// SPDX-FileCopyrightText: 2016 Kitsune Ral <Kitsune-Ral@users.sf.net>
// SPDX-FileCopyrightText: 2017 Roman Plášil <me@rplasil.name>
// SPDX-FileCopyrightText: 2019 Alexey Andreyev <aa13q@ya.ru>
// SPDX-License-Identifier: LGPL-2.1-or-later

#pragma once

#include "quotient_common.h"
#include "ssosession.h"
#include "util.h"

#include "csapi/create_room.h"
#include "csapi/login.h"

#include "events/accountdataevents.h"

#include <QtCore/QDir>
#include <QtCore/QObject>
#include <QtCore/QSize>
#include <QtCore/QUrl>

#include <functional>

#ifdef Quotient_E2EE_ENABLED
#include "e2ee/e2ee_common.h"
#include "e2ee/qolmoutboundsession.h"
#include "keyverificationsession.h"
#include "events/keyverificationevent.h"
#endif

Q_DECLARE_METATYPE(Quotient::GetLoginFlowsJob::LoginFlow)

namespace Quotient {

class Room;
class User;
class ConnectionData;
class RoomEvent;

class SyncJob;
class SyncData;
class RoomMessagesJob;
class PostReceiptJob;
class ForgetRoomJob;
class MediaThumbnailJob;
class JoinRoomJob;
class UploadContentJob;
class GetContentJob;
class DownloadFileJob;
class SendToDeviceJob;
class SendMessageJob;
class LeaveRoomJob;
class Database;
struct EncryptedFileMetadata;

class QOlmAccount;
class QOlmInboundGroupSession;

using LoginFlow = GetLoginFlowsJob::LoginFlow;

//! Predefined login flows
namespace LoginFlows {
    inline const LoginFlow Password { "m.login.password"_ls };
    inline const LoginFlow SSO { "m.login.sso"_ls };
    inline const LoginFlow Token { "m.login.token"_ls };
}

// To simplify comparisons of LoginFlows

inline bool operator==(const LoginFlow& lhs, const LoginFlow& rhs)
{
    return lhs.type == rhs.type;
}

inline bool operator!=(const LoginFlow& lhs, const LoginFlow& rhs)
{
    return !(lhs == rhs);
}

class Connection;

using room_factory_t =
    std::function<Room*(Connection*, const QString&, JoinState)>;
using user_factory_t = std::function<User*(Connection*, const QString&)>;

//! \brief The default factory to create room objects
//!
//! Just a wrapper around operator new.
//! \sa Connection::setRoomFactory, Connection::setRoomType
template <typename T = Room>
auto defaultRoomFactory(Connection* c, const QString& id, JoinState js)
{
    return new T(c, id, js);
}

//! \brief The default factory to create user objects
//!
//! Just a wrapper around operator new.
//! \sa Connection::setUserFactory, Connection::setUserType
template <typename T = User>
auto defaultUserFactory(Connection* c, const QString& id)
{
    return new T(id, c);
}

// Room ids, rather than room pointers, are used in the direct chat
// map types because the library keeps Invite rooms separate from
// rooms in Join and Leave state; and direct chats in account data
// are stored with no regard to their state.
using DirectChatsMap = QMultiHash<const User*, QString>;
using DirectChatUsersMap = QMultiHash<QString, User*>;
using IgnoredUsersList = IgnoredUsersEvent::value_type;

class QUOTIENT_API Connection : public QObject {
    Q_OBJECT

    Q_PROPERTY(User* localUser READ user NOTIFY stateChanged)
    Q_PROPERTY(QString localUserId READ userId NOTIFY stateChanged)
    Q_PROPERTY(QString domain READ domain NOTIFY stateChanged STORED false)
    Q_PROPERTY(QString deviceId READ deviceId NOTIFY stateChanged)
    Q_PROPERTY(QByteArray accessToken READ accessToken NOTIFY stateChanged)
    Q_PROPERTY(bool isLoggedIn READ isLoggedIn NOTIFY stateChanged STORED false)
    Q_PROPERTY(QString defaultRoomVersion READ defaultRoomVersion NOTIFY capabilitiesLoaded)
    Q_PROPERTY(QUrl homeserver READ homeserver WRITE setHomeserver NOTIFY homeserverChanged)
    Q_PROPERTY(QVector<GetLoginFlowsJob::LoginFlow> loginFlows READ loginFlows NOTIFY loginFlowsChanged)
    Q_PROPERTY(bool isUsable READ isUsable NOTIFY loginFlowsChanged STORED false)
    Q_PROPERTY(bool supportsSso READ supportsSso NOTIFY loginFlowsChanged STORED false)
    Q_PROPERTY(bool supportsPasswordAuth READ supportsPasswordAuth NOTIFY loginFlowsChanged STORED false)
    Q_PROPERTY(bool cacheState READ cacheState WRITE setCacheState NOTIFY cacheStateChanged)
    Q_PROPERTY(bool lazyLoading READ lazyLoading WRITE setLazyLoading NOTIFY lazyLoadingChanged)
    Q_PROPERTY(bool canChangePassword READ canChangePassword NOTIFY capabilitiesLoaded)
    Q_PROPERTY(bool encryptionEnabled READ encryptionEnabled WRITE enableEncryption NOTIFY encryptionChanged)

