// App

class UserApp : Application() {

    lateinit var userApi: UsersApi

    override fun onCreate() {
        super.onCreate()

        configureRetrofit()
    }

    private fun configureRetrofit() {

        val httpLoggingInterceptor = HttpLoggingInterceptor()
        httpLoggingInterceptor.level = HttpLoggingInterceptor.Level.BODY

        val okHttpClient = OkHttpClient.Builder()
            .addInterceptor(httpLoggingInterceptor)
            .build()

        val retrofit = Retrofit.Builder()
            .baseUrl("https://reqres.in/")
            .client(okHttpClient)
            .addConverterFactory(GsonConverterFactory.create())
            .addCallAdapterFactory(RxJava2CallAdapterFactory.create())
            .build()

        userApi = retrofit.create(UsersApi::class.java)
    }
}

// ViewModel

class UserListViewModel(application: Application) : AndroidViewModel(application) {

    private val compositeDisposable = CompositeDisposable()

    override fun onCleared() {
        compositeDisposable.clear()
        super.onCleared()
    }

    fun fetchUserList(usersApi: UsersApi?) {

        usersApi?.let {
            compositeDisposable.add(
                usersApi.getUserList()
                    .subscribeOn(Schedulers.io())
                    .observeOn(AndroidSchedulers.mainThread())
                    .subscribe({

                    }, {

                    })
            )
        }
    }
}

// Api
interface UsersApi {
    @GET("./api/users")
    @Headers("Content-Type: application/json")
    fun getUserList() : Single<UserListResponse>
}

// User Response
data class UserListResponse(
    @SerializedName("data")
    val users : List<UserItem>
) {}

data class UserItem(
    @SerializedName("id")
    val userId: Int,

    @SerializedName("email")
    val userEmail: String,

    @SerializedName("first_name")
    val userFirstName: String,

    @SerializedName("last_name")
    val userLastName: String,

    @SerializedName("avatar")
    val userImgUrl: String
){}