Fix Alice rules (en passant)

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

diff --git a/client/src/variants/Alice.js b/client/src/variants/Alice.js
index e193bbd..57de568 100644 (file)
--- a/client/src/variants/Alice.js
+++ b/client/src/variants/Alice.js
@@ -34,6 +34,32 @@ export class AliceRules extends ChessRules {
     return (Object.keys(V.ALICE_PIECES).includes(b[1]) ? "Alice/" : "") + b;
   }
 
+  getEpSquare(moveOrSquare) {
+    if (!moveOrSquare) return undefined;
+    if (typeof moveOrSquare === "string") {
+      const square = moveOrSquare;
+      if (square == "-") return undefined;
+      return V.SquareToCoords(square);
+    }
+    // Argument is a move:
+    const move = moveOrSquare;
+    const s = move.start,
+          e = move.end;
+    if (
+      s.y == e.y &&
+      Math.abs(s.x - e.x) == 2 &&
+      // Special conditions: a pawn can be on the other side
+      ['p','s'].includes(move.appear[0].p) &&
+      ['p','s'].includes(move.vanish[0].p)
+    ) {
+      return {
+        x: (s.x + e.x) / 2,
+        y: s.y
+      };
+    }
+    return undefined; //default
+  }
+
   setOtherVariables(fen) {
     super.setOtherVariables(fen);
     const rows = V.ParseFen(fen).position.split("/");
@@ -165,6 +191,31 @@ export class AliceRules extends ChessRules {
     return res;
   }
 
+  getEnpassantCaptures([x, y], shiftX) {
+    const Lep = this.epSquares.length;
+    const epSquare = this.epSquares[Lep - 1]; //always at least one element
+    let enpassantMove = null;
+    if (
+      !!epSquare &&
+      epSquare.x == x + shiftX &&
+      Math.abs(epSquare.y - y) == 1
+    ) {
+      enpassantMove = this.getBasicMove([x, y], [epSquare.x, epSquare.y]);
+      // May capture in same world or different:
+      const capturedPiece =
+        this.board[x][epSquare.y] != V.EMPTY
+          ? this.getPiece(x, epSquare.y)
+          : ['p','s'][1 - "ps".indexOf(this.getPiece(x, y))];
+      enpassantMove.vanish.push({
+        x: x,
+        y: epSquare.y,
+        p: capturedPiece,
+        c: V.GetOppCol(this.turn)
+      });
+    }
+    return !!enpassantMove ? [enpassantMove] : [];
+  }
+
   filterValid(moves, sideBoard) {
     if (moves.length == 0) return [];
     if (!sideBoard) sideBoard = [this.getSideBoard(1), this.getSideBoard(2)];
@@ -235,7 +286,8 @@ export class AliceRules extends ChessRules {
     return res;
   }
 
-  getCheckSquares(color) {
+  getCheckSquares() {
+    const color = this.turn;
     const pieces = Object.keys(V.ALICE_CODES);
     const kp = this.kingPos[color];
     const mirrorSide = pieces.includes(this.getPiece(kp[0], kp[1])) ? 1 : 2;