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
+#ifndef CONFIG_SERVICE_H
-#define CONFIG_MANAGER_H
+#define CONFIG_SERVICE_H
 
 #include <Arduino.h>
 #include <Preferences.h>
 
 // ============================================
-// Configuration Structure
+// Config Service
+// Manages persistent configuration in NVS
 // ============================================
-struct DeviceConfig {
+class ConfigService {
-    bool configured = false;
-    String wifiSsid = "";
-    String wifiPassword = "";
-    String mqttHost = "";
-    uint16_t mqttPort = 1883;
-    String deviceId = "";
-};
-
-// ============================================
-// Configuration Manager Class
-// ============================================
-class ConfigManager {
 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& getWifiSsid() const { return wifiSsid; }
-    const String& getWifiPassword() const { return config.wifiPassword; }
+    const String& getWifiPassword() const { return wifiPassword; }
-    const String& getMqttHost() const { return config.mqttHost; }
+    const String& getMqttHost() const { return mqttHost; }
-    uint16_t getMqttPort() const { return config.mqttPort; }
+    uint16_t getMqttPort() const { return mqttPort; }
-    const String& getDeviceId() const { return config.deviceId; }
+    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
+#define configService ConfigService::getInstance()
-extern ConfigManager configManager;
 
-#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

firmware/esp32_ble_sim/src/config_manager.cpp

@@ -1,79 +0,0 @@
-#include "config_manager.h"
-#include "config.h"
-
-// Global instance
-ConfigManager configManager;
-
-ConfigManager::ConfigManager() {}
-
-bool ConfigManager::load() {
-    preferences.begin(NVS_NAMESPACE, true);  // Read-only
-
-    config.configured = preferences.getBool("configured", false);
-    config.wifiSsid = preferences.getString("wifi_ssid", "");
-    config.wifiPassword = preferences.getString("wifi_pass", "");
-    config.mqttHost = preferences.getString("mqtt_host", "");
-    config.mqttPort = preferences.getUShort("mqtt_port", DEFAULT_MQTT_PORT);
-    config.deviceId = preferences.getString("device_id", getDefaultDeviceId());
-
-    preferences.end();
-
-    return config.configured;
-}
-
-void ConfigManager::save() {
-    preferences.begin(NVS_NAMESPACE, false);  // Read-write
-
-    preferences.putBool("configured", config.configured);
-    preferences.putString("wifi_ssid", config.wifiSsid);
-    preferences.putString("wifi_pass", config.wifiPassword);
-    preferences.putString("mqtt_host", config.mqttHost);
-    preferences.putUShort("mqtt_port", config.mqttPort);
-    preferences.putString("device_id", config.deviceId);
-
-    preferences.end();
-
-    Serial.println("Configuration saved to NVS");
-}
-
-void ConfigManager::clear() {
-    preferences.begin(NVS_NAMESPACE, false);
-    preferences.clear();
-    preferences.end();
-
-    config = DeviceConfig();
-    Serial.println("Configuration cleared");
-}
-
-void ConfigManager::setWifiCredentials(const String& ssid, const String& password) {
-    config.wifiSsid = ssid;
-    config.wifiPassword = password;
-    if (ssid.length() > 0) {
-        config.configured = true;
-    }
-}
-
-void ConfigManager::setMqttConfig(const String& host, uint16_t port) {
-    config.mqttHost = host;
-    config.mqttPort = port;
-}
-
-void ConfigManager::setDeviceId(const String& id) {
-    config.deviceId = id.length() > 0 ? id : getDefaultDeviceId();
-}
-
-String ConfigManager::getAPName() const {
-    uint32_t chipId = 0;
-    for (int i = 0; i < 17; i += 8) {
-        chipId |= ((ESP.getEfuseMac() >> (40 - i)) & 0xff) << i;
-    }
-    return String(AP_SSID_PREFIX) + String(chipId, HEX);
-}
-
-String ConfigManager::getDefaultDeviceId() const {
-    uint32_t chipId = 0;
-    for (int i = 0; i < 17; i += 8) {
-        chipId |= ((ESP.getEfuseMac() >> (40 - i)) & 0xff) << i;
-    }
-    return String(DEFAULT_DEVICE_ID_PREFIX) + String(chipId, HEX);
-}

firmware/esp32_ble_sim/src/device_state.cpp

@@ -0,0 +1,104 @@
+#include "device_state.h"
+
+DeviceState& DeviceState::getInstance() {
+    static DeviceState instance;
+    return instance;
+}
+
+const char* DeviceState::getDeviceTypeString() const {
+    switch (deviceType) {
+        case DeviceType::HEART_RATE: return "Heart Rate";
+        case DeviceType::TREADMILL: return "Treadmill";
+        default: return "Not configured";
+    }
+}
+
+void DeviceState::setDeviceType(DeviceType type) {
+    if (deviceType != type) {
+        deviceType = type;
+        if (deviceTypeCallback) {
+            deviceTypeCallback(type);
+        }
+    }
+}
+
+void DeviceState::setHeartRate(uint8_t bpm) {
+    values.heartRate = bpm;
+    notifyValuesChanged();
+}
+
+void DeviceState::setBatteryLevel(uint8_t level) {
+    if (level > 100) level = 100;
+    values.batteryLevel = level;
+    notifyValuesChanged();
+}
+
+void DeviceState::setTreadmillSpeed(float speedKmh) {
+    values.treadmillSpeed = (uint16_t)(speedKmh * 100);
+    notifyValuesChanged();
+}
+
+void DeviceState::setTreadmillIncline(float inclinePercent) {
+    values.treadmillIncline = (int16_t)(inclinePercent * 10);
+    notifyValuesChanged();
+}
+
+void DeviceState::setTreadmillDistance(uint32_t meters) {
+    values.treadmillDistance = meters;
+    values.distanceAccumulator = (float)meters;
+    notifyValuesChanged();
+}
+
+void DeviceState::resetTreadmillDistance() {
+    values.treadmillDistance = 0;
+    values.distanceAccumulator = 0.0;
+    Serial.println("Treadmill distance reset to 0");
+    notifyValuesChanged();
+}
+
+void DeviceState::accumulateTreadmillDistance(float deltaSeconds) {
+    // Speed is in 0.01 km/h units
+    // meters per second = (speed/100) * 1000 / 3600 = speed / 360
+    values.distanceAccumulator += (values.treadmillSpeed / 360.0) * deltaSeconds;
+    values.treadmillDistance = (uint32_t)values.distanceAccumulator;
+}
+
+void DeviceState::setWifiConnected(bool connected, const String& ip) {
+    connectionState.wifiConnected = connected;
+    connectionState.ipAddress = connected ? ip : "";
+    notifyConnectionChanged();
+}
+
+void DeviceState::setMqttConnected(bool connected) {
+    connectionState.mqttConnected = connected;
+    notifyConnectionChanged();
+}
+
+void DeviceState::setBleClientConnected(bool connected) {
+    connectionState.bleClientConnected = connected;
+    notifyConnectionChanged();
+}
+
+void DeviceState::onDeviceTypeChanged(DeviceTypeChangedCallback callback) {
+    deviceTypeCallback = callback;
+}
+
+void DeviceState::onValuesChanged(ValuesChangedCallback callback) {
+    valuesCallback = callback;
+}
+
+void DeviceState::onConnectionChanged(ConnectionChangedCallback callback) {
+    connectionCallback = callback;
+}
+
+void DeviceState::notifyValuesChanged() {
+    if (valuesCallback) {
+        valuesCallback(values);
+    }
+}
+
+void DeviceState::notifyConnectionChanged() {
+    if (connectionCallback) {
+        connectionCallback(connectionState);
+    }
+}

