server: refactor pagination

* fix transaction usgae in repos
* other bug fixes

apps/server/src/kysely/utils.ts

@@ -1,13 +1,33 @@
 import { KyselyDB, KyselyTransaction } from './types/kysely.types';
 
+/*
+ * Executes a transaction or a callback using the provided database instance.
+ * If an existing transaction is provided, it directly executes the callback with it.
+ * Otherwise, it starts a new transaction using the provided database instance and executes the callback within that transaction.
+ */
 export async function executeTx<T>(
   db: KyselyDB,
   callback: (trx: KyselyTransaction) => Promise<T>,
   existingTrx?: KyselyTransaction,
 ): Promise<T> {
   if (existingTrx) {
-    return await callback(existingTrx);
+    return await callback(existingTrx); // Execute callback with existing transaction
   } else {
-    return await db.transaction().execute((trx) => callback(trx));
+    return await db.transaction().execute((trx) => callback(trx)); // Start new transaction and execute callback
+  }
+}
+
+/*
+ * This function returns either an existing transaction if provided,
+ * or the normal database instance.
+ */
+export function dbOrTx(
+  db: KyselyDB,
+  existingTrx?: KyselyTransaction,
+): KyselyDB | KyselyTransaction {
+  if (existingTrx) {
+    return existingTrx; // Use existing transaction
+  } else {
+    return db; // Use normal database instance
   }
 }