From 676bd7a9784bdbdd9cd822297d4009a35560a4bd Mon Sep 17 00:00:00 2001
From: MasterGordon <gologo.x@gmail.com>
Date: Tue, 10 Mar 2026 18:54:33 +0100
Subject: [PATCH] fixed possible race condition when paying with gems

---
 backend/repositories/gemsRepository.ts | 42 +++++++++++++++-----------
 1 file changed, 25 insertions(+), 17 deletions(-)

diff --git a/backend/repositories/gemsRepository.ts b/backend/repositories/gemsRepository.ts
index 36693a8..4b32885 100644
--- a/backend/repositories/gemsRepository.ts
+++ b/backend/repositories/gemsRepository.ts
@@ -18,17 +18,21 @@ export const addGems = async (
   user: string,
   gems: number,
 ) => {
-  const { count, totalCount } = await getGems(db, user);
-  if ((await db.select().from(Gems).where(eq(Gems.user, user))).length === 0) {
-    await db
-      .insert(Gems)
-      .values({ user, count: count + gems, totalCount: totalCount + gems });
-    return;
-  }
-  await db
-    .update(Gems)
-    .set({ count: count + gems, totalCount: totalCount + gems })
-    .where(eq(Gems.user, user));
+  await db.transaction(async (tx) => {
+    const res = (await tx.select().from(Gems).where(eq(Gems.user, user)))[0];
+    const count = res?.count ?? 0;
+    const totalCount = res?.totalCount ?? 0;
+    if (!res) {
+      await tx
+        .insert(Gems)
+        .values({ user, count: count + gems, totalCount: totalCount + gems });
+      return;
+    }
+    await tx
+      .update(Gems)
+      .set({ count: count + gems, totalCount: totalCount + gems })
+      .where(eq(Gems.user, user));
+  });
 };
 
 export const removeGems = async (
@@ -36,10 +40,14 @@ export const removeGems = async (
   user: string,
   gems: number,
 ) => {
-  const { count, totalCount } = await getGems(db, user);
-  if (count - gems < 0) throw new Error("Not enough gems");
-  await db
-    .update(Gems)
-    .set({ count: count - gems, totalCount: totalCount })
-    .where(eq(Gems.user, user));
+  await db.transaction(async (tx) => {
+    const res = (await tx.select().from(Gems).where(eq(Gems.user, user)))[0];
+    const count = res?.count ?? 0;
+    const totalCount = res?.totalCount ?? 0;
+    if (count - gems < 0) throw new Error("Not enough gems");
+    await tx
+      .update(Gems)
+      .set({ count: count - gems, totalCount: totalCount })
+      .where(eq(Gems.user, user));
+  });
 };