/*
    KWin - the KDE window manager
    This file is part of the KDE project.

    SPDX-FileCopyrightText: 2016 Martin Gräßlin <mgraesslin@kde.org>

    SPDX-License-Identifier: GPL-2.0-or-later
*/
#include "inputmethod.h"
#include "abstract_client.h"
#include "virtualkeyboard_dbus.h"
#include "input.h"
#include "inputpanelv1client.h"
#include "keyboard_input.h"
#include "utils.h"
#include "screens.h"
#include "wayland_server.h"
#include "workspace.h"
#include "screenlockerwatcher.h"
#include "deleted.h"
#include "touch_input.h"
#include "pointer_input.h"

#include <KWaylandServer/display.h>
#include <KWaylandServer/keyboard_interface.h>
#include <KWaylandServer/seat_interface.h>
#include <KWaylandServer/textinput_v3_interface.h>
#include <KWaylandServer/surface_interface.h>
#include <KWaylandServer/inputmethod_v1_interface.h>

#include <KShell>
#include <KStatusNotifierItem>
#include <KLocalizedString>

#include <QDBusConnection>
#include <QDBusPendingCall>
#include <QDBusMessage>
#include <QMenu>
#include <QKeyEvent>

#include <linux/input-event-codes.h>
#include <xkbcommon/xkbcommon-keysyms.h>
#include <unistd.h>

using namespace KWaylandServer;

namespace KWin
{

KWIN_SINGLETON_FACTORY(InputMethod)

InputMethod::InputMethod(QObject *parent)
    : QObject(parent)
{
    m_enabled = kwinApp()->config()->group("Wayland").readEntry("VirtualKeyboardEnabled", true);
    // this is actually too late. Other processes are started before init,
    // so might miss the availability of text input
    // but without Workspace we don't have the window listed at all
    if (workspace()) {
        init();
    } else {
        connect(kwinApp(), &Application::workspaceCreated, this, &InputMethod::init);
    }
}

InputMethod::~InputMethod()
{
    stopInputMethod();
    s_self = nullptr;
}

void InputMethod::init()
{
    // Stop restarting the input method if it starts crashing very frequently
    m_inputMethodCrashTimer.setInterval(20000);
    m_inputMethodCrashTimer.setSingleShot(true);
    connect(&m_inputMethodCrashTimer, &QTimer::timeout, this, [this] {
        m_inputMethodCrashes = 0;
    });
    connect(ScreenLockerWatcher::self(), &ScreenLockerWatcher::aboutToLock, this, &InputMethod::hide);

    new VirtualKeyboardDBus(this);
    qCDebug(KWIN_VIRTUALKEYBOARD) << "Registering the DBus interface";

    if (waylandServer()) {
        new TextInputManagerV2Interface(waylandServer()->display());
        new TextInputManagerV3Interface(waylandServer()->display());

        connect(waylandServer()->seat(), &SeatInterface::focusedTextInputSurfaceChanged, this, &InputMethod::handleFocusedSurfaceChanged);

        TextInputV2Interface *textInputV2 = waylandServer()->seat()->textInputV2();
        connect(textInputV2, &TextInputV2Interface::requestShowInputPanel, this, &InputMethod::show);
        connect(textInputV2, &TextInputV2Interface::requestHideInputPanel, this, &InputMethod::hide);
        connect(textInputV2, &TextInputV2Interface::surroundingTextChanged, this, &InputMethod::surroundingTextChanged);
        connect(textInputV2, &TextInputV2Interface::contentTypeChanged, this, &InputMethod::contentTypeChanged);
        connect(textInputV2, &TextInputV2Interface::stateUpdated, this, &InputMethod::textInputInterfaceV2StateUpdated);

