/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 *                                                                         *
 *  Copyright (C) 2018 Michael Zanetti <michael.zanetti@guh.io>            *
 *                                                                         *
 *  This file is part of nymea.                                            *
 *                                                                         *
 *  nymea is free software: you can redistribute it and/or modify          *
 *  it under the terms of the GNU General Public License as published by   *
 *  the Free Software Foundation, version 2 of the License.                *
 *                                                                         *
 *  nymea is distributed in the hope that it will be useful,               *
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of         *
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the          *
 *  GNU General Public License for more details.                           *
 *                                                                         *
 *  You should have received a copy of the GNU General Public License      *
 *  along with nymea. If not, see <http://www.gnu.org/licenses/>.          *
 *                                                                         *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

#ifndef MQTTSERVER_H
#define MQTTSERVER_H

#include <QObject>
#include <QTcpServer>
#include <QTcpSocket>
#include <QTimer>
#include <QLoggingCategory>

#include "mqttpacket.h"

class MqttServerPrivate;
class Subscription;

class MqttUserValidator {
public:
    virtual ~MqttUserValidator() = default;
    virtual Mqtt::ConnectReturnCode validateConnect(const QString &clientId, const QString &username, const QString &password, const QHostAddress &peerAddress) = 0;
    virtual bool validateSubscribe(const QString &topicFilter, const QString &clientId, const QString &username) = 0;
};

class MqttServer : public QObject
{
    Q_OBJECT
public:
    explicit MqttServer(QObject *parent = nullptr);

    Mqtt::QoS maximumSubscriptionsQoS() const;
    void setMaximumSubscriptionsQoS(Mqtt::QoS maximumSubscriptionQoS);

    bool listen(const QHostAddress &address = QHostAddress::Any, quint16 port = 1883, MqttUserValidator *userValidator = nullptr);

    QStringList clients() const;

    // allows publishing from the server, including topcis starting with $
    QHash<QString, quint16> publish(const QString &topic, const QByteArray &payload = QByteArray());

signals:
    // emitted whenever a client connects, after the mqtt connect handshake has been done.
    void clientConnected(const QString &clientId, const QString &username, const QHostAddress &clientAddress);
    // emitted whenever a client disconnects, that is, when a DISCONNECT message has been received or the keep alive timeout has been reached.
    void clientDisconnected(const QString &clientId);
    // emitted whenever a client has been seen, that is, a control message or a keep alive message has been received.
    void clientAlive(const QString &clientId);
    // emitted whenever a client subscribes, a client can also subscribe to topics starting with $ but those won't be relayed from other clients. Only internal server publishes to $ topcis will be sent to subscribed clients.
    void clientSubscribed(const QString &clientId, const QString &topicFilter, Mqtt::QoS requestedQoS);
    // emitted whenever a client unsubscribes from a topic
    void clientUnsubscribed(const QString &clientId, const QString &topicFiltr);
    // emitted whenever a publish message is received from a client before the message is relayed to other clients. Topics starting with $ will be received here, but not relayed to other clients.
    void publishReceived(const QString &clientId, quint16 packetId, const QString &topic, const QByteArray &payload, bool dup);
    // emitted whenever a publish message is sent to a client. Note: this might be fired often if many clients are connected and subsribed to matching topic filters.
    void published(const QString &clientId, quint16 packetId, const QString &topic, const QByteArray &payload);

private:
    MqttServerPrivate *d_ptr;
};

#endif // MQTTSERVER_H