add DB setup with migrations

src/services/migrationService.ts

@@ -0,0 +1,63 @@
+type SqlValue = string | number | null | Uint8Array;
+
+export interface QueryExecResult {
+  columns: Array<string>;
+  values: Array<Array<SqlValue>>;
+}
+
+interface Migration {
+  name: string;
+  sql: string;
+}
+
+export class MigrationService {
+  private static instance: MigrationService;
+  private migrations: Migration[] = [];
+
+  private constructor() {}
+
+  static getInstance(): MigrationService {
+    if (!MigrationService.instance) {
+      MigrationService.instance = new MigrationService();
+    }
+    return MigrationService.instance;
+  }
+
+  async registerMigration(migration: Migration): Promise<void> {
+    this.migrations.push(migration);
+  }
+
+  async runMigrations(
+    sqlExec: (sql: string, params?: any[]) => Promise<Array<QueryExecResult>>
+  ): Promise<void> {
+    // Create migrations table if it doesn't exist
+    await sqlExec(`
+      CREATE TABLE IF NOT EXISTS migrations (
+        id INTEGER PRIMARY KEY AUTOINCREMENT,
+        name TEXT NOT NULL UNIQUE,
+        executed_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
+      )
+    `);
+
+    // Get list of executed migrations
+    const result = await sqlExec('SELECT name FROM migrations');
+    const singleResult = result[0];
+    const executedMigrations = new Set(singleResult.values.map(row => row[0]));
+
+    // Run pending migrations in order
+    for (const migration of this.migrations) {
+      if (!executedMigrations.has(migration.name)) {
+        try {
+          await sqlExec(migration.sql);
+          await sqlExec('INSERT INTO migrations (name) VALUES (?)', [migration.name]);
+          console.log(`Migration ${migration.name} executed successfully`);
+        } catch (error) {
+          console.error(`Error executing migration ${migration.name}:`, error);
+          throw error;
+        }
+      }
+    }
+  }
+}
+
+export default MigrationService.getInstance();