// SPDX-FileCopyrightText: Copyright 2025 Eden Emulator Project
// SPDX-License-Identifier: GPL-3.0-or-later

// Copyright Citra Emulator Project / Azahar Emulator Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.

#include "user_data_migration.h"
#include <QMessageBox>
#include <QPushButton>
#include <QString>
#include <QTranslator>
#include "common/fs/path_util.h"
#include "../yuzu/migration_dialog.h"

// Needs to be included at the end due to https://bugreports.qt.io/browse/QTBUG-73263
#include <QGuiApplication>
#include <QButtonGroup>
#include <QCheckBox>
#include <QProgressDialog>
#include <QRadioButton>
#include <QThread>
#include <filesystem>

namespace fs = std::filesystem;

UserDataMigrator::UserDataMigrator(QMainWindow *main_window)
{
    // NOTE: Logging is not initialized yet, do not produce logs here.

    // Check migration if config directory does not exist
    // TODO: ProfileManager messes with us a bit here, and force-creates the /nand/system/save/8000000000000010/su/avators/profiles.dat
    // file. Find a way to reorder operations and have it create after this guy runs.
    if (!fs::is_directory(Common::FS::GetEdenPath(Common::FS::EdenPath::ConfigDir))) {
        ShowMigrationPrompt(main_window);
    }
}

void UserDataMigrator::ShowMigrationPrompt(QMainWindow *main_window)
{
    namespace fs = std::filesystem;

    // define strings here for easy access
    static constexpr const char *prompt_prefix_text
        = "Eden has detected user data for the following emulators:";

    static constexpr const char *migration_prompt_message
        = "Would you like to migrate your data for use in Eden?\n"
          "Select the corresponding button to migrate data from that emulator.\n"
          "This may take a while.";

    static constexpr const char *clear_shader_tooltip
        = "Clearing shader cache is recommended for all "
          "users.\nDo not uncheck unless you know what "
          "you're doing.";

    static constexpr const char *keep_old_data_tooltip
        = "Keeps the old data directory. This is recommended if you aren't\n"
          "space-constrained and want to keep separate data for the old emulator.";

    static constexpr const char *clear_old_data_tooltip
        = "Deletes the old data directory.\nThis is recommended on "
          "devices with space constraints.";

    static constexpr const char *link_old_dir_tooltip
        = "Creates a filesystem link between the old directory and Eden directory.\n"
          "This is recommended if you want to share data between emulators.";

    // actual migration code

    MigrationDialog migration_prompt;
    migration_prompt.setWindowTitle(QObject::tr("Migration"));

    // mutually exclusive
    QButtonGroup *group = new QButtonGroup(&migration_prompt);

    // MACRO MADNESS

#define BUTTON(clazz, name, text, tooltip, checkState) \
    clazz *name = new clazz(&migration_prompt); \
    name->setText(QObject::tr(text)); \
    name->setToolTip(QObject::tr(tooltip)); \
    name->setChecked(checkState); \
    migration_prompt.addBox(name);

    BUTTON(QCheckBox, clear_shaders, "Clear Shader Cache", clear_shader_tooltip, true)

    u32 id = 0;

#define RADIO(name, text, tooltip, checkState) \
    BUTTON(QRadioButton, name, text, tooltip, checkState) \
    group->addButton(name, ++id);

    RADIO(keep_old, "Keep Old Data", keep_old_data_tooltip, true)
    RADIO(clear_old, "Clear Old Data", clear_old_data_tooltip, false)
    RADIO(link_old, "Link Old Directory", link_old_dir_tooltip, false)

#undef RADIO
#undef BUTTON

    std::vector<Emulator> found{};

    for (const Emulator &emu : legacy_emus)
        if (fs::is_directory(emu.get_user_dir()))
            found.emplace_back(emu);

    if (found.empty()) {
        return;
    }

    // makes my life easier
    qRegisterMetaType<Emulator>();

    QString prompt_text = QObject::tr(prompt_prefix_text);

    // natural language processing is a nightmare
    for (const Emulator &emu : found) {
        prompt_text.append(QStringLiteral("\n- %1").arg(QObject::tr(emu.name)));

        QAbstractButton *button = migration_prompt.addButton(QObject::tr(emu.name));

        // This is cursed, but it's actually the most efficient way by a mile
        button->setProperty("emulator", QVariant::fromValue(emu));
    }

    prompt_text.append(QObject::tr("\n\n"));
    prompt_text.append(QObject::tr(migration_prompt_message));

    migration_prompt.setText(prompt_text);
    migration_prompt.addButton(QObject::tr("No"), true);

    migration_prompt.exec();

    QAbstractButton *button = migration_prompt.clickedButton();

    if (button->text() == QObject::tr("No")) {
        return ShowMigrationCancelledMessage(main_window);
    }

    MigrationWorker::MigrationStrategy strategy;

    switch (group->checkedId()) {
    default:
        [[fallthrough]];
    case 1:
        strategy = MigrationWorker::MigrationStrategy::Copy;
        break;
    case 2:
        strategy = MigrationWorker::MigrationStrategy::Move;
        break;
    case 3:
        strategy = MigrationWorker::MigrationStrategy::Link;
        break;
    }

    MigrateUserData(main_window,
                    button->property("emulator").value<Emulator>(),
                    clear_shaders->isChecked(),
                    strategy);
}

void UserDataMigrator::ShowMigrationCancelledMessage(QMainWindow *main_window)
{
    QMessageBox::information(main_window,
                             QObject::tr("Migration"),
                             QObject::tr("You can manually re-trigger this prompt by deleting the "
                                         "new config directory:\n%1")
                                 .arg(QString::fromStdString(Common::FS::GetEdenPathString(
                                     Common::FS::EdenPath::ConfigDir))),
                             QMessageBox::Ok);
}

void UserDataMigrator::MigrateUserData(QMainWindow *main_window,
                                       const Emulator selected_legacy_emu,
                                       const bool clear_shader_cache,
                                       const MigrationWorker::MigrationStrategy strategy)
{
    selected_emu = selected_legacy_emu;

    // Create a dialog to let the user know it's migrating
    QProgressDialog *progress = new QProgressDialog(main_window);
    progress->setWindowTitle(QObject::tr("Migrating"));
    progress->setLabelText(QObject::tr("Migrating, this may take a while..."));
    progress->setRange(0, 0);
    progress->setCancelButton(nullptr);
    progress->setWindowModality(Qt::WindowModality::ApplicationModal);

    QThread *thread = new QThread(main_window);
    MigrationWorker *worker = new MigrationWorker(selected_legacy_emu, clear_shader_cache, strategy);
    worker->moveToThread(thread);

    thread->connect(thread, &QThread::started, worker, &MigrationWorker::process);

    thread->connect(worker, &MigrationWorker::finished, progress, [=, this](const QString &success_text, const std::string &path) {
        progress->close();
        QMessageBox::information(main_window,
                                 QObject::tr("Migration"),
                                 success_text,
                                 QMessageBox::Ok);

        migrated = true;
        thread->quit();
    });

    thread->connect(worker, &MigrationWorker::finished, worker, &QObject::deleteLater);
    thread->connect(thread, &QThread::finished, thread, &QObject::deleteLater);

    thread->start();
    progress->exec();
}