/*
 * Copyright (c) 2017-present Robert Jaros
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
package pl.treksoft.kvision.remote

import com.fasterxml.jackson.databind.module.SimpleModule
import com.fasterxml.jackson.module.kotlin.jacksonObjectMapper
import com.fasterxml.jackson.module.kotlin.readValue
import com.google.inject.Injector
import io.javalin.Javalin
import io.javalin.core.security.Role
import io.javalin.http.Context
import io.javalin.websocket.WsContext
import io.javalin.websocket.WsHandler
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.ExperimentalCoroutinesApi
import kotlinx.coroutines.GlobalScope
import kotlinx.coroutines.channels.Channel
import kotlinx.coroutines.channels.ReceiveChannel
import kotlinx.coroutines.channels.SendChannel
import kotlinx.coroutines.coroutineScope
import kotlinx.coroutines.future.future
import kotlinx.coroutines.launch
import org.slf4j.Logger
import org.slf4j.LoggerFactory
import pl.treksoft.kvision.types.*
import java.math.BigDecimal
import java.time.LocalDate
import java.time.LocalDateTime
import java.time.LocalTime
import java.time.OffsetDateTime
import java.time.OffsetTime
import kotlin.reflect.KClass

/**
 * Multiplatform service manager for Javalin.
 */
@Suppress("LargeClass", "TooManyFunctions", "BlockingMethodInNonBlockingContext")
actual open class KVServiceManager<T : Any> actual constructor(val serviceClass: KClass<T>) {

    companion object {
        val LOG: Logger = LoggerFactory.getLogger(KVServiceManager::class.java.name)
        const val KV_WS_INCOMING_KEY = "pl.treksoft.kvision.ws.incoming.key"
        const val KV_WS_OUTGOING_KEY = "pl.treksoft.kvision.ws.outgoing.key"
    }

    val getRequests: MutableMap<String, (Context) -> Unit> = mutableMapOf()
    val postRequests: MutableMap<String, (Context) -> Unit> = mutableMapOf()
    val putRequests: MutableMap<String, (Context) -> Unit> = mutableMapOf()
    val deleteRequests: MutableMap<String, (Context) -> Unit> =
        mutableMapOf()
    val optionsRequests: MutableMap<String, (Context) -> Unit> =
        mutableMapOf()
    val webSocketRequests: MutableMap<String, (WsHandler) -> Unit> =
        mutableMapOf()

    val mapper = jacksonObjectMapper().apply {
        val module = SimpleModule()
        module.addSerializer(LocalDateTime::class.java, LocalDateTimeSerializer())
        module.addSerializer(LocalDate::class.java, LocalDateSerializer())
        module.addSerializer(LocalTime::class.java, LocalTimeSerializer())
        module.addSerializer(OffsetDateTime::class.java, OffsetDateTimeSerializer())
        module.addSerializer(OffsetTime::class.java, OffsetTimeSerializer())
        module.addSerializer(BigDecimal::class.java, BigDecimalSerializer())
        module.addDeserializer(LocalDateTime::class.java, LocalDateTimeDeserializer())
        module.addDeserializer(LocalDate::class.java, LocalDateDeserializer())
        module.addDeserializer(LocalTime::class.java, LocalTimeDeserializer())
        module.addDeserializer(OffsetDateTime::class.java, OffsetDateTimeDeserializer())
        module.addDeserializer(OffsetTime::class.java, OffsetTimeDeserializer())
        module.addDeserializer(BigDecimal::class.java, BigDecimalDeserializer())
        this.registerModule(module)
    }
    var counter: Int = 0

    /**
     * @suppress internal function
     */
    @Suppress("DEPRECATION")
    fun initializeService(service: T, ctx: Context) {
        if (service is WithContext) {
            service.ctx = ctx
        }
        if (service is WithHttpSession) {
            service.httpSession = ctx.req.session
        }
    }

    /**
     * @suppress internal function
     */
    @Suppress("DEPRECATION")
    fun initializeWsService(service: T, wsCtx: WsContext) {
        if (service is WithWsContext) {
            service.wsCtx = wsCtx
        }
        if (service is WithWsSession) {
            service.wsSession = wsCtx.session
        }
    }

