Initial commit: NestJS backend for Child Gold Land

Co-authored-by: Cursor <cursoragent@cursor.com>

src/database/database.service.ts

@@ -0,0 +1,55 @@
+import { Inject, Injectable, Logger, OnModuleDestroy, OnModuleInit, Optional } from '@nestjs/common'
+import { ConfigService } from '@nestjs/config'
+import Database from 'better-sqlite3'
+import { mkdirSync } from 'node:fs'
+import { dirname, join } from 'node:path'
+import { EXPECTED_TABLES, listUserTables, runSchemaMigrations } from './migration.service'
+
+@Injectable()
+export class DatabaseService implements OnModuleInit, OnModuleDestroy {
+  private readonly logger = new Logger(DatabaseService.name)
+  private db: Database.Database | null = null
+  private readonly dbPath: string
+
+  constructor(@Optional() @Inject(ConfigService) private readonly config?: ConfigService) {
+    const configured = this.config?.get<string>('DB_PATH') ?? process.env.DB_PATH
+    this.dbPath = configured ?? join(process.cwd(), 'data', 'app.db')
+  }
+
+  onModuleInit(): void {
+    mkdirSync(dirname(this.dbPath), { recursive: true })
+    this.db = new Database(this.dbPath)
+    this.db.pragma('journal_mode = WAL')
+    runSchemaMigrations(this.db)
+    this.logger.log(`SQLite ready at ${this.dbPath}`)
+  }
+
+  onModuleDestroy(): void {
+    if (this.db) {
+      this.db.close()
+      this.db = null
+      this.logger.log('SQLite connection closed')
+    }
+  }
+
+  getDbPath(): string {
+    return this.dbPath
+  }
+
+  getDb(): Database.Database {
+    if (!this.db) {
+      throw new Error('Database is not initialized')
+    }
+    return this.db
+  }
+
+  transaction<T>(fn: () => T): T {
+    return this.getDb().transaction(fn)()
+  }
+
+  verifyMigrationsApplied(): { ok: boolean; tables: string[]; missing: string[] } {
+    const tables = listUserTables(this.getDb())
+    const missing = EXPECTED_TABLES.filter((name) => !tables.includes(name))
+    return { ok: missing.length === 0, tables, missing }
+  }
+}