Add Twokings variant

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

diff --git a/client/src/variants/Twokings.js b/client/src/variants/Twokings.js
new file mode 100644 (file)
index 0000000..9e82a24
--- /dev/null
+++ b/client/src/variants/Twokings.js
@@ -0,0 +1,83 @@
+import { ChessRules } from "@/base_rules";
+import { CoregalRules } from "@/variants/Coregal";
+
+export class TwokingsRules extends CoregalRules {
+  static get PawnSpecs() {
+    return Object.assign(
+      {},
+      ChessRules.PawnSpecs,
+      { promotions: ChessRules.PawnSpecs.promotions.concat([V.KING]) }
+    );
+  }
+
+  static IsGoodPosition(position) {
+    if (position.length == 0) return false;
+    const rows = position.split("/");
+    if (rows.length != V.size.x) return false;
+    let kings = { "w": 0, "b": 0 };
+    for (let row of rows) {
+      let sumElts = 0;
+      for (let i = 0; i < row.length; i++) {
+        if (['K','k'].includes(row[i])) kings[row[i]]++;
+        if (V.PIECES.includes(row[i].toLowerCase())) sumElts++;
+        else {
+          const num = parseInt(row[i]);
+          if (isNaN(num)) return false;
+          sumElts += num;
+        }
+      }
+      if (sumElts != V.size.y) return false;
+    }
+    // Two kings (at least) per side should be present:
+    if (Object.values(kings).some(v => v < 2)) return false;
+    return true;
+  }
+
+  // Not scanning king positions. In this variant, scan the board everytime.
+  scanKings(fen) {}
+
+  getCheckSquares(color) {
+    let squares = [];
+    const oppCol = V.GetOppCol(color);
+    for (let i=0; i<V.size.x; i++) {
+      for (let j=0; j<V.size.y; j++) {
+        if (
+          this.getColor(i, j) == color &&
+          this.getPiece(i, j) == V.KING &&
+          this.isAttacked([i, j], oppCol)
+        ) {
+          squares.push([i, j]);
+        }
+      }
+    }
+    return squares;
+  }
+
+  static GenRandInitFen(randomness) {
+    const fen = CoregalRules.GenRandInitFen(randomness);
+    return fen.replace("q", "k").replace("Q", "K");
+  }
+
+  underCheck(color) {
+    const oppCol = V.GetOppCol(color);
+    for (let i=0; i<V.size.x; i++) {
+      for (let j=0; j<V.size.y; j++) {
+        if (
+          this.getColor(i, j) == color &&
+          this.getPiece(i, j) == V.KING &&
+          this.isAttacked([i, j], oppCol)
+        ) {
+          return true;
+        }
+      }
+    }
+    return false;
+  }
+
+  postPlay(move) {
+    const piece = move.vanish[0].p;
+    super.updateCastleFlags(move, piece, "twoKings");
+  }
+
+  postUndo() {}
+};