core/services/posts/server/src/jvmMain/kotlin/dev/inmo/postssystem/services/posts/server/ServerPostsServiceRoutingConfigurator.kt

package dev.inmo.postssystem.services.posts.server

import com.benasher44.uuid.uuid4
import dev.inmo.micro_utils.common.*
import dev.inmo.micro_utils.coroutines.launchSafelyWithoutExceptions
import dev.inmo.micro_utils.ktor.common.decodeHex
import dev.inmo.micro_utils.ktor.server.*
import dev.inmo.micro_utils.ktor.server.configurators.ApplicationRoutingConfigurator
import dev.inmo.micro_utils.mime_types.findBuiltinMimeType
import dev.inmo.micro_utils.repos.ktor.common.crud.createRouting
import dev.inmo.micro_utils.repos.ktor.common.crud.updateRouting
import dev.inmo.micro_utils.repos.ktor.common.one_to_many.removeRoute
import dev.inmo.micro_utils.repos.ktor.server.crud.configureReadCRUDRepoRoutes
import dev.inmo.postssystem.features.common.common.FileBasedInputProvider
import dev.inmo.postssystem.features.content.common.*
import dev.inmo.postssystem.features.files.common.FileId
import dev.inmo.postssystem.features.posts.common.*
import dev.inmo.postssystem.services.posts.common.*
import io.ktor.http.HttpStatusCode
import io.ktor.http.content.PartData
import io.ktor.http.content.streamProvider
import io.ktor.server.application.ApplicationCall
import io.ktor.server.application.call
import io.ktor.server.auth.authenticate
import io.ktor.server.request.receive
import io.ktor.server.request.receiveMultipart
import io.ktor.server.response.respond
import io.ktor.server.routing.*
import io.ktor.util.asStream
import io.ktor.util.pipeline.PipelineContext
import io.ktor.utils.io.core.use
import io.ktor.utils.io.streams.asInput
import kotlinx.coroutines.*
import kotlinx.coroutines.sync.Mutex
import kotlinx.coroutines.sync.withLock
import java.io.File
import java.nio.file.Files
import java.nio.file.attribute.FileTime
import java.util.concurrent.TimeUnit

class ServerPostsServiceRoutingConfigurator(
    private val readPostsService: ReadPostsService,
    private val writePostsService: WritePostsService? = readPostsService as? WritePostsService,
    private val scope: CoroutineScope
) : ApplicationRoutingConfigurator.Element {

    private val temporalFilesMap = mutableMapOf<FileId, MPPFile>()
    private val temporalFilesMutex = Mutex()
    private val removingJob = scope.launchSafelyWithoutExceptions {
        while (isActive) {
            val filesWithCreationInfo = temporalFilesMap.mapNotNull { (fileId, file) ->
                fileId to ((Files.getAttribute(file.toPath(), "creationTime") as? FileTime) ?.toMillis() ?: return@mapNotNull null)
            }
            if (filesWithCreationInfo.isEmpty()) {
                delay(TimeUnit.HOURS.toMillis(1L))
                continue
            }
            var min = filesWithCreationInfo.first()
            for (fileWithCreationInfo in filesWithCreationInfo) {
                if (fileWithCreationInfo.second < min.second) {
                    min = fileWithCreationInfo
                }
            }
            delay(System.currentTimeMillis() - (min.second + TimeUnit.HOURS.toMillis(1)))
            temporalFilesMutex.withLock {
                temporalFilesMap.remove(min.first)
            } ?.delete()
        }
    }

    private suspend fun mapBinary(content: BinaryContent): BinaryContent? {
        val provider = content.inputProvider
        if (provider is TempFileIdentifierInputProvider) {
            val newProvider = temporalFilesMutex.withLock {
                temporalFilesMap.remove(provider.tempFile)
            } ?.let(::FileBasedInputProvider)

            if (newProvider != null) {
                return content.copy(
                    inputProvider = newProvider
                )
            }
        }
        return null
    }

    private suspend fun PipelineContext<Unit, ApplicationCall>.receiveContents(): List<Content> {
        return call.receive<ContentsWrapper>().content.mapNotNull {
            mapBinary(it as? BinaryContent ?: return@mapNotNull it)
        }
    }

    private suspend fun PipelineContext<Unit, ApplicationCall>.receiveContentsEithers(): List<Either<ContentId, Content>> {
        return call.receive<ContentsEithersWrapper>().content.mapNotNull {
            it.mapOnSecond {
                mapBinary(it as? BinaryContent ?: return@mapOnSecond null) ?.either()
            } ?: it
        }
    }



    override fun Route.invoke() {
        authenticate {
            route(postsRootPath) {
                configureReadCRUDRepoRoutes(
                    readPostsService
                ) { PostId(it.toLong()) }

                writePostsService ?.let {

                    post(createRouting) {
                        val data = receiveContents()

                        call.respond(
                            writePostsService.create(FullNewPost(data)) ?: HttpStatusCode.NoContent
                        )
                    }

                    post(updateRouting) {
                        call.respond(
                            writePostsService.update(
                                call.getQueryParameterOrSendError(postsPostIdParameter)?.toLong()?.let(::PostId) ?: return@post,
                                receiveContentsEithers()
                            ) ?: HttpStatusCode.NoContent
                        )
                    }

                    post(removeRoute) {
                        call.respond(
                            writePostsService.remove(
                                call.receive()
                            )
                        )
                    }

                    post(postsCreateTempPathPart) {
                        val multipart = call.receiveMultipart()

                        var fileInfo: Pair<FileId, MPPFile>? = null
                        var part = multipart.readPart()
                        while (part != null) {
                            if (part is PartData.FileItem) {
                                break
                            }
                            part = multipart.readPart()
                        }
                        part ?.let {
                            if (it is PartData.FileItem) {
                                val fileId = FileId(uuid4().toString())
                                val fileName = it.originalFileName ?.let { FileName(it) } ?: return@let
                                fileInfo = fileId to File.createTempFile(fileId.string, ".${fileName.extension}").apply {
                                    outputStream().use { outputStream ->
                                        it.streamProvider().use {
                                            it.copyTo(outputStream)
                                        }
                                    }
                                    deleteOnExit()
                                }
                            }
                        }

                        fileInfo ?.also { (fileId, file) ->
                            temporalFilesMutex.withLock {
                                temporalFilesMap[fileId] = file
                            }
                            call.respond(fileId.string)
                        } ?: call.respond(HttpStatusCode.BadRequest)

                    }

                }
            }
        }
    }
}