/******************************************************************************
**
** Copyright (C) 2017 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of the QtMqtt module.
**
** $QT_BEGIN_LICENSE:GPL$
** Commercial License Usage
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** accordance with the commercial license agreement provided with the
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**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3 or (at your option) any later version
** approved by the KDE Free Qt Foundation. The licenses are as published by
** the Free Software Foundation and appearing in the file LICENSE.GPL3
** included in the packaging of this file. Please review the following
** information to ensure the GNU General Public License requirements will
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******************************************************************************/

#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/QBuffer>
#include <QtCore/QHash>
#include <QtCore/QObject>
#include <QtCore/QSharedPointer>
#include <QtCore/QTimer>
#include <QtCore/QtEndian>

QT_BEGIN_NAMESPACE

class QMqttClientPrivate;

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

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

    void setTransport(QIODevice *device, QMqttClient::TransportType transport);
    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 sendControlDisconnect();

    void setClientPrivate(QMqttClientPrivate *clientPrivate);

    inline quint16 unusedPacketIdentifier() const;
    inline InternalConnectionState internalState() const { return m_internalState; }

    void cleanSubscriptions();

public Q_SLOTS:
    void transportConnectionEstablished();
    void transportConnectionClosed();
    void transportReadReady();
    void transportError(QAbstractSocket::SocketError e);

public:
    QIODevice *m_transport{nullptr};
    QMqttClient::TransportType m_transportType{QMqttClient::IODevice};
    bool m_ownTransport{false};
    QMqttClientPrivate *m_clientPrivate{nullptr};
private:
    Q_DISABLE_COPY(QMqttConnection)
    void finalize_auth();
    void finalize_connack();
    void finalize_suback();
    void finalize_unsuback();
    void finalize_publish();
    void finalize_pubAckRecComp();
    void finalize_pubrel();
    void finalize_pingresp();
    void processData();
    bool processDataHelper();
    void readBuffer(char *data, quint64 size);
    qint32 readVariableByteInteger(qint32 *byteCount = 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);
    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);
    QHash<quint16, QMqttSubscription *> m_pendingSubscriptionAck;
    QHash<quint16, QMqttSubscription *> m_pendingUnsubscriptions;
    QHash<QMqttTopicFilter, QMqttSubscription *> m_activeSubscriptions;
    QHash<quint16, QSharedPointer<QMqttControlPacket>> m_pendingMessages;
    QHash<quint16, QSharedPointer<QMqttControlPacket>> m_pendingReleaseMessages;
    InternalConnectionState m_internalState{BrokerDisconnected};
    QTimer m_pingTimer;

    QVector<QMqttTopicName> m_receiveAliases;
    QVector<QMqttTopicName> m_publishAliases;
};

QT_END_NAMESPACE

#endif // QMQTTCONNECTION_P_H