v1.2.0: Firmware refactor to service-oriented architecture + WiFi fixes

Firmware:
- Fixed WiFi reconnection bug after power cycle by adding WiFi.persistent(false)
  and disabling auto-connect/auto-reconnect
- Fixed AP mode not broadcasting by properly handling WIFI_AP_STA mode transitions
- Refactored to service-oriented architecture:
  - device_state: Central state management with event callbacks
  - config_service: NVS persistence (renamed from config_manager)
  - wifi_service: WiFi STA/AP management (extracted from main.cpp)
  - mqtt_service: MQTT client and message routing (extracted from main.cpp)
  - ble_service: BLE GATT services (renamed from ble_services)
  - web_service: HTTP configuration portal (renamed from web_portal)
- main.cpp reduced from ~470 lines to ~60 lines (thin orchestrator)
- Each service is self-contained with setup()/loop() pattern

Backend:
- Added heart rate variation endpoint
- UI improvements

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

firmware/esp32_ble_sim/include/ble_services.h

@@ -1,70 +0,0 @@
-#ifndef BLE_SERVICES_H
-#define BLE_SERVICES_H
-
-#include <Arduino.h>
-
-// ============================================
-// BLE Service UUIDs (Bluetooth SIG standard)
-// ============================================
-
-// Heart Rate Service
-#define HEART_RATE_SERVICE_UUID        "180D"
-#define HEART_RATE_MEASUREMENT_UUID    "2A37"
-#define BODY_SENSOR_LOCATION_UUID      "2A38"
-
-// Battery Service
-#define BATTERY_SERVICE_UUID           "180F"
-#define BATTERY_LEVEL_UUID             "2A19"
-
-// Fitness Machine Service
-#define FITNESS_MACHINE_SERVICE_UUID   "1826"
-#define TREADMILL_DATA_UUID            "2ACD"
-#define FITNESS_MACHINE_FEATURE_UUID   "2ACC"
-
-// ============================================
-// Function Prototypes
-// ============================================
-
-/**
- * Initialize NimBLE stack (call once at startup)
- */
-void initBLE();
-
-/**
- * Stop BLE advertising and deinit
- */
-void stopBLE();
-
-/**
- * Setup BLE as Heart Rate Monitor
- * Creates Heart Rate Service with measurement characteristic
- */
-void setupBLE_HeartRate();
-
-/**
- * Setup BLE as Treadmill (Fitness Machine)
- * Creates Fitness Machine Service with treadmill data
- */
-void setupBLE_Treadmill();
-
-/**
- * Send heart rate notification
- * @param bpm Heart rate in beats per minute
- */
-void notifyHeartRate(uint8_t bpm);
-
-/**
- * Update battery level
- * @param level Battery level 0-100%
- */
-void updateBatteryLevel(uint8_t level);
-
-/**
- * Send treadmill data notification
- * @param speed Speed in 0.01 km/h units
- * @param incline Incline in 0.1% units
- * @param distance Total distance in meters
- */
-void notifyTreadmill(uint16_t speed, int16_t incline, uint32_t distance);
-
-#endif // BLE_SERVICES_H

firmware/esp32_ble_sim/include/config.h

@@ -4,7 +4,7 @@
 // ============================================
 // Firmware Version
 // ============================================
-#define FIRMWARE_VERSION "1.0.5"
+#define FIRMWARE_VERSION "1.0.6"
 
