assign new device id on unpair

NukiDeviceId.cpp

@@ -0,0 +1,44 @@
+#include <cstring>
+#include <Arduino.h>
+#include "NukiDeviceId.h"
+#include "PreferencesKeys.h"
+
+NukiDeviceId::NukiDeviceId(Preferences* preferences, const std::string& preferencesId)
+: _preferences(preferences),
+  _preferencesId(preferencesId)
+{
+    _deviceId = _preferences->getUInt(_preferencesId.c_str());
+
+    if(_deviceId == 0)
+    {
+        assignNewId();
+    }
+}
+
+uint32_t NukiDeviceId::get()
+{
+    return _deviceId;
+}
+
+void NukiDeviceId::assignId(const uint32_t& id)
+{
+    _deviceId = id;
+    _preferences->putUInt(_preferencesId.c_str(), id);
+}
+
+void NukiDeviceId::assignNewId()
+{
+    assignId(getRandomId());
+}
+
+uint32_t NukiDeviceId::getRandomId()
+{
+    uint8_t rnd[4];
+    for(int i=0; i<4; i++)
+    {
+        rnd[i] = random(255);
+    }
+    uint32_t deviceId;
+    memcpy(&deviceId, &rnd, sizeof(deviceId));
+    return deviceId;
+}