MicroUtils/ktor/server/src/jvmMain/kotlin/dev/inmo/micro_utils/ktor/server/ServerRoutingShortcuts.kt

package dev.inmo.micro_utils.ktor.server

import dev.inmo.micro_utils.common.*
import dev.inmo.micro_utils.coroutines.safely
import dev.inmo.micro_utils.ktor.common.*
import io.ktor.http.*
import io.ktor.http.content.*
import io.ktor.server.application.ApplicationCall
import io.ktor.server.application.call
import io.ktor.server.request.receive
import io.ktor.server.request.receiveMultipart
import io.ktor.server.response.respond
import io.ktor.server.response.respondBytes
import io.ktor.server.routing.Route
import io.ktor.server.websocket.WebSocketServerSession
import io.ktor.util.pipeline.PipelineContext
import io.ktor.utils.io.core.Input
import io.ktor.utils.io.core.use
import io.ktor.utils.io.streams.asInput
import kotlinx.coroutines.flow.Flow
import kotlinx.serialization.DeserializationStrategy
import kotlinx.serialization.SerializationStrategy

class UnifiedRouter(
    val serialFormat: StandardKtorSerialFormat = standardKtorSerialFormat,
    val serialFormatContentType: ContentType = standardKtorSerialFormatContentType
) {
    fun <T> Route.includeWebsocketHandling(
        suburl: String,
        flow: Flow<T>,
        serializer: SerializationStrategy<T>,
        protocol: URLProtocol = URLProtocol.WS,
        filter: (suspend WebSocketServerSession.(T) -> Boolean)? = null
    ) = includeWebsocketHandling(suburl, flow, serializer, serialFormat, protocol, filter)

    suspend fun <T> PipelineContext<*, ApplicationCall>.unianswer(
        answerSerializer: SerializationStrategy<T>,
        answer: T
    ) {
        call.respondBytes (
            serialFormat.encodeDefault(answerSerializer, answer),
            serialFormatContentType
        )
    }

    suspend fun <T> PipelineContext<*, ApplicationCall>.uniload(
        deserializer: DeserializationStrategy<T>
    ) = safely {
        serialFormat.decodeDefault(
            deserializer,
            call.receive()
        )
    }

    suspend fun PipelineContext<*, ApplicationCall>.getParameterOrSendError(
        field: String
    ) = call.parameters[field].also {
        if (it == null) {
            call.respond(HttpStatusCode.BadRequest, "Request must contains $field")
        }
    }

    fun PipelineContext<*, ApplicationCall>.getQueryParameter(
        field: String
    ) = call.request.queryParameters[field]

    suspend fun PipelineContext<*, ApplicationCall>.getQueryParameterOrSendError(
        field: String
    ) = getQueryParameter(field).also {
        if (it == null) {
            call.respond(HttpStatusCode.BadRequest, "Request query parameters must contains $field")
        }
    }

    fun <T> PipelineContext<*, ApplicationCall>.decodeUrlQueryValue(
        field: String,
        deserializer: DeserializationStrategy<T>
    ) = getQueryParameter(field) ?.let {
        serialFormat.decodeHex(
            deserializer,
            it
        )
    }

    suspend fun <T> PipelineContext<*, ApplicationCall>.decodeUrlQueryValueOrSendError(
        field: String,
        deserializer: DeserializationStrategy<T>
    ) = decodeUrlQueryValue(field, deserializer).also {
        if (it == null) {
            call.respond(HttpStatusCode.BadRequest, "Request query parameters must contains $field")
        }
    }

    companion object {
        val default
            get() = defaultUnifiedRouter
    }
}

val defaultUnifiedRouter = UnifiedRouter()

suspend fun <T> ApplicationCall.unianswer(
    answerSerializer: SerializationStrategy<T>,
    answer: T
) {
    respondBytes (
        standardKtorSerialFormat.encodeDefault(answerSerializer, answer),
        standardKtorSerialFormatContentType
    )
}

suspend fun <T> ApplicationCall.uniload(
    deserializer: DeserializationStrategy<T>
) = safely {
    standardKtorSerialFormat.decodeDefault(
        deserializer,
        receive()
    )
}

suspend fun ApplicationCall.uniloadMultipart(
    onFormItem: (PartData.FormItem) -> Unit = {},
    onCustomFileItem: (PartData.FileItem) -> Unit = {},
    onBinaryContent: (PartData.BinaryItem) -> Unit = {}
) = safely {
    val multipartData = receiveMultipart()

    var resultInput: Input? = null

    multipartData.forEachPart {
        when (it) {
            is PartData.FormItem -> onFormItem(it)
            is PartData.FileItem -> {
                when (it.name) {
                    "bytes" -> resultInput = it.streamProvider().asInput()
                    else -> onCustomFileItem(it)
                }
            }
            is PartData.BinaryItem -> onBinaryContent(it)
        }
    }

