Add Koth (experimental)

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

diff --git a/client/src/variants/Koth.js b/client/src/variants/Koth.js
new file mode 100644 (file)
index 0000000..e286862
--- /dev/null
+++ b/client/src/variants/Koth.js
@@ -0,0 +1,48 @@
+import { ChessRules } from "@/base_rules";
+
+export class KothRules extends ChessRules {
+  filterValid(moves) {
+    if (moves.length == 0) return [];
+    const color = this.turn;
+    const oppCol = V.GetOppCol(color);
+    return moves.filter(m => {
+      this.play(m);
+      // Giving check is forbidden as well:
+      const res = !this.underCheck(color) && !this.underCheck(oppCol);
+      this.undo(m);
+      return res;
+    });
+  }
+
+  getCurrentScore() {
+    // Turn has changed:
+    const color = V.GetOppCol(this.turn);
+    if (
+      [3,4].includes(this.kingPos[color][0]) &&
+      [3,4].includes(this.kingPos[color][1])
+    ) {
+      // The middle is reached!
+      return color == "w" ? "1-0" : "0-1";
+    }
+    if (this.atLeastOneMove()) return "*";
+    // Stalemate (will probably never happen)
+    return "1/2";
+  }
+
+  evalPosition() {
+    // Count material:
+    let evaluation = super.evalPosition();
+    // Ponder with king position:
+    return (
+      evaluation/5 +
+      (
+        Math.abs(this.kingPos["w"][0] - 3.5) +
+        Math.abs(this.kingPos["w"][1] - 3.5)
+      ) / 2 -
+      (
+        Math.abs(this.kingPos["b"][0] - 3.5) +
+        Math.abs(this.kingPos["b"][1] - 3.5)
+      ) / 2
+    );
+  }
+};