/*
    SPDX-FileCopyrightText: 2014, 2015 Ivan Cukic <ivan.cukic(at)kde.org>
    SPDX-FileCopyrightText: 2009 Martin Gräßlin <mgraesslin@kde.org>
    SPDX-FileCopyrightText: 2003 Lubos Lunak <l.lunak@kde.org>
    SPDX-FileCopyrightText: 1999, 2000 Matthias Ettrich <ettrich@kde.org>

    SPDX-License-Identifier: GPL-2.0-or-later
*/

// Self
#include "switcherbackend.h"

// Qt
#include <QAction>
#include <QDBusConnection>
#include <QDBusMessage>
#include <QDateTime>
#include <QGuiApplication>
#include <QRasterWindow>

// Qml and QtQuick
#include <QQmlEngine>
#include <QQuickImageProvider>

// KDE
#include <KConfig>
#include <KConfigGroup>
#include <KGlobalAccel>
#include <KIO/PreviewJob>
#include <KLocalizedString>
#include <KWindowSystem>
#include <windowtasksmodel.h>
#include <xwindowtasksmodel.h>

static const char *s_action_name_next_activity = "next activity";
static const char *s_action_name_previous_activity = "previous activity";

namespace
{
bool areModifiersPressed(const QKeySequence &seq)
{
    if (seq.isEmpty()) {
        return false;
    }
    int mod = seq[seq.count() - 1] & Qt::KeyboardModifierMask;
    auto activeMods = qGuiApp->queryKeyboardModifiers();
    return activeMods & mod;
}

bool isReverseTab(const QKeySequence &prevAction)
{
    if (prevAction == QKeySequence(Qt::ShiftModifier | Qt::Key_Tab)) {
        return areModifiersPressed(Qt::SHIFT);
    } else {
        return false;
    }
}

class ThumbnailImageResponse : public QQuickImageResponse
{
public:
    ThumbnailImageResponse(const QString &id, const QSize &requestedSize);

    QQuickTextureFactory *textureFactory() const override;

    void run();

private:
    QString m_id;
    QSize m_requestedSize;
    QQuickTextureFactory *m_texture = nullptr;
};

ThumbnailImageResponse::ThumbnailImageResponse(const QString &id, const QSize &requestedSize)
    : m_id(id)
    , m_requestedSize(requestedSize)
    , m_texture(nullptr)
{
    int width = m_requestedSize.width();
    int height = m_requestedSize.height();

    if (width <= 0) {
        width = 320;
    }

    if (height <= 0) {
        height = 240;
    }

    if (m_id.isEmpty()) {
        Q_EMIT finished();
        return;
    }

    const auto file = QUrl::fromUserInput(m_id);

    KFileItemList list;
    list.append(KFileItem(file, QString(), 0));

    auto job = KIO::filePreview(list, QSize(width, height));
    job->setScaleType(KIO::PreviewJob::Scaled);
    job->setIgnoreMaximumSize(true);

    connect(
        job,
        &KIO::PreviewJob::gotPreview,
        this,
        [this, file](const KFileItem &item, const QPixmap &pixmap) {
            Q_UNUSED(item);

            auto image = pixmap.toImage();

            m_texture = QQuickTextureFactory::textureFactoryForImage(image);
            Q_EMIT finished();
        },
        Qt::QueuedConnection);

    connect(job, &KIO::PreviewJob::failed, this, [this, job](const KFileItem &item) {
        Q_UNUSED(item);
        qWarning() << "SwitcherBackend: FAILED to get the thumbnail" << job->errorString() << job->detailedErrorStrings();
        Q_EMIT finished();
    });
}

QQuickTextureFactory *ThumbnailImageResponse::textureFactory() const
{
    return m_texture;
}

class ThumbnailImageProvider : public QQuickAsyncImageProvider
{
public:
    QQuickImageResponse *requestImageResponse(const QString &id, const QSize &requestedSize) override
    {
        return new ThumbnailImageResponse(id, requestedSize);
    }
};

} // local namespace

template<typename Handler>
inline void SwitcherBackend::registerShortcut(const QString &actionName, const QString &text, const QKeySequence &shortcut, Handler &&handler)
{
    auto action = new QAction(this);

    m_actionShortcut[actionName] = shortcut;

    action->setObjectName(actionName);
    action->setText(text);