    resultInput ?: error("Bytes has not been received")
}

suspend fun <T> ApplicationCall.uniloadMultipart(
    deserializer: DeserializationStrategy<T>,
    onFormItem: (PartData.FormItem) -> Unit = {},
    onCustomFileItem: (PartData.FileItem) -> Unit = {},
    onBinaryContent: (PartData.BinaryItem) -> Unit = {}
): Pair<Input, T> {
    var data: Optional<T>? = null
    val resultInput = uniloadMultipart(
        onFormItem,
        {
            if (it.name == "data") {
                data = standardKtorSerialFormat.decodeDefault(deserializer, it.streamProvider().readBytes()).optional
            } else {
                onCustomFileItem(it)
            }
        },
        onBinaryContent
    )

    val completeData = data ?: error("Data has not been received")
    return resultInput to (completeData.dataOrNull().let { it as T })
}

suspend fun <T> ApplicationCall.uniloadMultipartFile(
    deserializer: DeserializationStrategy<T>,
    onFormItem: (PartData.FormItem) -> Unit = {},
    onCustomFileItem: (PartData.FileItem) -> Unit = {},
    onBinaryContent: (PartData.BinaryItem) -> Unit = {},
) = safely {
    val multipartData = receiveMultipart()

    var resultInput: MPPFile? = null
    var data: Optional<T>? = null

    multipartData.forEachPart {
        when (it) {
            is PartData.FormItem -> onFormItem(it)
            is PartData.FileItem -> {
                when (it.name) {
                    "bytes" -> {
                        val name = FileName(it.originalFileName ?: error("File name is unknown for default part"))
                        resultInput = MPPFile.createTempFile(
                            name.nameWithoutExtension.let {
                                var resultName = it
                                while (resultName.length < 3) {
                                    resultName += "_"
                                }
                                resultName
                            },
                            ".${name.extension}"
                        ).apply {
                            outputStream().use { fileStream ->
                                it.streamProvider().use {
                                    it.copyTo(fileStream)
                                }
                            }
                        }
                    }
                    "data" -> data = standardKtorSerialFormat.decodeDefault(deserializer, it.streamProvider().readBytes()).optional
                    else -> onCustomFileItem(it)
                }
            }
            is PartData.BinaryItem -> onBinaryContent(it)
        }
    }

    val completeData = data ?: error("Data has not been received")
    (resultInput ?: error("Bytes has not been received")) to (completeData.dataOrNull().let { it as T })
}

suspend fun ApplicationCall.uniloadMultipartFile(
    onFormItem: (PartData.FormItem) -> Unit = {},
    onCustomFileItem: (PartData.FileItem) -> Unit = {},
    onBinaryContent: (PartData.BinaryItem) -> Unit = {},
) = safely {
    val multipartData = receiveMultipart()

    var resultInput: MPPFile? = null

    multipartData.forEachPart {
        when (it) {
            is PartData.FormItem -> onFormItem(it)
            is PartData.FileItem -> {
                if (it.name == "bytes") {
                    val name = FileName(it.originalFileName ?: error("File name is unknown for default part"))
                    resultInput = MPPFile.createTempFile(
                        name.nameWithoutExtension.let {
                            var resultName = it
                            while (resultName.length < 3) {
                                resultName += "_"
                            }
                            resultName
                        },
                        ".${name.extension}"
                    ).apply {
                        outputStream().use { fileStream ->
                            it.streamProvider().use {
                                it.copyTo(fileStream)
                            }
                        }
                    }
                } else {
                    onCustomFileItem(it)
                }
            }
            is PartData.BinaryItem -> onBinaryContent(it)
        }
    }

    resultInput ?: error("Bytes has not been received")
}

suspend fun ApplicationCall.getParameterOrSendError(
    field: String
) = parameters[field].also {
    if (it == null) {
        respond(HttpStatusCode.BadRequest, "Request must contains $field")
    }
}

fun ApplicationCall.getQueryParameter(
    field: String
) = request.queryParameters[field]

suspend fun ApplicationCall.getQueryParameterOrSendError(
    field: String
) = getQueryParameter(field).also {
    if (it == null) {
        respond(HttpStatusCode.BadRequest, "Request query parameters must contains $field")
    }
}

fun <T> ApplicationCall.decodeUrlQueryValue(
    field: String,
    deserializer: DeserializationStrategy<T>
) = getQueryParameter(field) ?.let {
    standardKtorSerialFormat.decodeHex(
        deserializer,
        it
    )
}

suspend fun <T> ApplicationCall.decodeUrlQueryValueOrSendError(
    field: String,
    deserializer: DeserializationStrategy<T>
) = decodeUrlQueryValue(field, deserializer).also {
    if (it == null) {
        respond(HttpStatusCode.BadRequest, "Request query parameters must contains $field")
    }
}