1 files changed, 32 insertions, 0 deletions
diff --git a/frontend/app/states/watch.ts b/frontend/app/states/watch.ts
index 8c7faa7..2c255f4 100644
--- a/frontend/app/states/watch.ts
+++ b/frontend/app/states/watch.ts
@@ -93,3 +93,35 @@ export function calcCodeSize(code: string): number {
 	const utf8Encoded = new TextEncoder().encode(trimmed);
 	return utf8Encoded.length;
 }
+
+export type GameResultKind = "winA" | "winB" | "draw";
+
+export function checkGameResultKind(
+	gameStateKind: GameStateKind,
+	stateA: LatestGameState | null,
+	stateB: LatestGameState | null,
+): GameResultKind | null {
+	if (gameStateKind !== "finished") {
+		return null;
+	}
+
+	const scoreA = stateA?.score;
+	const scoreB = stateB?.score;
+	if (scoreA == null && scoreB == null) {
+		return "draw";
+	}
+	if (scoreA == null) {
+		return "winB";
+	}
+	if (scoreB == null) {
+		return "winA";
+	}
+	if (scoreA === scoreB) {
+		// If score is non-null, state and best_score_submitted_at should also be non-null.
+		const submittedAtA = stateA!.best_score_submitted_at!;
+		const submittedAtB = stateB!.best_score_submitted_at!;
+		return submittedAtA < submittedAtB ? "winA" : "winB";
+	} else {
+		return scoreA < scoreB ? "winA" : "winB";
+	}
+}