/***************************************************************************************************
 Copyright (C) 2023 The Qt Company Ltd.
 SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
***************************************************************************************************/

#pragma once

#include "qdotnetfunction.h"

#ifdef __GNUC__
#   pragma GCC diagnostic push
#   pragma GCC diagnostic ignored "-Wconversion"
#endif
#include <QCoreApplication>
#include <QDebug>
#include <QDir>
#include <QLibrary>
#include <QFile>
#include <QProcess>
#include <QRegularExpression>
#include <QString>
#include <QTemporaryFile>
#include <QVersionNumber>
#ifdef __GNUC__
#   pragma GCC diagnostic pop
#endif

class QDotNetHost
{
public:
    QDotNetHost() = default;

    ~QDotNetHost()
    {
        unload();
    }

    bool load(const QString& runtimeConfig = defaultRuntimeConfig, const QString &runtimePath = {})
    {
        if (isLoaded())
            return true;
        if (!loadRuntime(runtimePath))
            return false;
        if (!init(runtimeConfig)) {
            unloadRuntime();
            return false;
        }
        return true;
    }

    void unload()
    {
        if (!isLoaded())
            return;
        close();
        unloadRuntime();
    }

    bool isLoaded() const
    {
        return (hostContext != nullptr);
    }

    bool resolveFunction(QDotNetFunction<quint32, void *, qint32> &outFunc,
        const QString &assemblyPath, const QString &typeName, const QString &methodName)
    {
        return resolveFunction(outFunc, assemblyPath, typeName, methodName, {});
    }

    template<typename TResult, typename... TArgs>
    bool resolveFunction(QDotNetFunction<TResult, TArgs...> &outFunc, const QString &assemblyPath,
        const QString &typeName, const QString &methodName, const QString &delegateType)
    {
        if (!isLoaded() && !load())
            return false;
        outFunc = resolveFunction(assemblyPath, typeName, methodName, delegateType);
        return outFunc.isValid();
    }

    QMap<QString, QString> runtimeProperties() const
    {
        if (!isLoaded())
            return {};
        size_t queryCount = 0;
        const auto result = fnAllRuntimeProperties(hostContext, &queryCount, nullptr, nullptr);
        if (result != Success && result != HostApiBufferTooSmall) {
            qCritical() << "Error calling function: hostfxr_get_runtime_properties";
            return {};
        }
        const size_t count = queryCount;
        const char_t **keys = new const char_t * [count] { nullptr };
        const char_t **values = new const char_t * [count] { nullptr };
        if (HOSTFN_FAILED(fnAllRuntimeProperties(hostContext, &queryCount, keys, values))) {
            qCritical() << "Error calling function: hostfxr_get_runtime_properties";
            delete[] keys;
            delete[] values;
            return {};
        }
        QMap<QString, QString> properties;
        for (size_t i = 0; i < count; ++i) {
            const char_t *key = keys[i];
            const char_t *value = values[i];
            if (key && value)
                properties.insert(QSTR(key), QSTR(value));
        }
        delete[] keys;
        delete[] values;
        return properties;
    }

    QString runtimeProperty(const QString &name) const
    {
        if (!isLoaded())
            return {};
        const char_t *value = nullptr;
        if (HOSTFN_FAILED(fnRuntimeProperty(hostContext, STR(name), &value))) {
            qCritical() << "Error calling function: hostfxr_get_runtime_property_value";
            return {};
        }
        if (!value)
            return {};
        return QSTR(value);
    }

    bool setRuntimeProperty(const QString &name, const QString &value) const
    {
        if (!isLoaded())
            return false;
        if (HOSTFN_FAILED(fnSetRuntimeProperty(hostContext, STR(name), STR(value)))) {
            qCritical() << "Error calling function: hostfxr_set_runtime_property_value";
            return false;
        }
        return true;
    }

    void setErrorWriter(hostfxr_error_writer_fn errorWriter)
    {
        if (fnSetErrorWriter == nullptr || hostContext == nullptr)
            return;
        fnSetErrorWriter(errorWriter);
    }

private:
    void *resolveFunction(const QString &assemblyPath, const QString &typeName,
        const QString &methodName, const QString &delegateType) const
    {
        if (hostContext == nullptr)
            return nullptr;
        void *funcPtr = nullptr;
        auto result = fnLoadAssemblyAndGetFunctionPointer(
            STR(assemblyPath),
            STR(typeName),
            STR(methodName),
            delegateType.isEmpty() ? nullptr : STR(delegateType),
            nullptr,
            &funcPtr);
        if (HOSTFN_FAILED(result)) {
            qCritical() << "Error getting function pointer:"
                << methodName << QString::number(static_cast<unsigned>(result), 16);
            return nullptr;
        }
        return funcPtr;
    }