firmware/esp32_ble_sim/src/main.cpp

@@ -4,377 +4,24 @@
  * Simulates BLE fitness devices (Heart Rate Monitor, Treadmill)
  * Controlled via MQTT from pyBTMCP server
  *
- * Features:
+ * Architecture:
- * - AP mode for configuration when not connected to WiFi (192.168.4.1)
+ * - device_state: Central state management with event callbacks
- * - Connects to configured WiFi for MQTT control
+ * - config_service: NVS persistence for configuration
- * - Configuration stored in NVS (flash once, configure via web)
+ * - wifi_service: WiFi STA/AP management
+ * - mqtt_service: MQTT client and message routing
+ * - ble_service: BLE GATT services and notifications
+ * - web_service: HTTP configuration portal
  */
 
 #include <Arduino.h>
-#include <WiFi.h>
-#include <PubSubClient.h>
-#include <ArduinoJson.h>
-#include <NimBLEDevice.h>
-
 #include "config.h"
-#include "config_manager.h"
+#include "device_state.h"
-#include "web_portal.h"
+#include "services/config_service.h"
-#include "ble_services.h"
+#include "services/wifi_service.h"
+#include "services/mqtt_service.h"
+#include "services/ble_service.h"
+#include "services/web_service.h"
 
-// ============================================
-// Global State
-// ============================================
-WiFiClient wifiClient;
-PubSubClient mqtt(wifiClient);
-
-// Current device configuration
-enum DeviceType {
-    DEVICE_NONE,
-    DEVICE_HEART_RATE,
-    DEVICE_TREADMILL
-};
-
-DeviceType currentDeviceType = DEVICE_NONE;
-bool bleStarted = false;
-bool wifiConnected = false;
-bool mqttConnected = false;
-bool apModeActive = false;
-
-// Simulated values
-uint8_t heartRate = 70;
-uint8_t batteryLevel = 100;       // Battery level 0-100%
-uint16_t treadmillSpeed = 0;      // 0.01 km/h resolution
-int16_t treadmillIncline = 0;     // 0.1% resolution
-uint32_t treadmillDistance = 0;   // Total distance in meters
-float distanceAccumulator = 0.0;  // Fractional distance accumulator
-
-// Timing
-unsigned long lastNotify = 0;
-unsigned long lastStatus = 0;
-unsigned long lastWifiAttempt = 0;
-unsigned long lastMqttAttempt = 0;
-
-// ============================================
-// WiFi Functions
-// ============================================
-void startAPMode() {
-    if (apModeActive) return;
-
-    WiFi.mode(WIFI_AP);
-    WiFi.softAPConfig(AP_IP, AP_GATEWAY, AP_SUBNET);
-    String apName = configManager.getAPName();
-    WiFi.softAP(apName.c_str(), AP_PASSWORD);
-    apModeActive = true;
-
-    Serial.println("\n========================================");
-    Serial.println("Access Point Started");
-    Serial.print("  SSID: ");
-    Serial.println(apName);
-    Serial.print("  Config URL: http://");
-    Serial.println(WiFi.softAPIP());
-    Serial.println("========================================\n");
-}
-
-void stopAPMode() {
-    if (!apModeActive) return;
-
-    WiFi.softAPdisconnect(true);
-    WiFi.mode(WIFI_STA);
-    apModeActive = false;
-
-    Serial.println("Access Point stopped (WiFi connected)");
-}
-
-void setupWiFi() {
-    if (configManager.isConfigured()) {
-        // Start in STA mode, try to connect
-        WiFi.mode(WIFI_STA);
-        Serial.println("Starting in STA mode (configured)");
-    } else {
-        // No config - start AP for setup
-        startAPMode();
-    }
-}
-
-void connectToWiFi() {
-    if (!configManager.isConfigured()) {
-        // Not configured - ensure AP is running
-        if (!apModeActive) {
-            startAPMode();
-        }
-        return;
-    }
-
-    if (WiFi.status() == WL_CONNECTED) {
-        if (!wifiConnected) {
-            wifiConnected = true;
-            Serial.print("WiFi connected! IP: ");
-            Serial.println(WiFi.localIP());
-
-            // Stop AP mode when connected
-            stopAPMode();
-        }
-        return;
-    }
-
-    // WiFi not connected
-    if (wifiConnected) {
-        // Was connected, now disconnected - start AP
-        wifiConnected = false;
-        mqttConnected = false;
-        Serial.println("WiFi disconnected!");
-        startAPMode();
-    }
-
-    // Don't spam connection attempts
-    if (millis() - lastWifiAttempt < WIFI_CONNECT_TIMEOUT) {
-        return;
-    }
-    lastWifiAttempt = millis();
-
-    // If AP is active, switch to AP+STA to allow connection attempts
-    if (apModeActive) {
-        WiFi.mode(WIFI_AP_STA);
-    }
-
-    Serial.print("Connecting to WiFi: ");
-    Serial.println(configManager.getWifiSsid());
-
-    WiFi.begin(
-        configManager.getWifiSsid().c_str(),
-        configManager.getWifiPassword().c_str()
-    );
-}
-
-// ============================================
-// MQTT Functions
-// ============================================
-void publishStatus() {
-    if (!mqtt.connected()) return;
-
-    JsonDocument doc;
-    doc["online"] = true;
-    doc["firmware_version"] = FIRMWARE_VERSION;
-
-    const char* typeStr = "none";
-    if (currentDeviceType == DEVICE_HEART_RATE) typeStr = "heart_rate";
-    else if (currentDeviceType == DEVICE_TREADMILL) typeStr = "treadmill";
-    doc["type"] = typeStr;
-
-    doc["ble_started"] = bleStarted;
-    doc["ip"] = WiFi.localIP().toString();
-
-    String payload;
-    serializeJson(doc, payload);
-
-    String topic = String("ble-sim/") + configManager.getDeviceId() + "/status";
-    mqtt.publish(topic.c_str(), payload.c_str(), true);  // retained
-}
-
-void publishValues() {
-    if (!mqtt.connected()) return;
-
-    JsonDocument doc;
-
-    if (currentDeviceType == DEVICE_HEART_RATE) {
-        doc["heart_rate"] = heartRate;
-        doc["battery"] = batteryLevel;
-    } else if (currentDeviceType == DEVICE_TREADMILL) {
-        doc["speed"] = treadmillSpeed / 100.0;
-        doc["incline"] = treadmillIncline / 10.0;
-        doc["distance"] = treadmillDistance;
-    }
-
-    String payload;
-    serializeJson(doc, payload);
-
-    String topic = String("ble-sim/") + configManager.getDeviceId() + "/values";
-    mqtt.publish(topic.c_str(), payload.c_str());
-}
-
-void handleMqttMessage(char* topic, byte* payload, unsigned int length) {
-    JsonDocument doc;
-    DeserializationError error = deserializeJson(doc, payload, length);
-
-    if (error) {
-        Serial.print("JSON parse error: ");
-        Serial.println(error.c_str());
-        return;
-    }
-
-    String topicStr = String(topic);
-    String baseTopic = String("ble-sim/") + configManager.getDeviceId();
-
-    // Handle configuration
