Upstream lichess-org/lila state of the touched files before dc0269b236

ui/lib/src/game/endgame.ts

@@ -0,0 +1,114 @@
+import type { DrawShape } from '@lichess-org/chessground/draw';
+import type { Outcome } from 'chessops';
+import { parseFen } from 'chessops/fen';
+import { makeSquare, opposite } from 'chessops/util';
+
+import { fenColor } from './chess';
+import { endgameGlyphs } from './glyphs';
+import type { StatusName } from './status';
+
+export interface EndgameResult {
+  winner?: Color;
+  status?: StatusName;
+}
+
+type EndgameNode = {
+  fen: FEN;
+  outcome: () => Outcome | undefined;
+  check: () => boolean;
+  dests: () => Dests;
+};
+
+const endgameResult = (
+  node: EndgameNode,
+  isLast: boolean,
+  gameWinner: Color | undefined,
+  gameStatus: StatusName,
+): EndgameResult => {
+  const isTerminal = node.dests().size === 0,
+    isMate = node.check() && isTerminal,
+    isStalemate = !node.check() && isTerminal,
+    isGameEnd = isLast || isTerminal;
+
+  if (!isGameEnd) return {};
+  return {
+    winner: isMate
+      ? opposite(fenColor(node.fen))
+      : isStalemate
+        ? undefined
+        : (node.outcome()?.winner ?? gameWinner),
+    status: isMate ? 'mate' : isStalemate ? 'stalemate' : gameStatus,
+  };
+};
+
+export function endgameShapesForNode(
+  node: EndgameNode,
+  isLast: boolean,
+  gameWinner: Color | undefined,
+  gameStatus: StatusName,
+): DrawShape[] {
+  const result = endgameResult(node, isLast, gameWinner, gameStatus);
+  return endgameShapes(node.fen, result.winner, result.status);
+}
+
+export function findKingSquare(fen: FEN, color: Color): Key | undefined {
+  const king = parseFen(fen).unwrap(
+    setup => setup.board.kingOf(color),
+    _ => undefined,
+  );
+  return king === undefined ? undefined : makeSquare(king);
+}
+
+type EndgameGlyph = keyof typeof endgameGlyphs;
+
+const loserGlyph = (status: StatusName | undefined): EndgameGlyph =>
+  status === 'mate'
+    ? 'mate'
+    : status === 'resign'
+      ? 'resign'
+      : status === 'timeout'
+        ? 'abandoned'
+        : status === 'outoftime'
+          ? 'outoftime'
+          : 'unknown';
+
+const drawGlyph = (status: StatusName | undefined): EndgameGlyph | undefined =>
+  status === 'stalemate'
+    ? 'stalemate'
+    : status === 'draw' ||
+        status === 'insufficientMaterialClaim' ||
+        status === 'outoftime' ||
+        status === 'timeout'
+      ? 'draw'
+      : undefined;
+
+export function endgameShapes(
+  fen: FEN,
+  winner: Color | undefined,
+  status: StatusName | undefined,
+): DrawShape[] {
+  if (status === 'aborted' || status === 'noStart') return [];
+
+  const shapes: DrawShape[] = [];
+  const add = (color: Color, glyph: EndgameGlyph) => {
+    const king = findKingSquare(fen, color);
+    if (king)
+      shapes.push({
+        orig: king,
+        brush: '',
+        customSvg: { html: endgameGlyphs[glyph](0), center: 'orig' },
+      });
+  };
+
+  if (winner) {
+    add(winner, 'win');
+    add(opposite(winner), loserGlyph(status));
+  } else {
+    const glyph = drawGlyph(status);
+    if (glyph) {
+      add('white', glyph);
+      add('black', glyph);
+    }
+  }
+  return shapes;
+}