 // ============================================
 // AP Mode Configuration

firmware/esp32_ble_sim/include/device_state.h

@@ -0,0 +1,105 @@
+#ifndef DEVICE_STATE_H
+#define DEVICE_STATE_H
+
+#include <Arduino.h>
+#include <functional>
+
+// ============================================
+// Device Types
+// ============================================
+enum class DeviceType {
+    NONE,
+    HEART_RATE,
+    TREADMILL
+};
+
+// ============================================
+// Connection State
+// ============================================
+struct ConnectionState {
+    bool wifiConnected = false;
+    bool mqttConnected = false;
+    bool bleClientConnected = false;
+    String ipAddress = "";
+};
+
+// ============================================
+// Simulated Device Values
+// ============================================
+struct SimulatedValues {
+    // Heart Rate Monitor
+    uint8_t heartRate = 70;
+    uint8_t batteryLevel = 100;
+
+    // Treadmill
+    uint16_t treadmillSpeed = 0;      // 0.01 km/h resolution
+    int16_t treadmillIncline = 0;     // 0.1% resolution
+    uint32_t treadmillDistance = 0;   // meters
+    float distanceAccumulator = 0.0;  // fractional distance
+};
+
+// ============================================
+// Event Callbacks
+// ============================================
+using DeviceTypeChangedCallback = std::function<void(DeviceType newType)>;
+using ValuesChangedCallback = std::function<void(const SimulatedValues& values)>;
+using ConnectionChangedCallback = std::function<void(const ConnectionState& state)>;
+
+// ============================================
+// Device State Manager (Singleton)
+// ============================================
+class DeviceState {
+public:
+    static DeviceState& getInstance();
+
+    // Prevent copying
+    DeviceState(const DeviceState&) = delete;
+    DeviceState& operator=(const DeviceState&) = delete;
+
+    // Device type
+    DeviceType getDeviceType() const { return deviceType; }
+    void setDeviceType(DeviceType type);
+    bool isBleStarted() const { return deviceType != DeviceType::NONE; }
+    const char* getDeviceTypeString() const;
+
+    // Simulated values
+    const SimulatedValues& getValues() const { return values; }
+    void setHeartRate(uint8_t bpm);
+    void setBatteryLevel(uint8_t level);
+    void setTreadmillSpeed(float speedKmh);
+    void setTreadmillIncline(float inclinePercent);
+    void setTreadmillDistance(uint32_t meters);
+    void resetTreadmillDistance();
+    void accumulateTreadmillDistance(float deltaSeconds);
+
+    // Connection state
+    const ConnectionState& getConnectionState() const { return connectionState; }
+    void setWifiConnected(bool connected, const String& ip = "");
+    void setMqttConnected(bool connected);
+    void setBleClientConnected(bool connected);
+
+    // Event registration
+    void onDeviceTypeChanged(DeviceTypeChangedCallback callback);
+    void onValuesChanged(ValuesChangedCallback callback);
+    void onConnectionChanged(ConnectionChangedCallback callback);
+
+private:
+    DeviceState() = default;
+
+    DeviceType deviceType = DeviceType::NONE;
+    SimulatedValues values;
+    ConnectionState connectionState;
+
+    // Callbacks
+    DeviceTypeChangedCallback deviceTypeCallback = nullptr;
+    ValuesChangedCallback valuesCallback = nullptr;
+    ConnectionChangedCallback connectionCallback = nullptr;
+
+    void notifyValuesChanged();
+    void notifyConnectionChanged();
+};
+
+// Convenience macro for accessing singleton
+#define deviceState DeviceState::getInstance()
+
+#endif // DEVICE_STATE_H

firmware/esp32_ble_sim/include/services/ble_service.h

@@ -0,0 +1,58 @@
+#ifndef BLE_SERVICE_H
+#define BLE_SERVICE_H
+
+#include <Arduino.h>
+
+// ============================================
+// BLE Service UUIDs (Bluetooth SIG standard)
+// ============================================
+#define HEART_RATE_SERVICE_UUID        "180D"
+#define HEART_RATE_MEASUREMENT_UUID    "2A37"
+#define BODY_SENSOR_LOCATION_UUID      "2A38"
+#define BATTERY_SERVICE_UUID           "180F"
+#define BATTERY_LEVEL_UUID             "2A19"
+#define FITNESS_MACHINE_SERVICE_UUID   "1826"
+#define TREADMILL_DATA_UUID            "2ACD"
+#define FITNESS_MACHINE_FEATURE_UUID   "2ACC"
+
+// ============================================
+// BLE Service
+// Manages BLE advertising and GATT services
+// ============================================
+class BleService {
+public:
+    static BleService& getInstance();
+
+    // Prevent copying
+    BleService(const BleService&) = delete;
+    BleService& operator=(const BleService&) = delete;
+
+    // Lifecycle
+    void setup();
+    void loop();
+
+    // Configuration
+    void setupHeartRate();
+    void setupTreadmill();
+    void stop();
+
+    // Notifications
+    void notifyHeartRate(uint8_t bpm);
+    void notifyTreadmill(uint16_t speed, int16_t incline, uint32_t distance);
+    void updateBattery(uint8_t level);
+
+    // State
+    bool isClientConnected() const { return deviceConnected; }
+
+private:
+    BleService() = default;
+
+    bool deviceConnected = false;
+    unsigned long lastNotify = 0;
+
+    void initBLE();
+};
+
+#define bleService BleService::getInstance()
+
+#endif // BLE_SERVICE_H