    /**
     * Binds a given route with a function of the receiver.
     * @param function a function of the receiver
     * @param method a HTTP method
     * @param route a route
     */
    @Suppress("TooGenericExceptionCaught")
    protected actual inline fun <reified RET> bind(
        noinline function: suspend T.() -> RET,
        method: HttpMethod, route: String?
    ) {
        val routeDef = route ?: "route${this::class.simpleName}${counter++}"
        addRoute(method, "/kv/$routeDef") { ctx ->
            val jsonRpcRequest = if (method == HttpMethod.GET) {
                JsonRpcRequest(ctx.queryParam<Int>("id").get(), "", listOf())
            } else {
                ctx.body<JsonRpcRequest>()
            }
            val injector = ctx.attribute<Injector>(KV_INJECTOR_KEY)!!
            val service = injector.getInstance(serviceClass.java)
            initializeService(service, ctx)
            val future = GlobalScope.future {
                try {
                    val result = function.invoke(service)
                    JsonRpcResponse(
                        id = jsonRpcRequest.id,
                        result = mapper.writeValueAsString(result)
                    )
                } catch (e: Exception) {
                    if (e !is ServiceException) LOG.error(e.message, e)
                    JsonRpcResponse(
                        id = jsonRpcRequest.id, error = e.message ?: "Error",
                        exceptionType = e.javaClass.canonicalName
                    )
                }
            }
            ctx.json(future)
        }
    }

    /**
     * Binds a given route with a function of the receiver.
     * @param function a function of the receiver
     * @param method a HTTP method
     * @param route a route
     */
    @Suppress("TooGenericExceptionCaught")
    protected actual inline fun <reified PAR, reified RET> bind(
        noinline function: suspend T.(PAR) -> RET,
        method: HttpMethod, route: String?
    ) {
        if (method == HttpMethod.GET)
            throw UnsupportedOperationException("GET method is only supported for methods without parameters")
        val routeDef = route ?: "route${this::class.simpleName}${counter++}"
        addRoute(method, "/kv/$routeDef") { ctx ->
            val jsonRpcRequest = ctx.body<JsonRpcRequest>()
            if (jsonRpcRequest.params.size == 1) {
                val param = getParameter<PAR>(jsonRpcRequest.params[0])
                val injector = ctx.attribute<Injector>(KV_INJECTOR_KEY)!!
                val service = injector.getInstance(serviceClass.java)
                initializeService(service, ctx)
                val future = GlobalScope.future {
                    try {
                        val result = function.invoke(service, param)
                        JsonRpcResponse(
                            id = jsonRpcRequest.id,
                            result = mapper.writeValueAsString(result)
                        )
                    } catch (e: Exception) {
                        if (e !is ServiceException) LOG.error(e.message, e)
                        JsonRpcResponse(
                            id = jsonRpcRequest.id, error = e.message ?: "Error",
                            exceptionType = e.javaClass.canonicalName
                        )
                    }
                }
                ctx.json(future)
            } else {
                ctx.json(JsonRpcResponse(id = jsonRpcRequest.id, error = "Invalid parameters"))
            }
        }
    }