    KGlobalAccel::self()->setShortcut(action, {shortcut});

    using KActivities::Controller;

    connect(action, &QAction::triggered, this, std::forward<Handler>(handler));
}

SwitcherBackend::SwitcherBackend(QObject *parent)
    : QObject(parent)
    , m_shouldShowSwitcher(false)
    , m_dropModeActive(false)
    , m_runningActivitiesModel(new SortedActivitiesModel({KActivities::Info::Running, KActivities::Info::Stopping}, this))
    , m_stoppedActivitiesModel(new SortedActivitiesModel({KActivities::Info::Stopped, KActivities::Info::Starting}, this))
{
    registerShortcut(QString::fromLatin1(s_action_name_next_activity),
                     i18n("Walk through activities"),
                     Qt::META | Qt::Key_Tab,
                     &SwitcherBackend::keybdSwitchToNextActivity);

    registerShortcut(QString::fromLatin1(s_action_name_previous_activity),
                     i18n("Walk through activities (Reverse)"),
                     Qt::META | Qt::SHIFT | Qt::Key_Tab,
                     &SwitcherBackend::keybdSwitchToPreviousActivity);

    connect(this, &SwitcherBackend::shouldShowSwitcherChanged, m_runningActivitiesModel, &SortedActivitiesModel::setInhibitUpdates);

    m_modKeyPollingTimer.setInterval(100);
    connect(&m_modKeyPollingTimer, &QTimer::timeout, this, &SwitcherBackend::showActivitySwitcherIfNeeded);

    m_dropModeHider.setInterval(500);
    m_dropModeHider.setSingleShot(true);
    connect(&m_dropModeHider, &QTimer::timeout, this, [this] {
        setShouldShowSwitcher(false);
    });

    connect(&m_activities, &KActivities::Controller::currentActivityChanged, this, &SwitcherBackend::onCurrentActivityChanged);
    m_previousActivity = m_activities.currentActivity();
}

SwitcherBackend::~SwitcherBackend()
{
}

QObject *SwitcherBackend::instance(QQmlEngine *engine, QJSEngine *scriptEngine)
{
    Q_UNUSED(scriptEngine)
    engine->addImageProvider(QStringLiteral("wallpaperthumbnail"), new ThumbnailImageProvider());
    return new SwitcherBackend();
}

void SwitcherBackend::keybdSwitchToNextActivity()
{
    if (isReverseTab(m_actionShortcut[QString::fromLatin1(s_action_name_previous_activity)])) {
        switchToActivity(Previous);
    } else {
        switchToActivity(Next);
    }
}

void SwitcherBackend::keybdSwitchToPreviousActivity()
{
    switchToActivity(Previous);
}

void SwitcherBackend::switchToActivity(Direction direction)
{
    const auto activityToSet = m_runningActivitiesModel->relativeActivity(direction == Next ? 1 : -1);

    if (activityToSet.isEmpty())
        return;

    QTimer::singleShot(0, this, [this, activityToSet]() {
        setCurrentActivity(activityToSet);
    });

    keybdSwitchedToAnotherActivity();
}

void SwitcherBackend::keybdSwitchedToAnotherActivity()
{
    m_lastInvokedAction = dynamic_cast<QAction *>(sender());
    if (KWindowSystem::isPlatformWayland() && !qGuiApp->focusWindow() && !m_inputWindow) {
        // create a new Window so the compositor sends us modifier info
        m_inputWindow = new QRasterWindow();
        m_inputWindow->setGeometry(0, 0, 1, 1);
        // Only show once the initial switch has been completed, not cause a switch back
        connect(&m_activities, &KActivities::Consumer::currentActivityChanged, m_inputWindow, [this] {
            m_inputWindow->show();
            m_inputWindow->update();
        });
        connect(m_inputWindow, &QWindow::activeChanged, this, [this] {
            showActivitySwitcherIfNeeded();
        });
    } else {
        QTimer::singleShot(100, this, &SwitcherBackend::showActivitySwitcherIfNeeded);
    }
}

void SwitcherBackend::showActivitySwitcherIfNeeded()
{
    if (!m_lastInvokedAction || m_dropModeActive) {
        return;
    }

    auto actionName = m_lastInvokedAction->objectName();

    if (!m_actionShortcut.contains(actionName)) {
        return;
    }

    if (!areModifiersPressed(m_actionShortcut[actionName])) {
        m_lastInvokedAction = nullptr;
        setShouldShowSwitcher(false);
        return;
    }

    setShouldShowSwitcher(true);
}

void SwitcherBackend::init()
{
    // nothing
}

void SwitcherBackend::onCurrentActivityChanged(const QString &id)
{
    if (m_shouldShowSwitcher) {
        // If we are showing the switcher because the user is
        // pressing Meta+Tab, we are not ready to commit the
        // activity change to memory
        return;
    }

    if (m_previousActivity == id)
        return;

