NetworkError

NetworkError.kt

import com.google.gson.Gson
import com.swishhoop.util.TLog
import retrofit2.HttpException
import java.io.IOException
import java.net.ConnectException
import java.net.SocketTimeoutException
import java.net.UnknownHostException
import kotlin.reflect.KClass

/**
 * Created by vtrifonov on 8/29/19.
 */
fun Throwable.toNetworkError(): NetworkError<Nothing>? {
    return NetworkError.create(this)
}

fun <T : Any> Throwable.toNetworkError(errorResponseType: KClass<T>?): NetworkError<T>? {
    return NetworkError.create(this, errorResponseType)
}

fun Throwable.isNetworkError() = this is HttpException || this is UnknownHostException
        || this is SocketTimeoutException || this is ConnectException

class NetworkError<T>(
        val status: Status,
        val code: Int,
        val message: String?,
        val body: T? = null

) {
    enum class Status {
        NO_NETWORK,
        FAILURE,
        UNAUTHORIZED,
        FORBIDDEN,
        BAD_REQUEST,
    }

    companion object {
        fun create(throwable: Throwable): NetworkError<Nothing>? {
            return create(throwable, null)
        }

        fun <T : Any> create(throwable: Throwable, errorResponseType: KClass<T>?): NetworkError<T>? {
            if (!throwable.isNetworkError()) {
                return null
            }

            return if (throwable is HttpException) {
                val errorBody = errorResponseType?.let {
                    getErrorBodyAs(it, throwable)
                }

                when (val code = throwable.code()) {
                    400 -> NetworkError(Status.FAILURE, code, throwable.message, errorBody)
                    401 -> NetworkError(Status.UNAUTHORIZED, code, throwable.message, errorBody)
                    403 -> NetworkError(Status.FORBIDDEN, code, throwable.message, errorBody)
                    else -> NetworkError(Status.BAD_REQUEST, code, throwable.message, errorBody)
                }
            } else {
                NetworkError(Status.NO_NETWORK, 0, "No internet connection.")
            }
        }

        private fun <T : Any> getErrorBodyAs(type: KClass<T>, error: HttpException?): T? {
            var errorObject: T? = null

            error?.response()?.errorBody()?.let {
                try {
                    errorObject = Gson().fromJson(it.string(), type.java)
                } catch (e: IOException) {
                    TLog.i(e, e.localizedMessage)
                }
            }

            return errorObject
        }
    }
}