#include "stpclient.h"

stpClient::stpClient(QHostAddress address, int port, QObject *parent)
    : QObject{parent},
    _state(stpClient_ns::stpState::DISCONNECTED),
    _pingState(stpClient_ns::pingState::IDLE),
    _socket(new QUdpSocket()),
    _address(address),       
    _port(port),
    _pingTimer(new QTimer()),
    _pingTimeoutCount(0),
    _reconnectionTimer(new QTimer())
{
    _reconnectionTimer->setInterval(STP_RECONNECTION_PERIOD);        

    QObject::connect(_reconnectionTimer, &QTimer::timeout, [=]{        
            connectToHost();
    });

    QObject::connect(_socket, &QUdpSocket::readyRead,
            this, [=](){

            #ifdef STP_MANY_PACKETS_DEBUG
                int __count = 0;
            #endif

            while (_socket->hasPendingDatagrams()) {
                  #ifdef STP_MANY_PACKETS_DEBUG
                    __count++;
                  #endif
                  _processData(_socket->receiveDatagram());
            }

            #ifdef STP_MANY_PACKETS_DEBUG
                if (__count > 44) qDebug() << "Received packets at once(!): " << __count;
            #endif
    });

    _pingTimer->setTimerType(Qt::PreciseTimer);
    _pingTimer->setInterval(STP_PING_INTERVAL_MS);

    QObject::connect(_pingTimer, &QTimer::timeout, [=]{
        if (_state ==  stpClient_ns::stpState::CONNECTED) {
            _socket->writeDatagram(_pack(stpProtocol_ns::packetType::PING), _address, _port);
            _pingState =  stpClient_ns::pingState::PENDING;
            QTimer::singleShot(STP_TIMEOUT_MS, [=]{
                if (_pingState ==  stpClient_ns::pingState::PENDING) {
                    #ifdef STP_DEBUG
                        qDebug() << QTime::currentTime().toString() << "ping timeout";
                    #endif

                    _pingTimeoutCount++;

                    if (_pingTimeoutCount >= STP_TIMEOUT_COUNT) {
                        disconnectFromHost();
                        emit STP_disconnected();
                    }
                }
            });
        }
    });
}

stpClient::~stpClient()
{    
    delete _pingTimer;
    delete _reconnectionTimer;
    delete _socket;
    #ifdef STP_DEBUG
        qDebug() << "stpClient desctructor";
    #endif
}

void stpClient::connectToHost()
{
    if ((_state ==  stpClient_ns::stpState::DISCONNECTED) ||
        (_state ==  stpClient_ns::stpState::CONNECTING)) {
        _socket->writeDatagram(_pack(stpProtocol_ns::packetType::SYNCReq), _address, _port);
        _state =  stpClient_ns::stpState::CONNECTING;
        _reconnectionTimer->start();
    }
}

void stpClient::disconnectFromHost()
{
    if (_state != stpClient_ns::stpState::DISCONNECTED) {
        _socket->writeDatagram(_pack(stpProtocol_ns::packetType::RESET), _address, _port);
        _state =  stpClient_ns::stpState::DISCONNECTED;
        _pingState =  stpClient_ns::pingState::IDLE;
        _pingTimer->stop();
    }
}

void stpClient::sendData(QByteArray *buff)
{
     if (_state ==  stpClient_ns::stpState::CONNECTED) {
         _socket->writeDatagram(_pack(stpProtocol_ns::packetType::DATA, buff), _address, _port);
     }
}

QByteArray stpClient::_pack(stpProtocol_ns::packetType packetType, QByteArray *data)
{
    QByteArray __result;

    if (    (packetType == stpProtocol_ns::packetType::DATA)
            && (data != nullptr)    ) {
        // data packet
        trans_ns::bytes2word __size;
        __size.word = data->size();

        __result.resize(CONST_HEADER_SIZE);
        __result[0] = packetType;
        __result[1] = __size.bytes.L;
        __result[2] = __size.bytes.H;
        __result.append(*data);
    } else {
        // system packets
        __result.resize(CONST_HEADER_SIZE);
        __result[0] = packetType;
        __result[1] = 0;
        __result[2] = 0;
    }

    return __result;
}

QByteArray stpClient::packIdRequest()
{
    QByteArray __result;

    __result.resize(CONST_HEADER_SIZE + 1);
    __result[0] = stpProtocol_ns::packetType::DATA;
    __result[1] = 0x01;
    __result[2] = 0x00;
    __result[3] = (uint8_t)stpProtocol_ns::stpCommand::REQ_ID;
    return __result;
}

QByteArray stpClient::packIdSnRequest(uint16_t sn)
{
    trans_ns::bytes2word __sn;

    __sn.word = sn;

    QByteArray __result;

    __result.resize(CONST_HEADER_SIZE + 3);
    __result[0] = stpProtocol_ns::packetType::DATA;
    __result[1] = 0x03;
    __result[2] = 0x00;
    __result[3] = (uint8_t)stpProtocol_ns::stpCommand::REQ_ID_SN;
    __result[4] = __sn.bytes.L;
    __result[5] = __sn.bytes.H;
    return __result;
}

void stpClient::_processData(QNetworkDatagram dg)
{
    int __size = dg.data().size();

    if (__size < CONST_HEADER_SIZE) return;

    QByteArray __header = dg.data().first(CONST_HEADER_SIZE);
    QByteArray __data = dg.data().last(__size - CONST_HEADER_SIZE);

    trans_ns::bytes2word __declaredSize;

    __declaredSize.bytes.L = __header[1];
    __declaredSize.bytes.H = __header[2];

    if (__data.size() != __declaredSize.word) {
        #ifdef STP_DEBUG
            qDebug() << dg.senderAddress().toString() << "badPacketSize (packetSize: " << __data.size() << "; declaredSize: " << __declaredSize.word << ")";
        #endif
        return;
    }

    switch (__header[0]) {
        case stpProtocol_ns::packetType::PING:
            if (_state ==  stpClient_ns::stpState::CONNECTED) {
                _socket->writeDatagram(_pack(stpProtocol_ns::packetType::PONG), _address, _port);
            } else {
                _socket->writeDatagram(_pack(stpProtocol_ns::packetType::RESET), _address, _port);
            }
        break;

        case stpProtocol_ns::packetType::PONG:
            if (_pingState ==  stpClient_ns::pingState::PENDING) {
                _pingState =  stpClient_ns::pingState::IDLE;
                _pingTimeoutCount = 0;
            }
        break;

        case stpProtocol_ns::packetType::DATA:
            emit STP_newDataPacketReceived(__data);
        break;

        case stpProtocol_ns::packetType::RESET:
            #ifdef STP_DEBUG
                qDebug() << "stp conection reset from: " << dg.senderAddress().toString();
            #endif
            _state =  stpClient_ns::stpState::DISCONNECTED;
            _pingState =  stpClient_ns::pingState::IDLE;
            _pingTimer->stop();
            emit STP_disconnected();
        break;

        case stpProtocol_ns::packetType::SYNCAck:
            if (_state ==  stpClient_ns::stpState::CONNECTED) {
            #ifdef STP_DEBUG
                qDebug() << _address.toString() << "(!!!) <SYNCAck> came when client is already connected";
            #endif
            } else {
                _state =  stpClient_ns::stpState::CONNECTED;
                _pingTimer->start();
                emit STP_connected();
            }
        break;

        case stpProtocol_ns::packetType::SYNCReq:
            // клиент не реагирует
        break;
    }
}