firmware/esp32_ble_sim/include/services/config_service.h

@@ -1,27 +1,20 @@
-#ifndef CONFIG_MANAGER_H
-#define CONFIG_MANAGER_H
+#ifndef CONFIG_SERVICE_H
+#define CONFIG_SERVICE_H
 
 #include <Arduino.h>
 #include <Preferences.h>
 
 // ============================================
-// Configuration Structure
+// Config Service
+// Manages persistent configuration in NVS
 // ============================================
-struct DeviceConfig {
-    bool configured = false;
-    String wifiSsid = "";
-    String wifiPassword = "";
-    String mqttHost = "";
-    uint16_t mqttPort = 1883;
-    String deviceId = "";
-};
-
-// ============================================
-// Configuration Manager Class
-// ============================================
-class ConfigManager {
+class ConfigService {
 public:
-    ConfigManager();
+    static ConfigService& getInstance();
+
+    // Prevent copying
+    ConfigService(const ConfigService&) = delete;
+    ConfigService& operator=(const ConfigService&) = delete;
 
     // Load config from NVS
     bool load();
@@ -33,14 +26,14 @@ public:
     void clear();
 
     // Check if configured
-    bool isConfigured() const { return config.configured; }
+    bool isConfigured() const { return configured; }
 
     // Getters
-    const String& getWifiSsid() const { return config.wifiSsid; }
-    const String& getWifiPassword() const { return config.wifiPassword; }
-    const String& getMqttHost() const { return config.mqttHost; }
-    uint16_t getMqttPort() const { return config.mqttPort; }
-    const String& getDeviceId() const { return config.deviceId; }
+    const String& getWifiSsid() const { return wifiSsid; }
+    const String& getWifiPassword() const { return wifiPassword; }
+    const String& getMqttHost() const { return mqttHost; }
+    uint16_t getMqttPort() const { return mqttPort; }
+    const String& getDeviceId() const { return deviceId; }
 
     // Setters
     void setWifiCredentials(const String& ssid, const String& password);
@@ -54,11 +47,18 @@ public:
     String getDefaultDeviceId() const;
 
 private:
-    DeviceConfig config;
+    ConfigService() = default;
+
+    bool configured = false;
+    String wifiSsid = "";
+    String wifiPassword = "";
+    String mqttHost = "";
+    uint16_t mqttPort = 1883;
+    String deviceId = "";
+
     Preferences preferences;
 };
 
-// Global instance
-extern ConfigManager configManager;
+#define configService ConfigService::getInstance()
 
