// Example: Article API Client
@GET("v4/articles")
suspend fun getArticles(
    @Query("search") query: String? = null,
    @Query("offset") offset: Int? = null,
    @Query("limit") limit: Int? = 10,
    @Query("ordering") sort: Array<String>? = arrayOf("-published_at")
): Response<PaginationDto>

// Example: GetArticlesUseCase
class GetArticlesUseCase @Inject constructor(
    private val repository: ArticleRepository
) {
    suspend fun getArticles(query: String? = null): Resource<List<Article>> {
        return repository.getArticles(query)
    }
}

// Example: Fragment with ViewModel
@AndroidEntryPoint
class ArticlesFragment : Fragment() {
    private val viewModel: ArticlesViewModel by viewModels()
    
    private fun observeArticle() {
        viewModel.articles.observe(viewLifecycleOwner) { resource ->
            when (resource) {
                is Resource.Success -> loadData(resource.data)
                is Resource.Loading -> showLoading()
                is Resource.Error -> showError()
            }
        }
    }
}

app/src/main/java/com/bsvillarraga/spaceflightnews/
├── core/                    # Core utilities and extensions
│   ├── common/             # Common classes like Resource
│   ├── extensions/         # Kotlin extensions
│   └── network/            # Network helpers
├── data/                   # Data layer
│   ├── local/             # Room database
│   ├── model/             # DTOs and data models
│   ├── remote/            # API clients
│   └── repository/        # Repository implementations
├── domain/                 # Domain layer
│   ├── model/             # Domain models
│   ├── repository/        # Repository interfaces
│   └── usecase/           # Business logic
├── di/                     # Dependency injection modules
└── presentation/           # Presentation layer
    ├── permission/        # Permission handling
    └── ui/                # Fragments, ViewModels, Adapters

sealed class Resource<out T> {
    data class Success<out T>(val data: T?) : Resource<T>()
    data class Error<out T>(val code: String?, val msg: String, val error: Throwable? = null) : Resource<T>()
    data class Loading<out T>(val data: T? = null) : Resource<T>()
}

val client = OkHttpClient.Builder()
    .addInterceptor { chain ->
        val original = chain.request()
        val originalUrl = original.url()
        
        val newUrl = originalUrl.newBuilder()
            .addQueryParameter("format", "json")
            .build()
        
        val newRequest = original.newBuilder()
            .url(newUrl)
            .build()
        
        chain.proceed(newRequest)
    }
    .build()

return Retrofit.Builder()
    .baseUrl("https://api.spaceflightnewsapi.net/")
    .client(client)
    .addConverterFactory(GsonConverterFactory.create())
    .build()