    // Safe, we have a long-lived Consumer object
    KActivities::Info activity(id);
    Q_EMIT showSwitchNotification(id, activity.name(), activity.icon());

    KConfig config(QStringLiteral("kactivitymanagerd-switcher"));
    KConfigGroup times(&config, "LastUsed");

    const auto now = QDateTime::currentDateTime().toTime_t();

    // Updating the time for the activity we just switched to
    // in the case we do not power off properly, and on the next
    // start, kamd switches to another activity for some reason
    times.writeEntry(id, now);

    if (!m_previousActivity.isEmpty()) {
        // When leaving an activity, say goodbye and fondly remember
        // the last time we saw it
        times.writeEntry(m_previousActivity, now);
    }

    times.sync();

    m_previousActivity = id;
}

bool SwitcherBackend::shouldShowSwitcher() const
{
    return m_shouldShowSwitcher;
}

void SwitcherBackend::setShouldShowSwitcher(bool shouldShowSwitcher)
{
    if (m_inputWindow) {
        delete m_inputWindow;
        m_inputWindow = nullptr;
    }

    if (m_shouldShowSwitcher == shouldShowSwitcher)
        return;

    m_shouldShowSwitcher = shouldShowSwitcher;

    if (m_shouldShowSwitcher) {
        // TODO: We really should NOT do this by polling
        m_modKeyPollingTimer.start();
    } else {
        m_modKeyPollingTimer.stop();

        // We might have an unprocessed onCurrentActivityChanged
        onCurrentActivityChanged(m_activities.currentActivity());
    }

    Q_EMIT shouldShowSwitcherChanged(m_shouldShowSwitcher);
}

QAbstractItemModel *SwitcherBackend::runningActivitiesModel() const
{
    return m_runningActivitiesModel;
}

QAbstractItemModel *SwitcherBackend::stoppedActivitiesModel() const
{
    return m_stoppedActivitiesModel;
}

void SwitcherBackend::setCurrentActivity(const QString &activity)
{
    m_activities.setCurrentActivity(activity);
}

void SwitcherBackend::stopActivity(const QString &activity)
{
    m_activities.stopActivity(activity);
}

bool SwitcherBackend::dropEnabled() const
{
#if HAVE_X11
    return true;
#else
    return false;
#endif
}

void SwitcherBackend::dropCopy(QMimeData *mimeData, const QVariant &activityId)
{
    drop(mimeData, Qt::ControlModifier, activityId);
}

void SwitcherBackend::dropMove(QMimeData *mimeData, const QVariant &activityId)
{
    drop(mimeData, 0, activityId);
}

void SwitcherBackend::drop(QMimeData *mimeData, int modifiers, const QVariant &activityId)
{
    setDropMode(false);

#if HAVE_X11
    if (KWindowSystem::isPlatformX11()) {
        bool ok = false;
        const QList<WId> &ids = TaskManager::XWindowTasksModel::winIdsFromMimeData(mimeData, &ok);

        if (!ok) {
            return;
        }

        const QString newActivity = activityId.toString();
        const QStringList runningActivities = m_activities.runningActivities();

        if (!runningActivities.contains(newActivity)) {
            return;
        }

        for (const auto &id : ids) {
            QStringList activities = KWindowInfo(id, NET::Properties(), NET::WM2Activities).activities();

            if (modifiers & Qt::ControlModifier) {
                // Add to the activity instead of moving.
                // This is a hack because the task manager reports that
                // is supports only the 'Move' DND action.
                if (!activities.contains(newActivity)) {
                    activities << newActivity;
                }

            } else {
                // Move to this activity
                // if on only one activity, set it to only the new activity
                // if on >1 activity, remove it from the current activity and add it to the new activity

                const QString currentActivity = m_activities.currentActivity();
                activities.removeAll(currentActivity);
                activities << newActivity;
            }

            KWindowSystem::setOnActivities(id, activities);
        }
    }
#endif
}

void SwitcherBackend::setDropMode(bool value)
{
    if (m_dropModeActive == value)
        return;

    m_dropModeActive = value;
    if (value) {
        setShouldShowSwitcher(true);
        m_dropModeHider.stop();
    } else {
        m_dropModeHider.start();
    }
}

void SwitcherBackend::toggleActivityManager()
{
    auto message = QDBusMessage::createMethodCall(QStringLiteral("org.kde.plasmashell"),
                                                  QStringLiteral("/PlasmaShell"),
                                                  QStringLiteral("org.kde.PlasmaShell"),
                                                  QStringLiteral("toggleActivityManager"));
    QDBusConnection::sessionBus().call(message, QDBus::NoBlock);
}