Fix hidden queen captured en-passant when not starting on 2nd row

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

diff --git a/client/src/variants/Hiddenqueen.js b/client/src/variants/Hiddenqueen.js
index 15d9b1e..b180c6f 100644 (file)
--- a/client/src/variants/Hiddenqueen.js
+++ b/client/src/variants/Hiddenqueen.js
@@ -2,7 +2,7 @@ import { ChessRules, PiPo, Move } from "@/base_rules";
 import { ArrayFun } from "@/utils/array";
 import { randInt } from "@/utils/alea";
 
-export const VariantRules = class HiddenqueenRules extends ChessRules {
+export class HiddenqueenRules extends ChessRules {
   // Analyse in Hiddenqueen mode makes no sense
   static get CanAnalyze() {
     return false;
@@ -12,8 +12,12 @@ export const VariantRules = class HiddenqueenRules extends ChessRules {
     return 't';
   }
 
+  static get SomeHiddenMoves() {
+    return true;
+  }
+
   static get PIECES() {
-    return ChessRules.PIECES.concat(Object.values(V.HIDDEN_CODE));
+    return ChessRules.PIECES.concat([V.HIDDEN_QUEEN]);
   }
 
   getPiece(i, j) {
@@ -38,6 +42,31 @@ export const VariantRules = class HiddenqueenRules extends ChessRules {
     return b;
   }
 
+  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;
+    const color = move.vanish[0].c;
+    if (
+      s.y == e.y &&
+      Math.abs(s.x - e.x) == 2 &&
+      ((color == 'w' && s.x == 6) || (color == 'b' && s.x == 1)) &&
+      [V.PAWN, V.HIDDEN_QUEEN].includes(move.vanish[0].p)
+    ) {
+      return {
+        x: (s.x + e.x) / 2,
+        y: s.y
+      };
+    }
+    return undefined; //default
+  }
+
   isValidPawnMove(move) {
     const color = move.vanish[0].c;
     const pawnShift = color == "w" ? -1 : 1;
@@ -87,79 +116,34 @@ export const VariantRules = class HiddenqueenRules extends ChessRules {
     return super.getPotentialMovesFrom([x, y]);
   }
 
-  // TODO: find a more general way to describe pawn movements to avoid
-  // re-writing almost the same function for several variants.
-  getPotentialPawnMoves([x, y]) {
-    const color = this.turn;
-    const piece = this.getPiece(x, y);
-    let moves = [];
-    const [sizeX, sizeY] = [V.size.x, V.size.y];
-    const shiftX = color == "w" ? -1 : 1;
-    const startRank = color == "w" ? sizeX - 2 : 1;
-    const lastRank = color == "w" ? 0 : sizeX - 1;
-
-    const finalPieces =
-      x + shiftX == lastRank
-        ? piece == V.PAWN
-          ? [V.ROOK, V.KNIGHT, V.BISHOP, V.QUEEN]
-          : [V.QUEEN] //hidden queen revealed
-        : [piece]; //V.PAWN
-    if (this.board[x + shiftX][y] == V.EMPTY) {
-      // One square forward
-      for (let p of finalPieces) {
-        moves.push(
-          this.getBasicMove([x, y], [x + shiftX, y], {
-            c: color,
-            p: p
-          })
-        );
-      }
-      if (
-        x == startRank &&
-        this.board[x + 2 * shiftX][y] == V.EMPTY
-      ) {
-        // Two squares jump
-        moves.push(this.getBasicMove([x, y], [x + 2 * shiftX, y]));
-      }
-    }
-    // Captures
-    for (let shiftY of [-1, 1]) {
-      if (
-        y + shiftY >= 0 &&
-        y + shiftY < sizeY &&
-        this.board[x + shiftX][y + shiftY] != V.EMPTY &&
-        this.canTake([x, y], [x + shiftX, y + shiftY])
-      ) {
-        for (let p of finalPieces) {
-          moves.push(
-            this.getBasicMove([x, y], [x + shiftX, y + shiftY], {
-              c: color,
-              p: p
-            })
-          );
-        }
-      }
-    }
-
-    // En passant
+  getEnpassantCaptures([x, y], shiftX) {
     const Lep = this.epSquares.length;
-    const epSquare = this.epSquares[Lep - 1]; //always at least one element
+    const epSquare = this.epSquares[Lep - 1];
+    let enpassantMove = null;
     if (
       !!epSquare &&
       epSquare.x == x + shiftX &&
       Math.abs(epSquare.y - y) == 1
     ) {
-      let enpassantMove = this.getBasicMove([x, y], [epSquare.x, epSquare.y]);
+      enpassantMove = this.getBasicMove([x, y], [epSquare.x, epSquare.y]);
       enpassantMove.vanish.push({
         x: x,
         y: epSquare.y,
-        p: "p",
+        // Captured piece may be a hidden queen
+        p: this.board[x][epSquare.y][1],
         c: this.getColor(x, epSquare.y)
       });
-      moves.push(enpassantMove);
     }
+    return !!enpassantMove ? [enpassantMove] : [];
+  }
 
-    return moves;
+  getPotentialPawnMoves([x, y]) {
+    const piece = this.getPiece(x, y);
+    const promotions =
+      piece == V.PAWN
+        ? [V.ROOK, V.KNIGHT, V.BISHOP, V.QUEEN]
+        : [V.QUEEN]; //hidden queen revealed
+    return super.getPotentialPawnMoves([x, y], promotions);
   }
 
   getPossibleMovesFrom(sq) {
@@ -222,10 +206,23 @@ export const VariantRules = class HiddenqueenRules extends ChessRules {
   }
 
   getNotation(move) {
-    const notation = super.getNotation(move);
-    if (notation.charAt(0) == 'T')
-      // Do not reveal hidden queens
-      return notation.substr(1);
+    // Not using getPiece() method because it would transform HQ into pawn:
+    if (this.board[move.start.x][move.start.y][1] != V.HIDDEN_QUEEN)
+      return super.getNotation(move);
+    const finalSquare = V.CoordsToSquare(move.end);
+    if (move.appear[0].p == V.QUEEN) {
+      return (
+        "Q" +
+        (move.vanish.length > move.appear.length ? "x" : "") +
+        finalSquare
+      );
+    }
+    // Do not reveal hidden queens playing as pawns
+    let notation = "";
+    if (move.vanish.length == 2)
+      // Capture
+      notation = V.CoordToColumn(move.start.y) + "x" + finalSquare;
+    else notation = finalSquare;
     return notation;
   }
 };