/*
 * ============LICENSE_START=======================================================
 * dcaegen2-collectors-veshv
 * ================================================================================
 * Copyright (C) 2019 NOKIA
 * ================================================================================
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * ============LICENSE_END=========================================================
 */
package org.onap.dcae.collectors.veshv.impl.socket

import arrow.core.Option
import arrow.core.Try
import arrow.syntax.collections.firstOption
import io.netty.handler.ssl.SslHandler
import io.netty.util.concurrent.Future
import org.onap.dcae.collectors.veshv.model.ClientContext
import reactor.core.publisher.Mono
import reactor.netty.ByteBufFlux
import reactor.netty.Connection
import reactor.netty.NettyInbound
import reactor.netty.NettyOutbound
import java.net.InetAddress
import java.security.cert.X509Certificate
import javax.net.ssl.SSLSession

internal fun InetAddress.isLocalClientAddress() = hostAddress == "127.0.0.1" || hostName == "localhost"

internal fun Connection.getSslSession(): Option<SSLSession> =
        Option.fromNullable(
                channel()
                        .pipeline()
                        .get(SslHandler::class.java)
                        ?.engine()
                        ?.session
        )

internal fun SSLSession.findClientCert(): Option<X509Certificate> =
        peerCertificates
                .firstOption()
                .flatMap { Option.fromNullable(it as? X509Certificate) }

internal fun withConnectionFrom(nettyInboud: NettyInbound, task: (Connection) -> Unit) =
        nettyInboud.withConnection(task)

internal fun Connection.closeChannel() = channel().close()

internal fun Connection.closeChannelAndThen(task: (Future<in Void>) -> Unit) =
        closeChannel().addListener { task(it) }

internal fun <T> NettyInbound.closeConnectionAndReturn(returnValue: T): T =
        withConnectionFrom(this) { it.closeChannel() }.let { returnValue }

internal fun NettyInbound.createDataStream(): ByteBufFlux = receive().retain()

//
// ClientContext related
//

internal inline fun withNewClientContextFrom(nettyInbound: NettyInbound,
                                             nettyOutbound: NettyOutbound,
                                             reactiveTask: (ClientContext) -> Mono<Void>) =
        ClientContext(nettyOutbound.alloc())
                .also { populateClientContextFromInbound(it, nettyInbound) }
                .run(reactiveTask)

internal fun populateClientContextFromInbound(clientContext: ClientContext, nettyInbound: NettyInbound) =
        withConnectionFrom(nettyInbound) { connection ->
            clientContext.clientAddress = Try { connection.address().address }.toOption()
            clientContext.clientCert = connection.getSslSession().flatMap { it.findClientCert() }
        }