[V.BISHOP]);
+ else steps = V.steps[piece];
+ steps.forEach(s => {
+ let [i, j] = [x + s[0], y + s[1]];
+ while (
+ V.OnBoard(i, j) &&
+ this.board[i][j] == V.EMPTY &&
+ piece != V.KNIGHT
+ ) {
+ i += s[0];
+ j += s[1];
+ }
+ if (V.OnBoard(i, j) && this.getColor(i, j) == color) {
+ const attacked = this.getPiece(i, j);
+ if ([V.ROOK, V.BISHOP, V.KNIGHT].includes(attacked)) {
+ if (!movements[attacked]) movements[attacked] = true;
+ }
+ else if (attacked == V.QUEEN) {
+ if (!movements[V.ROOK]) movements[V.ROOK] = true;
+ if (!movements[V.BISHOP]) movements[V.BISHOP] = true;
+ }
+ }
+ });
+ Object.keys(movements).forEach(type => {
+ if (
+ (piece != V.QUEEN && type != piece) ||
+ (piece == V.QUEEN && type == V.KNIGHT)
+ ) {
+ Array.prototype.push.apply(moves,
+ this.getSlideNJumpMoves([x, y], V.steps[type], type == V.KNIGHT));
+ }
+ });
+ return moves;
+ }
+
+ // Detect indirect attacks:
+ isAttackedBy_aux(
+ [x, y], color, steps1, oneStep1, piece1, steps2, oneStep2, pieces2)
+ {
+ for (let s1 of steps1) {
+ let i = x + s1[0],
+ j = y + s1[1];
+ while (V.OnBoard(i, j) && this.board[i][j] == V.EMPTY && !oneStep1) {
+ i += s1[0];
+ j += s1[1];
+ }
+ if (
+ V.OnBoard(i, j) &&
+ this.board[i][j] != V.EMPTY &&
+ this.getPiece(i, j) == piece1 &&
+ this.getColor(i, j) == color
+ ) {
+ // Continue to detect "copycat" attacks
+ for (let s2 of steps2) {
+ let ii = i + s2[0],
+ jj = j + s2[1];
+ while (
+ V.OnBoard(ii, jj) &&
+ this.board[ii][jj] == V.EMPTY &&
+ !oneStep2
+ ) {
+ ii += s2[0];
+ jj += s2[1];
+ }
+ if (
+ V.OnBoard(ii, jj) &&
+ this.board[ii][jj] != V.EMPTY &&
+ pieces2.includes(this.getPiece(ii, jj)) &&
+ this.getColor(ii, jj) == color
+ ) {
+ return true;
+ }
+ }
+ }
+ }
+ return false;
+ }
+
+ isAttackedByKnight(sq, color) {
+ if (super.isAttackedByKnight(sq, color)) return true;
+ return (
+ this.isAttackedBy_aux(sq, color,
+ V.steps[V.ROOK], false, V.KNIGHT,
+ V.steps[V.KNIGHT], true, [V.ROOK, V.QUEEN]
+ ) ||
+ this.isAttackedBy_aux(sq, color,
+ V.steps[V.BISHOP], false, V.KNIGHT,
+ V.steps[V.KNIGHT], true, [V.BISHOP, V.QUEEN]
+ )
+ );
+ }
+
+ isAttackedByRook(sq, color) {
+ if (super.isAttackedByRook(sq, color)) return true;
+ return (
+ this.isAttackedBy_aux(sq, color,
+ V.steps[V.KNIGHT], true, V.ROOK,
+ V.steps[V.ROOK], false, [V.KNIGHT]
+ ) ||
+ this.isAttackedBy_aux(sq, color,
+ V.steps[V.BISHOP], false, V.ROOK,
+ V.steps[V.ROOK], false, [V.BISHOP, V.QUEEN]
+ )
+ );
+ }
+
+ isAttackedByBishop(sq, color) {
+ if (super.isAttackedByBishop(sq, color)) return true;
+ return (
+ this.isAttackedBy_aux(sq, color,
+ V.steps[V.KNIGHT], true, V.BISHOP,
+ V.steps[V.BISHOP], false, [V.KNIGHT]
+ ) ||
+ this.isAttackedBy_aux(sq, color,
+ V.steps[V.ROOK], false, V.BISHOP,
+ V.steps[V.BISHOP], false, [V.ROOK, V.QUEEN]
+ )
+ );
+ }
+
+ isAttackedByQueen(sq, color) {
+ if (super.isAttackedByQueen(sq, color)) return true;
+ return (
+ this.isAttackedBy_aux(sq, color,
+ V.steps[V.KNIGHT], true, V.QUEEN,
+ V.steps[V.ROOK].concat(V.steps[V.BISHOP]), false, [V.KNIGHT]
+ )
+ );
+ }
+
+};
projects / vchess.git / commitdiff