#include "qbluetoothleuart.h"

QBluetoothLeUart::QBluetoothLeUart(QObject *parent) : QObject(parent)
{
    currentBluetoothDevice = nullptr;
    bluetoothController = nullptr;
    bluetoothService = nullptr;

    state = Idle;

    this->setUUIDs("6e400001-b5a3-f393-e0a9-e50e24dcca9e", "6e400002-b5a3-f393-e0a9-e50e24dcca9e", "6e400003-b5a3-f393-e0a9-e50e24dcca9e");

    // init device discovery agent for scanning
    this->bluetoothDeviceDiscoveryAgent = new QBluetoothDeviceDiscoveryAgent(this);

    connect(this->bluetoothDeviceDiscoveryAgent, &QBluetoothDeviceDiscoveryAgent::deviceDiscovered, this, &QBluetoothLeUart::handleDeviceDiscovered);
    connect(bluetoothDeviceDiscoveryAgent, SIGNAL(error(QBluetoothDeviceDiscoveryAgent::Error)),
            this, SLOT(handleDeviceScanError(QBluetoothDeviceDiscoveryAgent::Error)));
    connect(this->bluetoothDeviceDiscoveryAgent, &QBluetoothDeviceDiscoveryAgent::finished, this, &QBluetoothLeUart::handleScanFinished);

    // device model for QML
    this->availableDevicesModel = new QBluetoothLeUartDeviceModel(this->availableDevices, this);
}

QBluetoothLeUart::~QBluetoothLeUart(){

}

// ------------------------------
// - Slots for QBluetoothLeUart -
// ------------------------------

bool QBluetoothLeUart::startScanningForDevices(){
    if(this->state != Idle && this->state != ScanFinished)
        return false;

    this->availableDevicesModel->clear();

    foreach(QBluetoothLeUartDevice* oldDevice, this->availableDevices)
        oldDevice->deleteLater();

    this->availableDevices.clear();

    this->setState(Scanning);
    this->bluetoothDeviceDiscoveryAgent->start();

    return true;
}

bool QBluetoothLeUart::stopScanningForDevices() {
    if(this->state != Scanning)
        return false;

    this->bluetoothDeviceDiscoveryAgent->stop();
    this->setState(ScanFinished);
    return true;
}

QList<QBluetoothLeUartDevice*> QBluetoothLeUart::getAvailableDevices() {
    return this->availableDevices;
}

QVariantList QBluetoothLeUart::getAvailableDevicesDetailList() {

    QVariantList result;

    for(int i=0; i < this->availableDevices.length(); i++) {
        if(this->availableDevices[i]->getName().isEmpty())
            continue;

        QVariantMap device;

        device.insert("id", i);
        device.insert("name", this->availableDevices[i]->getName());
        device.insert("address", this->availableDevices[i]->getAddress());

        result.append(device);
    }

    return result;
}

QBluetoothLeUartDeviceModel* QBluetoothLeUart::getAvailableDevicesModel() {
    return this->availableDevicesModel;
}

QBluetoothLeUartDevice* QBluetoothLeUart::getCurrentDevice() {
    return this->currentBluetoothDevice;
}

bool QBluetoothLeUart::connectToDevice(int deviceId) {
    if(deviceId < 0 || deviceId >= this->availableDevices.length())
        return false;

    this->connectToDevice(this->availableDevices[deviceId]);
    return true;
}

bool QBluetoothLeUart::connectToDevice(QBluetoothLeUartDevice *device){
    if(!this->availableDevices.contains(device))
        return false;

    if(this->state == Scanning)
        this->stopScanningForDevices();

    this->currentBluetoothDevice = device;
    emit this->currentDeviceChanged();

    if (bluetoothController) {
        bluetoothController->disconnectFromDevice();
        delete bluetoothController;
        bluetoothController = 0;
    }

    // initialize QLowEnergyController
    bluetoothController = new QLowEnergyController(currentBluetoothDevice->getDevice(), this);
    bluetoothController->setRemoteAddressType(QLowEnergyController::RandomAddress);

    connect(this->bluetoothController, &QLowEnergyController::serviceDiscovered, this, &QBluetoothLeUart::handleServiceDiscovered);
    connect(this->bluetoothController, &QLowEnergyController::discoveryFinished, this, &QBluetoothLeUart::handleServiceScanDone);
    connect(bluetoothController, SIGNAL(error(QLowEnergyController::Error)),
            this, SLOT(handleControllerError(QLowEnergyController::Error)));
    connect(this->bluetoothController, &QLowEnergyController::connected, this, &QBluetoothLeUart::handleDeviceConnected);
    connect(this->bluetoothController, &QLowEnergyController::disconnected, this, &QBluetoothLeUart::handleDeviceDisconnected);