    /**
     * Binds a given route with a function of the receiver.
     * @param function a function of the receiver
     * @param method a HTTP method
     * @param route a route
     */
    @Suppress("TooGenericExceptionCaught")
    protected actual inline fun <reified PAR1, reified PAR2, reified RET> bind(
        noinline function: suspend T.(PAR1, PAR2) -> RET,
        method: HttpMethod, route: String?
    ) {
        if (method == HttpMethod.GET)
            throw UnsupportedOperationException("GET method is only supported for methods without parameters")
        val routeDef = route ?: "route${this::class.simpleName}${counter++}"
        addRoute(method, "/kv/$routeDef") { ctx ->
            val jsonRpcRequest = ctx.body<JsonRpcRequest>()
            if (jsonRpcRequest.params.size == 2) {
                val param1 = getParameter<PAR1>(jsonRpcRequest.params[0])
                val param2 = getParameter<PAR2>(jsonRpcRequest.params[1])
                val injector = ctx.attribute<Injector>(KV_INJECTOR_KEY)!!
                val service = injector.getInstance(serviceClass.java)
                initializeService(service, ctx)
                val future = GlobalScope.future {
                    try {
                        val result = function.invoke(service, param1, param2)
                        JsonRpcResponse(
                            id = jsonRpcRequest.id,
                            result = mapper.writeValueAsString(result)
                        )
                    } catch (e: Exception) {
                        if (e !is ServiceException) LOG.error(e.message, e)
                        JsonRpcResponse(
                            id = jsonRpcRequest.id, error = e.message ?: "Error",
                            exceptionType = e.javaClass.canonicalName
                        )
                    }
                }
                ctx.json(future)
            } else {
                ctx.json(JsonRpcResponse(id = jsonRpcRequest.id, error = "Invalid parameters"))
            }
        }
    }

    /**
     * Binds a given route with a function of the receiver.
     * @param function a function of the receiver
     * @param method a HTTP method
     * @param route a route
     */
    @Suppress("TooGenericExceptionCaught")
    protected actual inline fun <reified PAR1, reified PAR2, reified PAR3, reified RET> bind(
        noinline function: suspend T.(PAR1, PAR2, PAR3) -> RET,
        method: HttpMethod, route: String?
    ) {
        if (method == HttpMethod.GET)
            throw UnsupportedOperationException("GET method is only supported for methods without parameters")
        val routeDef = route ?: "route${this::class.simpleName}${counter++}"
        addRoute(method, "/kv/$routeDef") { ctx ->
            val jsonRpcRequest = ctx.body<JsonRpcRequest>()
            @Suppress("MagicNumber")
            if (jsonRpcRequest.params.size == 3) {
                val param1 = getParameter<PAR1>(jsonRpcRequest.params[0])
                val param2 = getParameter<PAR2>(jsonRpcRequest.params[1])
                val param3 = getParameter<PAR3>(jsonRpcRequest.params[2])
                val injector = ctx.attribute<Injector>(KV_INJECTOR_KEY)!!
                val service = injector.getInstance(serviceClass.java)
                initializeService(service, ctx)
                val future = GlobalScope.future {
                    try {
                        val result = function.invoke(service, param1, param2, param3)
                        JsonRpcResponse(
                            id = jsonRpcRequest.id,
                            result = mapper.writeValueAsString(result)
                        )
                    } catch (e: Exception) {
                        if (e !is ServiceException) LOG.error(e.message, e)
                        JsonRpcResponse(
                            id = jsonRpcRequest.id, error = e.message ?: "Error",
                            exceptionType = e.javaClass.canonicalName
                        )
                    }
                }
                ctx.json(future)
            } else {
                ctx.json(JsonRpcResponse(id = jsonRpcRequest.id, error = "Invalid parameters"))
            }
        }
    }

    /**
     * Binds a given route with a function of the receiver.
     * @param function a function of the receiver
     * @param method a HTTP method
     * @param route a route
     */
    @Suppress("TooGenericExceptionCaught")
    protected actual inline fun <reified PAR1, reified PAR2, reified PAR3, reified PAR4, reified RET> bind(
        noinline function: suspend T.(PAR1, PAR2, PAR3, PAR4) -> RET,
        method: HttpMethod, route: String?
    ) {
        if (method == HttpMethod.GET)
            throw UnsupportedOperationException("GET method is only supported for methods without parameters")
        val routeDef = route ?: "route${this::class.simpleName}${counter++}"
        addRoute(method, "/kv/$routeDef") { ctx ->
            val jsonRpcRequest = ctx.body<JsonRpcRequest>()
            @Suppress("MagicNumber")
            if (jsonRpcRequest.params.size == 4) {
                val param1 = getParameter<PAR1>(jsonRpcRequest.params[0])
                val param2 = getParameter<PAR2>(jsonRpcRequest.params[1])
                val param3 = getParameter<PAR3>(jsonRpcRequest.params[2])
                val param4 = getParameter<PAR4>(jsonRpcRequest.params[3])
                val injector = ctx.attribute<Injector>(KV_INJECTOR_KEY)!!
                val service = injector.getInstance(serviceClass.java)
                initializeService(service, ctx)
                val future = GlobalScope.future {
                    try {
                        val result = function.invoke(service, param1, param2, param3, param4)
                        JsonRpcResponse(
                            id = jsonRpcRequest.id,
                            result = mapper.writeValueAsString(result)
                        )
                    } catch (e: Exception) {
                        if (e !is ServiceException) LOG.error(e.message, e)
                        JsonRpcResponse(
                            id = jsonRpcRequest.id, error = e.message ?: "Error",
                            exceptionType = e.javaClass.canonicalName
                        )
                    }
                }
                ctx.json(future)
            } else {
                ctx.json(JsonRpcResponse(id = jsonRpcRequest.id, error = "Invalid parameters"))
            }
        }
    }

