// SPDX-FileCopyrightText: Nheko Contributors
//
// SPDX-License-Identifier: GPL-3.0-or-later

#pragma once

#include <CacheStructs.h>
#include <QAbstractListModel>
#include <QHash>
#include <QQmlEngine>
#include <QSharedPointer>
#include <QSortFilterProxyModel>
#include <QString>
#include <set>

#include <mtx/responses/sync.hpp>

#include "TimelineModel.h"

#ifdef NHEKO_DBUS_SYS
#include "dbus/NhekoDBusBackend.h"
#endif

class TimelineViewManager;

class RoomPreview
{
    Q_GADGET
    Q_PROPERTY(QString roomid READ roomid CONSTANT)
    Q_PROPERTY(QString roomName READ roomName CONSTANT)
    Q_PROPERTY(QString roomTopic READ roomTopic CONSTANT)
    Q_PROPERTY(QString roomAvatarUrl READ roomAvatarUrl CONSTANT)
    Q_PROPERTY(QString reason READ reason CONSTANT)
    Q_PROPERTY(QString inviterAvatarUrl READ inviterAvatarUrl CONSTANT)
    Q_PROPERTY(QString inviterDisplayName READ inviterDisplayName CONSTANT)
    Q_PROPERTY(QString inviterUserId READ inviterUserId CONSTANT)
    Q_PROPERTY(bool isInvite READ isInvite CONSTANT)
    Q_PROPERTY(bool isFetched READ isFetched CONSTANT)

public:
    RoomPreview() {}

    QString roomid() const { return roomid_; }
    QString roomName() const { return roomName_; }
    QString roomTopic() const { return roomTopic_; }
    QString roomAvatarUrl() const { return roomAvatarUrl_; }
    QString reason() const { return reason_; }
    QString inviterAvatarUrl() const;
    QString inviterDisplayName() const;
    QString inviterUserId() const;
    bool isInvite() const { return isInvite_; }
    bool isFetched() const { return isFetched_; }

    QString roomid_, roomName_, roomAvatarUrl_, roomTopic_, reason_;
    bool isInvite_ = false, isFetched_ = true;
};

class RoomlistModel final : public QAbstractListModel
{
    Q_OBJECT
    Q_PROPERTY(
      TimelineModel *currentRoom READ currentRoom NOTIFY currentRoomChanged RESET resetCurrentRoom)
    Q_PROPERTY(RoomPreview currentRoomPreview READ currentRoomPreview NOTIFY currentRoomChanged
                 RESET resetCurrentRoom)
public:
    enum Roles
    {
        AvatarUrl = Qt::UserRole,
        RoomName,
        RoomId,
        LastMessage,
        Time,
        Timestamp,
        HasUnreadMessages,
        HasLoudNotification,
        NotificationCount,
        IsInvite,
        IsSpace,
        IsPreview,
        IsPreviewFetched,
        Tags,
        ParentSpaces,
        IsDirect,
        DirectChatOtherUserId,
    };

    RoomlistModel(TimelineViewManager *parent = nullptr);
    QHash<int, QByteArray> roleNames() const override;
    int rowCount(const QModelIndex &parent = QModelIndex()) const override
    {
        (void)parent;
        return (int)roomids.size();
    }
    QVariant data(const QModelIndex &index, int role) const override;
    QSharedPointer<TimelineModel> getRoomById(QString id) const
    {
        if (models.contains(id))
            return models.value(id);
        else
            return {};
    }
    RoomPreview getRoomPreviewById(QString roomid) const;

    void refetchOnlineKeyBackupKeys();

public slots:
    void initializeRooms();
    void sync(const mtx::responses::Sync &sync_);
    void clear();
    int roomidToIndex(const QString &roomid)
    {
        for (int i = 0; i < (int)roomids.size(); i++) {
            if (roomids[i] == roomid)
                return i;
        }

        return -1;
    }
    void joinPreview(const QString &roomid);
    void acceptInvite(QString roomid);
    void declineInvite(QString roomid);
    void leave(QString roomid, QString reason = "");
    TimelineModel *currentRoom() const { return currentRoom_.get(); }
    RoomPreview currentRoomPreview() const { return currentRoomPreview_.value_or(RoomPreview{}); }
    void setCurrentRoom(const QString &roomid);
    void resetCurrentRoom()
    {
        currentRoom_ = nullptr;
        currentRoomPreview_.reset();
        emit currentRoomChanged("");
    }

private slots:
    void updateReadStatus(const std::map<QString, bool> &roomReadStatus_);

signals:
    void totalUnreadMessageCountUpdated(int unreadMessages);
    void currentRoomChanged(QString currentRoomId);
    void fetchedPreview(QString roomid, RoomInfo info);
    void spaceSelected(QString roomId);

private:
    void addRoom(const QString &room_id, bool suppressInsertNotification = false);
    void fetchPreviews(QString roomid, const std::string &from = "");
    std::set<QString> updateDMs(mtx::events::AccountDataEvent<mtx::events::account_data::Direct> e);

