librepods/linux/ble/blemanager.cpp

#include "blemanager.h"
#include <QDebug>
#include <QTimer>

BleManager::BleManager(QObject *parent) : QObject(parent)
{
    discoveryAgent = new QBluetoothDeviceDiscoveryAgent(this);
    discoveryAgent->setLowEnergyDiscoveryTimeout(0); // Continuous scanning

    connect(discoveryAgent, &QBluetoothDeviceDiscoveryAgent::deviceDiscovered,
            this, &BleManager::onDeviceDiscovered);
    connect(discoveryAgent, &QBluetoothDeviceDiscoveryAgent::finished,
            this, &BleManager::onScanFinished);
    connect(discoveryAgent, &QBluetoothDeviceDiscoveryAgent::errorOccurred,
            this, &BleManager::onErrorOccurred);

    // Set up pruning timer
    pruneTimer = new QTimer(this);
    connect(pruneTimer, &QTimer::timeout, this, &BleManager::pruneOldDevices);
    pruneTimer->start(PRUNE_INTERVAL_MS); // Start timer (runs every 5 seconds)
}

BleManager::~BleManager()
{
    delete discoveryAgent;
    delete pruneTimer;
}

void BleManager::startScan()
{
    qDebug() << "Starting BLE scan...";
    devices.clear();
    discoveryAgent->start(QBluetoothDeviceDiscoveryAgent::LowEnergyMethod);
    pruneTimer->start(PRUNE_INTERVAL_MS); // Ensure timer is running
}

void BleManager::stopScan()
{
    qDebug() << "Stopping BLE scan...";
    discoveryAgent->stop();
}

const QMap<QString, DeviceInfo> &BleManager::getDevices() const
{
    return devices;
}

void BleManager::onDeviceDiscovered(const QBluetoothDeviceInfo &info)
{
    // Check for Apple's manufacturer ID (0x004C)
    if (info.manufacturerData().contains(0x004C))
    {
        QByteArray data = info.manufacturerData().value(0x004C);
        // Ensure data is long enough and starts with prefix 0x07 (indicates Proximity Pairing Message)
        if (data.size() >= 10 && data[0] == 0x07)
        {
            QString address = info.address().toString();
            DeviceInfo deviceInfo;
            deviceInfo.name = info.name().isEmpty() ? "AirPods" : info.name();
            deviceInfo.address = address;
            deviceInfo.rawData = data;

            // data[1] is the length of the data, so we can skip it

            // Check if pairing mode is paired (0x01) or pairing (0x00)
            if (data[2] == 0x00)
            {
                return; // Skip pairing mode devices (the values are differently structured)
            }

            // Parse device model (big-endian: high byte at data[3], low byte at data[4])
            deviceInfo.deviceModel = static_cast<quint16>(data[4]) | (static_cast<quint8>(data[3]) << 8);

            // Status byte for primary pod and other flags
            quint8 status = static_cast<quint8>(data[5]);
            deviceInfo.status = status;

            // Pods battery byte (upper nibble: one pod, lower nibble: other pod)
            quint8 podsBatteryByte = static_cast<quint8>(data[6]);

            // Flags and case battery byte (upper nibble: case battery, lower nibble: flags)
            quint8 flagsAndCaseBattery = static_cast<quint8>(data[7]);

            // Lid open counter and device color
            quint8 lidIndicator = static_cast<quint8>(data[8]);
            deviceInfo.deviceColor = static_cast<quint8>(data[9]);

            deviceInfo.connectionState = static_cast<DeviceInfo::ConnectionState>(data[10]);

            // Next: Encrypted Payload: 16 bytes

            // Determine primary pod (bit 5 of status) and value flipping
            bool primaryLeft = (status & 0x20) != 0; // Bit 5: 1 = left primary, 0 = right primary
            bool areValuesFlipped = !primaryLeft;    // Flipped when right pod is primary