    /**
     * Binds a given route with a function of the receiver.
     * @param function a function of the receiver
     * @param method a HTTP method
     * @param route a route
     */
    @Suppress("TooGenericExceptionCaught")
    protected actual inline fun <reified PAR1, reified PAR2, reified PAR3,
            reified PAR4, reified PAR5, reified RET> bind(
        noinline function: suspend T.(PAR1, PAR2, PAR3, PAR4, PAR5) -> RET,
        method: HttpMethod, route: String?
    ) {
        if (method == HttpMethod.GET)
            throw UnsupportedOperationException("GET method is only supported for methods without parameters")
        val routeDef = route ?: "route${this::class.simpleName}${counter++}"
        addRoute(method, "/kv/$routeDef") { ctx ->
            val jsonRpcRequest = ctx.body<JsonRpcRequest>()
            @Suppress("MagicNumber")
            if (jsonRpcRequest.params.size == 5) {
                val param1 = getParameter<PAR1>(jsonRpcRequest.params[0])
                val param2 = getParameter<PAR2>(jsonRpcRequest.params[1])
                val param3 = getParameter<PAR3>(jsonRpcRequest.params[2])
                val param4 = getParameter<PAR4>(jsonRpcRequest.params[3])
                val param5 = getParameter<PAR5>(jsonRpcRequest.params[4])
                val injector = ctx.attribute<Injector>(KV_INJECTOR_KEY)!!
                val service = injector.getInstance(serviceClass.java)
                initializeService(service, ctx)
                val future = GlobalScope.future {
                    try {
                        val result = function.invoke(service, param1, param2, param3, param4, param5)
                        JsonRpcResponse(
                            id = jsonRpcRequest.id,
                            result = mapper.writeValueAsString(result)
                        )
                    } catch (e: Exception) {
                        if (e !is ServiceException) LOG.error(e.message, e)
                        JsonRpcResponse(
                            id = jsonRpcRequest.id, error = e.message ?: "Error",
                            exceptionType = e.javaClass.canonicalName
                        )
                    }
                }
                ctx.json(future)
            } else {
                ctx.json(JsonRpcResponse(id = jsonRpcRequest.id, error = "Invalid parameters"))
            }
        }
    }

