app/sources/baseconn.cpp

#include "headers/baseconn.h"

BaseConn * pGlobalBaseConn = nullptr;

BaseConn::BaseConn(QObject *parent) : QObject(parent)
{
    pGlobalBaseConn = this;
    socket = new QTcpSocket();
    this->setState("disconnected");

    connect(this->socket, SIGNAL(error(QAbstractSocket::SocketError)),
            this, SLOT(gotError(QAbstractSocket::SocketError)));

    connect(this->socket, &QAbstractSocket::stateChanged, this, &BaseConn::socketStateChanged);

    this->nextConnectionId = 1;
    this->connections = QVariantList({});
}

bool BaseConn::connectToHost() {
    qDebug() << "connecting";
    setState("connecting");
    this->connection_progress = 0;

    QEventLoop loop;

    // quit loop when state changed (successfull connection is handled elswhere
    loop.connect(this, SIGNAL(stateChanged()), &loop, SLOT(quit()));

    //connect
    this->socket->connectToHost(this->ip, this->port);

    while(this->state != "connected" && this->state != "disconnected"){
        loop.exec();
    }

    if(this->state == "connected") {
        return true;
    }
    return false;
}

bool BaseConn::init() {
    connect(this->socket, &QTcpSocket::readyRead, this, &BaseConn::readyRead);
    this->connection_progress = 50;

    return true;
}

void BaseConn::deInit() {
    this->connections.clear();
}

void BaseConn::closeConnection()
{
    this->connections = QVariantList({});
    emit this->connectionsChanged();

    qDebug() << "closing connection";
    switch (socket->state())
    {
    case 0:
        socket->disconnectFromHost();
        break;
    case 2:
        socket->abort();
        break;
    default:
        socket->abort();
    }

    this->deInit();
    setState("disconnected");
    //    for(int i = 0; i < this->waitingRequests.length(); i++){
    //            this->waitingRequests[i].reply = "ERR_NOT_CONNECTED";
    //            this->waitingRequests[i].loop->quit();
    //            return;
    //    }
}

void BaseConn::gotError(QAbstractSocket::SocketError err)
{
    //qDebug() << "got error";
    QString strError = "unknown";
    switch (err)
    {
    case 0:
        strError = "Connection was refused";
        break;
    case 1:
        strError = "Remote host closed the connection";
        this->closeConnection();
        break;
    case 2:
        strError = "Host address was not found";
        break;
    case 5:
        strError = "Connection timed out";
        break;
    default:
        strError = "Unknown error";
    }

    emit gotError(strError);
    qDebug() << "got socket error: " << strError;
}

// -------------------------------------
// --- socket communication handling ---
// -------------------------------------

void BaseConn::socketStateChanged(QAbstractSocket::SocketState socketState) {
    switch (socketState) {
    case QAbstractSocket::UnconnectedState:
    {
        this->deInit();
        this->setState("disconnected");
        break;
    }
    case QAbstractSocket::ConnectedState:
    {
        if(this->init()) {
            this->setState("connected");
        }
        else {
            this->closeConnection();
        }

        break;
    }
    default:
    {
        //qDebug() << "+ --- UNKNOWN SOCKET STATE: " << socketState;
        break;
    }
    }
}

QVariantMap BaseConn::sendCommand(int header, QJsonValue data){
    if(this->state != "connected"){
        return {{"status", 910}, {"data", "not connected"}};
    }

    // generate id and witing requests entry
    int thisId = nextConnectionId;
    //qDebug() << "sending command: " << header << " with data: " << data << " and id: " << thisId;
    nextConnectionId ++;

    QEventLoop loop;
    QJsonObject reply;

    this->waitingRequests.append({thisId, &loop, reply});

    QJsonObject requestObj;
    requestObj.insert("id", thisId);
    requestObj.insert("header", header);
    requestObj.insert("data", data);


    QString jsonRequest = QJsonDocument(requestObj).toJson();

    QTimer timer;

    timer.setSingleShot(true);
    // quit the loop when the timer times out
    loop.connect(&timer, SIGNAL(timeout()), &loop, SLOT(quit()));
    // quit the loop when the connection was established
    // loop.connect(this, &BaseConn::gotReply, &loop, &QEventLoop::quit);
    // start the timer before starting to connect
    timer.start(3000);

    //write data

    socket->write(jsonRequest.toLatin1());

    //wait for an answer to finish (programm gets stuck in here)
    loop.exec();

    //loop finished
    if(timer.remainingTime() == -1){
        //the time has been triggered -> timeout

        return {{"status", 911}, {"data", ""}};
    }

    for(int i = 0; i<this->waitingRequests.length(); i++){
        if(this->waitingRequests[i].id == thisId){
            reply = this->waitingRequests[i].reply;
        }
    }

    // stop the timer as the connection has been established
    timer.stop();

    return {{"status", reply.value("header").toInt()}, {"data", reply.value("data").toVariant()}};

}

void BaseConn::readyRead() {

    //qDebug() << "ready to ready " << socket->bytesAvailable() << " bytes" ;
    QString reply = socket->readAll();

