Add Diamond Chess

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

diff --git a/client/src/variants/Diamond.js b/client/src/variants/Diamond.js
new file mode 100644 (file)
index 0000000..2a3869e
--- /dev/null
+++ b/client/src/variants/Diamond.js
@@ -0,0 +1,139 @@
+import { ChessRules } from "@/base_rules";
+import { ArrayFun } from "@/utils/array";
+import { shuffle } from "@/utils/alea";
+
+export class DiamondRules extends ChessRules {
+  static get HasFlags() {
+    return false;
+  }
+
+  static get HasEnpassant() {
+    return false;
+  }
+
+  static GenRandInitFen(randomness) {
+    if (randomness == 0)
+      return "krbp4/rqnp4/nbpp4/pppp4/4PPPP/4PPBN/4PNQR/4PBRK w 0";
+    let pieces = { w: new Array(8), b: new Array(8) };
+    for (let c of ["w", "b"]) {
+      if (c == 'b' && randomness == 1) {
+        pieces['b'] = pieces['w'];
+        break;
+      }
+      // Get random squares for every piece, totally freely
+      let positions = shuffle(ArrayFun.range(8));
+      const composition = ['b', 'b', 'r', 'r', 'n', 'n', 'k', 'q'];
+      const rem2 = positions[0] % 2;
+      if (rem2 == positions[1] % 2) {
+        // Fix bishops (on different colors)
+        for (let i=2; i<8; i++) {
+          if (positions[i] % 2 != rem2)
+            [positions[1], positions[i]] = [positions[i], positions[1]];
+        }
+      }
+      for (let i = 0; i < 8; i++) pieces[c][positions[i]] = composition[i];
+    }
+    return (
+      pieces["b"].slice(0, 3).join("") + "p4/" +
+      pieces["b"].slice(3, 6).join("") + "p4/" +
+      pieces["b"].slice(6, 8).join("") + "pp4/" +
+      "pppp4/4PPPP/" +
+      "4PP" + pieces["w"].slice(6, 8).reverse().join("").toUpperCase() + "/" +
+      "4P" + pieces["w"].slice(3, 6).reverse().join("").toUpperCase() + "/" +
+      "4P" + pieces["w"].slice(0, 3).reverse().join("").toUpperCase() +
+      " w 0"
+    );
+  }
+
+  // Special pawns movements
+  getPotentialPawnMoves([x, y]) {
+    const color = this.turn;
+    let moves = [];
+    const [sizeX, sizeY] = [V.size.x, V.size.y];
+    const shift = (color == "w" ? -1 : 1);
+    const lastRank = (color == "w" ? 0 : 7);
+
+    // One square forward (diagonally along h1-a8)
+    if (this.board[x + shift][y + shift] == V.EMPTY) {
+      const finalPieces =
+        [x + shift, y + shift].includes(lastRank)
+          ? [V.ROOK, V.KNIGHT, V.BISHOP, V.QUEEN]
+          : [V.PAWN];
+      for (let piece of finalPieces) {
+        moves.push(
+          this.getBasicMove(
+            [x, y], [x + shift, y + shift], { c: color, p: piece })
+        );
+      }
+    }
+    // Capture
+    for (let pShift of [[0, shift], [shift, 0]]) {
+      if (
+        this.board[x + pShift[0]][y + pShift[1]] != V.EMPTY &&
+        this.canTake([x, y], [x + pShift[0], y + pShift[1]])
+      ) {
+        const finalPieces =
+          [x + pShift[0], y + pShift[1]].includes(lastRank)
+            ? [V.ROOK, V.KNIGHT, V.BISHOP, V.QUEEN]
+            : [V.PAWN];
+        for (let piece of finalPieces) {
+          moves.push(
+            this.getBasicMove(
+              [x, y],
+              [x + pShift[0], y + pShift[1]],
+              {
+                c: color,
+                p: piece
+              }
+            )
+          );
+        }
+      }
+    }
+
+    return moves;
+  }
+
+  isAttackedByPawn([x, y], color) {
+    let pawnShift = (color == "w" ? 1 : -1);
+    return (
+      (
+        x + pawnShift >= 0 && x + pawnShift < V.size.x &&
+        this.getPiece(x + pawnShift, y) == V.PAWN &&
+        this.getColor(x + pawnShift, y) == color
+      )
+      ||
+      (
+        y + pawnShift >= 0 && y + pawnShift < V.size.y &&
+        this.getPiece(x, y + pawnShift) == V.PAWN &&
+        this.getColor(x, y + pawnShift) == color
+      )
+    );
+  }
+
+  static get SEARCH_DEPTH() {
+    return 2;
+  }
+
+  getNotation(move) {
+    const piece = this.getPiece(move.start.x, move.start.y);
+    if (piece == V.PAWN) {
+      // Pawn move
+      const finalSquare = V.CoordsToSquare(move.end);
+      let notation = "";
+      if (move.vanish.length == 2)
+        // Capture
+        notation = "Px" + finalSquare;
+      else {
+        // No capture: indicate the initial square for potential ambiguity
+        const startSquare = V.CoordsToSquare(move.start);
+        notation = startSquare + finalSquare;
+      }
+      if (move.appear[0].p != V.PAWN)
+        // Promotion
+        notation += "=" + move.appear[0].p.toUpperCase();
+      return notation;
+    }
+    return super.getNotation(move); //all other pieces are orthodox
+  }
+};