RemoteDataSource.kt

class RemoteDataSource(private val context: Context) {

    fun api(): Api {
        val mockFitInterceptor = provideMockFitInterceptor(context)
        val okHttpClient = provideOkHttpClient(mockFitInterceptor)
        val retrofit = provideRetrofit(okHttpClient)
        return retrofit.create(Api::class.java)
    }

    private fun provideRetrofit(okHttpClient: OkHttpClient): Retrofit = Retrofit.Builder()
        .baseUrl(BASE_URL)
        .addConverterFactory(GsonConverterFactory.create())
        .client(okHttpClient)
        .build()

    private fun provideMockFitInterceptor(context: Context) = MockFitInterceptor(
        bodyFactory = { input -> context.resources.assets.open(input) }, // read asset file
        logger = { tag, message -> Log.d(tag, message) }, // pass logger to log events in logcat
        baseUrl = BASE_URL, // base url of your api
        requestPathToMockPathRule = REQUEST_TO_JSON, // autogenerated constant, just press build button
        mockFilesPath = MOCK_FILES_PATH, // path to json files
        mockFitEnable = true, // master setting to enable or disable mocking
        apiEnableMock = true, // enable or disable mock when there are includes and excludes configs
        apiIncludeIntoMock = arrayOf(), // include endpoint if `apiEnableMock` is false
        apiExcludeFromMock = arrayOf(), // exclude endpoint if `apiEnableMock` is true 
        apiResponseLatency = 500L // latency of retrieving data
    )

    private fun provideOkHttpClient(mockFitInterceptor: MockFitInterceptor) = OkHttpClient.Builder()
        .addInterceptor(mockFitInterceptor)
        .connectTimeout(CONNECT_TIMEOUT, TimeUnit.SECONDS)
        .writeTimeout(WRITE_TIMEOUT, TimeUnit.SECONDS)
        .readTimeout(READ_TIMEOUT, TimeUnit.SECONDS)
        .build()

    companion object {
        private const val BASE_URL = "https://picsum.photos/v2/"
        private const val MOCK_FILES_PATH = "mock_json" // located at assets/mock_json/
        private const val CONNECT_TIMEOUT = 20L
        private const val WRITE_TIMEOUT = 20L
        private const val READ_TIMEOUT = 30L
    }
}