public:
    using UsersToDevicesToContent = QHash<QString, QHash<QString, QJsonObject>>;

    enum RoomVisibility {
        PublishRoom,
        UnpublishRoom
    }; // FIXME: Should go inside CreateRoomJob

    explicit Connection(QObject* parent = nullptr);
    explicit Connection(const QUrl& server, QObject* parent = nullptr);
    ~Connection() override;

    //! \brief Get all rooms known within this Connection
    //!
    //! This includes Invite, Join and Leave rooms, in no particular order.
    //! \note Leave rooms will only show up in the list if they have been left
    //!       in the same running session. The library doesn't cache left rooms
    //!       between runs and it doesn't retrieve the full list of left rooms
    //!       from the server.
    //! \sa rooms, room, roomsWithTag
    Q_INVOKABLE QVector<Quotient::Room*> allRooms() const;

    //! \brief Get rooms that have either of the given join state(s)
    //!
    //! This method returns, in no particular order, rooms which join state
    //! matches the mask passed in \p joinStates.
    //! \note Similar to allRooms(), this won't retrieve the full list of
    //!       Leave rooms from the server.
    //! \sa allRooms, room, roomsWithTag
    Q_INVOKABLE QVector<Quotient::Room*>
    rooms(Quotient::JoinStates joinStates) const;

    //! Get the total number of rooms in the given join state(s)
    Q_INVOKABLE int roomsCount(Quotient::JoinStates joinStates) const;

    //! \brief Check whether the account has data of the given type
    //!
    //! Direct chats map is not supported by this method _yet_.
    bool hasAccountData(const QString& type) const;

    //! \brief Get a generic account data event of the given type
    //!
    //! \return an account data event of the given type stored on the server,
    //!         or nullptr if there's none of that type.
    //! \note Direct chats map cannot be retrieved using this method _yet_;
    //!       use directChats() instead.
    const EventPtr& accountData(const QString& type) const;

    //! \brief Get an account data event of the given type
    //!
    //! \return the account data content for the given event type stored
    //!         on the server, or a default-constructed object if there's none
    //!         of that type.
    //! \note Direct chats map cannot be retrieved using this method _yet_;
    //!       use directChats() instead.
    template <EventClass EventT>
    const EventT* accountData() const
    {
        return eventCast<EventT>(accountData(EventT::TypeId));
    }

    //! \brief Get account data as a JSON object
    //!
    //! This returns the content part of the account data event
    //! of the given type. Direct chats map cannot be retrieved using
    //! this method _yet_; use directChats() instead.
    Q_INVOKABLE QJsonObject accountDataJson(const QString& type) const;

    //! Set a generic account data event of the given type
    void setAccountData(EventPtr&& event);

    Q_INVOKABLE void setAccountData(const QString& type,
                                    const QJsonObject& content);

    //! \brief Get all Invited and Joined rooms grouped by tag
    //! \return a hashmap from tag name to a vector of room pointers,
    //!         sorted by their order in the tag - details are at
    //!         https://spec.matrix.org/v1.5/client-server-api/#room-tagging
    QHash<QString, QVector<Room*>> tagsToRooms() const;

    //! Get all room tags known on this connection
    QStringList tagNames() const;

    //! Get the list of rooms with the specified tag
    QVector<Room*> roomsWithTag(const QString& tagName) const;

    //! \brief Mark the room as a direct chat with the user
    //!
    //! This function marks \p room as a direct chat with \p user.
    //! Emits the signal synchronously, without waiting to complete
    //! synchronisation with the server.
    //! \sa directChatsListChanged
    void addToDirectChats(const Room* room, User* user);

    //! \brief Unmark the room from direct chats
    //!
    //! This function removes the room id from direct chats either for
    //! a specific \p user or for all users if \p user in nullptr.
    //! The room id is used to allow removal of, e.g., ids of forgotten
    //! rooms; a Room object need not exist. Emits the signal
    //! immediately, without waiting to complete synchronisation with
    //! the server.
    //! \sa directChatsListChanged
    void removeFromDirectChats(const QString& roomId, User* user = nullptr);

