// Copyright (C) 2022 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only

#include "qwasmevent.h"

#include "qwasmkeytranslator.h"

#include <QtCore/private/qmakearray_p.h>
#include <QtCore/private/qstringiterator_p.h>
#include <QtCore/qregularexpression.h>

QT_BEGIN_NAMESPACE

namespace {
constexpr std::string_view WebDeadKeyValue = "Dead";

bool isDeadKeyEvent(const char *key)
{
    return qstrncmp(key, WebDeadKeyValue.data(), WebDeadKeyValue.size()) == 0;
}

Qt::Key getKeyFromCode(const std::string &code)
{
    if (auto mapping = QWasmKeyTranslator::mapWebKeyTextToQtKey(code.c_str()))
        return *mapping;

    static QRegularExpression regex(QString(QStringLiteral(R"re((?:Key|Digit)(\w))re")));
    const auto codeQString = QString::fromStdString(code);
    const auto match = regex.match(codeQString);

    if (!match.hasMatch())
        return Qt::Key_unknown;

    constexpr size_t CharacterIndex = 1;
    return static_cast<Qt::Key>(match.capturedView(CharacterIndex).at(0).toLatin1());
}

Qt::Key webKeyToQtKey(const std::string &code, const std::string &key, bool isDeadKey,
                      QFlags<Qt::KeyboardModifier> modifiers)
{
    if (isDeadKey) {
        auto mapped = getKeyFromCode(code);
        switch (mapped) {
        case Qt::Key_U:
            return Qt::Key_Dead_Diaeresis;
        case Qt::Key_E:
            return Qt::Key_Dead_Acute;
        case Qt::Key_I:
            return Qt::Key_Dead_Circumflex;
        case Qt::Key_N:
            return Qt::Key_Dead_Tilde;
        case Qt::Key_QuoteLeft:
            return modifiers.testFlag(Qt::ShiftModifier) ? Qt::Key_Dead_Tilde : Qt::Key_Dead_Grave;
        case Qt::Key_6:
            return Qt::Key_Dead_Circumflex;
        case Qt::Key_Apostrophe:
            return modifiers.testFlag(Qt::ShiftModifier) ? Qt::Key_Dead_Diaeresis
                                                         : Qt::Key_Dead_Acute;
        case Qt::Key_AsciiTilde:
            return Qt::Key_Dead_Tilde;
        default:
            return Qt::Key_unknown;
        }
    } else if (auto mapping = QWasmKeyTranslator::mapWebKeyTextToQtKey(key.c_str())) {
        return *mapping;
    }

    // cast to unicode key
    QString str = QString::fromUtf8(key.c_str()).toUpper();
    if (str.length() > 1)
        return Qt::Key_unknown;

    QStringIterator i(str);
    return static_cast<Qt::Key>(i.next(0));
}
} // namespace

namespace KeyboardModifier
{
template <>
QFlags<Qt::KeyboardModifier> getForEvent<EmscriptenKeyboardEvent>(
    const EmscriptenKeyboardEvent& event)
{
    return internal::Helper<EmscriptenKeyboardEvent>::getModifierForEvent(event) |
        (event.location == DOM_KEY_LOCATION_NUMPAD ? Qt::KeypadModifier : Qt::NoModifier);
}
}  // namespace KeyboardModifier

Event::Event(EventType type, emscripten::val webEvent)
    : webEvent(webEvent), type(type)
{
}

Event::~Event() = default;

Event::Event(const Event &other) = default;

Event::Event(Event &&other) = default;

Event &Event::operator=(const Event &other) = default;

Event &Event::operator=(Event &&other) = default;

KeyEvent::KeyEvent(EventType type, emscripten::val event) : Event(type, event)
{
    const auto code = event["code"].as<std::string>();
    const auto webKey = event["key"].as<std::string>();
    deadKey = isDeadKeyEvent(webKey.c_str());

    modifiers = KeyboardModifier::getForEvent(event);
    key = webKeyToQtKey(code, webKey, deadKey, modifiers);

    text = QString::fromUtf8(webKey);
    if (text.size() > 1)
        text.clear();

    if (key == Qt::Key_Tab)
        text = "\t";
}

KeyEvent::~KeyEvent() = default;

