// Copyright (C) 2024 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only WITH Qt-GPL-exception-1.0

#include <coreplugin/editormanager/editormanager.h>

#include <languageclient/languageclientinterface.h>
#include <languageclient/languageclientmanager.h>
#include <languageclient/languageclientsettings.h>
#include <languageclient/languageclienttr.h>

#include <lua/bindings/inheritance.h>
#include <lua/luaengine.h>

#include <extensionsystem/iplugin.h>
#include <extensionsystem/pluginmanager.h>

#include <projectexplorer/project.h>

#include <utils/commandline.h>
#include <utils/layoutbuilder.h>

#include <QJsonDocument>

using namespace Utils;
using namespace Core;
using namespace TextEditor;
using namespace ProjectExplorer;

namespace LanguageClient::Lua {

static void registerLuaApi();

class LuaClient : public LanguageClient::Client
{
    Q_OBJECT

public:
    Utils::Id m_settingsId;

    LuaClient(BaseClientInterface *interface, Utils::Id settingsId)
        : LanguageClient::Client(interface)
        , m_settingsId(settingsId)
    {}
};

class LuaLanguageClientPlugin final : public ExtensionSystem::IPlugin
{
    Q_OBJECT
    Q_PLUGIN_METADATA(IID "org.qt-project.Qt.QtCreatorPlugin" FILE "LuaLanguageClient.json")

public:
    LuaLanguageClientPlugin() {}

private:
    void initialize() final { registerLuaApi(); }
};

class LuaLocalSocketClientInterface : public LocalSocketClientInterface
{
public:
    LuaLocalSocketClientInterface(const CommandLine &cmd, const QString &serverName)
        : LocalSocketClientInterface(serverName)
        , m_cmd(cmd)
        , m_logFile("lua-lspclient.XXXXXX.log")

    {}

    void startImpl() override
    {
        if (m_process) {
            QTC_CHECK(!m_process->isRunning());
            delete m_process;
        }
        m_process = new Process;
        m_process->setProcessMode(ProcessMode::Writer);
        connect(m_process,
                &Process::readyReadStandardError,
                this,
                &LuaLocalSocketClientInterface::readError);
        connect(m_process,
                &Process::readyReadStandardOutput,
                this,
                &LuaLocalSocketClientInterface::readOutput);
        connect(m_process, &Process::started, this, [this]() {
            this->LocalSocketClientInterface::startImpl();
            emit started();
        });
        connect(m_process, &Process::done, this, [this] {
            if (m_process->result() != ProcessResult::FinishedWithSuccess)
                emit error(QString("%1 (see logs in \"%2\")")
                               .arg(m_process->exitMessage())
                               .arg(m_logFile.fileName()));
            emit finished();
        });
        m_logFile.write(
            QString("Starting server: %1\nOutput:\n\n").arg(m_cmd.toUserOutput()).toUtf8());
        m_process->setCommand(m_cmd);
        m_process->setWorkingDirectory(m_workingDirectory);
        if (m_env.hasChanges())
            m_process->setEnvironment(m_env);
        m_process->start();
    }

    void setWorkingDirectory(const FilePath &workingDirectory)
    {
        m_workingDirectory = workingDirectory;
    }

    FilePath serverDeviceTemplate() const override { return m_cmd.executable(); }

    void readError()
    {
        QTC_ASSERT(m_process, return);

        const QByteArray stdErr = m_process->readAllRawStandardError();
        m_logFile.write(stdErr);
    }

    void readOutput()
    {
        QTC_ASSERT(m_process, return);
        const QByteArray &out = m_process->readAllRawStandardOutput();
        parseData(out);
    }

private:
    Utils::CommandLine m_cmd;
    Utils::FilePath m_workingDirectory;
    Utils::Process *m_process = nullptr;
    Utils::Environment m_env;
    QTemporaryFile m_logFile;
};

class LuaClientWrapper;

class LuaClientSettings : public BaseSettings
{
    std::weak_ptr<LuaClientWrapper> m_wrapper;

public:
    LuaClientSettings(const std::weak_ptr<LuaClientWrapper> &wrapper);
    ~LuaClientSettings() override = default;

    bool applyFromSettingsWidget(QWidget *widget) override;

    Utils::Store toMap() const override;
    void fromMap(const Utils::Store &map) override;

    QWidget *createSettingsWidget(QWidget *parent = nullptr) const override;