    //! Check whether the room id corresponds to a direct chat
    bool isDirectChat(const QString& roomId) const;

    //! Get the whole map from users to direct chat rooms
    DirectChatsMap directChats() const;

    //! \brief Retrieve the list of users the room is a direct chat with
    //! \return The list of users for which this room is marked as
    //!         a direct chat; an empty list if the room is not a direct chat
    QList<User*> directChatUsers(const Room* room) const;

    //! Check whether a particular user id is in the ignore list
    Q_INVOKABLE bool isIgnored(const QString& userId) const;

    //! Check whether a particular user is in the ignore list
    Q_INVOKABLE bool isIgnored(const Quotient::User* user) const;

    //! Get the whole list of ignored users
    Q_INVOKABLE Quotient::IgnoredUsersList ignoredUsers() const;

    //! \brief Add the user to the ignore list
    //! The change signal is emitted synchronously, without waiting
    //! to complete synchronisation with the server.
    //!
    //! \sa ignoredUsersListChanged
    Q_INVOKABLE void addToIgnoredUsers(const Quotient::User* user);

    //! \brief Remove the user from the ignore list
    //!
    //! Similar to adding, the change signal is emitted synchronously.
    //! \sa ignoredUsersListChanged
    Q_INVOKABLE void removeFromIgnoredUsers(const Quotient::User* user);

    //! Get the full list of users known to this account
    QMap<QString, User*> users() const;

    //! Get the base URL of the homeserver to connect to
    QUrl homeserver() const;
    //! Get the domain name used for ids/aliases on the server
    QString domain() const;
    //! Check if the homeserver is known to be reachable and working
    bool isUsable() const;
    //! Get the list of supported login flows
    QVector<GetLoginFlowsJob::LoginFlow> loginFlows() const;
    //! Check whether the current homeserver supports password auth
    bool supportsPasswordAuth() const;
    //! Check whether the current homeserver supports SSO
    bool supportsSso() const;
    //! Find a room by its id and a mask of applicable states
    Q_INVOKABLE Quotient::Room* room(
        const QString& roomId,
        Quotient::JoinStates states = JoinState::Invite | JoinState::Join) const;
    //! Find a room by its alias and a mask of applicable states
    Q_INVOKABLE Quotient::Room* roomByAlias(
        const QString& roomAlias,
        Quotient::JoinStates states = JoinState::Invite | JoinState::Join) const;
    //! \brief Update the internal map of room aliases to IDs
    //!
    //! This is used to maintain the internal index of room aliases.
    //! It does NOT change aliases on the server,
    //! \sa Room::setLocalAliases
    void updateRoomAliases(const QString& roomId,
                           const QStringList& previousRoomAliases,
                           const QStringList& roomAliases);
    Q_INVOKABLE Quotient::Room* invitation(const QString& roomId) const;
    Q_INVOKABLE Quotient::User* user(const QString& uId);
    const User* user() const;
    User* user();
    QString userId() const;
    QString deviceId() const;
    QByteArray accessToken() const;
    bool isLoggedIn() const;
#ifdef Quotient_E2EE_ENABLED
    QOlmAccount* olmAccount() const;
    Database* database() const;

    UnorderedMap<QByteArray, QOlmInboundGroupSession> loadRoomMegolmSessions(
        const Room* room) const;
    void saveMegolmSession(const Room* room,
                           const QOlmInboundGroupSession& session) const;
    [[deprecated("Use database()->loadCurrentOutboundMegolmSession()")]]
    Omittable<QOlmOutboundGroupSession> loadCurrentOutboundMegolmSession(
        const QString& roomId) const;
    [[deprecated("Use database()->saveCurrentOutboundMegolmSession()")]]
    void saveCurrentOutboundMegolmSession(
        const QString& roomId, const QOlmOutboundGroupSession& session) const;

    QString edKeyForUserDevice(const QString& userId,
                               const QString& deviceId) const;
    bool hasOlmSession(const QString& user, const QString& deviceId) const;

    // This assumes that an olm session already exists. If it doesn't, no message is sent.
    void sendToDevice(const QString& targetUserId, const QString& targetDeviceId,
                      const Event& event, bool encrypted);

    //! Returns true if this megolm session comes from a verified device
    bool isVerifiedSession(const QByteArray& megolmSessionId) const;

    //! Returns whether the device is verified
    bool isVerifiedDevice(const QString& userId, const QString& deviceId) const;

    //! \brief Returns whether the device is known and supports end-to-end encryption.
    //!
    //! This might give unexpected results for users we're not tracking,
    //! i.e., users that we don't share an encrypted room with
    bool isKnownE2eeCapableDevice(const QString& userId, const QString& deviceId) const;


    void sendSessionKeyToDevices(const QString& roomId,
                                 const QOlmOutboundGroupSession& outboundSession,
                                 const QMultiHash<QString, QString>& devices);