KeyEvent::KeyEvent(const KeyEvent &other) = default;

KeyEvent::KeyEvent(KeyEvent &&other) = default;

KeyEvent &KeyEvent::operator=(const KeyEvent &other) = default;

KeyEvent &KeyEvent::operator=(KeyEvent &&other) = default;

std::optional<KeyEvent> KeyEvent::fromWebWithDeadKeyTranslation(emscripten::val event,
                                                                QWasmDeadKeySupport *deadKeySupport)
{
    const auto eventType = ([&event]() -> std::optional<EventType> {
        const auto eventTypeString = event["type"].as<std::string>();

        if (eventTypeString == "keydown")
            return EventType::KeyDown;
        else if (eventTypeString == "keyup")
            return EventType::KeyUp;
        return std::nullopt;
    })();
    if (!eventType)
        return std::nullopt;

    auto result = KeyEvent(*eventType, event);
    deadKeySupport->applyDeadKeyTranslations(&result);

    return result;
}

MouseEvent::MouseEvent(EventType type, emscripten::val event) : Event(type, event)
{
    mouseButton = MouseEvent::buttonFromWeb(event["button"].as<int>());
    mouseButtons = MouseEvent::buttonsFromWeb(event["buttons"].as<unsigned short>());
    // The current button state (event.buttons) may be out of sync for some PointerDown
    // events where the "down" state is very brief, for example taps on Apple trackpads.
    // Qt expects that the current button state is in sync with the event, so we sync
    // it up here.
    if (type == EventType::PointerDown)
        mouseButtons |= mouseButton;
    localPoint = QPointF(event["offsetX"].as<qreal>(), event["offsetY"].as<qreal>());
    pointInPage = QPointF(event["pageX"].as<qreal>(), event["pageY"].as<qreal>());
    pointInViewport = QPointF(event["clientX"].as<qreal>(), event["clientY"].as<qreal>());
    modifiers = KeyboardModifier::getForEvent(event);
}

MouseEvent::~MouseEvent() = default;

MouseEvent::MouseEvent(const MouseEvent &other) = default;

MouseEvent::MouseEvent(MouseEvent &&other) = default;

MouseEvent &MouseEvent::operator=(const MouseEvent &other) = default;

MouseEvent &MouseEvent::operator=(MouseEvent &&other) = default;

PointerEvent::PointerEvent(EventType type, emscripten::val event) : MouseEvent(type, event)
{
    pointerId = event["pointerId"].as<int>();
    pointerType = ([type = event["pointerType"].as<std::string>()]() {
        if (type == "mouse")
            return PointerType::Mouse;
        if (type == "touch")
            return PointerType::Touch;
        if (type == "pen")
            return PointerType::Pen;
        return PointerType::Other;
    })();
    width = event["width"].as<qreal>();
    height = event["height"].as<qreal>();
    pressure = event["pressure"].as<qreal>();
    tiltX = event["tiltX"].as<qreal>();
    tiltY = event["tiltY"].as<qreal>();
    tangentialPressure = event["tangentialPressure"].as<qreal>();
    twist = event["twist"].as<qreal>();
    isPrimary = event["isPrimary"].as<bool>();
}

PointerEvent::~PointerEvent() = default;

PointerEvent::PointerEvent(const PointerEvent &other) = default;

PointerEvent::PointerEvent(PointerEvent &&other) = default;

PointerEvent &PointerEvent::operator=(const PointerEvent &other) = default;