-    if (topicStr == baseTopic + "/config") {
-        String type = doc["type"] | "";
-
-        Serial.print("Configuring as: ");
-        Serial.println(type);
-
-        if (type == "heart_rate") {
-            currentDeviceType = DEVICE_HEART_RATE;
-            setupBLE_HeartRate();
-            bleStarted = true;
-        } else if (type == "treadmill") {
-            currentDeviceType = DEVICE_TREADMILL;
-            setupBLE_Treadmill();
-            bleStarted = true;
-        } else {
-            currentDeviceType = DEVICE_NONE;
-            stopBLE();
-            bleStarted = false;
-        }
-
-        publishStatus();
-    }
-    // Handle value updates
-    else if (topicStr == baseTopic + "/set") {
-        if (doc["heart_rate"].is<int>()) {
-            heartRate = doc["heart_rate"];
-            Serial.print("Heart rate set to: ");
-            Serial.println(heartRate);
-        }
-        if (doc["battery"].is<int>()) {
-            batteryLevel = doc["battery"];
-            if (batteryLevel > 100) batteryLevel = 100;
-            updateBatteryLevel(batteryLevel);
-            Serial.print("Battery level set to: ");
-            Serial.println(batteryLevel);
-        }
-        if (doc["speed"].is<float>()) {
-            float speed = doc["speed"];
-            treadmillSpeed = (uint16_t)(speed * 100);
-            Serial.print("Speed set to: ");
-            Serial.println(speed);
-        }
-        if (doc["incline"].is<float>()) {
-            float incline = doc["incline"];
-            treadmillIncline = (int16_t)(incline * 10);
-            Serial.print("Incline set to: ");
-            Serial.println(incline);
-        }
-        if (doc["distance"].is<int>()) {
-            treadmillDistance = doc["distance"];
-            distanceAccumulator = (float)treadmillDistance;  // Sync accumulator
-            Serial.print("Distance set to: ");
-            Serial.println(treadmillDistance);
-        }
-
-        publishValues();
-    }
-}
-
-void setupMQTT() {
-    mqtt.setCallback(handleMqttMessage);
-    mqtt.setBufferSize(512);
-}
-
-void connectToMQTT() {
-    if (!configManager.isConfigured() || !wifiConnected) {
-        return;
-    }
-
-    if (mqtt.connected()) {
-        if (!mqttConnected) {
-            mqttConnected = true;
-        }
-        return;
-    }
-
-    // Don't spam connection attempts
-    if (millis() - lastMqttAttempt < MQTT_RECONNECT_INTERVAL) {
-        return;
-    }
-    lastMqttAttempt = millis();
-
-    mqttConnected = false;
-
-    // Update MQTT server config
-    mqtt.setServer(
-        configManager.getMqttHost().c_str(),
-        configManager.getMqttPort()
-    );
-
-    Serial.print("Connecting to MQTT at ");
-    Serial.print(configManager.getMqttHost());
-    Serial.print(":");
-    Serial.println(configManager.getMqttPort());
-
-    String clientId = String("esp32-") + String(random(0xffff), HEX);
-
-    // Set up Last Will and Testament (LWT) for disconnect detection
-    String statusTopic = String("ble-sim/") + configManager.getDeviceId() + "/status";
-    String willMessage = "{\"online\":false}";
-
-    // Connect with LWT: topic, QoS 1, retain true, message
-    if (mqtt.connect(clientId.c_str(), statusTopic.c_str(), 1, true, willMessage.c_str())) {
-        mqttConnected = true;
-        Serial.println("MQTT connected with LWT!");
-
-        // Subscribe to control topics
-        String configTopic = String("ble-sim/") + configManager.getDeviceId() + "/config";
-        String setTopic = String("ble-sim/") + configManager.getDeviceId() + "/set";
-
-        mqtt.subscribe(configTopic.c_str());
-        mqtt.subscribe(setTopic.c_str());
-
-        Serial.print("Subscribed to: ");
-        Serial.println(configTopic);
-
-        // Publish initial status (with retain so new subscribers see current state)
-        publishStatus();
-    } else {
-        Serial.print("MQTT connection failed, rc=");
-        Serial.println(mqtt.state());
-    }
-}
-
-// ============================================
-// Reset Treadmill Distance
-// ============================================
-void resetTreadmillDistance() {
-    treadmillDistance = 0;
-    distanceAccumulator = 0.0;
-    Serial.println("Treadmill distance reset to 0");
-}
-
-// ============================================
-// Set Battery Level (from web UI)
-// ============================================
-void setBatteryLevelCallback(uint8_t level) {
-    batteryLevel = level;
-    updateBatteryLevel(batteryLevel);
-    Serial.print("Battery level set via web UI: ");
-    Serial.println(batteryLevel);
-}
-
-// ============================================
-// Update Portal Status
-// ============================================
-void updateStatus() {
-    PortalStatus status;
-    status.wifiConnected = wifiConnected;
-    status.mqttConnected = mqttConnected;
-    status.bleStarted = bleStarted;
-    status.ipAddress = wifiConnected ? WiFi.localIP().toString() : "";
-    status.treadmillDistance = treadmillDistance;
-    status.batteryLevel = batteryLevel;
-
-    if (currentDeviceType == DEVICE_HEART_RATE) {
-        status.deviceType = "Heart Rate";
-    } else if (currentDeviceType == DEVICE_TREADMILL) {
-        status.deviceType = "Treadmill";
-    } else {
-        status.deviceType = "Not configured";
-    }
-
-    updatePortalStatus(status);
-}
-
-// ============================================
-// Main Setup & Loop
-// ============================================
 void setup() {
     Serial.begin(115200);
     delay(1000);
@@ -386,28 +33,20 @@ void setup() {
     Serial.println("========================================\n");
 
     // Load configuration from NVS
-    bool hasConfig = configManager.load();
+    bool hasConfig = configService.load();
     Serial.print("Device ID: ");
-    Serial.println(configManager.getDeviceId());
+    Serial.println(configService.getDeviceId());
     Serial.print("Configured: ");
     Serial.println(hasConfig ? "Yes" : "No");
 
-    // Start WiFi (AP always on, STA if configured)
+    // Initialize all services
-    setupWiFi();
+    wifiService.setup();
-
+    webService.setup();
-    // Start web configuration portal
+    mqttService.setup();
-    setupWebPortal();
+    bleService.setup();
-    setResetDistanceCallback(resetTreadmillDistance);
-    setSetBatteryCallback(setBatteryLevelCallback);
-
-    // Initialize MQTT
-    setupMQTT();
-
-    // Initialize BLE (don't start advertising yet)
-    initBLE();
 