    BaseSettings *copy() const override { return new LuaClientSettings(*this); }

protected:
    Client *createClient(BaseClientInterface *interface) const final;

    BaseClientInterface *createInterface(ProjectExplorer::Project *project) const override;
};
enum class TransportType { StdIO, LocalSocket };

class LuaClientWrapper : public QObject
{
public:
    TransportType m_transportType{TransportType::StdIO};
    std::function<expected_str<void>(CommandLine &)> m_cmdLineCallback;
    AspectContainer *m_aspects{nullptr};
    QString m_name;
    Utils::Id m_settingsTypeId;
    QString m_initializationOptions;
    CommandLine m_cmdLine;
    QString m_serverName;
    LanguageFilter m_languageFilter;
    BaseSettings::StartBehavior m_startBehavior = BaseSettings::RequiresFile;

    std::optional<sol::protected_function> m_onInstanceStart;
    std::optional<sol::protected_function> m_startFailedCallback;
    QMap<QString, sol::protected_function> m_messageCallbacks;

    QList<Client *> m_clients;

public:
    static BaseSettings::StartBehavior startBehaviorFromString(const QString &str)
    {
        if (str == "RequiresProject")
            return BaseSettings::RequiresProject;
        if (str == "RequiresFile")
            return BaseSettings::RequiresFile;
        if (str == "AlwaysOn")
            return BaseSettings::AlwaysOn;

        throw sol::error("Unknown start behavior: " + str.toStdString());
    }

    LuaClientWrapper(const sol::table &options)
    {
        m_cmdLineCallback = addValue<CommandLine>(
            options,
            "cmd",
            m_cmdLine,
            [](const sol::protected_function_result &res) -> expected_str<CommandLine> {
                if (res.get_type(0) != sol::type::table)
                    return make_unexpected(QString("cmd callback did not return a table"));
                return cmdFromTable(res.get<sol::table>());
            });

        m_name = options.get<QString>("name");
        m_settingsTypeId = Utils::Id::fromString(QString("Lua_%1").arg(m_name));
        m_serverName = options.get_or<QString>("serverName", "");

        m_startBehavior = startBehaviorFromString(
            options.get_or<QString>("startBehavior", "AlwaysOn"));

        m_startFailedCallback = options.get<sol::protected_function>("onStartFailed");

        QString transportType = options.get_or<QString>("transport", "stdio");
        if (transportType == "stdio")
            m_transportType = TransportType::StdIO;
        else if (transportType == "localsocket")
            m_transportType = TransportType::LocalSocket;
        else
            qWarning() << "Unknown transport type:" << transportType;

        auto languageFilter = options.get<std::optional<sol::table>>("languageFilter");
        if (languageFilter) {
            auto patterns = languageFilter->get<std::optional<sol::table>>("patterns");
            auto mimeTypes = languageFilter->get<std::optional<sol::table>>("mimeTypes");

            if (patterns)
                for (auto [_, v] : *patterns)
                    m_languageFilter.filePattern.push_back(v.as<QString>());

            if (mimeTypes)
                for (auto [_, v] : *mimeTypes)
                    m_languageFilter.mimeTypes.push_back(v.as<QString>());
        }

        auto initOptionsTable = options.get<sol::optional<sol::table>>("initializationOptions");
        if (initOptionsTable) {
            QJsonValue json = ::Lua::LuaEngine::toJson(*initOptionsTable);
            QJsonDocument doc;
            if (json.isArray()) {
                doc.setArray(json.toArray());
                m_initializationOptions = QString::fromUtf8(doc.toJson());
            } else if (json.isObject()) {
                doc.setObject(json.toObject());
                m_initializationOptions = QString::fromUtf8(doc.toJson());
            }
        }
        auto initOptionsString = options.get<sol::optional<QString>>("initializationOptions");
        if (initOptionsString)
            m_initializationOptions = *initOptionsString;

