#include "ConfigHelper.h"
#include <QApplication>
#include <QDir>
#include <QFile>
#include <QFileInfo>
#include <QJsonDocument>
#include <QJsonObject>
#include <QSaveFile>
#include <QSettings>
#include <QDebug>

ConfigHelper& ConfigHelper::instance()
{
    static ConfigHelper obj;
    return obj;
}

ConfigHelper::ConfigHelper()
{
    m_configPath = QApplication::applicationDirPath() + "/config/app_config.json";
    migrateLegacyIniIfNeeded();
    qDebug() << "Loading app config path:" << m_configPath;
    qDebug() << "File exists?" << QFile::exists(m_configPath);
}

QString ConfigHelper::configPath() const
{
    return m_configPath;
}

QString ConfigHelper::installRoot() const
{
    QString relativeRoot = getValue("Runtime", "install_root").trimmed();
    if (relativeRoot.isEmpty())
        relativeRoot = ".";
    return QDir::cleanPath(QDir(runtimeRoot()).filePath(relativeRoot));
}

QString ConfigHelper::runtimeRoot() const
{
    return QDir::cleanPath(QApplication::applicationDirPath());
}

QString ConfigHelper::updateRoot() const
{
    return QDir(runtimeRoot()).filePath("update");
}

QString ConfigHelper::runtimeRelativePath() const
{
    QString relative = QDir::fromNativeSeparators(QDir(installRoot()).relativeFilePath(runtimeRoot()));
    relative = QDir::cleanPath(relative);
    if (relative == ".")
        return QString();
    while (relative.startsWith("./"))
        relative = relative.mid(2);
    return relative.trimmed();
}

QString ConfigHelper::lastError() const
{
    return m_error;
}

QString ConfigHelper::getValue(const QString& section, const QString& key) const
{
    Q_UNUSED(section);
    QFile file(m_configPath);
    if (!file.open(QIODevice::ReadOnly))
        return QString();

    QJsonParseError error;
    const QJsonDocument document = QJsonDocument::fromJson(file.readAll(), &error);
    if (error.error != QJsonParseError::NoError || !document.isObject())
        return QString();

    return document.object().value(key).toVariant().toString();
}

bool ConfigHelper::setValue(const QString& section, const QString& key, const QString& value)
{
    Q_UNUSED(section);
    m_error.clear();

    QFile input(m_configPath);
    QJsonObject config;
    if (input.exists())
    {
        if (!input.open(QIODevice::ReadOnly))
        {
            m_error = QString("Cannot open config for reading: %1").arg(input.errorString());
            return false;
        }
        QJsonParseError parseError;
        const QByteArray raw = input.readAll();
        input.close();
        const QJsonDocument document = QJsonDocument::fromJson(raw, &parseError);
        if (parseError.error != QJsonParseError::NoError || !document.isObject())
        {
            m_error = QString("Invalid config JSON: %1").arg(parseError.errorString());
            return false;
        }
        config = document.object();
    }

    config.insert(key, value);
    QDir dir(QFileInfo(m_configPath).path());
    if (!dir.exists() && !dir.mkpath("."))
    {
        m_error = QString("Cannot create config directory: %1").arg(dir.path());
        return false;
    }

    QSaveFile output(m_configPath);
    if (!output.open(QIODevice::WriteOnly))
    {
        m_error = QString("Cannot open config for writing: %1").arg(output.errorString());
        return false;
    }
    const QByteArray payload = QJsonDocument(config).toJson(QJsonDocument::Indented);
    if (output.write(payload) != payload.size())
    {
        m_error = QString("Cannot write full config file: %1").arg(output.errorString());
        output.cancelWriting();
        return false;
    }
    if (!output.commit())
    {
        m_error = QString("Cannot commit config file: %1").arg(output.errorString());
        return false;
    }
    return true;
}

bool ConfigHelper::migrateLegacyIniIfNeeded()
{
    if (QFile::exists(m_configPath))
        return true;

    const QString legacyPath = QApplication::applicationDirPath() + "/client.ini";
    if (!QFile::exists(legacyPath))
        return false;

    QSettings ini(legacyPath, QSettings::IniFormat);
    QJsonObject config;
    const auto copyText = [&](const QString& section, const QString& key, const QString& fallback = QString()) {
        const QString value = ini.value(section + "/" + key, fallback).toString();
        config.insert(key, value);
    };

    copyText("App", "app_id");
    copyText("App", "app_name", "Marsco Demo App");
    copyText("App", "channel", "stable");
    copyText("App", "current_version", "1.0.0");
    copyText("App", "client_protocol", "3");
    copyText("App", "launch_token");
    copyText("License", "license_key");
    copyText("Server", "api_base_url");
    copyText("Server", "client_token");
    copyText("Update", "request_timeout_ms", "5000");
    copyText("Update", "temp_folder", "update_temp");
    copyText("Update", "device_id");
    copyText("Runtime", "install_root", ".");
    copyText("Runtime", "main_executable", "MainApp.exe");
    copyText("Runtime", "launcher_executable", "Launcher.exe");
    copyText("Runtime", "updater_executable", "Updater.exe");
    copyText("Runtime", "bootstrap_executable", "Bootstrap.exe");
    copyText("Runtime", "health_check_timeout_ms", "15000");
    config.insert("platform", "windows");
    config.insert("arch", "x64");

    QDir().mkpath(QFileInfo(m_configPath).path());
    QSaveFile output(m_configPath);
    if (!output.open(QIODevice::WriteOnly))
        return false;
    output.write(QJsonDocument(config).toJson(QJsonDocument::Indented));
    const bool saved = output.commit();
    if (saved)
        qDebug() << "Migrated legacy client.ini to" << m_configPath;
    return saved;
}