// Copyright (C) 2023 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only

#include <QtCore/private/qandroidtypeconverter_p.h>
#include <QtCore/private/qandroidtypes_p.h>
#include <QtQuick/private/qandroidquickviewembedding_p.h>
#include <QtQuick/private/qandroidviewsignalmanager_p.h>

#include <QtCore/qcoreapplication.h>
#include <QtCore/qjnienvironment.h>
#include <QtCore/qjniobject.h>
#include <QtCore/qjniarray.h>
#include <QtCore/qjnitypes.h>
#include <QtQml/qqmlengine.h>
#include <QtQuick/qquickitem.h>

QT_BEGIN_NAMESPACE

Q_DECLARE_JNI_CLASS(QtDelegate, "org/qtproject/qt/android/QtEmbeddedContextDelegate");
Q_DECLARE_JNI_CLASS(QtQuickView, "org/qtproject/qt/android/QtQuickView");
Q_DECLARE_JNI_CLASS(QtWindow, "org/qtproject/qt/android/QtWindow");
Q_DECLARE_JNI_CLASS(View, "android/view/View");

namespace QtAndroidQuickViewEmbedding
{
    constexpr const char *uninitializedViewMessage = "because QtQuickView is not loaded or ready yet.";

    void createQuickView(JNIEnv *, jobject nativeWindow, jstring qmlUri, jint width, jint height,
                         jlong parentWindowReference, jlong viewReference,
                         const QJniArray<jstring> &qmlImportPaths)
    {
        static_assert (sizeof(jlong) >= sizeof(void*),
                      "Insufficient size of Java type to hold the c++ pointer");
        const QUrl qmlUrl(QJniObject(qmlUri).toString());

        const QStringList importPaths = qmlImportPaths.toContainer();
        QMetaObject::invokeMethod(qApp, [qtViewObject = QJniObject(nativeWindow),
                                        parentWindowReference,
                                        viewReference,
                                        width,
                                        height,
                                        qmlUrl,
                                        importPaths] {
            // If the view does not exists (viewReference==0) we should create and set it up.
            // Else we only reset the source of the view.
            QAndroidQuickView *view = reinterpret_cast<QAndroidQuickView *>(viewReference);
            if (!view) {
                QWindow *parentWindow = reinterpret_cast<QWindow *>(parentWindowReference);
                view = new QAndroidQuickView(parentWindow);
                QObject::connect(view, &QAndroidQuickView::statusChanged, view,
                                 [qtViewObject](QAndroidQuickView::Status status) {
                                     qtViewObject.callMethod<void>("handleStatusChange", status);
                                 });
                view->setResizeMode(QAndroidQuickView::SizeRootObjectToView);
                view->setColor(QColor(Qt::transparent));
                view->setWidth(width);
                view->setHeight(height);
                QQmlEngine *engine = view->engine();
                for (const QString &path : importPaths)
                    engine->addImportPath(path);

                QObject::connect(engine, &QQmlEngine::quit, QCoreApplication::instance(),
                                 &QCoreApplication::quit);

                const QtJniTypes::QtWindow window = reinterpret_cast<jobject>(view->winId());
                qtViewObject.callMethod<void>("addQtWindow",
                                              window,
                                              reinterpret_cast<jlong>(view),
                                              parentWindowReference);
            }
            view->setSource(qmlUrl);
        });
    }

    std::pair<QAndroidQuickView *, QQuickItem *> getViewAndRootObject(jlong windowReference)
    {
        QAndroidQuickView *view = reinterpret_cast<QAndroidQuickView *>(windowReference);
        QQuickItem *rootObject = Q_LIKELY(view) ? view->rootObject() : nullptr;
        return std::make_pair(view, rootObject);
    }

    void setRootObjectProperty(JNIEnv *env, jobject object, jlong windowReference,
                               jstring propertyName, jobject value)
    {
        Q_UNUSED(env);
        Q_UNUSED(object);

        auto [_, rootObject] = getViewAndRootObject(windowReference);
        if (!rootObject) {
            qWarning("Cannot set property %s %s", qPrintable(QJniObject(propertyName).toString()),
                     uninitializedViewMessage);
            return;
        }

        const QString property = QJniObject(propertyName).toString();
        const QMetaObject *rootMetaObject = rootObject->metaObject();
        int propertyIndex = rootMetaObject->indexOfProperty(qPrintable(property));
        if (propertyIndex < 0) {
            qWarning("Property %s does not exist in the root QML object.", qPrintable(property));
            return;
        }