            // Parse battery levels
            int leftNibble = areValuesFlipped ? (podsBatteryByte >> 4) & 0x0F : podsBatteryByte & 0x0F;
            int rightNibble = areValuesFlipped ? podsBatteryByte & 0x0F : (podsBatteryByte >> 4) & 0x0F;
            deviceInfo.leftPodBattery = (leftNibble == 15) ? -1 : leftNibble * 10;
            deviceInfo.rightPodBattery = (rightNibble == 15) ? -1 : rightNibble * 10;
            int caseNibble = flagsAndCaseBattery & 0x0F; // Extracts lower nibble
            deviceInfo.caseBattery = (caseNibble == 15) ? -1 : caseNibble * 10;

            // Parse charging statuses from flags (uper 4 bits of data[7])
            quint8 flags = (flagsAndCaseBattery >> 4) & 0x0F;                                        // Extracts lower nibble
            deviceInfo.rightCharging = areValuesFlipped ? (flags & 0x01) != 0 : (flags & 0x02) != 0; // Depending on primary, bit 0 or 1
            deviceInfo.leftCharging = areValuesFlipped ? (flags & 0x02) != 0 : (flags & 0x01) != 0;  // Depending on primary, bit 1 or 0
            deviceInfo.caseCharging = (flags & 0x04) != 0;                                           // bit 2

            // Additional status flags from status byte (data[5])
            deviceInfo.isThisPodInTheCase = (status & 0x40) != 0; // Bit 6
            deviceInfo.isOnePodInCase = (status & 0x10) != 0;     // Bit 4
            deviceInfo.areBothPodsInCase = (status & 0x04) != 0;  // Bit 2

            // In-ear detection with XOR logic
            bool xorFactor = areValuesFlipped ^ deviceInfo.isThisPodInTheCase;
            deviceInfo.isLeftPodInEar = xorFactor ? (status & 0x08) != 0 : (status & 0x02) != 0;  // Bit 3 or 1
            deviceInfo.isRightPodInEar = xorFactor ? (status & 0x02) != 0 : (status & 0x08) != 0; // Bit 1 or 3

            // Microphone status
            deviceInfo.isLeftPodMicrophone = primaryLeft ^ deviceInfo.isThisPodInTheCase;
            deviceInfo.isRightPodMicrophone = !primaryLeft ^ deviceInfo.isThisPodInTheCase;

            deviceInfo.lidOpenCounter = lidIndicator & 0x07; // Extract bits 0-2 (count)
            quint8 lidState = static_cast<quint8>((lidIndicator >> 3) & 0x01); // Extract bit 3 (lid state)
            if (deviceInfo.isThisPodInTheCase) {
                deviceInfo.lidState = static_cast<DeviceInfo::LidState>(lidState);
            }

            // Update timestamp
            deviceInfo.lastSeen = QDateTime::currentDateTime();

            // Store device info in the map
            devices[address] = deviceInfo;

            // Debug output
            qDebug() << "Found device:" << deviceInfo.name
                     << "Left:" << (deviceInfo.leftPodBattery >= 0 ? QString("%1%").arg(deviceInfo.leftPodBattery) : "N/A")
                     << "Right:" << (deviceInfo.rightPodBattery >= 0 ? QString("%1%").arg(deviceInfo.rightPodBattery) : "N/A")
                     << "Case:" << (deviceInfo.caseBattery >= 0 ? QString("%1%").arg(deviceInfo.caseBattery) : "N/A");
        }
    }
}

void BleManager::onScanFinished()
{
    qDebug() << "Scan finished.";
    if (discoveryAgent->isActive())
    {
        discoveryAgent->start(QBluetoothDeviceDiscoveryAgent::LowEnergyMethod);
    }
}

void BleManager::onErrorOccurred(QBluetoothDeviceDiscoveryAgent::Error error)
{
    qDebug() << "Error occurred:" << error;
    stopScan();
}

void BleManager::pruneOldDevices()
{
    QDateTime now = QDateTime::currentDateTime();
    auto it = devices.begin();
    while (it != devices.end())
    {
        if (it.value().lastSeen.msecsTo(now) > DEVICE_TIMEOUT_MS)
        {
            qDebug() << "Removing old device:" << it.value().name << "at" << it.key();
            it = devices.erase(it); // Remove device if not seen recently
        }
        else
        {
            ++it;
        }
    }
}