    QJsonObject decryptNotification(const QJsonObject &notification);
    QStringList devicesForUser(const QString& userId) const;
    Q_INVOKABLE bool isQueryingKeys() const;
#endif // Quotient_E2EE_ENABLED
    Q_INVOKABLE Quotient::SyncJob* syncJob() const;
    Q_INVOKABLE QString nextBatchToken() const;
    Q_INVOKABLE int millisToReconnect() const;

    Q_INVOKABLE void getTurnServers();

    struct SupportedRoomVersion {
        QString id;
        QString status;

        static const QString StableTag; // "stable", as of CS API 0.5
        bool isStable() const { return status == StableTag; }

        friend QDebug operator<<(QDebug dbg, const SupportedRoomVersion& v)
        {
            QDebugStateSaver _(dbg);
            return dbg.nospace() << v.id << '/' << v.status;
        }
    };

    //! Find out if capabilites are still loading from the server
    Q_INVOKABLE bool loadingCapabilities() const;

    //! \brief Get the room version recommended by the server
    //!
    //! Only works after server capabilities have been loaded.
    //! \sa loadingCapabilities
    QString defaultRoomVersion() const;
    //! \brief Get the room version considered stable by the server
    //!
    //! Only works after server capabilities have been loaded.
    //! \sa loadingCapabilities
    QStringList stableRoomVersions() const;
    //! \brief Get all room versions supported by the server
    //! Only works after server capabilities have been loaded.
    //! \sa loadingCapabilities
    QVector<SupportedRoomVersion> availableRoomVersions() const;

    //! Indicate if the user can change its password from the client.
    //! This is often not the case when SSO is enabled.
    //! \sa loadingCapabilities
    bool canChangePassword() const;

    //! \brief Check whether encryption is enabled on this connection
    //!
    //! There are two conditions for encryption to be enabled:
    //! 1) the library must be compiled with Quotient_E2EE_ENABLED;
    //! 2) encryption should be switched on explicitly with enableEncryption()
    //!
    //! The reason for the latter is E2EE still being in beta state as of 0.8,
    //! so clients are strongly advised to keep E2EE off by default and warn
    //! users opting in that their E2EE things may fall apart, leak etc.
    //!
    //! \sa enableEncryption
    bool encryptionEnabled() const;

    //! \brief Enable or disable encryption on this connection
    //!
    //! \note This has no effect if the library is compiled without E2EE support
    //!
    //! \sa encryptionEnabled
    void enableEncryption(bool enable);

    //! \brief Load room state from a previously saved file
    //!
    //! Call this before first sync.
    //! \sa saveState
    Q_INVOKABLE void loadState();

    //! \brief Save the current state for all rooms to a file
    //!
    //! This method saves the current state of rooms (but not messages
    //! in them) to a local cache file, so that it could be loaded by
    //! loadState() on a next run of the client.
    //! \sa loadState
    Q_INVOKABLE void saveState() const;

    //! This method saves the current state of a single room.
    void saveRoomState(Room* r) const;

    //! \brief Get the default directory path to save the room state to
    //! \sa stateCacheDir
    Q_INVOKABLE QString stateCachePath() const;

    //! \brief Get the default directory to save the room state to
    //!
    //! This function returns the default directory to store the cached
    //! room state, defined as follows:
    //! \code
    //!     QStandardPaths::writeableLocation(QStandardPaths::CacheLocation) +
    //! _safeUserId + "_state.json" \endcode where `_safeUserId` is userId() with
    //! `:` (colon) replaced by
    //! `_` (underscore), as colons are reserved characters on Windows.
    //! \sa loadState, saveState, stateCachePath
    QDir stateCacheDir() const;

    //! \brief Whether or not the rooms state should be cached locally
    //! \sa loadState, saveState
    bool cacheState() const;
    void setCacheState(bool newValue);

    bool lazyLoading() const;
    void setLazyLoading(bool newValue);

    //! Start a pre-created job object on this connection
    Q_INVOKABLE BaseJob* run(BaseJob* job,
                             RunningPolicy runningPolicy = ForegroundRequest);

    //! \brief Start a job of a given type with specified arguments and policy
    //!
    //! This is a universal method to create and start a job of a type passed
    //! as a template parameter. The policy allows to fine-tune the way
    //! the job is executed - as of this writing it means a choice
    //! between "foreground" and "background".
    //!
    //! \param runningPolicy controls how the job is executed
    //! \param jobArgs arguments to the job constructor
    //!
    //! \sa BaseJob::isBackground. QNetworkRequest::BackgroundRequestAttribute
    template <typename JobT, typename... JobArgTs>
    JobT* callApi(RunningPolicy runningPolicy, JobArgTs&&... jobArgs)
    {
        auto job = new JobT(std::forward<JobArgTs>(jobArgs)...);
        run(job, runningPolicy);
        return job;
    }