    QString findRuntimePath() const
    {
        QProcess procDotNetInfo;
        procDotNetInfo.start("dotnet", { "--list-runtimes" });
        if (!procDotNetInfo.waitForFinished() || procDotNetInfo.exitCode() != 0) {
            qCritical() << "Error calling dotnet";
            return {};
        }
        const QString dotNetInfo(procDotNetInfo.readAllStandardOutput());

        QString runtimeDirPath = {};
        QString hostVersion = {};
        QVersionNumber maxVersion;
        const QRegularExpression dotNetInfoParser(regexParseDotNetInfo,
            QRegularExpression::MultilineOption | QRegularExpression::DotMatchesEverythingOption);
        for (const auto &match : dotNetInfoParser.globalMatch(dotNetInfo)) {
            const auto version = QVersionNumber::fromString(match.captured("version"));
            if (version > maxVersion) {
                maxVersion = version;
                hostVersion = match.captured("version");
                runtimeDirPath = match.captured("path");
            }
        }

        if (runtimeDirPath.isEmpty()) {
            qCritical() << "Error parsing dotnet info";
            return {};
        }

        QDir runtimeDir(runtimeDirPath);
        if (!runtimeDir.exists()) {
            qCritical() << "Error dotnet runtime directory not found";
            return {};
        }

        runtimeDir.cd(QString("../../host/fxr/%1").arg(hostVersion));
        if (!runtimeDir.exists()) {
            qCritical() << "Error dotnet host fxr directory not found";
            return {};
        }
#ifdef Q_OS_WINDOWS
        QString runtimePath = runtimeDir.absoluteFilePath("hostfxr.dll");
#else
        QString runtimePath = runtimeDir.absoluteFilePath("libhostfxr.so");
#endif
        if (!QFile::exists(runtimePath)) {
            qCritical() << "Error dotnet host fxr dll not found";
            return {};
        }
        return runtimePath;
    }

    bool loadRuntime(const QString & runtimePath)
    {
        if (fnInitHost != nullptr)
            return true;

        if (!runtimePath.isEmpty()) {
            if (!QFile::exists(runtimePath))
                return false;
            runtime.setFileName(runtimePath);
        } else {
            const QString defaultRuntimePath = findRuntimePath();
            if (defaultRuntimePath.isEmpty())
                return false;
            runtime.setFileName(defaultRuntimePath);
        }

        if (!runtime.load()) {
            qCritical() << "Error loading library: hostfxr";
            return false;
        }

        fnInitHost = GET_FN(runtime, hostfxr_initialize_for_runtime_config_fn);
        if (!fnInitHost) {
            qCritical() << "Error loading function: hostfxr_initialize_for_runtime_config";
            return false;
        }

        fnGetRuntimeDelegate = GET_FN(runtime, hostfxr_get_runtime_delegate_fn);
        if (!fnGetRuntimeDelegate) {
            qCritical() << "Error loading function: hostfxr_get_runtime_delegate";
            return false;
        }

        fnCloseHost = GET_FN(runtime, hostfxr_close_fn);
        if (!fnCloseHost) {
            qCritical() << "Error loading function: hostfxr_close";
            return false;
        }

        fnSetErrorWriter = GET_FN(runtime, hostfxr_set_error_writer_fn);
        if (!fnSetErrorWriter) {
            qCritical() << "Error loading function: hostfxr_set_error_writer";
            return false;
        }

        fnAllRuntimeProperties = GET_FN(runtime, hostfxr_get_runtime_properties_fn);
        if (!fnAllRuntimeProperties) {
            qCritical() << "Error loading function: hostfxr_get_runtime_properties_fn";
            return false;
        }

        fnRuntimeProperty = GET_FN(runtime, hostfxr_get_runtime_property_value_fn);
        if (!fnRuntimeProperty) {
            qCritical() << "Error loading function: hostfxr_get_runtime_property_value_fn";
            return false;
        }

