class ApiManager(private val context: Context) {
    val CURRENT_SERVER_ADDRESS: String = BuildConfig.SERVER_ADDRESS

    lateinit var apiService: ApiService

    companion object {
        lateinit var httpClient: OkHttpClient
    }

    init {
        val retrofit = initRetrofit()
        initServices(retrofit)
    }

    private fun initRetrofit(): Retrofit {
        val loggingInterceptor = HttpLoggingInterceptor().apply {
            level = HttpLoggingInterceptor.Level.BODY
        }

        val cookieManager = CookieManager()
        cookieManager.setCookiePolicy(CookiePolicy.ACCEPT_ALL)

        val cacheSize = 10 * 1024 * 1024L // 10 MB
        val cache = Cache(context.cacheDir, cacheSize)

        httpClient = OkHttpClient.Builder()
            .readTimeout(45, TimeUnit.SECONDS)
            .writeTimeout(45, TimeUnit.SECONDS)
            .cookieJar(JavaNetCookieJar(cookieManager))
            .addInterceptor(loggingInterceptor)
            .addInterceptor({ chain ->
                try {
                    chain.proceed(chain.request())
                } catch (e: Exception) {
                    val offlineRequest = chain.request().newBuilder()
                        .header(
                            "Cache-Control", "public, only-if-cached," +
                                    "max-stale=" + 60 * 60
                        )
                        .build()
                    chain.proceed(offlineRequest)
                }
            })
            .cache(cache)
            .build()

        return Retrofit.Builder()
            .addCallAdapterFactory(RxJava2CallAdapterFactory.create())
            .addConverterFactory(GsonConverterFactory.create())
            .client(httpClient)
            .baseUrl(CURRENT_SERVER_ADDRESS)
            .build()
    }

    private fun initServices(retrofit: Retrofit) {
        apiService = retrofit.create(ApiService::class.java)
    }

    fun toRequestBody(value: String): RequestBody {
        return RequestBody.create(MediaType.parse("text/plain"), value)
    }
}