    //! \brief Start a job of a specified type with specified arguments
    //!
    //! This is an overload that runs the job with "foreground" policy.
    template <typename JobT, typename... JobArgTs>
    JobT* callApi(JobArgTs&&... jobArgs)
    {
        return callApi<JobT>(ForegroundRequest,
                             std::forward<JobArgTs>(jobArgs)...);
    }

    //! \brief Get a request URL for a job with specified type and arguments
    //!
    //! This calls JobT::makeRequestUrl() prepending the connection's homeserver
    //! to the list of arguments.
    template <typename JobT, typename... JobArgTs>
    QUrl getUrlForApi(JobArgTs&&... jobArgs) const
    {
        return JobT::makeRequestUrl(homeserver(),
                                    std::forward<JobArgTs>(jobArgs)...);
    }

    //! \brief Start a local HTTP server and generate a single sign-on URL
    //!
    //! This call does the preparatory steps to carry out single sign-on
    //! sequence
    //! \sa https://matrix.org/docs/guides/sso-for-client-developers
    //! \return A proxy object holding two URLs: one for SSO on the chosen
    //!         homeserver and another for the local callback address. Normally
    //!         you won't need the callback URL unless you proxy the response
    //!         with a custom UI. You do not need to delete the SsoSession
    //!         object; the Connection that issued it will dispose of it once
    //!         the login sequence completes (with any outcome).
    Q_INVOKABLE SsoSession* prepareForSso(const QString& initialDeviceName,
                                          const QString& deviceId = {});

    //! \brief Generate a new transaction id
    //!
    //! Transaction id's are unique within a single Connection object
    Q_INVOKABLE QString generateTxnId() const;

    //! Convert an mxc: URL into a CS API URL
    Q_INVOKABLE QUrl makeMediaUrl(QUrl mxcUrl) const;

    Q_INVOKABLE bool roomSucceeds(const QString& maybePredecessorId,
                                  const QString& maybeSuccessorId) const;

#ifdef Quotient_E2EE_ENABLED
    //! Set the E2EE default state for any Connection created further
    static void setEncryptionDefault(bool useByDefault);
#endif

    //! Set a room factory function
    static void setRoomFactory(room_factory_t f);

    //! Set a user factory function
    static void setUserFactory(user_factory_t f);

    //! Get a room factory function
    static room_factory_t roomFactory();

    //! Get a user factory function
    static user_factory_t userFactory();

    //! Set the room factory to default with the overriden room type
    template <typename T>
    static void setRoomType()
    {
        setRoomFactory(defaultRoomFactory<T>);
    }

    //! Set the user factory to default with the overriden user type
    template <typename T>
    static void setUserType()
    {
        setUserFactory(defaultUserFactory<T>);
    }

public Q_SLOTS:
    //! \brief Set the homeserver base URL and retrieve its login flows
    //!
    //! \sa LoginFlowsJob, loginFlows, loginFlowsChanged, homeserverChanged
    void setHomeserver(const QUrl& baseUrl);

    //! \brief Determine and set the homeserver from MXID
    //!
    //! This attempts to resolve the homeserver by requesting
    //! .well-known/matrix/client record from the server taken from the MXID
    //! serverpart. If there is no record found, the serverpart itself is
    //! attempted as the homeserver base URL; if the record is there but
    //! is malformed (e.g., the homeserver base URL cannot be found in it)
    //! resolveError() is emitted and further processing stops. Otherwise,
    //! setHomeserver is called, preparing the Connection object for the login
    //! attempt.
    //! \param mxid user Matrix ID, such as @someone:example.org
    //! \sa setHomeserver, homeserverChanged, loginFlowsChanged, resolveError
    void resolveServer(const QString& mxid);

    //! \brief Log in using a username and password pair
    //!
    //! Before logging in, this method checks if the homeserver is valid and
    //! supports the password login flow. If the homeserver is invalid but
    //! a full user MXID is provided, this method calls resolveServer() using
    //! this MXID.
    //! \sa resolveServer, resolveError, loginError
    void loginWithPassword(const QString& userId, const QString& password,
                           const QString& initialDeviceName,
                           const QString& deviceId = {});

    //! \brief Log in using a login token
    //!
    //! One usual case for this method is the final stage of logging in via SSO.
    //! Unlike loginWithPassword() and assumeIdentity(), this method cannot
    //! resolve the server from the user name because the full user MXID is
    //! encoded in the login token. Callers should ensure the homeserver
    //! sanity in advance.
    void loginWithToken(const QString& loginToken,
                        const QString& initialDeviceName,
                        const QString& deviceId = {});