     Serial.println("\nReady!");
-    if (!configManager.isConfigured()) {
+    if (!configService.isConfigured()) {
         Serial.println("Configure at: http://192.168.4.1");
     } else {
         Serial.println("Connecting to WiFi...");
@@ -416,39 +55,9 @@ void setup() {
 }
 
 void loop() {
-    // Handle web portal requests
+    // Run all service loops
-    handleWebPortal();
+    wifiService.loop();
-
+    webService.loop();
-    // Maintain WiFi STA connection (if configured)
+    mqttService.loop();
-    connectToWiFi();
+    bleService.loop();
-
-    // Maintain MQTT connection
-    connectToMQTT();
-    mqtt.loop();
-
-    // Update portal status display
-    updateStatus();
-
-    // Send BLE notifications
-    if (bleStarted && millis() - lastNotify >= BLE_NOTIFY_INTERVAL) {
-        lastNotify = millis();
-
-        if (currentDeviceType == DEVICE_HEART_RATE) {
-            notifyHeartRate(heartRate);
-        } else if (currentDeviceType == DEVICE_TREADMILL) {
-            // Accumulate distance based on speed
-            // Speed is in 0.01 km/h units, interval is 1 second
-            // meters per second = (speed/100) * 1000 / 3600 = speed / 360
-            distanceAccumulator += treadmillSpeed / 360.0;
-            treadmillDistance = (uint32_t)distanceAccumulator;
-
-            notifyTreadmill(treadmillSpeed, treadmillIncline, treadmillDistance);
-        }
-    }
-
-    // Periodic status report to MQTT
-    if (mqttConnected && millis() - lastStatus >= STATUS_REPORT_INTERVAL) {
-        lastStatus = millis();
-        publishStatus();
-    }
 }

firmware/esp32_ble_sim/src/services/ble_service.cpp

@@ -1,14 +1,6 @@
-/**
+#include "services/ble_service.h"
- * BLE Services Implementation
+#include "device_state.h"
- *
- * Implements standard Bluetooth SIG GATT services:
- * - Heart Rate Service (0x180D)
- * - Fitness Machine Service (0x1826) - Treadmill
- */
-
-#include "ble_services.h"
 #include "config.h"
-#include "config_manager.h"
 #include <NimBLEDevice.h>
 
 // ============================================
@@ -16,41 +8,80 @@
 // ============================================
 static NimBLEServer* pServer = nullptr;
 static NimBLEAdvertising* pAdvertising = nullptr;
-
-// Heart Rate
 static NimBLECharacteristic* pHeartRateMeasurement = nullptr;
-
-// Battery
 static NimBLECharacteristic* pBatteryLevel = nullptr;
-
-// Treadmill
 static NimBLECharacteristic* pTreadmillData = nullptr;
 
-static bool deviceConnected = false;
+static bool bleInitialized = false;
-static bool oldDeviceConnected = false;
+
+// Forward declare for callback
+static void onBleConnect();
+static void onBleDisconnect();
 
 // ============================================
 // Server Callbacks
 // ============================================
 class ServerCallbacks : public NimBLEServerCallbacks {
     void onConnect(NimBLEServer* pServer) override {
-        deviceConnected = true;
+        onBleConnect();
-        Serial.println("BLE client connected");
     }
 
     void onDisconnect(NimBLEServer* pServer) override {
-        deviceConnected = false;
+        onBleDisconnect();
-        Serial.println("BLE client disconnected");
-
-        // Restart advertising
-        NimBLEDevice::startAdvertising();
     }
 };
 
+static void onBleConnect() {
+    deviceState.setBleClientConnected(true);
+    Serial.println("BLE client connected");
+}
+
+static void onBleDisconnect() {
+    deviceState.setBleClientConnected(false);
+    Serial.println("BLE client disconnected");
+    NimBLEDevice::startAdvertising();
+}
+
 // ============================================
-// BLE Initialization
+// Singleton
 // ============================================
-void initBLE() {
+BleService& BleService::getInstance() {
+    static BleService instance;
+    return instance;
+}
+
+// ============================================
+// Lifecycle
+// ============================================
+void BleService::setup() {
+    initBLE();
+}
+
+void BleService::loop() {
+    if (!deviceState.isBleStarted()) return;
+
+    // Send notifications at regular intervals
+    if (millis() - lastNotify >= BLE_NOTIFY_INTERVAL) {
+        lastNotify = millis();
+
+        const auto& values = deviceState.getValues();
+
+        if (deviceState.getDeviceType() == DeviceType::HEART_RATE) {
+            notifyHeartRate(values.heartRate);
+        } else if (deviceState.getDeviceType() == DeviceType::TREADMILL) {
+            // Accumulate distance
+            deviceState.accumulateTreadmillDistance(BLE_NOTIFY_INTERVAL / 1000.0);
+            const auto& updatedValues = deviceState.getValues();
+            notifyTreadmill(updatedValues.treadmillSpeed,
+                           updatedValues.treadmillIncline,
+                           updatedValues.treadmillDistance);
+        }
+    }
+}
+
+void BleService::initBLE() {
+    if (bleInitialized) return;
+
     NimBLEDevice::init("BLE Simulator");
     NimBLEDevice::setPower(ESP_PWR_LVL_P9);
 
@@ -59,15 +90,15 @@ void initBLE() {
 
     pAdvertising = NimBLEDevice::getAdvertising();
 
+    bleInitialized = true;
     Serial.println("BLE initialized");
 }
 
-void stopBLE() {
+void BleService::stop() {
     if (pAdvertising) {
         pAdvertising->stop();
     }
 
-    // Clear services (will be recreated on next setup)
     pHeartRateMeasurement = nullptr;
     pBatteryLevel = nullptr;
     pTreadmillData = nullptr;
@@ -78,10 +109,9 @@ void stopBLE() {
 // ============================================
 // Heart Rate Service Setup
 // ============================================
-void setupBLE_HeartRate() {
+void BleService::setupHeartRate() {
     Serial.println("Setting up Heart Rate Service...");
 
-    // Stop any current advertising
     if (pAdvertising) {
         pAdvertising->stop();
     }
@@ -89,16 +119,11 @@ void setupBLE_HeartRate() {
     // Create Heart Rate Service
     NimBLEService* pHRService = pServer->createService(HEART_RATE_SERVICE_UUID);
 
-    // Heart Rate Measurement Characteristic
-    // Flags: Notify
     pHeartRateMeasurement = pHRService->createCharacteristic(
         HEART_RATE_MEASUREMENT_UUID,
         NIMBLE_PROPERTY::NOTIFY
     );
 
-    // Body Sensor Location Characteristic
-    // Flags: Read
-    // Value: 1 = Chest
     NimBLECharacteristic* pBodySensorLocation = pHRService->createCharacteristic(
         BODY_SENSOR_LOCATION_UUID,
         NIMBLE_PROPERTY::READ
@@ -106,22 +131,18 @@ void setupBLE_HeartRate() {
     uint8_t sensorLocation = 1; // Chest
     pBodySensorLocation->setValue(&sensorLocation, 1);
 
-    // Start Heart Rate service
     pHRService->start();
 
