// Copyright (C) 2017 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only
// Qt-Security score:significant reason:default

#ifndef QMQTTCONNECTION_P_H
#define QMQTTCONNECTION_P_H

//
//  W A R N I N G
//  -------------
//
// This file is not part of the Qt API.  It exists purely as an
// implementation detail.  This header file may change from version to
// version without notice, or even be removed.
//
// We mean it.
//

#include "qmqttclient.h"
#include "qmqttcontrolpacket_p.h"
#include "qmqttmessage.h"
#include "qmqttsubscription.h"
#include <QtCore/QBasicTimer>
#include <QtCore/QBuffer>
#include <QtCore/QHash>
#include <QtCore/QObject>
#include <QtCore/QSharedPointer>
#include <QtCore/QtEndian>

#include <memory>

QT_BEGIN_NAMESPACE

class QMqttClientPrivate;

class Q_AUTOTEST_EXPORT QMqttConnection : public QObject
{
    Q_OBJECT
public:
    enum InternalConnectionState {
        BrokerDisconnected = 0,
        BrokerConnecting,
        BrokerWaitForConnectAck,
        BrokerConnected,
        ClientDestruction
    };

    explicit QMqttConnection(QObject *parent = nullptr);
    ~QMqttConnection() override;

    void disconnectAndResetTransport();
    void setTransport(QIODevice *device, QMqttClient::TransportType transport);
    void connectTransport(QMqttClient::TransportType transport, const std::shared_ptr<QIODevice> &device);
    QIODevice *transport() const;

    bool ensureTransport(bool createSecureIfNeeded = false);
    bool ensureTransportOpen(const QString &sslPeerName = QString());

    bool sendControlConnect();
    bool sendControlAuthenticate(const QMqttAuthenticationProperties &properties);
    qint32 sendControlPublish(const QMqttTopicName &topic, const QByteArray &message, quint8 qos = 0, bool retain = false,
                              const QMqttPublishProperties &properties = QMqttPublishProperties());
    bool sendControlPublishAcknowledge(quint16 id);
    bool sendControlPublishRelease(quint16 id);
    bool sendControlPublishReceive(quint16 id);
    bool sendControlPublishComp(quint16 id);
    QMqttSubscription *sendControlSubscribe(const QMqttTopicFilter &topic, quint8 qos, const QMqttSubscriptionProperties &properties);
    bool sendControlUnsubscribe(const QMqttTopicFilter &topic, const QMqttUnsubscriptionProperties &properties);
    bool sendControlPingRequest(bool isAuto = true);
    bool sendControlDisconnect();

    void setClientPrivate(QMqttClientPrivate *clientPrivate);

    inline quint16 unusedPacketIdentifier() const;
    inline InternalConnectionState internalState() const { return m_internalState; }
    inline void setClientDestruction() { m_internalState = ClientDestruction; }

    void cleanSubscriptions();

private:
    void transportConnectionEstablished();
    void transportConnectionClosed();
    void transportReadyRead();
    void transportError(QAbstractSocket::SocketError e);

protected:
    void timerEvent(QTimerEvent *event) override;

public:
    std::shared_ptr<QIODevice> m_transport;
    QMqttClient::TransportType m_transportType{QMqttClient::IODevice};
    bool m_transportIsSet{false}; // connectTo* does not reset m_transport;
    bool m_connectedTransport{false}; // We have connected the signals for m_transport if true
    QMqttClientPrivate *m_clientPrivate{nullptr};
#ifndef QT_NO_SSL
    QSslConfiguration m_sslConfiguration;
#endif
private:
    Q_DISABLE_COPY(QMqttConnection)
    void finalize_auth();
    void finalize_connack();
    void finalize_suback();
    void finalize_unsuback();
    void finalize_publish();
    void finalize_pubAckRecRelComp();
    void finalize_pingresp();
    void processData();
    bool processDataHelper();
    bool readBuffer(char *data, quint64 size);
    qint32 readVariableByteInteger(qint64 *dataSize = nullptr);
    void readAuthProperties(QMqttAuthenticationProperties &properties);
    void readConnackProperties(QMqttServerConnectionProperties &properties);
    void readMessageStatusProperties(QMqttMessageStatusProperties &properties);
    void readPublishProperties(QMqttPublishProperties &properties);
    void readSubscriptionProperties(QMqttSubscription *sub);
    QByteArray writeConnectProperties();
    QByteArray writeLastWillProperties() const;
    QByteArray writePublishProperties(const QMqttPublishProperties &properties);
    QByteArray writeSubscriptionProperties(const QMqttSubscriptionProperties &properties);
    QByteArray writeUnsubscriptionProperties(const QMqttUnsubscriptionProperties &properties);
    QByteArray writeAuthenticationProperties(const QMqttAuthenticationProperties &properties);
    void closeConnection(QMqttClient::ClientError error);
    QByteArray readBuffer(quint64 size);
    template<typename T> T readBufferTyped(qint64 *dataSize = nullptr);
    bool isPendingUnsubscribe(QMqttSubscription *) const;
    QMqttSubscription *findActiveSubscription(const QMqttTopicFilter &topic) const;

    QByteArray m_readBuffer;
    int m_readPosition{0};
    qint64 m_missingData{0};
    struct PublishData {
        quint8 qos;
        bool dup;
        bool retain;
    };
    PublishData m_currentPublish{0, false, false};
    QMqttControlPacket::PacketType m_currentPacket{QMqttControlPacket::UNKNOWN};

    bool writePacketToTransport(const QMqttControlPacket &p);

    // I: There can be many occurences of different QMqttSubscription * with
    //    the same QMqttTopicFilter, but only one that is not in
    //    m_pendingUnsubscriptions.
    QHash<quint16, QMqttSubscription *> m_pendingSubscriptionAck;
    QHash<quint16, QMqttSubscription *> m_pendingUnsubscriptions;
    QMultiHash<QMqttTopicFilter, QMqttSubscription *> m_activeSubscriptions;
    QHash<quint16, QSharedPointer<QMqttControlPacket>> m_pendingMessages;
    QHash<quint16, QSharedPointer<QMqttControlPacket>> m_pendingReleaseMessages;
    InternalConnectionState m_internalState{BrokerDisconnected};
    QBasicTimer m_pingTimer;
    int m_pingTimeout{0};

    QList<QMqttTopicName> m_receiveAliases;
    QList<QMqttTopicName> m_publishAliases;
};

QT_END_NAMESPACE

#endif // QMQTTCONNECTION_P_H