    //qWarning() << "socket read: " << reply;

    processSocketMessage(reply);
}

void BaseConn::processSocketMessage(QString message){
    QString startKey = "<message>";
    QString endKey = "</message>";

    //qWarning() << "... processing message now ... : " << message;

    if(message == ""){
        return;
    }

    if((message.startsWith(startKey) && message.endsWith(endKey)) && (message.count(startKey) == 1 && message.count(endKey) == 1)){
        // non-split message ( e.g.: <message>123456789</message>
    }
    else if(!message.contains(endKey) && (!this->readBuffer.isEmpty() || message.startsWith(startKey))){
        // begin of a split message ( e.g.: <message>123 )
        // or middle of a split message ( e.g.: 456 )
        //qWarning() << "this is a begin or middle of split a message";
        this->readBuffer += message;
        return;
    }
    else if(!message.contains(startKey) && message.endsWith(endKey)) {
        // end of a split message ( e.g.: 789</message> )

        if(!this->readBuffer.isEmpty()){
            message = readBuffer + message;
            readBuffer.clear();
        }
    }
    else if((message.count(startKey) > 1 || message.count(endKey) > 1) || (message.contains(endKey) && !message.endsWith(endKey) && message.contains(startKey) && !message.startsWith(startKey))) {
        // multiple messages in one packet ( e.g.: <message>123456789</message><message>987654321</message> )
        // or multiple message fragments in one message ( e.g.: 56789</message><message>987654321</message> or 56789</message><message>98765 )
        //qDebug() << "detected multiple messages";

        int startOfSecondMessage = message.lastIndexOf(startKey);
        // process first part of message
        QString firstMessage = message.left(startOfSecondMessage);
        this->processSocketMessage(firstMessage);
        // process second part of message
        QString secondMessage = message.right(message.length() - startOfSecondMessage);
        this->processSocketMessage(secondMessage);

        return;
    }
    else {
        // invalid message
        return;
    }

    //qWarning() << "... done processing, message: " << message;
    this->socketReplyRecieved(message);
}

void BaseConn::socketReplyRecieved(QString reply) {
    reply.replace("<message>", "");
    reply.replace("</message>", "");

    int id = 0;

    QJsonDocument jsonReply = QJsonDocument::fromJson(reply.toUtf8());
    QJsonObject replyObj = jsonReply.object();

    //qDebug() << "got: " << reply;

    if(!replyObj.isEmpty()){
        id = replyObj.value("id").toInt();

        for(int i = 0; i < this->waitingRequests.length(); i++){
            if(this->waitingRequests[i].id == id){
                this->waitingRequests[i].reply = replyObj;
                if(this->waitingRequests[i].loop != nullptr){
                    this->waitingRequests[i].loop->quit();
                }
                return;
            }
        }
    }

    latestReadReply = reply;
    emit gotUnexpectedReply(reply);
}

// ------------------------
// --- helper functions ---
// ------------------------

int BaseConn::writeRemoteSetting(QString key, QString value) {
    QJsonArray requestData;
    requestData.append(key);
    requestData.append(value);
    return this->sendCommand(3000, requestData)["status"].toInt();
}

void BaseConn::setIP(const QString &ipAdress){
    this->ip = ipAdress;
}

QString BaseConn::getIP() const
{
    return(this->ip);
}

QString BaseConn::getState() const
{
    return(this->state);
}

void BaseConn::setState(QString newState){
    if(this->state != newState) {
        this->state = newState;
        emit stateChanged();
        if(this->state == "disconnected") {
            this->deInit();
        }
    }
}

int BaseConn::getProgress() const
{
    return(connection_progress);
}

bool BaseConn::refreshConnections() {
    QVariantMap reply = this->sendCommand(2006);

    if(reply["status"] != 200){
        //handle Error!!
        if(reply["status"] == 910){
            this->connections = QVariantList({});
            return true;
        }
        qDebug() << "+ --- error refreshing connections: " << reply["status"];
        return false;
    }

    QVariantList tmpConnections = reply["data"].toList();

    if(this->connections != reply["data"].toList()){
        this->connections = reply["data"].toList();
        emit this->connectionsChanged();
    }

    return true;

}

QVariant BaseConn::getConnections() {
    return(connections);
    /*
     "id": "id of the extention (int)",
     "type": "type of the extention (can be: 'STARTPAD', 'TOPPAD')",
     "name": "name of the extention",
     "ip": "ip-adress of he extention (string)",
     "state": "state of the extention (can be: 'disconnected', 'connecting', 'connected')"
     */
    //QVariantMap conn = {{"id",0}, {"type","STARTPAD"}, {"name", "startpad1"}, {"ip", "192.168.4.11"}, {"state", "connected"}};
    //QVariantMap conn1 = {{"id",0}, {"type","TOPPAD"}, {"name", "buzzer1"}, {"ip", "192.168.4.10"}, {"state", "connected"}};
    //QVariantList conns = {conn, conn1};
    //return conns;
}