        TextInputV3Interface *textInputV3 = waylandServer()->seat()->textInputV3();
        connect(textInputV3, &TextInputV3Interface::surroundingTextChanged, this, &InputMethod::surroundingTextChanged);
        connect(textInputV3, &TextInputV3Interface::contentTypeChanged, this, &InputMethod::contentTypeChanged);
        connect(textInputV3, &TextInputV3Interface::stateCommitted, this, &InputMethod::stateCommitted);

        if (m_enabled) {
            connect(textInputV2, &TextInputV2Interface::enabledChanged, this, &InputMethod::textInputInterfaceV2EnabledChanged);
            connect(textInputV3, &TextInputV3Interface::enabledChanged, this, &InputMethod::textInputInterfaceV3EnabledChanged);
        }

        connect(input()->keyboard()->xkb(), &Xkb::modifierStateChanged, this, &InputMethod::forwardModifiers);
    }
}

void InputMethod::show()
{
    setActive(true);
}

void InputMethod::hide()
{
    setActive(false);
}

bool InputMethod::touchEventTriggered() const
{
    return input()->touch()
           && input()->touch()->lastEventTime() > input()->keyboard()->lastEventTime()
           && input()->touch()->lastEventTime() > input()->pointer()->lastEventTime();
}

void InputMethod::setActive(bool active)
{
    const bool wasActive = waylandServer()->inputMethod()->context();
    if (wasActive && !active) {
        waylandServer()->inputMethod()->sendDeactivate();
    }

    if (active) {
        if (!m_enabled) {
            return;
        }

        if (!wasActive) {
            waylandServer()->inputMethod()->sendActivate();
        } else {
            waylandServer()->inputMethod()->context()->sendReset();
        }
        adoptInputMethodContext();
    } else {
        updateInputPanelState();
    }

    if (wasActive != isActive()) {
        Q_EMIT activeChanged(active);
    }
}

void InputMethod::setPanel(InputPanelV1Client *client)
{
    Q_ASSERT(client->isInputMethod());
    if (m_inputClient) {
        qCWarning(KWIN_VIRTUALKEYBOARD) << "Replacing input client" << m_inputClient << "with" << client;
        disconnect(m_inputClient, nullptr, this, nullptr);
    }

    m_inputClient = client;
    connect(client->surface(), &SurfaceInterface::inputChanged, this, &InputMethod::updateInputPanelState);
    connect(client, &QObject::destroyed, this, [this] {
        if (m_trackedClient) {
            m_trackedClient->setVirtualKeyboardGeometry({});
        }
    });
    connect(m_inputClient, &AbstractClient::frameGeometryChanged, this, &InputMethod::updateInputPanelState);
    connect(m_inputClient, &AbstractClient::windowHidden, this, &InputMethod::updateInputPanelState);
    connect(m_inputClient, &AbstractClient::windowClosed, this, &InputMethod::updateInputPanelState);
    connect(m_inputClient, &AbstractClient::windowShown, this, &InputMethod::visibleChanged);
    connect(m_inputClient, &AbstractClient::windowHidden, this, &InputMethod::visibleChanged);
    connect(m_inputClient, &AbstractClient::windowClosed, this, &InputMethod::visibleChanged);
    Q_EMIT visibleChanged();
    updateInputPanelState();
}

void InputMethod::setTrackedClient(AbstractClient* trackedClient)
{
    // Reset the old client virtual keybaord geom if necessary
    // Old and new clients could be the same if focus moves between subsurfaces
    if (m_trackedClient == trackedClient) {
        return;
    }
    if (m_trackedClient) {
        m_trackedClient->setVirtualKeyboardGeometry(QRect());
        disconnect(m_trackedClient, &AbstractClient::frameGeometryChanged, this, &InputMethod::updateInputPanelState);
    }
    m_trackedClient = trackedClient;
    if (m_trackedClient) {
        connect(m_trackedClient, &AbstractClient::frameGeometryChanged, this, &InputMethod::updateInputPanelState, Qt::QueuedConnection);
    }
    updateInputPanelState();
}

void InputMethod::handleFocusedSurfaceChanged()
{
    SurfaceInterface *focusedSurface = waylandServer()->seat()->focusedTextInputSurface();
    setTrackedClient(waylandServer()->findClient(focusedSurface));
    if (!focusedSurface) {
        setActive(false);
    }
}

void InputMethod::surroundingTextChanged()
{
    auto t2 = waylandServer()->seat()->textInputV2();
    auto t3 = waylandServer()->seat()->textInputV3();
    auto inputContext = waylandServer()->inputMethod()->context();
    if (!inputContext) {
        return;
    }
    if (t2 && t2->isEnabled()) {
        inputContext->sendSurroundingText(t2->surroundingText(), t2->surroundingTextCursorPosition(), t2->surroundingTextSelectionAnchor());
        return;
    }
    if (t3 && t3->isEnabled()) {
        inputContext->sendSurroundingText(t3->surroundingText(), t3->surroundingTextCursorPosition(), t3->surroundingTextSelectionAnchor());
        return;
    }
}