        // get<sol::optional<>> because on MSVC, get_or(..., nullptr) fails to compile
        m_aspects = options.get<sol::optional<AspectContainer *>>("settings").value_or(nullptr);

        if (m_aspects) {
            connect(m_aspects, &AspectContainer::applied, this, [this] {
                updateOptions();
                LanguageClientManager::applySettings();
            });
        }

        connect(
            LanguageClientManager::instance(),
            &LanguageClientManager::clientInitialized,
            this,
            [this](Client *c) {
                auto luaClient = qobject_cast<LuaClient *>(c);
                if (luaClient && luaClient->m_settingsId == m_settingsTypeId && m_onInstanceStart) {
                    QTC_CHECK(::Lua::LuaEngine::void_safe_call(*m_onInstanceStart, c));

                    m_clients.push_back(c);
                    updateMessageCallbacks();
                }
            });

        connect(
            LanguageClientManager::instance(),
            &LanguageClientManager::clientRemoved,
            this,
            &LuaClientWrapper::onClientRemoved);
    }

    void onClientRemoved(Client *c, bool unexpected)
    {
        auto luaClient = qobject_cast<LuaClient *>(c);
        if (!luaClient || luaClient->m_settingsId != m_settingsTypeId)
            return;

        if (m_clients.contains(c))
            m_clients.removeOne(c);

        if (unexpected && m_startFailedCallback) {
            QTC_CHECK_EXPECTED(::Lua::LuaEngine::void_safe_call(*m_startFailedCallback));
        }
    }

    ~LuaClientWrapper()
    {
        for (auto client : m_clients)
            LanguageClientManager::shutdownClient(client);

        // TODO: Unregister Client settings from LanguageClientManager
    }

    TransportType transportType() { return m_transportType; }

    void applySettings()
    {
        if (m_aspects)
            m_aspects->apply();

        updateOptions();
    }

    void fromMap(const Utils::Store &map)
    {
        if (m_aspects)
            m_aspects->fromMap(map);
        updateOptions();
    }

    void toMap(Utils::Store &map) const
    {
        if (m_aspects)
            m_aspects->toMap(map);
    }

    Layouting::LayoutModifier settingsLayout()
    {
        if (m_aspects)
            return [this](Layouting::Layout *iface) { m_aspects->addToLayout(*iface); };
        return {};
    }

    void registerMessageCallback(const QString &msg, const sol::function &callback)
    {
        m_messageCallbacks.insert(msg, callback);
        updateMessageCallbacks();
    }

    void updateMessageCallbacks()
    {
        for (Client *c : m_clients) {
            for (const auto &[msg, func] : m_messageCallbacks.asKeyValueRange()) {
                c->registerCustomMethod(
                    msg,
                    [self = QPointer<LuaClientWrapper>(this),
                     name = msg](const LanguageServerProtocol::JsonRpcMessage &m) {
                        if (!self)
                            return;

                        auto func = self->m_messageCallbacks.value(name);
                        auto table = ::Lua::LuaEngine::toTable(func.lua_state(), m.toJsonObject());
                        auto result = func.call(table);
                        if (!result.valid()) {
                            qWarning() << "Error calling message callback for:" << name << ":"
                                       << (result.get<sol::error>().what());
                        }
                    });
            }
        }
    }

    void sendMessage(const sol::table &message)
    {
        const QJsonValue messageValue = ::Lua::LuaEngine::toJson(message);
        if (!messageValue.isObject())
            throw sol::error("Message is not an object");
        const LanguageServerProtocol::JsonRpcMessage jsonrpcmessage(messageValue.toObject());
        for (Client *c : m_clients)
            c->sendMessage(jsonrpcmessage);
    }

    void updateOptions()
    {
        if (m_cmdLineCallback) {
            auto result = m_cmdLineCallback(m_cmdLine);
            if (!result)
                qWarning() << "Error applying option callback:" << result.error();
        }
    }

    static CommandLine cmdFromTable(const sol::table &tbl)
    {
        CommandLine cmdLine;
        cmdLine.setExecutable(FilePath::fromUserInput(tbl.get<QString>(1)));

        for (size_t i = 2; i < tbl.size() + 1; i++)
            cmdLine.addArg(tbl.get<QString>(i));

        return cmdLine;
    }

    template<typename T>
    std::function<expected_str<void>(T &)> addValue(
        const sol::table &options,
        const char *fieldName,
        T &dest,
        std::function<expected_str<T>(const sol::protected_function_result &)> transform)
    {
        auto fixed = options.get<sol::optional<sol::table>>(fieldName);
        auto cb = options.get<sol::optional<sol::protected_function>>(fieldName);

        if (fixed) {
            dest = fixed.value().get<T>(1);
        } else if (cb) {
            std::function<expected_str<void>(T &)> callback =
                [cb, transform](T &dest) -> expected_str<void> {
                auto res = cb.value().call();
                if (!res.valid()) {
                    sol::error err = res;
                    return Utils::make_unexpected(QString::fromLocal8Bit(err.what()));
                }

                expected_str<T> trResult = transform(res);
                if (!trResult)
                    return make_unexpected(trResult.error());

                dest = *trResult;
                return {};
            };