    //! \brief Use an existing access token to connect to the homeserver
    //!
    //! This is the old signature that will be deprecated in 0.8; since 0.7.2,
    //! device id is resolved from the access token. Use 2-arg assumeIdentity()
    [[deprecated("Device id is now resolved from accessToken; use "
                 "assumeIdentity(QString, QString) instead of this overload")]] //
    void assumeIdentity(const QString& mxId, const QString& accessToken,
                        [[maybe_unused]] const QString& deviceId);

    //! \brief Use an existing access token to connect to the homeserver
    //!
    //! Similar to loginWithPassword(), this method checks that the homeserver
    //! URL is valid and tries to resolve it from the MXID in case it is not.
    //! \since 0.7.2
    void assumeIdentity(const QString& mxId, const QString& accessToken);

    //! Explicitly request capabilities from the server
    void reloadCapabilities();

    void logout();

    void sync(int timeout = -1);
    void syncLoop(int timeout = 30000);

    void stopSync();

    virtual MediaThumbnailJob*
    getThumbnail(const QString& mediaId, QSize requestedSize,
                 RunningPolicy policy = BackgroundRequest);
    MediaThumbnailJob* getThumbnail(const QUrl& url, QSize requestedSize,
                                    RunningPolicy policy = BackgroundRequest);
    MediaThumbnailJob* getThumbnail(const QUrl& url, int requestedWidth,
                                    int requestedHeight,
                                    RunningPolicy policy = BackgroundRequest);

    // QIODevice* should already be open
    UploadContentJob* uploadContent(QIODevice* contentSource,
                                    const QString& filename = {},
                                    const QString& overrideContentType = {});
    UploadContentJob* uploadFile(const QString& fileName,
                                 const QString& overrideContentType = {});
    GetContentJob* getContent(const QString& mediaId);
    GetContentJob* getContent(const QUrl& url);
    // If localFilename is empty, a temporary file will be created
    DownloadFileJob* downloadFile(const QUrl& url,
                                  const QString& localFilename = {});

#ifdef Quotient_E2EE_ENABLED
    DownloadFileJob* downloadFile(const QUrl& url,
                                  const EncryptedFileMetadata& fileMetadata,
                                  const QString& localFilename = {});
#endif

    //! \brief Create a room (generic method)
    //!
    //! This method allows to customize room entirely to your liking,
    //! providing all the attributes the original CS API provides.
    CreateRoomJob*
    createRoom(RoomVisibility visibility, const QString& alias,
               const QString& name, const QString& topic, QStringList invites,
               const QString& presetName = {}, const QString& roomVersion = {},
               bool isDirect = false,
               const QVector<CreateRoomJob::StateEvent>& initialState = {},
               const QVector<CreateRoomJob::Invite3pid>& invite3pids = {},
               const QJsonObject& creationContent = {});

    //! \brief Get a direct chat with a single user
    //!
    //! This method may return synchronously or asynchoronously depending
    //! on whether a direct chat room with the respective person exists
    //! already.
    //! \sa directChatAvailable
    void requestDirectChat(const QString& userId);

    //! \brief Get a direct chat with a single user
    //!
    //! This method may return synchronously or asynchoronously depending
    //! on whether a direct chat room with the respective person exists
    //! already.
    //! \sa directChatAvailable
    void requestDirectChat(User* u);

    //! \brief Run an operation in a direct chat with the user
    //!
    //! This method may return synchronously or asynchoronously depending
    //! on whether a direct chat room with the respective person exists
    //! already. Instead of emitting a signal it executes the passed
    //! function object with the direct chat room as its parameter.
    void doInDirectChat(const QString& userId,
                        const std::function<void(Room*)>& operation);

    //! \brief Run an operation in a direct chat with the user
    //!
    //! This method may return synchronously or asynchoronously depending
    //! on whether a direct chat room with the respective person exists
    //! already. Instead of emitting a signal it executes the passed
    //! function object with the direct chat room as its parameter.
    void doInDirectChat(User* u, const std::function<void(Room*)>& operation);

    //! Create a direct chat with a single user, optional name and topic
    //!
    //! A room will always be created, unlike in requestDirectChat.
    //! It is advised to use requestDirectChat as a default way of getting
    //! one-on-one with a person, and only use createDirectChat when
    //! a new creation is explicitly desired.
    CreateRoomJob* createDirectChat(const QString& userId,
                                    const QString& topic = {},
                                    const QString& name = {});

    virtual JoinRoomJob* joinRoom(const QString& roomAlias,
                                  const QStringList& serverNames = {});