        QMetaProperty metaProperty = rootMetaObject->property(propertyIndex);
        const QJniObject propertyValue(value);
        const QVariant variantToWrite = QAndroidTypeConverter::toQVariant(propertyValue);

        if (!variantToWrite.isValid()) {
            qWarning("Setting the property type of %s is not supported.",
                     propertyValue.className().data());
        } else {
            metaProperty.write(rootObject, variantToWrite);
        }
    }

    jobject getRootObjectProperty(JNIEnv *env, jobject object, jlong windowReference,
                                  jstring propertyName)
    {
        Q_UNUSED(object);
        Q_ASSERT(env);

        const QString property = QJniObject(propertyName).toString();
        auto [_, rootObject] = getViewAndRootObject(windowReference);
        if (!rootObject) {
            qWarning("Cannot get property %s %s", qPrintable(property), uninitializedViewMessage);
            return nullptr;
        }

        const QMetaObject *rootMetaObject = rootObject->metaObject();
        int propertyIndex = rootMetaObject->indexOfProperty(property.toUtf8().constData());
        if (propertyIndex < 0) {
            qWarning("Cannot get property %s as it does not exist in the root QML object.",
                     qPrintable(property));
            return nullptr;
        }

        QMetaProperty metaProperty = rootMetaObject->property(propertyIndex);
        const QVariant propertyValue = metaProperty.read(rootObject);
        jobject jObject = QAndroidTypeConverter::toJavaObject(propertyValue, env);
        if (!jObject) {
            qWarning("Property %s cannot be converted to a supported Java data type.",
                     qPrintable(property));
        }
        return jObject;
    }

    int addRootObjectSignalListener(JNIEnv *env, jobject, jlong windowReference, jstring signalName,
                                   jclass argType, jobject listener)
    {
        Q_ASSERT(env);
        static QHash<QByteArray, int> javaToQMetaType = {
            { "java/lang/Void", QMetaType::Type::Void },
            { "java/lang/String", QMetaType::Type::QString },
            { "java/lang/Integer", QMetaType::Type::Int },
            { "java/lang/Double", QMetaType::Type::Double },
            { "java/lang/Float", QMetaType::Type::Float },
            { "java/lang/Boolean", QMetaType::Type::Bool }
        };

        auto [view, rootObject] = getViewAndRootObject(windowReference);
        if (!rootObject) {
            qWarning("Cannot connect to signal %s %s",
                     qPrintable(QJniObject(signalName).toString()), uninitializedViewMessage);
            return -1;
        }

        QAndroidViewSignalManager *signalManager = view->signalManager();
        const QByteArray javaArgClass = QJniObject(argType).className();
        const char *qArgName =
                QMetaType(javaToQMetaType.value(javaArgClass, QMetaType::Type::UnknownType)).name();
        const QString signalMethodName = QJniObject(signalName).toString();

        const QMetaObject *metaObject = rootObject->metaObject();
        int signalIndex = -1;
        int propertyIndex = -1;

        QByteArray signalSignature = QMetaObject::normalizedSignature(qPrintable(
                QStringLiteral("%1(%2)").arg(signalMethodName).arg(QLatin1StringView(qArgName))));
        signalIndex = metaObject->indexOfSignal(signalSignature.constData());

        // Try to check if the signal is a parameterless notifier of a property
        // or a property name itself.
        if (signalIndex == -1) {
            signalSignature = QMetaObject::normalizedSignature(
                    qPrintable(QStringLiteral("%1()").arg(signalMethodName)));
            for (int i = 0; i < metaObject->propertyCount(); ++i) {
                QMetaProperty metaProperty = metaObject->property(i);
                QMetaMethod notifyMethod = metaProperty.notifySignal();

                if (signalSignature == notifyMethod.methodSignature()) {
                    signalIndex = metaObject->property(i).notifySignalIndex();
                    propertyIndex = i;
                    break;
                } else if (signalMethodName == QLatin1StringView(metaProperty.name())) {
                    signalIndex = metaObject->property(i).notifySignalIndex();
                    signalSignature = notifyMethod.methodSignature();
                    propertyIndex = i;
                    break;
                }
            }
        }

        if (signalIndex == -1)
            return -1;

        const QMetaObject *helperMetaObject = signalManager->metaObject();
        QByteArray helperSignalSignature = signalSignature;
        helperSignalSignature.replace(0, signalSignature.indexOf('('), "forwardSignal");
        int helperSlotIndex = helperMetaObject->indexOfSlot(helperSignalSignature.constData());
        if (helperSlotIndex == -1)
            return -1;