            QTC_CHECK_EXPECTED(callback(dest));
            return callback;
        }
        return {};
    }

    BaseClientInterface *createInterface(ProjectExplorer::Project *project)
    {
        if (m_transportType == TransportType::StdIO) {
            auto interface = new StdIOClientInterface;
            interface->setCommandLine(m_cmdLine);
            if (project)
                interface->setWorkingDirectory(project->projectDirectory());
            return interface;
        } else if (m_transportType == TransportType::LocalSocket) {
            if (m_serverName.isEmpty())
                return nullptr;

            auto interface = new LuaLocalSocketClientInterface(m_cmdLine, m_serverName);
            if (project)
                interface->setWorkingDirectory(project->projectDirectory());
            return interface;
        }
        return nullptr;
    }
};

LuaClientSettings::LuaClientSettings(const std::weak_ptr<LuaClientWrapper> &wrapper)
    : m_wrapper(wrapper)
{
    if (auto w = m_wrapper.lock()) {
        m_name = w->m_name;
        m_settingsTypeId = w->m_settingsTypeId;
        m_languageFilter = w->m_languageFilter;
        m_initializationOptions = w->m_initializationOptions;
        m_startBehavior = w->m_startBehavior;
    }
}

bool LuaClientSettings::applyFromSettingsWidget(QWidget *widget)
{
    BaseSettings::applyFromSettingsWidget(widget);

    if (auto w = m_wrapper.lock())
        w->applySettings();

    return true;
}

Utils::Store LuaClientSettings::toMap() const
{
    auto store = BaseSettings::toMap();
    if (auto w = m_wrapper.lock())
        w->toMap(store);
    return store;
}

void LuaClientSettings::fromMap(const Utils::Store &map)
{
    BaseSettings::fromMap(map);
    if (auto w = m_wrapper.lock()) {
        w->m_name = m_name;
        w->m_initializationOptions = m_initializationOptions;
        w->m_languageFilter = m_languageFilter;
        w->m_startBehavior = m_startBehavior;
        w->fromMap(map);
    }
}

QWidget *LuaClientSettings::createSettingsWidget(QWidget *parent) const
{
    using namespace Layouting;

    if (auto w = m_wrapper.lock())
        return new BaseSettingsWidget(this, parent, w->settingsLayout());

    return new BaseSettingsWidget(this, parent);
}

Client *LuaClientSettings::createClient(BaseClientInterface *interface) const
{
    Client *client = new LuaClient(interface, m_settingsTypeId);
    return client;
}

BaseClientInterface *LuaClientSettings::createInterface(ProjectExplorer::Project *project) const
{
    if (auto w = m_wrapper.lock())
        return w->createInterface(project);

    return nullptr;
}

static void registerLuaApi()
{
    ::Lua::LuaEngine::registerProvider("LSP", [](sol::state_view lua) -> sol::object {
        sol::table result = lua.create_table();

        auto wrapperClass = result.new_usertype<LuaClientWrapper>(
            "Client",
            "on_instance_start",
            sol::property(
                [](const LuaClientWrapper *c) -> sol::function {
                    if (!c->m_onInstanceStart)
                        return sol::lua_nil;
                    return c->m_onInstanceStart.value();
                },
                [](LuaClientWrapper *c, const sol::function &f) { c->m_onInstanceStart = f; }),
            "registerMessage",
            &LuaClientWrapper::registerMessageCallback,
            "sendMessage",
            &LuaClientWrapper::sendMessage,
            "create",
            [](const sol::table &options) -> std::shared_ptr<LuaClientWrapper> {
                auto luaClient = std::make_shared<LuaClientWrapper>(options);
                auto client = new LuaClientSettings(luaClient);

                // The order is important!
                // First restore the settings ...
                const QList<Utils::Store> savedSettings
                    = LanguageClientSettings::storesBySettingsType(luaClient->m_settingsTypeId);

                if (!savedSettings.isEmpty())
                    client->fromMap(savedSettings.first());

                // ... then register the settings.
                LanguageClientManager::registerClientSettings(client);

                return luaClient;
            });

        return result;
    });
}

} // namespace LanguageClient::Lua

#include "lualanguageclient.moc"