initial version

src/db.ts

@@ -0,0 +1,33 @@
+import Database from 'better-sqlite3';
+import fs from 'node:fs';
+import path from 'node:path';
+import { fileURLToPath } from 'node:url';
+
+const __dirname = path.dirname(fileURLToPath(import.meta.url));
+
+const dataDir = path.join(process.cwd(), 'data');
+if (!fs.existsSync(dataDir)) {
+  fs.mkdirSync(dataDir, { recursive: true });
+}
+
+const dbPath = path.join(dataDir, 'app.db');
+const isNewDb = !fs.existsSync(dbPath);
+
+export const db = new Database(dbPath);
+db.pragma('foreign_keys = ON');
+db.pragma('journal_mode = WAL');
+
+if (isNewDb) {
+  const schema = fs.readFileSync(path.join(__dirname, 'schema.sql'), 'utf-8');
+  db.exec(schema);
+}
+
+const FIRST_ORDER_NUMBER = 8246;
+
+/** Allocates the next order number inside the caller's transaction. */
+export function nextOrderNumber(): number {
+  const row = db
+    .prepare(`SELECT COALESCE(MAX(order_number), ?) + 1 AS next FROM service_orders`)
+    .get(FIRST_ORDER_NUMBER) as { next: number };
+  return row.next;
+}