        fnSetRuntimeProperty = GET_FN(runtime, hostfxr_set_runtime_property_value_fn);
        if (!fnSetRuntimeProperty) {
            qCritical() << "Error loading function: hostfxr_set_runtime_property_value_fn";
            return false;
        }

        fnSetErrorWriter(defaultErrorWriter);
        return true;
    }

    void unloadRuntime()
    {
        runtime.unload();
        fnInitHost = nullptr;
        fnGetRuntimeDelegate = nullptr;
        fnCloseHost = nullptr;
        fnAllRuntimeProperties = nullptr;
        fnRuntimeProperty = nullptr;
        fnSetRuntimeProperty = nullptr;
    }

    bool init(const QString &runtimeConfig)
    {
        if (fnInitHost == nullptr)
            return false;

        const QString tempFileName = writeTempFile(runtimeConfig, runtimeConfigFileName);
        if (tempFileName.isEmpty()) {
            qCritical() << "Error writing runtime configuration file.";
            return false;
        }

        auto result = fnInitHost(STR(tempFileName), nullptr, &hostContext);
        if (HOSTFN_FAILED(result) || hostContext == nullptr) {
            qCritical() << "Error calling function: hostfxr_initialize_for_runtime_config";
            QFile::remove(tempFileName);
            return false;
        }

        if (!QFile::remove(tempFileName))
            qWarning() << "Error removing file:" << tempFileName;

        result = fnGetRuntimeDelegate(hostContext,
            hdt_load_assembly_and_get_function_pointer,
            reinterpret_cast<void **>(&fnLoadAssemblyAndGetFunctionPointer));
        if (HOSTFN_FAILED(result)) {
            qCritical() << "Error calling function:"
                << "hostfxr_get_runtime_delegate(hdt_load_assembly_and_get_function_pointer)";
            return false;
        }

        return true;
    }

    bool close()
    {
        if (fnCloseHost == nullptr || hostContext == nullptr)
            return false;
        if (HOSTFN_FAILED(fnCloseHost(hostContext)))
            qWarning() << "Error calling function: hostfxr_close";
        hostContext = nullptr;
        fnLoadAssemblyAndGetFunctionPointer = nullptr;
        return true;
    }

    static void defaultErrorWriter(const char_t *message)
    {
        qWarning() << "Qt/.NET: HostError:" << QSTR(message);
    }

    static QString writeTempFile(const QString &text, const QString &fileNameTemplate)
    {
        QTemporaryFile tempFile(fileNameTemplate);
        tempFile.setAutoRemove(false);
        if (!tempFile.open()) {
            qCritical() << "Error creating temp file:" << tempFile.errorString();
            return {};
        }

        QString tempFileName = tempFile.fileName();
        const QByteArray fileData = text.toUtf8();
        if (!tempFile.write(fileData)) {
            qCritical() << "Error writing file:" << tempFileName;
            return {};
        }
        tempFile.close();

        return tempFileName;
    }

    static inline const QString runtimeConfigFileName = QStringLiteral("runtimeconfig.XXXXXX.json");
    static inline const QString defaultRuntimeConfig = QStringLiteral(R"[json](
{
  "runtimeOptions": {
    "tfm": "net6.0",
    "rollForward": "LatestMinor",
    "framework": {
      "name": "Microsoft.NETCore.App",
      "version": "6.0.0"
    }
  }
}
)[json]");

    static inline const QString regexParseDotNetInfo = QStringLiteral(R"[regex](
\bMicrosoft\.NETCore\.App[^0-9]*(?<version>[0-9\.]+)[^\[]*\[(?<path>[^\]]+)\]
)[regex]").remove('\r').remove('\n');


    QLibrary runtime;
    hostfxr_initialize_for_runtime_config_fn fnInitHost = nullptr;
    hostfxr_get_runtime_delegate_fn fnGetRuntimeDelegate = nullptr;
    hostfxr_close_fn fnCloseHost = nullptr;
    hostfxr_set_error_writer_fn fnSetErrorWriter = nullptr;
    hostfxr_get_runtime_properties_fn fnAllRuntimeProperties = nullptr;
    hostfxr_get_runtime_property_value_fn fnRuntimeProperty = nullptr;
    hostfxr_set_runtime_property_value_fn fnSetRuntimeProperty = nullptr;
    hostfxr_handle hostContext = nullptr;

    load_assembly_and_get_function_pointer_fn fnLoadAssemblyAndGetFunctionPointer = nullptr;
};