     // Create Battery Service
     NimBLEService* pBatteryService = pServer->createService(BATTERY_SERVICE_UUID);
 
-    // Battery Level Characteristic
-    // Flags: Read, Notify
     pBatteryLevel = pBatteryService->createCharacteristic(
         BATTERY_LEVEL_UUID,
         NIMBLE_PROPERTY::READ | NIMBLE_PROPERTY::NOTIFY
     );
-    uint8_t initialBattery = 100;
+    uint8_t initialBattery = deviceState.getValues().batteryLevel;
     pBatteryLevel->setValue(&initialBattery, 1);
 
-    // Start Battery service
     pBatteryService->start();
 
     // Configure advertising
@@ -131,145 +152,94 @@ void setupBLE_HeartRate() {
     pAdvertising->setMinPreferred(0x06);
     pAdvertising->setMaxPreferred(0x12);
 
-    // Update device name
     NimBLEDevice::setDeviceName("HR Simulator");
-
-    // Start advertising
     NimBLEDevice::startAdvertising();
 
     Serial.println("Heart Rate + Battery Services started, advertising...");
 }
 
 // ============================================
-// Treadmill (Fitness Machine) Service Setup
+// Treadmill Service Setup
 // ============================================
-void setupBLE_Treadmill() {
+void BleService::setupTreadmill() {
     Serial.println("Setting up Fitness Machine Service (Treadmill)...");
 
-    // Stop any current advertising
     if (pAdvertising) {
         pAdvertising->stop();
     }
 
-    // Create Fitness Machine Service
     NimBLEService* pService = pServer->createService(FITNESS_MACHINE_SERVICE_UUID);
 
-    // Fitness Machine Feature Characteristic
-    // Flags: Read
     NimBLECharacteristic* pFeature = pService->createCharacteristic(
         FITNESS_MACHINE_FEATURE_UUID,
         NIMBLE_PROPERTY::READ
     );
 
-    // Feature flags for treadmill:
-    // Byte 0-3: Fitness Machine Features
-    //   Bit 0: Average Speed Supported
-    //   Bit 1: Cadence Supported
-    //   Bit 2: Total Distance Supported
-    //   Bit 3: Inclination Supported
-    //   Bit 13: Elapsed Time Supported
-    // Byte 4-7: Target Setting Features
     uint8_t featureData[8] = {
-        0x0B, 0x20, 0x00, 0x00,  // Features: Speed, Cadence, Distance, Inclination, Elapsed Time
+        0x0B, 0x20, 0x00, 0x00,
-        0x00, 0x00, 0x00, 0x00   // Target settings (none)
+        0x00, 0x00, 0x00, 0x00
     };
     pFeature->setValue(featureData, 8);
 
-    // Treadmill Data Characteristic
-    // Flags: Notify
     pTreadmillData = pService->createCharacteristic(
         TREADMILL_DATA_UUID,
         NIMBLE_PROPERTY::NOTIFY
     );
 
-    // Start the service
     pService->start();
 
-    // Configure advertising
     pAdvertising->addServiceUUID(FITNESS_MACHINE_SERVICE_UUID);
     pAdvertising->setScanResponse(true);
     pAdvertising->setMinPreferred(0x06);
     pAdvertising->setMaxPreferred(0x12);
 
-    // Update device name
     NimBLEDevice::setDeviceName("Treadmill Sim");
-
-    // Start advertising
     NimBLEDevice::startAdvertising();
 
     Serial.println("Fitness Machine Service (Treadmill) started, advertising...");
 }
 
 // ============================================
-// Heart Rate Notification
+// Notifications
 // ============================================
-void notifyHeartRate(uint8_t bpm) {
+void BleService::notifyHeartRate(uint8_t bpm) {
-    if (!pHeartRateMeasurement || !deviceConnected) return;
+    if (!pHeartRateMeasurement || !deviceState.getConnectionState().bleClientConnected) return;
 
-    // Heart Rate Measurement format:
-    // Byte 0: Flags
-    //   Bit 0: Heart Rate Value Format (0 = UINT8, 1 = UINT16)
-    //   Bit 1-2: Sensor Contact Status
-    //   Bit 3: Energy Expended Status
-    //   Bit 4: RR-Interval
-    // Byte 1: Heart Rate Value (UINT8)
     uint8_t hrData[2];
-    hrData[0] = 0x00;  // Flags: UINT8 format, no contact detection
+    hrData[0] = 0x00;  // Flags
     hrData[1] = bpm;
 
     pHeartRateMeasurement->setValue(hrData, 2);
     pHeartRateMeasurement->notify();
 }
 
-// ============================================
+void BleService::updateBattery(uint8_t level) {
-// Battery Level Update
-// ============================================
-void updateBatteryLevel(uint8_t level) {
     if (!pBatteryLevel) return;
 
-    // Clamp to 0-100
     if (level > 100) level = 100;
-
     pBatteryLevel->setValue(&level, 1);
     pBatteryLevel->notify();
 }
 
-// ============================================
+void BleService::notifyTreadmill(uint16_t speed, int16_t incline, uint32_t distance) {
-// Treadmill Data Notification
+    if (!pTreadmillData || !deviceState.getConnectionState().bleClientConnected) return;
-// ============================================
-void notifyTreadmill(uint16_t speed, int16_t incline, uint32_t distance) {
-    if (!pTreadmillData || !deviceConnected) return;
 
-    // Treadmill Data format (per Bluetooth FTMS spec):
-    // Byte 0-1: Flags
-    //   Bit 0: More Data (0 = Instantaneous Speed present)
-    //   Bit 1: Average Speed present
-    //   Bit 2: Total Distance present
-    //   Bit 3: Inclination and Ramp Angle present
-    // Following bytes: Data fields based on flags (in order of flag bits)
-
-    // We'll include: Instantaneous Speed + Total Distance + Inclination + Ramp Angle
     uint8_t data[11];
 
-    // Flags: Total Distance present (bit 2) + Inclination and Ramp Angle present (bit 3)
     uint16_t flags = 0x000C;
     data[0] = flags & 0xFF;
     data[1] = (flags >> 8) & 0xFF;
 
-    // Instantaneous Speed (always present when More Data=0, uint16, 0.01 km/h resolution)
     data[2] = speed & 0xFF;
     data[3] = (speed >> 8) & 0xFF;
 
-    // Total Distance (uint24, meters) - 3 bytes, little endian
     data[4] = distance & 0xFF;
     data[5] = (distance >> 8) & 0xFF;
     data[6] = (distance >> 16) & 0xFF;
 
-    // Inclination (sint16, 0.1% resolution)
     data[7] = incline & 0xFF;
     data[8] = (incline >> 8) & 0xFF;
 