    /* Start connecting to device */
    bluetoothController->connectToDevice();
    setState(Connecting);

    return true;
}

bool QBluetoothLeUart::disconnectFromDevice() {
    if(this->state < Connecting)
        return false;

    if(this->state >= Connected)
        this->bluetoothController->disconnectFromDevice();

    this->bluetoothController->deleteLater();
    this->bluetoothController = nullptr;

    if(this->bluetoothService != nullptr) {
        this->bluetoothService->deleteLater();
        this->bluetoothService = nullptr;
    }

    this->currentBluetoothDevice->deleteLater();
    this->currentBluetoothDevice = nullptr;
    emit this->currentDeviceChanged();

    this->setState(Idle);

    return true;
}

bool QBluetoothLeUart::sendData(QString data, bool asynchronous){
    Q_UNUSED(asynchronous)
    if(this->state != Connected)
        return false;

    const QLowEnergyCharacteristic  RxChar = bluetoothService->characteristic(QBluetoothUuid(QUuid(this->txUUID)));

    QByteArray Data;
    Data.append(data);

    bluetoothService->writeCharacteristic(RxChar, Data, QLowEnergyService::WriteWithoutResponse);

    return true;
}

// -------------------------------------------
// - Slots for QBluetothDeviceDiscoveryAgent -
// -------------------------------------------

void QBluetoothLeUart::handleDeviceDiscovered(const QBluetoothDeviceInfo &device)
{
    // Is it a BLE device?
    if (device.coreConfigurations() & QBluetoothDeviceInfo::LowEnergyCoreConfiguration) {
        qWarning() << "Discovered BLE Device: name: " << device.name() << " Address: "  << device.address().toString() << " UUIDs: " << device.serviceUuids();
        // ignore all devices that to not support our service
        if(!device.serviceUuids().contains(QBluetoothUuid(this->uartServiceUUID)))
            return;

        QBluetoothLeUartDevice *dev = new QBluetoothLeUartDevice(device, this);
        this->availableDevices.append(dev);
        this->availableDevicesModel->append(dev);
        emit this->foundNewDevice(dev);
        emit this->avaliableDevicesChanged(this->availableDevices);
    }
}

void QBluetoothLeUart::handleScanFinished()
{
    if (this->availableDevices.size() == 0)
    {
        qWarning() << "No Low Energy devices found";
    }

    emit this->scanFinished(this->availableDevices);

    setState(ScanFinished);
}

void QBluetoothLeUart::handleDeviceScanError(QBluetoothDeviceDiscoveryAgent::Error error)
{
    if (error == QBluetoothDeviceDiscoveryAgent::PoweredOffError)
        emit this->scanningErrorOccured(AdapterTurnedOffError);
    else if (error == QBluetoothDeviceDiscoveryAgent::InputOutputError)
        emit this->scanningErrorOccured(InputOutputError);
    else
        emit this->scanningErrorOccured(UnknownError);
}

// ----------------------------------
// - Slots for QLowEnergyController -
// ----------------------------------

void QBluetoothLeUart::handleServiceDiscovered(const QBluetoothUuid &uuid){

    qDebug() << "Found service with ID: " << uuid;

    if(uuid == QBluetoothUuid(QUuid(this->uartServiceUUID))){
        foundValidUARTService =true;
        qDebug() << "UART service found!";
    }
}

void QBluetoothLeUart::handleServiceScanDone(){

    delete bluetoothService;
    bluetoothService=0;

    if(foundValidUARTService){
        qDebug() << "Connecting to UART service...";
        bluetoothService = bluetoothController->createServiceObject(QBluetoothUuid(QUuid(this->uartServiceUUID)),this);
    }

    if(!bluetoothService){
        qDebug() <<"UART service not found";
        this->disconnectFromDevice();
        return;
    }