void InputMethod::contentTypeChanged()
{
    auto t2 = waylandServer()->seat()->textInputV2();
    auto t3 = waylandServer()->seat()->textInputV3();
    auto inputContext = waylandServer()->inputMethod()->context();
    if (!inputContext) {
        return;
    }
    if (t2 && t2->isEnabled()) {
        inputContext->sendContentType(t2->contentHints(), t2->contentPurpose());
    }
    if (t3 && t3->isEnabled()) {
        inputContext->sendContentType(t3->contentHints(), t3->contentPurpose());
    }
}

void InputMethod::textInputInterfaceV2StateUpdated(quint32 serial, KWaylandServer::TextInputV2Interface::UpdateReason reason)
{
    if (!m_enabled) {
        return;
    }
    Q_UNUSED(serial);

    auto t2 = waylandServer()->seat()->textInputV2();
    auto inputContext = waylandServer()->inputMethod()->context();
    if (!inputContext) {
        return;
    }
    if (!t2 || !t2->isEnabled()) {
        return;
    }
    if (m_inputClient && touchEventTriggered()) {
        m_inputClient->allow();
    }
    switch (reason) {
    case KWaylandServer::TextInputV2Interface::UpdateReason::StateChange:
        break;
    case KWaylandServer::TextInputV2Interface::UpdateReason::StateEnter:
    case KWaylandServer::TextInputV2Interface::UpdateReason::StateFull:
        adoptInputMethodContext();
        break;
    case KWaylandServer::TextInputV2Interface::UpdateReason::StateReset:
        inputContext->sendReset();
        break;
    }
}

void InputMethod::textInputInterfaceV2EnabledChanged()
{
    if (!m_enabled) {
        return;
    }

    auto t = waylandServer()->seat()->textInputV2();
    setActive(t->isEnabled());
}

void InputMethod::textInputInterfaceV3EnabledChanged()
{
    if (!m_enabled) {
        return;
    }

    auto t3 = waylandServer()->seat()->textInputV3();
    setActive(t3->isEnabled());
    if (!t3->isEnabled()) {
        // reset value of preedit when textinput is disabled
        preedit.text = QString();
        preedit.begin = 0;
        preedit.end = 0;
    }
    auto context = waylandServer()->inputMethod()->context();
    if (context) {
        context->sendReset();
        adoptInputMethodContext();
    }
}

void InputMethod::stateCommitted(uint32_t serial)
{
    if (!isEnabled()) {
        return;
    }
    TextInputV3Interface *textInputV3 = waylandServer()->seat()->textInputV3();
    if (!textInputV3) {
        return;
    }

    if (auto inputContext = waylandServer()->inputMethod()->context()) {
        inputContext->sendCommitState(serial);
    }
    setActive(textInputV3->isEnabled());
}

void InputMethod::setEnabled(bool enabled)
{
    if (m_enabled == enabled) {
        return;
    }
    m_enabled = enabled;
    Q_EMIT enabledChanged(m_enabled);

    // send OSD message
    QDBusMessage msg = QDBusMessage::createMethodCall(
        QStringLiteral("org.kde.plasmashell"),
        QStringLiteral("/org/kde/osdService"),
        QStringLiteral("org.kde.osdService"),
        QStringLiteral("virtualKeyboardEnabledChanged")
    );
    msg.setArguments({enabled});
    QDBusConnection::sessionBus().asyncCall(msg);
    if (!m_enabled) {
        hide();
        stopInputMethod();
    } else {
        startInputMethod();
    }
    // save value into config
    kwinApp()->config()->group("Wayland").writeEntry("VirtualKeyboardEnabled", m_enabled);
    kwinApp()->config()->sync();
}

static quint32 keysymToKeycode(quint32 sym)
{
    switch(sym) {
    case XKB_KEY_BackSpace:
        return KEY_BACKSPACE;
    case XKB_KEY_Return:
        return KEY_ENTER;
    case XKB_KEY_Left:
        return KEY_LEFT;
    case XKB_KEY_Right:
        return KEY_RIGHT;
    case XKB_KEY_Up:
        return KEY_UP;
    case XKB_KEY_Down:
        return KEY_DOWN;
    default:
        return KEY_UNKNOWN;
    }
}

