Adjustments + add en-passant to Zen rules

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

diff --git a/client/src/variants/Zen.js b/client/src/variants/Zen.js
index a6067f9..0424e07 100644 (file)
--- a/client/src/variants/Zen.js
+++ b/client/src/variants/Zen.js
@@ -1,9 +1,29 @@
 import { ChessRules } from "@/base_rules";
 
-export const VariantRules = class ZenRules extends ChessRules {
-  // NOTE: enPassant, if enabled, would need to redefine carefully getEpSquare
-  static get HasEnpassant() {
-    return false;
+export class ZenRules extends ChessRules {
+  getEpSquare(moveOrSquare) {
+    if (!moveOrSquare) return undefined;
+    if (typeof moveOrSquare === "string") {
+      const square = moveOrSquare;
+      if (square == "-") return undefined;
+      return V.SquareToCoords(square);
+    }
+    const move = moveOrSquare;
+    const s = move.start,
+          e = move.end;
+    if (
+      // Exclude captures (of rooks for example)
+      move.vanish.length == 1 &&
+      s.y == e.y &&
+      Math.abs(s.x - e.x) == 2 &&
+      move.appear[0].p == V.PAWN
+    ) {
+      return {
+        x: (s.x + e.x) / 2,
+        y: s.y
+      };
+    }
+    return undefined;
   }
 
   // TODO(?): some duplicated code in 2 next functions
@@ -88,45 +108,14 @@ export const VariantRules = class ZenRules extends ChessRules {
     return moves;
   }
 
-  getPotentialPawnMoves([x, y]) {
-    const color = this.getColor(x, y);
-    let moves = [];
-    const sizeY = V.size.y;
-    const shift = color == "w" ? -1 : 1;
-    const startRank = color == "w" ? sizeY - 2 : 1;
-    const firstRank = color == "w" ? sizeY - 1 : 0;
-    const lastRank = color == "w" ? 0 : sizeY - 1;
-
-    if (x + shift != lastRank) {
-      // Normal moves
-      if (this.board[x + shift][y] == V.EMPTY) {
-        moves.push(this.getBasicMove([x, y], [x + shift, y]));
-        if (
-          [startRank, firstRank].includes(x) &&
-          this.board[x + 2 * shift][y] == V.EMPTY
-        ) {
-          // Two squares jump
-          moves.push(this.getBasicMove([x, y], [x + 2 * shift, y]));
-        }
-      }
-    }
-    else {
-      // Promotion
-      let promotionPieces = [V.ROOK, V.KNIGHT, V.BISHOP, V.QUEEN];
-      promotionPieces.forEach(p => {
-        // Normal move
-        if (this.board[x + shift][y] == V.EMPTY)
-          moves.push(
-            this.getBasicMove([x, y], [x + shift, y], { c: color, p: p })
-          );
-      });
-    }
-
-    // No en passant here
+  canTake(sq1, sq2) {
+    return false; //captures handled separately
+  }
 
+  getPotentialPawnMoves([x, y]) {
+    let moves = super.getPotentialPawnMoves([x, y]);
     // Add "zen" captures
     Array.prototype.push.apply(moves, this.findCaptures([x, y]));
-
     return moves;
   }
 
@@ -176,7 +165,7 @@ export const VariantRules = class ZenRules extends ChessRules {
       return "0-0";
     }
 
-    // Translate initial square (because pieces may fly unusually in this variant!)
+    // Translate initial square (because pieces may fly unusually!)
     const initialSquare = V.CoordsToSquare(move.start);
 
     // Translate final square