feat: implement database functions migration and testing

scripts/migrations/database-functions.ts

@@ -0,0 +1,52 @@
+import { readFileSync } from "node:fs";
+import { join } from "node:path";
+import postgres from "postgres";
+
+export const SQL_FUNCTION_FILES = [
+	"deductFromRollovers.sql",
+	"deductFromMainBalance.sql",
+	"unwindFromLockReceipt.sql",
+	"getTotalBalance.sql",
+	"deductFromAdditionalBalance.sql",
+	"getAvailableOverageFromSpendLimit.sql",
+	"performDeduction.sql",
+	"syncBalances.sql",
+	"syncBalancesV2.sql",
+	"resetCusEnts.sql",
+] as const;
+
+const SQL_DIR = join(
+	import.meta.dir,
+	"..",
+	"..",
+	"server",
+	"src",
+	"internal",
+	"balances",
+	"utils",
+	"sql",
+);
+
+export const initializeDatabaseFunctions = async (
+	databaseUrl = process.env.DATABASE_URL,
+) => {
+	if (!databaseUrl) {
+		throw new Error("DATABASE_URL is required to initialize database functions");
+	}
+
+	const sql = postgres(databaseUrl, {
+		max: 1,
+		prepare: false,
+		connect_timeout: 30,
+	});
+
+	try {
+		for (const file of SQL_FUNCTION_FILES) {
+			const body = readFileSync(join(SQL_DIR, file), "utf8");
+			await sql.unsafe(body);
+			console.log(`loaded ${file}`);
+		}
+	} finally {
+		await sql.end({ timeout: 5 });
+	}
+};