void InputMethod::keysymReceived(quint32 serial, quint32 time, quint32 sym, bool pressed, quint32 modifiers)
{
    Q_UNUSED(serial)
    Q_UNUSED(time)
    auto t2 = waylandServer()->seat()->textInputV2();
    if (t2 && t2->isEnabled()) {
        if (pressed) {
            t2->keysymPressed(sym, modifiers);
        } else {
            t2->keysymReleased(sym, modifiers);
        }
        return;
    }
    auto t3 = waylandServer()->seat()->textInputV3();
    if (t3 && t3->isEnabled()) {
        KWaylandServer::KeyboardKeyState state;
        if (pressed) {
            state = KWaylandServer::KeyboardKeyState::Pressed;
        } else {
            state = KWaylandServer::KeyboardKeyState::Released;
        }
        waylandServer()->seat()->notifyKeyboardKey(keysymToKeycode(sym), state);
        return;
    }
}

void InputMethod::commitString(qint32 serial, const QString &text)
{
    Q_UNUSED(serial)
    if (auto t2 = waylandServer()->seat()->textInputV2(); t2 && t2->isEnabled()) {
        t2->commitString(text.toUtf8());
        t2->preEdit({}, {});
        return;
    } else if (auto t3 = waylandServer()->seat()->textInputV3(); t3 && t3->isEnabled()) {
        t3->commitString(text.toUtf8());
        t3->done();
        return;
    } else {
        qCWarning(KWIN_VIRTUALKEYBOARD) << "We have nobody to commit to!!!";
    }
}

void InputMethod::deleteSurroundingText(int32_t index, uint32_t length)
{
    auto t2 = waylandServer()->seat()->textInputV2();
    if (t2 && t2->isEnabled()) {
        t2->deleteSurroundingText(index, length);
    }
    auto t3 = waylandServer()->seat()->textInputV3();
    if (t3 && t3->isEnabled()) {
        t3->deleteSurroundingText(index, length);
    }
}

void InputMethod::setCursorPosition(qint32 index, qint32 anchor)
{
    auto t2 = waylandServer()->seat()->textInputV2();
    if (t2 && t2->isEnabled()) {
        t2->setCursorPosition(index, anchor);
    }
}

void InputMethod::setLanguage(uint32_t serial, const QString &language)
{
    Q_UNUSED(serial)
    auto t2 = waylandServer()->seat()->textInputV2();
    if (t2 && t2->isEnabled()) {
        t2->setLanguage(language.toUtf8());
    }
}

void InputMethod::setTextDirection(uint32_t serial, Qt::LayoutDirection direction)
{
    Q_UNUSED(serial)
    auto t2 = waylandServer()->seat()->textInputV2();
    if (t2 && t2->isEnabled()) {
        t2->setTextDirection(direction);
    }
}

void InputMethod::setPreeditCursor(qint32 index)
{
    auto t2 = waylandServer()->seat()->textInputV2();
    if (t2 && t2->isEnabled()) {
        t2->setPreEditCursor(index);
    }
    auto t3 = waylandServer()->seat()->textInputV3();
    if (t3 && t3->isEnabled()) {
        preedit.begin = index;
        preedit.end = index;
        t3->sendPreEditString(preedit.text, preedit.begin, preedit.end);
    }
}


void InputMethod::setPreeditString(uint32_t serial, const QString &text, const QString &commit)
{
    Q_UNUSED(serial)
    auto t2 = waylandServer()->seat()->textInputV2();
    if (t2 && t2->isEnabled()) {
        t2->preEdit(text.toUtf8(), commit.toUtf8());
    }
    auto t3 = waylandServer()->seat()->textInputV3();
    if (t3 && t3->isEnabled()) {
        preedit.text = text;
        t3->sendPreEditString(preedit.text, preedit.begin, preedit.end);
    }
}

void InputMethod::key(quint32 /*serial*/, quint32 /*time*/, quint32 keyCode, bool pressed)
{
    waylandServer()->seat()->notifyKeyboardKey(keyCode, pressed ? KWaylandServer::KeyboardKeyState::Pressed : KWaylandServer::KeyboardKeyState::Released);
}