-    // Ramp Angle Setting (sint16, 0.1 degree resolution) - set to 0
     int16_t rampAngle = 0;
     data[9] = rampAngle & 0xFF;
     data[10] = (rampAngle >> 8) & 0xFF;

firmware/esp32_ble_sim/src/services/config_service.cpp

@@ -0,0 +1,85 @@
+#include "services/config_service.h"
+#include "config.h"
+
+ConfigService& ConfigService::getInstance() {
+    static ConfigService instance;
+    return instance;
+}
+
+bool ConfigService::load() {
+    preferences.begin(NVS_NAMESPACE, true);  // Read-only
+
+    configured = preferences.getBool("configured", false);
+    wifiSsid = preferences.getString("wifi_ssid", "");
+    wifiPassword = preferences.getString("wifi_pass", "");
+    mqttHost = preferences.getString("mqtt_host", "");
+    mqttPort = preferences.getUShort("mqtt_port", DEFAULT_MQTT_PORT);
+    deviceId = preferences.getString("device_id", getDefaultDeviceId());
+
+    preferences.end();
+
+    return configured;
+}
+
+void ConfigService::save() {
+    preferences.begin(NVS_NAMESPACE, false);  // Read-write
+
+    preferences.putBool("configured", configured);
+    preferences.putString("wifi_ssid", wifiSsid);
+    preferences.putString("wifi_pass", wifiPassword);
+    preferences.putString("mqtt_host", mqttHost);
+    preferences.putUShort("mqtt_port", mqttPort);
+    preferences.putString("device_id", deviceId);
+
+    preferences.end();
+
+    Serial.println("Configuration saved to NVS");
+}
+
+void ConfigService::clear() {
+    preferences.begin(NVS_NAMESPACE, false);
+    preferences.clear();
+    preferences.end();
+
+    configured = false;
+    wifiSsid = "";
+    wifiPassword = "";
+    mqttHost = "";
+    mqttPort = DEFAULT_MQTT_PORT;
+    deviceId = "";
+
+    Serial.println("Configuration cleared");
+}
+
+void ConfigService::setWifiCredentials(const String& ssid, const String& password) {
+    wifiSsid = ssid;
+    wifiPassword = password;
+    if (ssid.length() > 0) {
+        configured = true;
+    }
+}
+
+void ConfigService::setMqttConfig(const String& host, uint16_t port) {
+    mqttHost = host;
+    mqttPort = port;
+}
+
+void ConfigService::setDeviceId(const String& id) {
+    deviceId = id.length() > 0 ? id : getDefaultDeviceId();
+}
+
+String ConfigService::getAPName() const {
+    uint32_t chipId = 0;
+    for (int i = 0; i < 17; i += 8) {
+        chipId |= ((ESP.getEfuseMac() >> (40 - i)) & 0xff) << i;
+    }
+    return String(AP_SSID_PREFIX) + String(chipId, HEX);
+}
+
+String ConfigService::getDefaultDeviceId() const {
+    uint32_t chipId = 0;
+    for (int i = 0; i < 17; i += 8) {
+        chipId |= ((ESP.getEfuseMac() >> (40 - i)) & 0xff) << i;
+    }
+    return String(DEFAULT_DEVICE_ID_PREFIX) + String(chipId, HEX);
+}

firmware/esp32_ble_sim/src/services/mqtt_service.cpp

@@ -0,0 +1,203 @@
+#include "services/mqtt_service.h"
+#include "services/config_service.h"
+#include "services/wifi_service.h"
+#include "services/ble_service.h"
+#include "device_state.h"
+#include "config.h"
+#include <WiFi.h>
+#include <PubSubClient.h>
+#include <ArduinoJson.h>
+
+// MQTT client (needs WiFiClient)
+static WiFiClient wifiClient;
+static PubSubClient mqtt(wifiClient);
+
+MqttService& MqttService::getInstance() {
+    static MqttService instance;
+    return instance;
+}
+
+void MqttService::messageCallback(char* topic, byte* payload, unsigned int length) {
+    getInstance().handleMessage(topic, payload, length);
+}
+
+void MqttService::setup() {
+    mqtt.setCallback(messageCallback);
+    mqtt.setBufferSize(512);
+}
+
+void MqttService::loop() {
+    connectToMQTT();
+    mqtt.loop();
+
+    // Periodic status report
+    if (mqttConnected && millis() - lastStatusReport >= STATUS_REPORT_INTERVAL) {
+        lastStatusReport = millis();
+        publishStatus();
+    }
+}
+
+void MqttService::connectToMQTT() {
+    if (!configService.isConfigured() || !wifiService.isConnected()) {
+        return;
+    }
+
+    if (mqtt.connected()) {
+        if (!mqttConnected) {
+            mqttConnected = true;
+            deviceState.setMqttConnected(true);
+        }
+        return;
+    }
+
+    // Don't spam connection attempts
+    if (millis() - lastMqttAttempt < MQTT_RECONNECT_INTERVAL) {
+        return;
+    }
+    lastMqttAttempt = millis();
+
+    mqttConnected = false;
+    deviceState.setMqttConnected(false);
+
+    mqtt.setServer(
+        configService.getMqttHost().c_str(),
+        configService.getMqttPort()
+    );
+
+    Serial.print("Connecting to MQTT at ");
+    Serial.print(configService.getMqttHost());
+    Serial.print(":");
+    Serial.println(configService.getMqttPort());
+
+    String clientId = String("esp32-") + String(random(0xffff), HEX);
+
+    // LWT for disconnect detection
+    String statusTopic = String("ble-sim/") + configService.getDeviceId() + "/status";
+    String willMessage = "{\"online\":false}";
+
+    if (mqtt.connect(clientId.c_str(), statusTopic.c_str(), 1, true, willMessage.c_str())) {
+        mqttConnected = true;
+        deviceState.setMqttConnected(true);
+        Serial.println("MQTT connected with LWT!");
+
+        // Subscribe to control topics
+        String configTopic = String("ble-sim/") + configService.getDeviceId() + "/config";
+        String setTopic = String("ble-sim/") + configService.getDeviceId() + "/set";
+
+        mqtt.subscribe(configTopic.c_str());
+        mqtt.subscribe(setTopic.c_str());
+
+        Serial.print("Subscribed to: ");
+        Serial.println(configTopic);
+
+        publishStatus();
+    } else {
+        Serial.print("MQTT connection failed, rc=");
+        Serial.println(mqtt.state());
+    }
+}
+
+void MqttService::handleMessage(char* topic, byte* payload, unsigned int length) {
+    JsonDocument doc;
+    DeserializationError error = deserializeJson(doc, payload, length);
+
+    if (error) {
+        Serial.print("JSON parse error: ");
+        Serial.println(error.c_str());
+        return;
+    }
+
+    String topicStr = String(topic);
+    String baseTopic = String("ble-sim/") + configService.getDeviceId();
+
+    // Handle device type configuration
+    if (topicStr == baseTopic + "/config") {
+        String type = doc["type"] | "";
+
+        Serial.print("Configuring as: ");
+        Serial.println(type);
+
+        if (type == "heart_rate") {
+            deviceState.setDeviceType(DeviceType::HEART_RATE);
+            bleService.setupHeartRate();
+        } else if (type == "treadmill") {
+            deviceState.setDeviceType(DeviceType::TREADMILL);
+            bleService.setupTreadmill();
+        } else {
+            deviceState.setDeviceType(DeviceType::NONE);
+            bleService.stop();
+        }
+
+        publishStatus();
+    }
+    // Handle value updates
+    else if (topicStr == baseTopic + "/set") {
+        if (doc["heart_rate"].is<int>()) {
+            deviceState.setHeartRate(doc["heart_rate"]);
+            Serial.print("Heart rate set to: ");
+            Serial.println(deviceState.getValues().heartRate);
+        }
+        if (doc["battery"].is<int>()) {
+            deviceState.setBatteryLevel(doc["battery"]);
+            bleService.updateBattery(deviceState.getValues().batteryLevel);
+            Serial.print("Battery level set to: ");
+            Serial.println(deviceState.getValues().batteryLevel);
+        }
+        if (doc["speed"].is<float>()) {
+            deviceState.setTreadmillSpeed(doc["speed"]);
+            Serial.print("Speed set to: ");
+            Serial.println(doc["speed"].as<float>());
+        }
+        if (doc["incline"].is<float>()) {
+            deviceState.setTreadmillIncline(doc["incline"]);
+            Serial.print("Incline set to: ");
+            Serial.println(doc["incline"].as<float>());
+        }
+        if (doc["distance"].is<int>()) {
+            deviceState.setTreadmillDistance(doc["distance"]);
+            Serial.print("Distance set to: ");
+            Serial.println(deviceState.getValues().treadmillDistance);
+        }
+
+        publishValues();
+    }
+}
+
+void MqttService::publishStatus() {
+    if (!mqtt.connected()) return;
+
+    JsonDocument doc;
+    doc["online"] = true;
+    doc["firmware_version"] = FIRMWARE_VERSION;
+    doc["type"] = deviceState.getDeviceTypeString();
+    doc["ble_started"] = deviceState.isBleStarted();
+    doc["ip"] = wifiService.getIP();
+
+    String payload;
+    serializeJson(doc, payload);
+
+    String topic = String("ble-sim/") + configService.getDeviceId() + "/status";
+    mqtt.publish(topic.c_str(), payload.c_str(), true);
+}
+
+void MqttService::publishValues() {
+    if (!mqtt.connected()) return;
+
+    JsonDocument doc;
+    const auto& values = deviceState.getValues();
+
+    if (deviceState.getDeviceType() == DeviceType::HEART_RATE) {
+        doc["heart_rate"] = values.heartRate;
+        doc["battery"] = values.batteryLevel;
+    } else if (deviceState.getDeviceType() == DeviceType::TREADMILL) {
+        doc["speed"] = values.treadmillSpeed / 100.0;
+        doc["incline"] = values.treadmillIncline / 10.0;
+        doc["distance"] = values.treadmillDistance;
+    }
+
+    String payload;
+    serializeJson(doc, payload);
+
+    String topic = String("ble-sim/") + configService.getDeviceId() + "/values";
+    mqtt.publish(topic.c_str(), payload.c_str());
+}