    /* 3 Step: Service Discovery */
    connect(this->bluetoothService, &QLowEnergyService::stateChanged, this, &QBluetoothLeUart::handleServiceStateChange);
    connect(this->bluetoothService, &QLowEnergyService::characteristicChanged, this, &QBluetoothLeUart::handleServiceCharacteristicChange);
    connect(this->bluetoothService, &QLowEnergyService::descriptorWritten, this, &QBluetoothLeUart::handleServiceDescriptorWritten);

    bluetoothService->discoverDetails();
    setState(ServiceFound);
}

void QBluetoothLeUart::handleControllerError(QLowEnergyController::Error error)
{
    qDebug() << "Cannot connect to remote device.";
    qWarning() << "Controller Error:" << error;
    this->disconnectFromDevice();
}

void QBluetoothLeUart::handleDeviceConnected()
{
    qDebug() << "Device connected";
    bluetoothController->discoverServices();
    setState(ScanningForService);
}

void QBluetoothLeUart::handleDeviceDisconnected()
{
    this->setState(Idle);
    qDebug() << "UART service disconnected";
    qWarning() << "Remote device disconnected";
}

// -------------------------------
// - Slots for QLowEnergyService -
// -------------------------------

void QBluetoothLeUart::handleServiceStateChange(QLowEnergyService::ServiceState s)
{

    // A descriptoc can only be written if the service is in the ServiceDiscovered state
    switch (s) {
    case QLowEnergyService::ServiceDiscovered:
    {

        //looking for the RX characteristic
        const QLowEnergyCharacteristic TxChar = bluetoothService->characteristic(QBluetoothUuid(QUuid(this->rxUUID)));
        if (!TxChar.isValid()){
            qDebug() << "Rx characteristic not found";
            this->disconnectFromDevice();
            return;
        }

        //looking for the TX characteristic
        const QLowEnergyCharacteristic  RxChar = bluetoothService->characteristic(QBluetoothUuid(QUuid(this->txUUID)));
        if (!RxChar.isValid()) {
            qDebug() << "Tx characteristic not found";
            this->disconnectFromDevice();
            return;
        }


        // Bluetooth LE spec Where a characteristic can be notified, a Client Characteristic Configuration descriptor
        // shall be included in that characteristic as required by the Bluetooth Core Specification
        // Tx notify is enabled
        const QLowEnergyDescriptor m_notificationDescTx = TxChar.descriptor(QBluetoothUuid::ClientCharacteristicConfiguration);

        if (m_notificationDescTx.isValid()) {
            // enable notification
            bluetoothService->writeDescriptor(m_notificationDescTx, QByteArray::fromHex("0100"));
            setState(Connected);
            emit this->connectedToDevice();
        }

        break;
    }
    default:
        //nothing for now
        break;
    }
}

void QBluetoothLeUart::handleServiceCharacteristicChange(const QLowEnergyCharacteristic &c,const QByteArray &value)
{
    // ignore any other characteristic change
    if (c.uuid() != QBluetoothUuid(QUuid(this->rxUUID)))
        return;

    emit dataReceived((QString) value);
}

void QBluetoothLeUart::handleServiceDescriptorWritten(const QLowEnergyDescriptor &d,
                                                     const QByteArray &value)
{
    if (d.isValid() && d == bluetoothTransmissionDescriptor && value == QByteArray("0000")) {
        //disabled notifications -> assume disconnect intent
        this->disconnectFromDevice();
    }
}

// --------------------
// - Helper functions -
// --------------------

void QBluetoothLeUart::init() {
#ifdef QBluetoothLeUart_QML
    qmlRegisterUncreatableType<QBluetoothLeUartDevice>("de.itsblue.bluetoothleuart", 1, 0, "QBluetoothLeUartDevice", "QBluetoothLeUartDevice cannot be created");
    qmlRegisterUncreatableType<QBluetoothLeUartDeviceModel>("de.itsblue.bluetoothleuart", 1, 0, "QBluetoothLeUartDeviceModel", "QBluetoothLeUartDeviceModel cannot be created");
    qmlRegisterType<QBluetoothLeUart>("de.itsblue.bluetoothleuart", 1, 0, "QBluetoothLeUart");
    qRegisterMetaType<QBluetoothLeUart::BluetoothLeUartState>("QBluetoothLeUart::BluetoothLeUartState");
    qRegisterMetaType<QBluetoothLeUart::BluetoothScanError>("QBluetoothLeUart::BluetoothScanError");
#endif
}

void QBluetoothLeUart::setState(QBluetoothLeUart::BluetoothLeUartState newState)
{
    if (state == newState)
        return;

    state = newState;
    emit stateChanged(newState);
}

QBluetoothLeUart::BluetoothLeUartState QBluetoothLeUart::getState() const {
    return state;
}

void QBluetoothLeUart::setUUIDs(const char uartServiceUUID[36], const char txUUID[36], const char rxUUID[36]) {
    this->uartServiceUUID = uartServiceUUID;
    this->txUUID = txUUID;
    this->rxUUID = rxUUID;
}