Add Joker Chess

[vchess.git] / client / src / variants / Joker.js

diff --git a/client/src/variants/Joker.js b/client/src/variants/Joker.js
new file mode 100644 (file)
index 0000000..137249c
--- /dev/null
+++ b/client/src/variants/Joker.js
@@ -0,0 +1,87 @@
+import { ChessRules, Move, PiPo } from "@/base_rules";
+import { Antiking2Rules } from "@/variants/Antiking2";
+
+export class JokerRules extends ChessRules {
+
+  static get PawnSpecs() {
+    return Object.assign(
+      {},
+      ChessRules.PawnSpecs,
+      { promotions: ChessRules.PawnSpecs.promotions.concat([V.JOKER]) }
+    );
+  }
+
+  static GenRandInitFen(randomness) {
+    const antikingFen = Antiking2Rules.GenRandInitFen(randomness);
+    return antikingFen.replace('a', 'J').replace('A', 'j');
+  }
+
+  static get JOKER() {
+    return 'j';
+  }
+
+  static get PIECES() {
+    return ChessRules.PIECES.concat([V.JOKER]);
+  }
+
+  getPpath(b) {
+    return (b.charAt(1) == 'j' ? "Joker/" : "") + b;
+  }
+
+  getPotentialMovesFrom([x, y]) {
+    const piece = this.getPiece(x, y);
+    if (piece == V.JOKER) return this.getPotentialJokerMoves([x, y]);
+    let moves = super.getPotentialMovesFrom([x, y]);
+    if (piece == V.PAWN) {
+      const c = this.turn;
+      const alreadyOneJoker = this.board.some(row =>
+        row.some(cell => cell == c + 'j'));
+      if (alreadyOneJoker) moves = moves.filter(m => m.appear[0].p != V.JOKER)
+    }
+    return moves;
+  }
+
+  canTake([x1, y1], [x2, y2]) {
+    if (this.getPiece(x1, y1) == V.JOKER) return false;
+    return super.canTake([x1, y1], [x2, y2]);
+  }
+
+  getPotentialJokerMoves([x, y]) {
+    const moving =
+      super.getSlideNJumpMoves([x, y], V.steps[V.KNIGHT], "oneStep")
+      .concat(super.getSlideNJumpMoves([x, y],
+        V.steps[V.ROOK].concat(V.steps[V.BISHOP])));
+    let swapping = [];
+    const c = this.turn;
+    for (let i=0; i<8; i++) {
+      for (let j=0; j<8; j++) {
+        // Following test is OK because only one Joker on board at a time
+        if (this.board[i][j] != V.EMPTY && this.getColor(i, j) == c) {
+          const p = this.getPiece(i, j);
+          swapping.push(
+            new Move({
+              vanish: [
+                new PiPo({ x: x, y: y, c: c, p: V.JOKER }),
+                new PiPo({ x: i, y: j, c: c, p: p })
+              ],
+              appear: [
+                new PiPo({ x: i, y: j, c: c, p: V.JOKER }),
+                new PiPo({ x: x, y: y, c: c, p: p })
+              ]
+            })
+          );
+        }
+      }
+    }
+    return moving.concat(swapping);
+  }
+
+  static get VALUES() {
+    return Object.assign({ j: 2 }, ChessRules.VALUES);
+  }
+
+  static get SEARCH_DEPTH() {
+    return 2;
+  }
+
+};