firmware/esp32_ble_sim/src/services/web_service.cpp

@@ -1,12 +1,11 @@
-#include "web_portal.h"
+#include "services/web_service.h"
-#include "config_manager.h"
+#include "services/config_service.h"
+#include "services/wifi_service.h"
+#include "device_state.h"
 #include <WebServer.h>
 #include <ArduinoJson.h>
 
-WebServer server(80);
+static WebServer server(80);
-PortalStatus currentStatus = {};
-ResetDistanceCallback resetDistanceCallback = nullptr;
-SetBatteryCallback setBatteryCallback = nullptr;
 
 // HTML template with embedded CSS and JS
 const char INDEX_HTML[] PROGMEM = R"rawliteral(
@@ -108,7 +107,7 @@ const char INDEX_HTML[] PROGMEM = R"rawliteral(
 </head>
 <body>
     <h1>BLE Simulator</h1>
-    <p class="subtitle"><span id="apName">Loading...</span> &bull; UI v1.1.0</p>
+    <p class="subtitle"><span id="apName">Loading...</span> &bull; UI v1.2.0</p>
 
     <div class="card">
         <h2>Status</h2>
@@ -178,7 +177,6 @@ const char INDEX_HTML[] PROGMEM = R"rawliteral(
     <script>
         let configLoaded = false;
 
-        // Load config once on page load
         async function loadConfig() {
             try {
                 const res = await fetch('/api/status');
@@ -197,7 +195,6 @@ const char INDEX_HTML[] PROGMEM = R"rawliteral(
             }
         }
 
-        // Update only status indicators (not form fields)
         async function updateStatus() {
             try {
                 const res = await fetch('/api/status');
@@ -205,7 +202,6 @@ const char INDEX_HTML[] PROGMEM = R"rawliteral(
                 updateStatusDots(data.status);
             } catch (e) {
                 console.error('Failed to update status:', e);
-                // Show disconnected state when device is unreachable
                 updateStatusDots({
                     wifiConnected: false,
                     mqttConnected: false,
@@ -230,7 +226,6 @@ const char INDEX_HTML[] PROGMEM = R"rawliteral(
 
             document.getElementById('ipAddr').textContent = status.ipAddress || '-';
 
-            // Show heart rate card only when configured as heart rate
             const heartRateCard = document.getElementById('heartRateCard');
             if (status.deviceType === 'Heart Rate') {
                 heartRateCard.classList.remove('hidden');
@@ -240,7 +235,6 @@ const char INDEX_HTML[] PROGMEM = R"rawliteral(
                 heartRateCard.classList.add('hidden');
             }
 
-            // Show treadmill card only when configured as treadmill
             const treadmillCard = document.getElementById('treadmillCard');
             if (status.deviceType === 'Treadmill') {
                 treadmillCard.classList.remove('hidden');
@@ -302,7 +296,6 @@ const char INDEX_HTML[] PROGMEM = R"rawliteral(
             }
         }
 
-        // Battery slider handler
         document.getElementById('batterySlider').addEventListener('input', async (e) => {
             const level = e.target.value;
             document.getElementById('batteryValue').textContent = level + '%';
@@ -317,7 +310,6 @@ const char INDEX_HTML[] PROGMEM = R"rawliteral(
             }
         });
 
-        // Load config with retry, then update status periodically
         async function init() {
             let retries = 3;
             while (retries > 0) {
@@ -337,36 +329,44 @@ const char INDEX_HTML[] PROGMEM = R"rawliteral(
 </html>
 )rawliteral";
 
-void handleRoot() {
+WebService& WebService::getInstance() {
+    static WebService instance;
+    return instance;
+}
+
+void WebService::handleRoot() {
     server.send(200, "text/html", INDEX_HTML);
 }
 
-void handleGetStatus() {
+void WebService::handleGetStatus() {
     JsonDocument doc;
 
-    doc["apName"] = configManager.getAPName();
+    doc["apName"] = configService.getAPName();
 
     JsonObject config = doc["config"].to<JsonObject>();
-    config["ssid"] = configManager.getWifiSsid();
+    config["ssid"] = configService.getWifiSsid();
-    config["mqttHost"] = configManager.getMqttHost();
+    config["mqttHost"] = configService.getMqttHost();
-    config["mqttPort"] = configManager.getMqttPort();
+    config["mqttPort"] = configService.getMqttPort();
-    config["deviceId"] = configManager.getDeviceId();
+    config["deviceId"] = configService.getDeviceId();
+
+    const auto& connState = deviceState.getConnectionState();
+    const auto& values = deviceState.getValues();
 