    /**
     * Binds a given route with a function of the receiver.
     * @param function a function of the receiver
     * @param method a HTTP method
     * @param route a route
     */
    @Suppress("TooGenericExceptionCaught")
    protected actual inline fun <reified PAR1, reified PAR2, reified PAR3,
            reified PAR4, reified PAR5, reified PAR6, reified RET> bind(
        noinline function: suspend T.(PAR1, PAR2, PAR3, PAR4, PAR5, PAR6) -> RET,
        method: HttpMethod, route: String?
    ) {
        if (method == HttpMethod.GET)
            throw UnsupportedOperationException("GET method is only supported for methods without parameters")
        val routeDef = route ?: "route${this::class.simpleName}${counter++}"
        addRoute(method, "/kv/$routeDef") { ctx ->
            val jsonRpcRequest = ctx.body<JsonRpcRequest>()
            @Suppress("MagicNumber")
            if (jsonRpcRequest.params.size == 6) {
                val param1 = getParameter<PAR1>(jsonRpcRequest.params[0])
                val param2 = getParameter<PAR2>(jsonRpcRequest.params[1])
                val param3 = getParameter<PAR3>(jsonRpcRequest.params[2])
                val param4 = getParameter<PAR4>(jsonRpcRequest.params[3])
                val param5 = getParameter<PAR5>(jsonRpcRequest.params[4])
                val param6 = getParameter<PAR6>(jsonRpcRequest.params[5])
                val injector = ctx.attribute<Injector>(KV_INJECTOR_KEY)!!
                val service = injector.getInstance(serviceClass.java)
                initializeService(service, ctx)
                val future = GlobalScope.future {
                    try {
                        val result = function.invoke(service, param1, param2, param3, param4, param5, param6)
                        JsonRpcResponse(
                            id = jsonRpcRequest.id,
                            result = mapper.writeValueAsString(result)
                        )
                    } catch (e: Exception) {
                        if (e !is ServiceException) LOG.error(e.message, e)
                        JsonRpcResponse(
                            id = jsonRpcRequest.id, error = e.message ?: "Error",
                            exceptionType = e.javaClass.canonicalName
                        )
                    }
                }
                ctx.json(future)
            } else {
                ctx.json(JsonRpcResponse(id = jsonRpcRequest.id, error = "Invalid parameters"))
            }
        }
    }

    /**
     * Binds a given web socket connection with a function of the receiver.
     * @param function a function of the receiver
     * @param route a route
     */
    @OptIn(ExperimentalCoroutinesApi::class)
    protected actual inline fun <reified PAR1 : Any, reified PAR2 : Any> bind(
        noinline function: suspend T.(ReceiveChannel<PAR1>, SendChannel<PAR2>) -> Unit,
        route: String?
    ) {
        val routeDef = route ?: "route${this::class.simpleName}${counter++}"
        webSocketRequests["/kvws/$routeDef"] = { ws ->
            ws.onConnect { ctx ->
                val incoming = Channel<String>()
                val outgoing = Channel<String>()
                ctx.attribute(KV_WS_INCOMING_KEY, incoming)
                ctx.attribute(KV_WS_OUTGOING_KEY, outgoing)
                val injector = ctx.attribute<Injector>(KV_INJECTOR_KEY)!!
                val service = injector.getInstance(serviceClass.java)
                initializeWsService(service, ctx)
                GlobalScope.launch {
                    coroutineScope {
                        launch(Dispatchers.IO) {
                            for (text in outgoing) {
                                ctx.send(text)
                            }
                            ctx.session.close()
                        }
                        launch {
                            val requestChannel = Channel<PAR1>()
                            val responseChannel = Channel<PAR2>()
                            coroutineScope {
                                launch {
                                    for (p in incoming) {
                                        val jsonRpcRequest = getParameter<JsonRpcRequest>(p)
                                        if (jsonRpcRequest.params.size == 1) {
                                            val par = getParameter<PAR1>(jsonRpcRequest.params[0])
                                            requestChannel.send(par)
                                        }
                                    }
                                    requestChannel.close()
                                }
                                launch(Dispatchers.IO) {
                                    for (p in responseChannel) {
                                        val text = mapper.writeValueAsString(
                                            JsonRpcResponse(
                                                id = 0,
                                                result = mapper.writeValueAsString(p)
                                            )
                                        )
                                        outgoing.send(text)
                                    }
                                }
                                launch {
                                    function.invoke(service, requestChannel, responseChannel)
                                    if (!responseChannel.isClosedForReceive) responseChannel.close()
                                }
                            }
                            if (!outgoing.isClosedForReceive) outgoing.close()
                        }
                    }
                }
            }
            ws.onClose { ctx ->
                GlobalScope.launch {
                    val outgoing = ctx.attribute<Channel<String>>(KV_WS_OUTGOING_KEY)!!
                    val incoming = ctx.attribute<Channel<String>>(KV_WS_INCOMING_KEY)!!
                    outgoing.close()
                    incoming.close()
                }
            }
            ws.onMessage { ctx ->
                GlobalScope.launch {
                    val incoming = ctx.attribute<Channel<String>>(KV_WS_INCOMING_KEY)!!
                    incoming.send(ctx.message())
                }
            }
        }
    }