    //! \brief Send /forget to the server and delete room locally
    //!
    //! This method is in Connection, not in Room, since it's a
    //! room lifecycle operation, and Connection is an acting room manager.
    //! It ensures that the local user is not a member of a room (running /leave,
    //! if necessary) then issues a /forget request and if that one doesn't fail
    //! deletion of the local Room object is ensured.
    //! \param id the room id to forget
    //! \return the ongoing /forget request to the server; note that the
    //!         success() signal of this request is connected to deleteLater()
    //!         of a respective room so by the moment this finishes, there
    //!         might be no Room object anymore.
    ForgetRoomJob* forgetRoom(const QString& id);

    SendToDeviceJob* sendToDevices(const QString& eventType,
                                   const UsersToDevicesToContent& contents);

    [[deprecated("This method is experimental and may be removed any time")]] //
    SendMessageJob* sendMessage(const QString& roomId, const RoomEvent& event);

    //! \deprecated Do not use this directly, use Room::leaveRoom() instead
    virtual LeaveRoomJob* leaveRoom(Room* room);

#ifdef Quotient_E2EE_ENABLED
    KeyVerificationSession* startKeyVerificationSession(const QString& userId,
                                                        const QString& deviceId);

    void encryptionUpdate(const Room* room, const QList<User*>& invited = {});
#endif

    static Connection* makeMockConnection(const QString& mxId,
                                          bool enableEncryption = E2EE_Enabled);

Q_SIGNALS:
    //! \brief Initial server resolution has failed
    //!
    //! This signal is emitted when resolveServer() did not manage to resolve
    //! the homeserver using its .well-known/client record or otherwise.
    //! \sa resolveServer
    void resolveError(QString error);

    void homeserverChanged(QUrl baseUrl);
    void loginFlowsChanged();
    void capabilitiesLoaded();

    void connected();
    void loggedOut();

    //! \brief Login data or state have changed
    //!
    //! This is a common change signal for userId, deviceId and
    //! accessToken - these properties normally only change at
    //! a successful login and logout and are constant at other times.
    void stateChanged();
    void loginError(QString message, QString details);

    //! \brief A network request (job) started by callApi() has failed
    //! \param request the pointer to the failed job
    //! \sa callApi
    void requestFailed(Quotient::BaseJob* request);

    //! \brief A network request (job) failed due to network problems
    //!
    //! This is _only_ emitted when the job will retry on its own;
    //! once it gives up, requestFailed() will be emitted.
    //!
    //! \param message message about the network problem
    //! \param details raw error details, if any available
    //! \param retriesTaken how many retries have already been taken
    //! \param nextRetryInMilliseconds when the job will retry again
    //!                                (-1 if no next retry is scheduled)
    void networkError(QString message, QString details, int retriesTaken,
                      int nextRetryInMilliseconds);

    void syncDone();
    void syncError(QString message, QString details);

    void newUser(Quotient::User* user);

    //! \group Signals emitted on room transitions
    //!
    //! Note: Rooms in Invite state are always stored separately from
    //! rooms in Join/Leave state, because of special treatment of
    //! invite_state in Matrix CS API (see The Spec on /sync for details).
    //! Therefore, objects below are: r - room in Join/Leave state;
    //! i - room in Invite state
    //!
    //! 1. none -> Invite: newRoom(r), invitedRoom(r,nullptr)
    //! 2. none -> Join: newRoom(r), joinedRoom(r,nullptr)
    //! 3. none -> Leave: newRoom(r), leftRoom(r,nullptr)
    //! 4. Invite -> Join:
    //!      newRoom(r), joinedRoom(r,i), aboutToDeleteRoom(i)
    //! 4a. Leave and Invite -> Join:
    //!      joinedRoom(r,i), aboutToDeleteRoom(i)
    //! 5. Invite -> Leave:
    //!      newRoom(r), leftRoom(r,i), aboutToDeleteRoom(i)
    //! 5a. Leave and Invite -> Leave:
    //!      leftRoom(r,i), aboutToDeleteRoom(i)
    //! 6. Join -> Leave: leftRoom(r)
    //! 7. Leave -> Invite: newRoom(i), invitedRoom(i,r)
    //! 8. Leave -> Join: joinedRoom(r)
    //! The following transitions are only possible via forgetRoom()
    //! so far; if a room gets forgotten externally, sync won't tell
    //! about it:
    //! 9. any -> none: as any -> Leave, then aboutToDeleteRoom(r)

    //! A new room object has been created
    void newRoom(Quotient::Room* room);

    //! \brief A room invitation is seen for the first time
    //!
    //! If the same room is in Left state, it's passed in prev. Beware
    //! that initial sync will trigger this signal for all rooms in
    //! Invite state.
    void invitedRoom(Quotient::Room* room, Quotient::Room* prev);