void InputMethod::modifiers(quint32 serial, quint32 mods_depressed, quint32 mods_latched, quint32 mods_locked, quint32 group)
{
    Q_UNUSED(serial)
    auto xkb = input()->keyboard()->xkb();
    xkb->updateModifiers(mods_depressed, mods_latched, mods_locked, group);
}

void InputMethod::forwardModifiers()
{
    auto xkb = input()->keyboard()->xkb();
    if (m_keyboardGrab) {
        m_keyboardGrab->sendModifiers(waylandServer()->display()->nextSerial(),
                                      xkb->modifierState().depressed,
                                      xkb->modifierState().latched,
                                      xkb->modifierState().locked,
                                      xkb->currentLayout());
    }
}

void InputMethod::adoptInputMethodContext()
{
    auto inputContext = waylandServer()->inputMethod()->context();

    TextInputV2Interface *t2 = waylandServer()->seat()->textInputV2();
    TextInputV3Interface *t3 = waylandServer()->seat()->textInputV3();

    if (t2 && t2->isEnabled()) {
        inputContext->sendSurroundingText(t2->surroundingText(), t2->surroundingTextCursorPosition(), t2->surroundingTextSelectionAnchor());
        inputContext->sendPreferredLanguage(t2->preferredLanguage());
        inputContext->sendContentType(t2->contentHints(), t2->contentPurpose());
        connect(inputContext, &KWaylandServer::InputMethodContextV1Interface::language, this, &InputMethod::setLanguage);
        connect(inputContext, &KWaylandServer::InputMethodContextV1Interface::textDirection, this, &InputMethod::setTextDirection);
    }

    if (t3 && t3->isEnabled()) {
        inputContext->sendSurroundingText(t3->surroundingText(), t3->surroundingTextCursorPosition(), t3->surroundingTextSelectionAnchor());
        inputContext->sendContentType(t3->contentHints(), t3->contentPurpose());
    }
    inputContext->sendCommitState(m_serial++);

    connect(inputContext, &KWaylandServer::InputMethodContextV1Interface::keysym, this, &InputMethod::keysymReceived, Qt::UniqueConnection);
    connect(inputContext, &KWaylandServer::InputMethodContextV1Interface::key, this, &InputMethod::key, Qt::UniqueConnection);
    connect(inputContext, &KWaylandServer::InputMethodContextV1Interface::modifiers, this, &InputMethod::modifiers, Qt::UniqueConnection);
    connect(inputContext, &KWaylandServer::InputMethodContextV1Interface::commitString, this, &InputMethod::commitString, Qt::UniqueConnection);
    connect(inputContext, &KWaylandServer::InputMethodContextV1Interface::deleteSurroundingText, this, &InputMethod::deleteSurroundingText, Qt::UniqueConnection);
    connect(inputContext, &KWaylandServer::InputMethodContextV1Interface::cursorPosition, this, &InputMethod::setCursorPosition, Qt::UniqueConnection);
    connect(inputContext, &KWaylandServer::InputMethodContextV1Interface::preeditString, this, &InputMethod::setPreeditString, Qt::UniqueConnection);
    connect(inputContext, &KWaylandServer::InputMethodContextV1Interface::preeditCursor, this, &InputMethod::setPreeditCursor, Qt::UniqueConnection);
    connect(inputContext, &KWaylandServer::InputMethodContextV1Interface::keyboardGrabRequested, this, &InputMethod::installKeyboardGrab, Qt::UniqueConnection);
    connect(inputContext, &KWaylandServer::InputMethodContextV1Interface::modifiersMap, this, &InputMethod::updateModifiersMap, Qt::UniqueConnection);
}

void InputMethod::updateInputPanelState()
{
    if (!waylandServer()) {
        return;
    }

    auto t = waylandServer()->seat()->textInputV2();

    if (!t) {
        return;
    }

    if (m_inputClient && touchEventTriggered()) {
        m_inputClient->allow();
    }

