Add D500V2 workaround for FTMS start simulation command

Implements a workaround for D500V2 bikes that require a START_RESUME (0x07) command before accepting simulation parameters (0x11). The code now tracks the command sequence and injects the necessary command if missing, ensuring compatibility with D500V2 models. Also adds detection and flag for D500V2 during device discovery.

Author: cagnulein

src/devices/ftmsbike/ftmsbike.cpp

@@ -1477,6 +1477,29 @@ void ftmsbike::ftmsCharacteristicChanged(const QLowEnergyCharacteristic &charact
     if (gattWriteCharControlPointId.isValid()) {
         qDebug() << "routing FTMS packet to the bike from virtualbike" << characteristic.uuid() << newValue.toHex(' ');
 
+        // D500V2 workaround: track request control (0x00) and start simulation (0x07) commands
+        // If we receive simulation params (0x11) without start simulation, inject it first
+        if (D500V2 && b.length() > 0) {
+            uint8_t commandCode = (uint8_t)b.at(0);
+
+            if (commandCode == FTMS_REQUEST_CONTROL) {
+                // Command 0x00: Request Control - expect start simulation next
+                awaiting_start_simulation_after_request_control = true;
+                qDebug() << "D500V2 workaround: received REQUEST_CONTROL (0x00), now awaiting START_RESUME (0x07)";
+            } else if (commandCode == FTMS_START_RESUME) {
+                // Command 0x07: Start Resume - no longer awaiting
+                awaiting_start_simulation_after_request_control = false;
+                qDebug() << "D500V2 workaround: received START_RESUME (0x07), ready for simulation params";
+            } else if (commandCode == FTMS_SET_INDOOR_BIKE_SIMULATION_PARAMS && D500V2 && awaiting_start_simulation_after_request_control) {
+                // Command 0x11: Set Simulation Params - but we're still awaiting start simulation
+                // For D500V2, inject the start simulation command (0x07) first
+                qDebug() << "D500V2 workaround: received SET_INDOOR_BIKE_SIMULATION_PARAMS (0x11) without START_RESUME, injecting 0x07 first";
+                uint8_t startSimulation[] = {FTMS_START_RESUME};
+                writeCharacteristic(startSimulation, sizeof(startSimulation), "injectWrite [D500V2 workaround: start simulation 0x07]", false, true);
+                awaiting_start_simulation_after_request_control = false;
+            }
+        }
+
         // handling gears
         if (b.at(0) == FTMS_SET_INDOOR_BIKE_SIMULATION_PARAMS && (zwiftPlayService == nullptr || !gears_zwift_ratio)) {
             double min_inclination = settings.value(QZSettings::min_inclination, QZSettings::default_min_inclination).toDouble();
@@ -1684,6 +1707,9 @@ void ftmsbike::deviceDiscovered(const QBluetoothDeviceInfo &device) {
             ergModeSupported = false;
             max_resistance = 32;
             DOMYOS = true;
+        } else if (bluetoothDevice.name().toUpper().startsWith("D500V2")) {
+            qDebug() << QStringLiteral("D500V2 found - enabling workaround for start simulation command");
+            D500V2 = true;           
         } else if ((bluetoothDevice.name().toUpper().startsWith("3G Cardio RB"))) {
             qDebug() << QStringLiteral("_3G_Cardio_RB found");
             _3G_Cardio_RB = true;

src/devices/ftmsbike/ftmsbike.h

@@ -135,9 +135,13 @@ class ftmsbike : public bike {
     bool resistance_received = false;
     inclinationResistanceTable _inclinationResistanceTable;
 
+    // D500V2 workaround: track if we're awaiting start simulation command after request control
+    bool awaiting_start_simulation_after_request_control = false;
+
     bool DU30_bike = false;
     bool ICSE = false;
     bool DOMYOS = false;
+    bool D500V2 = false;
     bool _3G_Cardio_RB = false;
     bool SCH_190U = false;
     bool SCH_290R = false;