    //! \brief A joined room is seen for the first time
    //!
    //! It's not the same as receiving a room in "join" section of sync
    //! response (rooms will be there even after joining); it's also
    //! not (exactly) the same as actual joining action of a user (all
    //! rooms coming in initial sync will trigger this signal too). If
    //! this room was in Invite state before, the respective object is
    //! passed in prev (and it will be deleted shortly afterwards).
    void joinedRoom(Quotient::Room* room, Quotient::Room* prev);

    //! \brief A room has just been left
    //!
    //! If this room has been in Invite state (as in case of rejecting
    //! an invitation), the respective object will be passed in prev
    //! (and will be deleted shortly afterwards). Note that, similar
    //! to invitedRoom and joinedRoom, this signal is triggered for all
    //! Left rooms upon initial sync (not only those that were left
    //! right before the sync).
    void leftRoom(Quotient::Room* room, Quotient::Room* prev);

    //! The room object is about to be deleted
    void aboutToDeleteRoom(Quotient::Room* room);

    //! \brief The room has just been created by createRoom or requestDirectChat
    //!
    //! This signal is not emitted in usual room state transitions,
    //! only as an outcome of room creation operations invoked by
    //! the client.
    //! \note requestDirectChat doesn't necessarily create a new chat;
    //!       directChatAvailable() is more appropriate if you need to obtain
    //!       a direct chat room after requestDirectChat().
    void createdRoom(Quotient::Room* room);

    //! \brief The first sync for the room has been completed
    //!
    //! This signal is emitted after the room has been synced the first
    //! time. This is the right signal to connect to if you need to
    //! access the room state (name, aliases, members); state transition
    //! signals (newRoom, joinedRoom etc.) come earlier, when the room
    //! has just been created.
    void loadedRoomState(Quotient::Room* room);

    //! Account data (except direct chats) have changed
    void accountDataChanged(QString type);

    //! \brief The direct chat room is ready for using
    //!
    //! This signal is emitted upon any successful outcome from
    //! requestDirectChat.
    void directChatAvailable(Quotient::Room* directChat);

    //! \brief The list of direct chats has changed
    //!
    //! This signal is emitted every time when the mapping of users
    //! to direct chat rooms is changed (because of either local updates
    //! or a different list arrived from the server).
    void directChatsListChanged(Quotient::DirectChatsMap additions,
                                Quotient::DirectChatsMap removals);

    void ignoredUsersListChanged(Quotient::IgnoredUsersList additions,
                                 Quotient::IgnoredUsersList removals);

    void cacheStateChanged();
    void lazyLoadingChanged();
    void turnServersChanged(const QJsonObject& servers);
    void devicesListLoaded();

    //! Encryption has been enabled or disabled
    void encryptionChanged(bool enabled);

#ifdef Quotient_E2EE_ENABLED
    void newKeyVerificationSession(Quotient::KeyVerificationSession* session);
    void keyVerificationStateChanged(
        const Quotient::KeyVerificationSession* session,
        Quotient::KeyVerificationSession::State state);
    void sessionVerified(const QString& userId, const QString& deviceId);
    bool finishedQueryingKeys();
#endif

protected:
    //! Access the underlying ConnectionData class
    const ConnectionData* connectionData() const;

    //! \brief Get a Room object for the given id in the given state
    //!
    //! Use this method when you need a Room object in the local list
    //! of rooms, with the given state. Note that this does not interact
    //! with the server; in particular, does not automatically create
    //! rooms on the server. This call performs necessary join state
    //! transitions; e.g., if it finds a room in Invite but
    //! `joinState == JoinState::Join` then the Invite room object
    //! will be deleted and a new room object with Join state created.
    //! In contrast, switching between Join and Leave happens within
    //! the same object.
    //! \param roomId room id (not alias!)
    //! \param joinState desired (target) join state of the room; if
    //! omitted, any state will be found and return unchanged, or a
    //! new Join room created.
    //! \return a pointer to a Room object with the specified id and the
    //! specified state; nullptr if roomId is empty or if roomFactory()
    //! failed to create a Room object.
    Room* provideRoom(const QString& roomId,
                      Omittable<JoinState> joinState = none);

    //! Process sync data from a successful sync request
    void onSyncSuccess(SyncData&& data, bool fromCache = false);

protected Q_SLOTS:
    void syncLoopIteration();

private:
    class Private;
    ImplPtr<Private> d;

    static room_factory_t _roomFactory;
    static user_factory_t _userFactory;
};
} // namespace Quotient
Q_DECLARE_METATYPE(Quotient::DirectChatsMap)
Q_DECLARE_METATYPE(Quotient::IgnoredUsersList)