    QRect overlap = QRect(0, 0, 0, 0);
    if (m_trackedClient) {
        const bool bottomKeyboard = m_inputClient && m_inputClient->mode() != InputPanelV1Client::Overlay && m_inputClient->isShown();
        m_trackedClient->setVirtualKeyboardGeometry(bottomKeyboard ? m_inputClient->inputGeometry() : QRect());

        if (m_inputClient) {
            overlap = m_trackedClient->frameGeometry() & m_inputClient->inputGeometry();
            overlap.moveTo(m_trackedClient->mapToLocal(overlap.topLeft()));
        }
    }
    t->setInputPanelState(m_inputClient && m_inputClient->isShown(), overlap);
}

void InputMethod::setInputMethodCommand(const QString &command)
{
    if (m_inputMethodCommand == command) {
        return;
    }

    m_inputMethodCommand = command;

    if (m_enabled) {
        startInputMethod();
    }
    Q_EMIT availableChanged();
}

void InputMethod::stopInputMethod()
{
    if (!m_inputMethodProcess) {
        return;
    }
    disconnect(m_inputMethodProcess, nullptr, this, nullptr);

    m_inputMethodProcess->terminate();
    if (!m_inputMethodProcess->waitForFinished()) {
        m_inputMethodProcess->kill();
        m_inputMethodProcess->waitForFinished();
    }
    m_inputMethodProcess->deleteLater();
    m_inputMethodProcess = nullptr;

    waylandServer()->destroyInputMethodConnection();
}

void InputMethod::startInputMethod()
{
    stopInputMethod();
    if (m_inputMethodCommand.isEmpty() || kwinApp()->isTerminating()) {
        return;
    }

    QStringList arguments = KShell::splitArgs(m_inputMethodCommand);
    if (arguments.isEmpty()) {
        qWarning("Failed to launch the input method server: %s is an invalid command", qPrintable(m_inputMethodCommand));
        return;
    }

    const QString program = arguments.takeFirst();
    int socket = waylandServer()->createInputMethodConnection();
    if (socket < 0) {
        qWarning("Failed to create the input method connection");
        return;
    }
    socket = dup(socket);

    QProcessEnvironment environment = kwinApp()->processStartupEnvironment();
    environment.insert(QStringLiteral("WAYLAND_SOCKET"), QByteArray::number(socket));
    environment.insert(QStringLiteral("QT_QPA_PLATFORM"), QStringLiteral("wayland"));
    environment.remove("WAYLAND_DISPLAY");

    m_inputMethodProcess = new Process(this);
    m_inputMethodProcess->setProcessChannelMode(QProcess::ForwardedErrorChannel);
    m_inputMethodProcess->setProcessEnvironment(environment);
    m_inputMethodProcess->setProgram(program);
    m_inputMethodProcess->setArguments(arguments);
    m_inputMethodProcess->start();
    close(socket);
    connect(m_inputMethodProcess, QOverload<int, QProcess::ExitStatus>::of(&QProcess::finished), this, [this](int exitCode, QProcess::ExitStatus exitStatus) {
        if (exitStatus == QProcess::CrashExit) {
            m_inputMethodCrashes++;
            m_inputMethodCrashTimer.start();
            qWarning() << "Input Method crashed" << m_inputMethodProcess->program() << m_inputMethodProcess->arguments() << exitCode << exitStatus;
            if (m_inputMethodCrashes < 5) {
                startInputMethod();
            } else {
                qWarning() << "Input Method keeps crashing, please fix" << m_inputMethodProcess->program() << m_inputMethodProcess->arguments();
                stopInputMethod();
            }
        }
    });
}
bool InputMethod::isActive() const
{
    return waylandServer()->inputMethod()->context();
}

KWaylandServer::InputMethodGrabV1 *InputMethod::keyboardGrab()
{
    return isActive() ? m_keyboardGrab : nullptr;
}

void InputMethod::installKeyboardGrab(KWaylandServer::InputMethodGrabV1 *keyboardGrab)
{
    auto xkb = input()->keyboard()->xkb();
    m_keyboardGrab = keyboardGrab;
    keyboardGrab->sendKeymap(xkb->keymapContents());
    forwardModifiers();
}

void InputMethod::updateModifiersMap(const QByteArray &modifiers)
{
    TextInputV2Interface *t2 = waylandServer()->seat()->textInputV2();

    if (t2 && t2->isEnabled()) {
        t2->setModifiersMap(modifiers);
    }
}

bool InputMethod::isVisible() const
{
    return m_inputClient && m_inputClient->isShown();
}

bool InputMethod::isAvailable() const
{
    return !m_inputMethodCommand.isEmpty();
}

}