-#endif // CONFIG_MANAGER_H
+#endif // CONFIG_SERVICE_H

firmware/esp32_ble_sim/include/services/mqtt_service.h

@@ -0,0 +1,45 @@
+#ifndef MQTT_SERVICE_H
+#define MQTT_SERVICE_H
+
+#include <Arduino.h>
+
+// ============================================
+// MQTT Service
+// Manages MQTT connection and message routing
+// ============================================
+class MqttService {
+public:
+    static MqttService& getInstance();
+
+    // Prevent copying
+    MqttService(const MqttService&) = delete;
+    MqttService& operator=(const MqttService&) = delete;
+
+    // Lifecycle
+    void setup();
+    void loop();
+
+    // State
+    bool isConnected() const { return mqttConnected; }
+
+    // Publishing
+    void publishStatus();
+    void publishValues();
+
+private:
+    MqttService() = default;
+
+    bool mqttConnected = false;
+    unsigned long lastMqttAttempt = 0;
+    unsigned long lastStatusReport = 0;
+
+    void connectToMQTT();
+    void handleMessage(char* topic, byte* payload, unsigned int length);
+
+    // Static callback wrapper for PubSubClient
+    static void messageCallback(char* topic, byte* payload, unsigned int length);
+};
+
+#define mqttService MqttService::getInstance()
+
+#endif // MQTT_SERVICE_H

firmware/esp32_ble_sim/include/services/web_service.h

@@ -0,0 +1,35 @@
+#ifndef WEB_SERVICE_H
+#define WEB_SERVICE_H
+
+#include <Arduino.h>
+
+// ============================================
+// Web Service
+// Manages HTTP server for configuration portal
+// ============================================
+class WebService {
+public:
+    static WebService& getInstance();
+
+    // Prevent copying
+    WebService(const WebService&) = delete;
+    WebService& operator=(const WebService&) = delete;
+
+    // Lifecycle
+    void setup();
+    void loop();
+
+private:
+    WebService() = default;
+
+    void handleRoot();
+    void handleGetStatus();
+    void handlePostConfig();
+    void handleReset();
+    void handleResetDistance();
+    void handleSetBattery();
+};
+
+#define webService WebService::getInstance()
+
+#endif // WEB_SERVICE_H

firmware/esp32_ble_sim/include/services/wifi_service.h

@@ -0,0 +1,49 @@
+#ifndef WIFI_SERVICE_H
+#define WIFI_SERVICE_H
+
+#include <Arduino.h>
+
+// ============================================
+// WiFi Service
+// Manages WiFi STA and AP modes
+// ============================================
+class WiFiService {
+public:
+    static WiFiService& getInstance();
+
+    // Prevent copying
+    WiFiService(const WiFiService&) = delete;
+    WiFiService& operator=(const WiFiService&) = delete;
+
+    // Lifecycle
+    void setup();
+    void loop();
+
+    // State queries
+    bool isConnected() const { return wifiConnected; }
+    bool isApActive() const { return apModeActive; }
+    String getIP() const;
+
+    // Actions
+    void startAP();
+    void stopAP();
+    void reconnect();  // Trigger reconnection attempt
+
+private:
+    WiFiService() = default;
+
+    bool wifiConnected = false;
+    bool apModeActive = false;
+    unsigned long lastWifiAttempt = 0;
+    int wifiRetryCount = 0;
+
+    static const int MAX_WIFI_RETRIES = 5;
+
+    void connectToWiFi();
+    void startAPMode();
+    void stopAPMode();
+};
+
+#define wifiService WiFiService::getInstance()
+
+#endif // WIFI_SERVICE_H

firmware/esp32_ble_sim/include/web_portal.h

@@ -1,40 +0,0 @@
-#ifndef WEB_PORTAL_H
-#define WEB_PORTAL_H
-
-#include <Arduino.h>
-
-/**
- * Initialize and start the web portal
- * Runs on AP interface at 192.168.4.1
- */
-void setupWebPortal();
-
-/**
- * Handle web portal requests (call in loop)
- */
-void handleWebPortal();
-
-/**
- * Get status info for web portal display
- */
-struct PortalStatus {
-    bool wifiConnected;
-    bool mqttConnected;
-    String ipAddress;
-    String deviceType;
-    bool bleStarted;
-    uint32_t treadmillDistance;
-    uint8_t batteryLevel;
-};
-
-// Callback for resetting treadmill distance
-typedef void (*ResetDistanceCallback)();
-void setResetDistanceCallback(ResetDistanceCallback callback);
-
-// Callback for setting battery level
-typedef void (*SetBatteryCallback)(uint8_t level);
-void setSetBatteryCallback(SetBatteryCallback callback);
-
-void updatePortalStatus(const PortalStatus& status);
-
-#endif // WEB_PORTAL_H