mangadex_at_home/src/main/kotlin/mdnet/BackendApi.kt

/*
Mangadex@Home
Copyright (c) 2020, MangaDex Network
This file is part of MangaDex@Home.

MangaDex@Home is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

MangaDex@Home is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this MangaDex@Home.  If not, see <http://www.gnu.org/licenses/>.
*/
package mdnet

import com.fasterxml.jackson.databind.DeserializationFeature
import com.fasterxml.jackson.module.kotlin.KotlinModule
import mdnet.ServerHandlerJackson.auto
import mdnet.logging.info
import mdnet.settings.*
import okhttp3.Dns
import okhttp3.OkHttpClient
import org.http4k.client.OkHttp
import org.http4k.core.*
import org.http4k.format.ConfigurableJackson
import org.http4k.format.asConfigurable
import org.http4k.format.withStandardMappings
import org.http4k.lens.LensFailure
import org.slf4j.LoggerFactory
import java.net.Inet4Address
import java.net.InetAddress

object ServerHandlerJackson : ConfigurableJackson(
    KotlinModule()
        .asConfigurable()
        .withStandardMappings()
        .done()
        .configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false)
)

class BackendApi(private val settings: ClientSettings) {
    private val client = OkHttp(
        client = OkHttpClient.Builder()
            .dns(object : Dns {
                override fun lookup(hostname: String): List<InetAddress> {
                    return Dns.SYSTEM.lookup(hostname).filterIsInstance<Inet4Address>()
                }
            })
            .build()
    )
    private val serverAddress = settings.devSettings.devUrl ?: SERVER_ADDRESS

    fun logoutFromControl(): Boolean {
        val serverSettings = settings.serverSettings

        LOGGER.info { "Disconnecting from the control server" }

        val request = LOGOUT_REQUEST_LENS(
            LogoutRequest(serverSettings.secret),
            Request(Method.POST, serverAddress + "stop")
        )

        val response = client(request)

        return response.status.successful
    }

    private fun getPingParams(tlsCreatedAt: String? = null): SettingsRequest {
        val serverSettings = settings.serverSettings
        return SettingsRequest(
            secret = serverSettings.secret,
            port = if (serverSettings.externalPort != 0) {
                serverSettings.externalPort
            } else {
                serverSettings.port
            },
            buildVersion = Constants.CLIENT_BUILD,
            diskSpace = settings.maxCacheSizeInMebibytes * 1024 * 1024,
            networkSpeed = serverSettings.externalMaxKilobitsPerSecond * 1000 / 8,
            ipAddress = serverSettings.externalIp,
            tlsCreatedAt = tlsCreatedAt,
        )
    }

    fun loginToControl(): PingResult {
        LOGGER.info { "Connecting to the control server" }

        val request = SETTINGS_REQUEST_LENS(
            getPingParams(null),
            Request(
                Method.POST,
                serverAddress + "ping"
            )
        )
        return client.makeRequest(request)
    }

    fun pingControl(old: RemoteSettings): PingResult {
        LOGGER.info { "Pinging the control server" }

        val request = SETTINGS_REQUEST_LENS(
            getPingParams(old.tls!!.createdAt),
            Request(
                Method.POST,
                serverAddress + "ping"
            )
        )
        return client.makeRequest(request)
    }

    private fun HttpHandler.makeRequest(request: Request): PingResult {
        val response = this(request)

        return when {
            response.status.successful -> {
                SERVER_SETTINGS_LENS(response)
            }
            else -> {
                try {
                    PING_FAILURE_LENS(response)
                } catch (e: LensFailure) {
                    PingFailure(response.status.code, response.status.description)
                }
            }
        }
    }

    companion object {
        private val LOGGER = LoggerFactory.getLogger(BackendApi::class.java)
        private val SETTINGS_REQUEST_LENS = Body.auto<SettingsRequest>().toLens()
        private val PING_FAILURE_LENS = Body.auto<PingFailure>().toLens()
        private val LOGOUT_REQUEST_LENS = Body.auto<LogoutRequest>().toLens()
        private val SERVER_SETTINGS_LENS = Body.auto<RemoteSettings>().toLens()
        private const val SERVER_ADDRESS = "https://api.mangadex.network/"
    }
}