From ea33101a949ae9b873f8e6e964fdf0a1c0a55d18 Mon Sep 17 00:00:00 2001
From: Matthew Slight <matthew@slight.me>
Date: Wed, 4 Jun 2025 23:38:53 +0400
Subject: [PATCH] Terminate engine worker when useStockfish unmounts

---
 src/hooks/useStockfish.ts                 | 4 ++++
 src/lib/StockfishEngine.ts                | 1 +
 src/pages/drills/components/DrillList.tsx | 6 +++++-
 3 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/hooks/useStockfish.ts b/src/hooks/useStockfish.ts
index ee056ed..c002a28 100644
--- a/src/hooks/useStockfish.ts
+++ b/src/hooks/useStockfish.ts
@@ -72,6 +72,10 @@ export function useStockfish(
 
     return () => {
       didCancel = true;
+      // When the engine instance is replaced or the component unmounts,
+      // ensure any ongoing search is halted and the worker is terminated.
+      engine.stop();
+      engine.quit();
     };
   }, [engine]);
 
diff --git a/src/lib/StockfishEngine.ts b/src/lib/StockfishEngine.ts
index 0cfbb80..b2e19a7 100644
--- a/src/lib/StockfishEngine.ts
+++ b/src/lib/StockfishEngine.ts
@@ -189,5 +189,6 @@ export class StockfishEngine {
   public quit() {
     if (DEBUG) console.log('[StockfishEngine] quit');
     this.send('quit');
+    this.worker.terminate();
   }
 }
diff --git a/src/pages/drills/components/DrillList.tsx b/src/pages/drills/components/DrillList.tsx
index a61eb42..3dcde1d 100644
--- a/src/pages/drills/components/DrillList.tsx
+++ b/src/pages/drills/components/DrillList.tsx
@@ -27,7 +27,11 @@ export default function DrillList({ drills, loading, onStartDrill }: Props) {
     <div className="space-y-8 sm:space-y-12">
       {drills.map((d) => {
         return (
-          <DrillCard key={d.id} drill={d} onStartDrill={() => onStartDrill(d.id)} />
+          <DrillCard
+            key={d.id}
+            drill={d}
+            onStartDrill={() => onStartDrill(d.id)}
+          />
         );
       })}
     </div>