        // Return the id if the signal is already connected to the same listener.
        QJniObject listenerJniObject(listener);
        if (signalManager->connectionInfoMap.contains(signalSignature)) {
            auto connectionInfos = signalManager->connectionInfoMap.values(signalSignature);
            auto isSameListener =
                    [listenerJniObject](
                            const QAndroidViewSignalManager::ConnectionInfo &connectionInfo) {
                        return connectionInfo.listener == listenerJniObject;
                    };
            auto iterator = std::find_if(connectionInfos.constBegin(),
                                         connectionInfos.constEnd(),
                                         isSameListener);
            if (iterator != connectionInfos.end()) {
                qWarning("Signal listener with the ID of %i is already connected to %s signal.",
                         iterator->id,
                         signalSignature.constData());
                return iterator->id;
            }
        }

        QMetaMethod signalMethod = metaObject->method(signalIndex);
        QMetaMethod signalForwarderMethod = helperMetaObject->method(helperSlotIndex);
        signalManager->connectionHandleCounter++;

        QMetaObject::Connection connection;
        if (signalManager->connectionInfoMap.contains(signalSignature)) {
            const int existingId = signalManager->connectionInfoMap.value(signalSignature).id;
            connection = signalManager->connections[existingId];
        } else {
            connection = QObject::connect(rootObject,
                                          signalMethod,
                                          signalManager,
                                          signalForwarderMethod);
        }

        QAndroidViewSignalManager::ConnectionInfo connectionInfo;
        connectionInfo.listener = listenerJniObject;
        connectionInfo.javaArgType = javaArgClass;
        connectionInfo.propertyIndex = propertyIndex;
        connectionInfo.signalSignature = signalSignature;
        connectionInfo.id = signalManager->connectionHandleCounter;

        signalManager->connectionInfoMap.insert(signalSignature, connectionInfo);
        signalManager->connections.insert(connectionInfo.id, connection);

        return connectionInfo.id;
    }

    bool removeRootObjectSignalListener(JNIEnv *, jobject, jlong windowReference,
                                       jint signalListenerId)
    {
        auto [view, rootObject] = getViewAndRootObject(windowReference);
        if (!rootObject) {
            qWarning("Cannot disconnect the signal connection with id: %i %s", signalListenerId,
                     uninitializedViewMessage);
            return false;
        }

        QAndroidViewSignalManager *signalManager = view->signalManager();
        if (!signalManager->connections.contains(signalListenerId))
            return false;

        QByteArray signalSignature;
        for (auto listenerInfoIter = signalManager->connectionInfoMap.begin();
             listenerInfoIter != signalManager->connectionInfoMap.end();) {
            if (listenerInfoIter->id == signalListenerId) {
                signalSignature = listenerInfoIter->signalSignature;
                signalManager->connectionInfoMap.erase(listenerInfoIter);
                break;
            } else {
                ++listenerInfoIter;
            }
        }

        // disconnect if its the last listener associated with the signal signatures
        if (!signalManager->connectionInfoMap.contains(signalSignature))
            rootObject->disconnect(signalManager->connections.value(signalListenerId));

        signalManager->connections.remove(signalListenerId);
        return true;
    }

    bool registerNatives(QJniEnvironment& env) {
        return env.registerNativeMethods(QtJniTypes::Traits<QtJniTypes::QtQuickView>::className(),
                                         {Q_JNI_NATIVE_SCOPED_METHOD(createQuickView,
                                                                     QtAndroidQuickViewEmbedding),
                                          Q_JNI_NATIVE_SCOPED_METHOD(setRootObjectProperty,
                                                                     QtAndroidQuickViewEmbedding),
                                          Q_JNI_NATIVE_SCOPED_METHOD(getRootObjectProperty,
                                                                     QtAndroidQuickViewEmbedding),
                                          Q_JNI_NATIVE_SCOPED_METHOD(addRootObjectSignalListener,
                                                                     QtAndroidQuickViewEmbedding),
                                          Q_JNI_NATIVE_SCOPED_METHOD(removeRootObjectSignalListener,
                                                                     QtAndroidQuickViewEmbedding)});
    }
}

Q_DECL_EXPORT jint JNICALL JNI_OnLoad(JavaVM *vm, void *reserved)
{
    Q_UNUSED(vm)
    Q_UNUSED(reserved)

    static bool initialized = false;
    if (initialized)
        return JNI_VERSION_1_6;
    initialized = true;

    QJniEnvironment env;
    if (!env.isValid())
        return JNI_ERR;
    if (!QtAndroidQuickViewEmbedding::registerNatives(env))
        return JNI_ERR;
    return JNI_VERSION_1_6;
}

QT_END_NAMESPACE