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#include "mqttdataproviderpool.h"
#include "mqttdataprovider.h"

#include <QtCore/QDebug>
#include <QtCore/QFile>
#include <QtCore/QJsonDocument>

MqttDataProviderPool::MqttDataProviderPool(QObject *parent)
    : DataProviderPool(parent)
    , m_client(new QMqttClient(this))
{
    m_poolName = "Mqtt";
}

void MqttDataProviderPool::startScanning()
{
    emit providerConnected("MQTT_CLOUD");
    emit providersUpdated();
    emit dataProvidersChanged();

    m_client->setHostname(MqttCredentials::getBroker());
    m_client->setPort(static_cast<quint16>(MqttCredentials::getPort()));
    m_client->setUsername(MqttCredentials::getUsername());
    m_client->setPassword(MqttCredentials::getPassword());

    connect(m_client, &QMqttClient::connected, [this]() {
        auto sub = m_client->subscribe(QLatin1String("sensors/active"));
        connect(sub, &QMqttSubscription::messageReceived, this, &MqttDataProviderPool::deviceUpdate);
    });
    connect(m_client, &QMqttClient::disconnected, []() {
        qDebug() << "Pool client disconnected";
    });
    m_client->connectToHost();
}

void MqttDataProviderPool::deviceUpdate(const QMqttMessage &msg)
{
    static QSet<QString> knownDevices;
    // Registration is: deviceName>Online
    const QByteArrayList payload = msg.payload().split('>');
    const QString deviceName = payload.first();
    const QString deviceStatus = payload.at(1);
    const QString subName = QString::fromLocal8Bit("sensors/%1/#").arg(deviceName);

    bool updateRequired = false;
    if (deviceStatus == QLatin1String("Online")) { // new device
        // Skip local items
        if (deviceName.startsWith(QSysInfo::machineHostName()))
            return;

        if (!knownDevices.contains(deviceName)) {
            auto prov = new MqttDataProvider(deviceName, m_client, this);
            prov->setState(SensorTagDataProvider::Connected);
            m_dataProviders.push_back(prov);
            if (m_currentProvider == nullptr)
                setCurrentProviderIndex(m_dataProviders.size() - 1);
            knownDevices.insert(deviceName);
            updateRequired = true;
        }
    } else if (deviceStatus == QLatin1String("Offline")) { // device died
        knownDevices.remove(deviceName);
        updateRequired = true;
        for (auto prov : m_dataProviders) {
            if (prov->id() == deviceName) {
                m_dataProviders.removeAll(prov);
                break;
            }
        }
    }

    if (updateRequired) {
        emit providersUpdated();
        emit dataProvidersChanged();
    }
}

namespace {
    static QString gBroker;
    static int gPort{0};
    static QString gUser;
    static QString gPassword;
    bool resolveCredentials() {
        static bool resolved = false;
        if (resolved)
            return true;

        QFile f(QLatin1String("broker.json"));
        if (!f.open(QIODevice::ReadOnly)) {
            qDebug() << "Could not find or open broker.json";
            return false;
        }
        const QByteArray data = f.readAll();
        if (data.isEmpty()) {
            qDebug() << "broker.json file empty";
            return false;
        }
        QJsonDocument doc = QJsonDocument::fromJson(data);
        if (doc.isNull()) {
            qDebug() << "broker.json does not contain valid data";
            return false;
        }
        gBroker = doc["broker"].toString();
        gPort = doc["port"].toInt();
        gUser = doc["user"].toString();
        gPassword = doc["password"].toString();
        qDebug() << "broker.json parsed. Using broker:" << gBroker << ":" << gPort;
        resolved = true;
        return true;
    }
}

QString MqttCredentials::getBroker()
{
    resolveCredentials();
    return gBroker;
}

int MqttCredentials::getPort()
{
    resolveCredentials();
    return gPort;
}

QString MqttCredentials::getUsername()
{
    resolveCredentials();
    return gUser;
}

QString MqttCredentials::getPassword()
{
    resolveCredentials();
    return gPassword;
}