PointerEvent &PointerEvent::operator=(PointerEvent &&other) = default;

std::optional<PointerEvent> PointerEvent::fromWeb(emscripten::val event)
{
    const auto eventType = ([&event]() -> std::optional<EventType> {
        const auto eventTypeString = event["type"].as<std::string>();

        if (eventTypeString == "pointermove")
            return EventType::PointerMove;
        else if (eventTypeString == "pointerup")
            return EventType::PointerUp;
        else if (eventTypeString == "pointerdown")
            return EventType::PointerDown;
        else if (eventTypeString == "pointerenter")
            return EventType::PointerEnter;
        else if (eventTypeString == "pointerleave")
            return EventType::PointerLeave;
        return std::nullopt;
    })();
    if (!eventType)
        return std::nullopt;

    return PointerEvent(*eventType, event);
}

DragEvent::DragEvent(EventType type, emscripten::val event, QWindow *window)
    : MouseEvent(type, event), dataTransfer(event["dataTransfer"]), targetWindow(window)
{
    dropAction = ([event]() {
        const std::string effect = event["dataTransfer"]["dropEffect"].as<std::string>();

        if (effect == "copy")
            return Qt::CopyAction;
        else if (effect == "move")
            return Qt::MoveAction;
        else if (effect == "link")
            return Qt::LinkAction;
        return Qt::IgnoreAction;
    })();
}

DragEvent::~DragEvent() = default;

DragEvent::DragEvent(const DragEvent &other) = default;

DragEvent::DragEvent(DragEvent &&other) = default;

DragEvent &DragEvent::operator=(const DragEvent &other) = default;

DragEvent &DragEvent::operator=(DragEvent &&other) = default;

std::optional<DragEvent> DragEvent::fromWeb(emscripten::val event, QWindow *targetWindow)
{
    const auto eventType = ([&event]() -> std::optional<EventType> {
        const auto eventTypeString = event["type"].as<std::string>();

        if (eventTypeString == "dragend")
            return EventType::DragEnd;
        if (eventTypeString == "dragover")
            return EventType::DragOver;
        if (eventTypeString == "dragstart")
            return EventType::DragStart;
        if (eventTypeString == "drop")
            return EventType::Drop;
        return std::nullopt;
    })();
    if (!eventType)
        return std::nullopt;
    return DragEvent(*eventType, event, targetWindow);
}

void DragEvent::cancelDragStart()
{
    Q_ASSERT_X(type == EventType::DragStart, Q_FUNC_INFO, "Only supported for DragStart");
    webEvent.call<void>("preventDefault");
}

void DragEvent::acceptDragOver()
{
    Q_ASSERT_X(type == EventType::DragOver, Q_FUNC_INFO, "Only supported for DragOver");
   webEvent.call<void>("preventDefault");
}

void DragEvent::acceptDrop()
{
    Q_ASSERT_X(type == EventType::Drop, Q_FUNC_INFO, "Only supported for Drop");
    webEvent.call<void>("preventDefault");
}

WheelEvent::WheelEvent(EventType type, emscripten::val event) : MouseEvent(type, event)
{
    deltaMode = ([event]() {
        const int deltaMode = event["deltaMode"].as<int>();
        const auto jsWheelEventType = emscripten::val::global("WheelEvent");
        if (deltaMode == jsWheelEventType["DOM_DELTA_PIXEL"].as<int>())
            return DeltaMode::Pixel;
        else if (deltaMode == jsWheelEventType["DOM_DELTA_LINE"].as<int>())
            return DeltaMode::Line;
        return DeltaMode::Page;
    })();

    delta = QPointF(event["deltaX"].as<qreal>(), event["deltaY"].as<qreal>());

    webkitDirectionInvertedFromDevice = event["webkitDirectionInvertedFromDevice"].as<bool>();
}

WheelEvent::~WheelEvent() = default;

WheelEvent::WheelEvent(const WheelEvent &other) = default;

WheelEvent::WheelEvent(WheelEvent &&other) = default;

WheelEvent &WheelEvent::operator=(const WheelEvent &other) = default;

WheelEvent &WheelEvent::operator=(WheelEvent &&other) = default;

std::optional<WheelEvent> WheelEvent::fromWeb(emscripten::val event)
{
    const auto eventType = ([&event]() -> std::optional<EventType> {
        const auto eventTypeString = event["type"].as<std::string>();

        if (eventTypeString == "wheel")
            return EventType::Wheel;
        return std::nullopt;
    })();
    if (!eventType)
        return std::nullopt;
    return WheelEvent(*eventType, event);
}

QT_END_NAMESPACE