Work on decoding using structs

TODO

@@ -2,3 +2,7 @@
 
 * Consider support for upper/lower case MAC address and optionaly ":"
 * Scanning - list devices publishing, should be able to get list even without knowing MAC / Encryption key
+* Struct vs Manual
+    * Sh3dNg version and examples uses structs to get data - seems to work
+    * Example generated uses manually managing a string
+    * Reconsider what is best and use

src/VictronBLE.cpp

@@ -213,6 +213,8 @@ void VictronBLE::processDevice(BLEAdvertisedDevice advertisedDevice) {
         return;
     }
 
+    // XXX Use struct like code in Sh3dNg
+
     // Check if it's Victron (manufacturer ID 0x02E1)
     uint16_t mfgId = (uint8_t)mfgData[1] << 8 | (uint8_t)mfgData[0];
     if (mfgId != VICTRON_MANUFACTURER_ID) {
@@ -236,9 +238,11 @@ bool VictronBLE::parseAdvertisement(const uint8_t* manufacturerData, size_t len,
                                     const String& macAddress) {
     auto it = devices.find(macAddress);
     if (it == devices.end()) {
+        debugPrint("parseAdvertisement: Device not found");
         return false;
     }
 
+    // XXX Work out second?
     DeviceInfo* deviceInfo = it->second;
 
     if (len < 6) {
@@ -246,18 +250,29 @@ bool VictronBLE::parseAdvertisement(const uint8_t* manufacturerData, size_t len,
         return false;
     }
 
+    // XXX map to struct - NOTE: Check size first (exact? or bigger?)
+    victronManufacturerData * vicData=(victronManufacturerData *)manufacturerData;
+    debugPrint("VendorID" + String(vicData->vendorID));
+    debugPrint("Record Type" + String(vicData->victronRecordType));
+
     // Structure: [MfgID(2)] [DeviceType(1)] [IV(2)] [EncryptedData(n)]
-    uint8_t deviceType = manufacturerData[2];
+    // XXX This is actually 4 - Struct would help - it was 2
+    uint8_t deviceType = manufacturerData[4];
 
     // Extract IV (initialization vector) - bytes 3-4, little-endian
+    // XXX These look wrong
     uint8_t iv[16] = {0};
     iv[0] = manufacturerData[3];
     iv[1] = manufacturerData[4];
     // Rest of IV is zero-padded
 
     // Encrypted data starts at byte 5
-    const uint8_t* encryptedData = manufacturerData + 5;
-    size_t encryptedLen = len - 5;
+    // const uint8_t* encryptedData = manufacturerData + 5;
+    // size_t encryptedLen = len - 5;
+
+    // XXX Experiment
+    const uint8_t* encryptedData = vicData->victronEncryptedData;
+    size_t encryptedLen = sizeof(vicData->victronEncryptedData);
 
     if (debugEnabled) {
         debugPrintHex("Encrypted data", encryptedData, encryptedLen);

src/VictronBLE.h

@@ -53,6 +53,39 @@ enum SolarChargerState {
     CHARGER_EXTERNAL_CONTROL = 252
 };
 
+// XXX HARD Core structs
+//  Used for decoding
+// But then data is put into specific device structs
+// Which means a lot of overlap - reconsider...
+//  NOTE: c struct vs classes
+
+// Must use the "packed" attribute to make sure the compiler doesn't add any padding to deal with
+// word alignment.
+typedef struct {
+  uint8_t deviceState;
+  uint8_t errorCode;
+  int16_t batteryVoltage;
+  int16_t batteryCurrent;
+  uint16_t todayYield;
+  uint16_t inputPower;
+  uint8_t outputCurrentLo;  // Low 8 bits of output current (in 0.1 Amp increments)
+  uint8_t outputCurrentHi;  // High 1 bit of ourput current (must mask off unused bits)
+  uint8_t unused[4];
+} __attribute__((packed)) victronPanelData; // XXX Specific type -
+
+typedef struct {
+  uint16_t vendorID;                 // vendor ID
+  uint8_t beaconType;                // Should be 0x10 (Product Advertisement) for the packets we want
+  uint8_t unknownData1[3];           // Unknown data
+  uint8_t victronRecordType;         // Should be 0x01 (Solar Charger) for the packets we want
+  uint16_t nonceDataCounter;         // Nonce
+  uint8_t encryptKeyMatch;           // Should match pre-shared encryption key byte 0
+  uint8_t victronEncryptedData[21];  // (31 bytes max per BLE spec - size of previous elements)
+  uint8_t nullPad;                   // extra byte because toCharArray() adds a \0 byte.
+} __attribute__((packed)) victronManufacturerData;
+
+// XXX End of new bit above
+
 // Base structure for all device data
 struct VictronDeviceData {
     String deviceName;