    TimelineViewManager *manager = nullptr;
    std::vector<QString> roomids;
    QHash<QString, RoomInfo> invites;
    QHash<QString, QSharedPointer<TimelineModel>> models;
    std::map<QString, bool> roomReadStatus;
    QHash<QString, std::optional<RoomInfo>> previewedRooms;

    QSharedPointer<TimelineModel> currentRoom_;
    std::optional<RoomPreview> currentRoomPreview_;

    std::map<QString, std::vector<QString>> directChatToUser;

#ifdef NHEKO_DBUS_SYS
    NhekoDBusBackend *dbusInterface_;
    friend class NhekoDBusBackend;
#endif

    friend class FilteredRoomlistModel;
};

class FilteredRoomlistModel final : public QSortFilterProxyModel
{
    Q_OBJECT

    QML_NAMED_ELEMENT(Rooms)
    QML_SINGLETON

    Q_PROPERTY(
      TimelineModel *currentRoom READ currentRoom NOTIFY currentRoomChanged RESET resetCurrentRoom)
    Q_PROPERTY(RoomPreview currentRoomPreview READ currentRoomPreview NOTIFY currentRoomChanged
                 RESET resetCurrentRoom)
public:
    FilteredRoomlistModel(RoomlistModel *model, QObject *parent = nullptr);

    static FilteredRoomlistModel *create(QQmlEngine *qmlEngine, QJSEngine *)
    {
        // The instance has to exist before it is used. We cannot replace it.
        Q_ASSERT(instance_);

        // The engine has to have the same thread affinity as the singleton.
        Q_ASSERT(qmlEngine->thread() == instance_->thread());

        // There can only be one engine accessing the singleton.
        static QJSEngine *s_engine = nullptr;
        if (s_engine)
            Q_ASSERT(qmlEngine == s_engine);
        else
            s_engine = qmlEngine;

        QJSEngine::setObjectOwnership(instance_, QJSEngine::CppOwnership);
        return instance_;
    }

    bool lessThan(const QModelIndex &left, const QModelIndex &right) const override;
    bool filterAcceptsRow(int sourceRow, const QModelIndex &) const override;

public slots:
    int roomidToIndex(QString roomid)
    {
        return mapFromSource(roomlistmodel->index(roomlistmodel->roomidToIndex(roomid))).row();
    }
    void joinPreview(QString roomid) { roomlistmodel->joinPreview(roomid); }
    void acceptInvite(QString roomid) { roomlistmodel->acceptInvite(roomid); }
    void declineInvite(QString roomid) { roomlistmodel->declineInvite(roomid); }
    void leave(QString roomid, QString reason = "") { roomlistmodel->leave(roomid, reason); }
    void toggleTag(const QString &roomid, const QString &tag, bool on);
    void copyLink(QString roomid);

    TimelineModel *currentRoom() const { return roomlistmodel->currentRoom(); }
    RoomPreview currentRoomPreview() const { return roomlistmodel->currentRoomPreview(); }
    void setCurrentRoom(QString roomid) { roomlistmodel->setCurrentRoom(std::move(roomid)); }
    void resetCurrentRoom() { roomlistmodel->resetCurrentRoom(); }
    TimelineModel *getRoomById(const QString &id) const
    {
        auto r = roomlistmodel->getRoomById(id).data();
        QQmlEngine::setObjectOwnership(r, QQmlEngine::CppOwnership);
        return r;
    }
    RoomPreview getRoomPreviewById(QString roomid) const
    {
        return roomlistmodel->getRoomPreviewById(roomid);
    }

    void nextRoomWithActivity();
    void nextRoom();
    void previousRoom();

    void updateFilterTag(QString tagId)
    {
        if (tagId.startsWith(QLatin1String("tag:"))) {
            filterType = FilterBy::Tag;
            filterStr  = tagId.mid(4);
        } else if (tagId.startsWith(QLatin1String("space:"))) {
            filterType = FilterBy::Space;
            filterStr  = tagId.mid(6);
            roomlistmodel->fetchPreviews(filterStr);
        } else if (tagId.startsWith(QLatin1String("dm"))) {
            filterType = FilterBy::DirectChats;
            filterStr.clear();
        } else {
            filterType = FilterBy::Nothing;
            filterStr.clear();
        }

        invalidateFilter();
    }

    void updateHiddenTagsAndSpaces();

signals:
    void currentRoomChanged(QString currentRoomId);

private:
    short int calculateImportance(const QModelIndex &idx) const;
    RoomlistModel *roomlistmodel;
    bool sortByImportance = true;
    bool sortByAlphabet   = false;

    enum class FilterBy
    {
        Tag,
        Space,
        DirectChats,
        Nothing,
    };
    QString filterStr   = QLatin1String("");
    FilterBy filterType = FilterBy::Nothing;
    QStringList hiddenTags, hiddenSpaces;
    bool hideDMs = false;

    inline static FilteredRoomlistModel *instance_ = nullptr;
};