    /**
     * Binds a given function of the receiver as a tabulator component source
     * @param function a function of the receiver
     */
    @Suppress("TooGenericExceptionCaught")
    protected actual inline fun <reified RET> bindTabulatorRemote(
        noinline function: suspend T.(Int?, Int?, List<RemoteFilter>?, List<RemoteSorter>?, String?) -> RemoteData<RET>,
        route: String?
    ) {
        val routeDef = route ?: "route${this::class.simpleName}${counter++}"
        addRoute(HttpMethod.POST, "/kv/$routeDef") { ctx ->
            val jsonRpcRequest = ctx.body<JsonRpcRequest>()
            @Suppress("MagicNumber")
            if (jsonRpcRequest.params.size == 5) {
                val param1 = getParameter<Int?>(jsonRpcRequest.params[0])
                val param2 = getParameter<Int?>(jsonRpcRequest.params[1])
                val param3 = getParameter<List<RemoteFilter>?>(jsonRpcRequest.params[2])

                @Suppress("MagicNumber")
                val param4 = getParameter<List<RemoteSorter>?>(jsonRpcRequest.params[3])

                @Suppress("MagicNumber")
                val param5 = getParameter<String?>(jsonRpcRequest.params[4])
                val injector = ctx.attribute<Injector>(KV_INJECTOR_KEY)!!
                val service = injector.getInstance(serviceClass.java)
                initializeService(service, ctx)
                val future = GlobalScope.future {
                    try {
                        val result = function.invoke(service, param1, param2, param3, param4, param5)
                        JsonRpcResponse(
                            id = jsonRpcRequest.id,
                            result = mapper.writeValueAsString(result)
                        )
                    } catch (e: Exception) {
                        if (e !is ServiceException) LOG.error(e.message, e)
                        JsonRpcResponse(
                            id = jsonRpcRequest.id, error = e.message ?: "Error",
                            exceptionType = e.javaClass.canonicalName
                        )
                    }
                }
                ctx.json(future)
            } else {
                ctx.json(JsonRpcResponse(id = jsonRpcRequest.id, error = "Invalid parameters"))
            }
        }
    }

    /**
     * @suppress Internal method
     */
    fun addRoute(
        method: HttpMethod,
        path: String,
        handler: (Context) -> Unit
    ) {
        when (method) {
            HttpMethod.GET -> getRequests[path] = handler
            HttpMethod.POST -> postRequests[path] = handler
            HttpMethod.PUT -> putRequests[path] = handler
            HttpMethod.DELETE -> deleteRequests[path] = handler
            HttpMethod.OPTIONS -> optionsRequests[path] = handler
        }
    }

    /**
     * @suppress Internal method
     */
    protected inline fun <reified T> getParameter(str: String?): T {
        return str?.let {
            if (T::class == String::class) {
                str as T
            } else {
                mapper.readValue(str)
            }
        } ?: null as T
    }

}

/**
 * A function to generate routes based on definitions from the service manager.
 */
fun <T : Any> Javalin.applyRoutes(serviceManager: KVServiceManager<T>, roles: Set<Role> = setOf()) {
    serviceManager.getRequests.forEach { (path, handler) ->
        get(path, handler, roles)
    }
    serviceManager.postRequests.forEach { (path, handler) ->
        post(path, handler, roles)
    }
    serviceManager.putRequests.forEach { (path, handler) ->
        put(path, handler, roles)
    }
    serviceManager.deleteRequests.forEach { (path, handler) ->
        delete(path, handler, roles)
    }
    serviceManager.optionsRequests.forEach { (path, handler) ->
        options(path, handler, roles)
    }
    serviceManager.webSocketRequests.forEach { (path, handler) ->
        ws(path, handler, roles)
    }
}