DataLayerExample2.kt

// Data Layer: Example of combining data sources
class UserRepositoryImpl(
    private val apiService: ApiService,
    private val userDao: UserDao
) : UserRepository {
    override suspend fun getUserById(userId: String): User {
        return try {
            // Fetch from remote API
            val userDto = apiService.getUserById(userId)
            // Save to local database for caching
            userDao.insertUser(userDto.toUserEntity())
            userDto.toUser() // Convert DTO to domain model
        } catch (exception: Exception) {
            // Fallback to local database if network fails
            userDao.getUserById(userId).toDomainModel()
        }
    }
}