X-Git-Url: https://git.auder.net/?a=blobdiff_plain;f=client%2Fsrc%2Fvariants%2FCopycat.js;fp=client%2Fsrc%2Fvariants%2FCopycat.js;h=089b92f86b98410014393d0e5602c89814e8962a;hb=b21e0e3a8f4af5c04b39c034d13bbb4e1e2abf18;hp=0000000000000000000000000000000000000000;hpb=8d15beb4880d40c89d893a3423fb1d0f0ffbc2c6;p=vchess.git

diff --git a/client/src/variants/Copycat.js b/client/src/variants/Copycat.js
new file mode 100644
index 00000000..089b92f8
--- /dev/null
+++ b/client/src/variants/Copycat.js
@@ -0,0 +1,144 @@
+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]
+      )
+    );
+  }
+
+};