add sqlite

mobile/services/db/client.ts

@@ -0,0 +1,32 @@
+import * as SQLite from 'expo-sqlite';
+import type { SQLiteDatabase } from 'expo-sqlite';
+import { migrateDatabase } from './migrations';
+import { DATABASE_NAME } from './schema';
+
+let database: SQLiteDatabase | null = null;
+
+export async function getDatabase(): Promise<SQLiteDatabase> {
+  if (database) return database;
+
+  const db = await SQLite.openDatabaseAsync(DATABASE_NAME);
+  await migrateDatabase(db);
+  database = db;
+  return db;
+}
+
+export async function closeDatabase(): Promise<void> {
+  if (!database) return;
+  await database.closeAsync();
+  database = null;
+}
+
+export async function withTransaction<T>(
+  work: (db: SQLiteDatabase) => Promise<T>,
+): Promise<T> {
+  const db = await getDatabase();
+  let result!: T;
+  await db.withTransactionAsync(async () => {
+    result = await work(db);
+  });
+  return result;
+}