     JsonObject status = doc["status"].to<JsonObject>();
-    status["wifiConnected"] = currentStatus.wifiConnected;
+    status["wifiConnected"] = connState.wifiConnected;
-    status["mqttConnected"] = currentStatus.mqttConnected;
+    status["mqttConnected"] = connState.mqttConnected;
-    status["bleStarted"] = currentStatus.bleStarted;
+    status["bleStarted"] = deviceState.isBleStarted();
-    status["deviceType"] = currentStatus.deviceType;
+    status["deviceType"] = deviceState.getDeviceTypeString();
-    status["ipAddress"] = currentStatus.ipAddress;
+    status["ipAddress"] = connState.ipAddress;
-    status["treadmillDistance"] = currentStatus.treadmillDistance;
+    status["treadmillDistance"] = values.treadmillDistance;
-    status["batteryLevel"] = currentStatus.batteryLevel;
+    status["batteryLevel"] = values.batteryLevel;
 
     String response;
     serializeJson(doc, response);
     server.send(200, "application/json", response);
 }
 
-void handlePostConfig() {
+void WebService::handlePostConfig() {
     if (!server.hasArg("plain")) {
         server.send(400, "application/json", "{\"error\":\"No body\"}");
         return;
@@ -380,26 +380,25 @@ void handlePostConfig() {
         return;
     }
 
-    // Update configuration
     String ssid = doc["ssid"] | "";
     String password = doc["password"] | "";
     String mqttHost = doc["mqtt_host"] | "";
     uint16_t mqttPort = doc["mqtt_port"] | 1883;
     String deviceId = doc["device_id"] | "";
 
-    configManager.setWifiCredentials(ssid, password);
+    configService.setWifiCredentials(ssid, password);
-    configManager.setMqttConfig(mqttHost, mqttPort);
+    configService.setMqttConfig(mqttHost, mqttPort);
-    configManager.setDeviceId(deviceId);
+    configService.setDeviceId(deviceId);
-    configManager.save();
+    configService.save();
 
     server.send(200, "application/json", "{\"success\":true}");
 
-    // Trigger reconnect (will be handled in main loop)
     Serial.println("Configuration updated, reconnecting...");
+    wifiService.reconnect();
 }
 
-void handleReset() {
+void WebService::handleReset() {
-    configManager.clear();
+    configService.clear();
     server.send(200, "application/json", "{\"success\":true}");
 
     Serial.println("Configuration reset, rebooting...");
@@ -407,19 +406,12 @@ void handleReset() {
     ESP.restart();
 }
 
-void handleResetDistance() {
+void WebService::handleResetDistance() {
-    if (resetDistanceCallback) {
+    deviceState.resetTreadmillDistance();
-        resetDistanceCallback();
-        Serial.println("Treadmill distance reset");
-    }
     server.send(200, "application/json", "{\"success\":true}");
 }
 
-void setResetDistanceCallback(ResetDistanceCallback callback) {
+void WebService::handleSetBattery() {
-    resetDistanceCallback = callback;
-}
-
-void handleSetBattery() {
     if (!server.hasArg("plain")) {
         server.send(400, "application/json", "{\"error\":\"No body\"}");
         return;
@@ -436,35 +428,25 @@ void handleSetBattery() {
     uint8_t level = doc["level"] | 100;
     if (level > 100) level = 100;
 
-    if (setBatteryCallback) {
+    deviceState.setBatteryLevel(level);
-        setBatteryCallback(level);
+    Serial.print("Battery level set via web UI: ");
-        Serial.print("Battery level set to: ");
+    Serial.println(level);
-        Serial.println(level);
-    }
 
     server.send(200, "application/json", "{\"success\":true}");
 }
 
-void setSetBatteryCallback(SetBatteryCallback callback) {
+void WebService::setup() {
-    setBatteryCallback = callback;
+    server.on("/", HTTP_GET, []() { webService.handleRoot(); });
-}
+    server.on("/api/status", HTTP_GET, []() { webService.handleGetStatus(); });
-
+    server.on("/api/config", HTTP_POST, []() { webService.handlePostConfig(); });
-void setupWebPortal() {
+    server.on("/api/reset", HTTP_POST, []() { webService.handleReset(); });
-    server.on("/", HTTP_GET, handleRoot);
+    server.on("/api/reset-distance", HTTP_POST, []() { webService.handleResetDistance(); });
-    server.on("/api/status", HTTP_GET, handleGetStatus);
+    server.on("/api/set-battery", HTTP_POST, []() { webService.handleSetBattery(); });
-    server.on("/api/config", HTTP_POST, handlePostConfig);
-    server.on("/api/reset", HTTP_POST, handleReset);
-    server.on("/api/reset-distance", HTTP_POST, handleResetDistance);
-    server.on("/api/set-battery", HTTP_POST, handleSetBattery);
 
     server.begin();
     Serial.println("Web portal started on http://192.168.4.1");
 }
 
-void handleWebPortal() {
+void WebService::loop() {
     server.handleClient();
 }
-
-void updatePortalStatus(const PortalStatus& status) {
-    currentStatus = status;
-}

firmware/esp32_ble_sim/src/services/wifi_service.cpp

@@ -0,0 +1,162 @@
+#include "services/wifi_service.h"
+#include "services/config_service.h"
+#include "device_state.h"
+#include "config.h"
+#include <WiFi.h>
+
+WiFiService& WiFiService::getInstance() {
+    static WiFiService instance;
+    return instance;
+}
+
+String WiFiService::getIP() const {
+    if (wifiConnected) {
+        return WiFi.localIP().toString();
+    }
+    return "";
+}
+
+void WiFiService::setup() {
+    // Disable ESP32's automatic WiFi persistence - we manage our own config
+    WiFi.persistent(false);
+    WiFi.setAutoConnect(false);
+    WiFi.setAutoReconnect(false);
+
+    // Force clean state on every boot
+    WiFi.disconnect(true);
+    WiFi.mode(WIFI_OFF);
+    delay(500);
+
+    if (configService.isConfigured()) {
+        WiFi.mode(WIFI_STA);
+        Serial.println("Starting in STA mode (configured)");
+    } else {
+        startAPMode();
+    }
+}
+
+void WiFiService::loop() {
+    connectToWiFi();
+}
+
+void WiFiService::reconnect() {
+    wifiRetryCount = 0;
+    lastWifiAttempt = 0;
+}
+
+void WiFiService::startAP() {
+    startAPMode();
+}
+
+void WiFiService::stopAP() {
+    stopAPMode();
+}
+
+void WiFiService::startAPMode() {
+    if (apModeActive) return;
+
+    WiFi.mode(WIFI_AP);
+    WiFi.softAPConfig(AP_IP, AP_GATEWAY, AP_SUBNET);
+    String apName = configService.getAPName();
+    WiFi.softAP(apName.c_str(), AP_PASSWORD);
+    apModeActive = true;
+
+    Serial.println("\n========================================");
+    Serial.println("Access Point Started");
+    Serial.print("  SSID: ");
+    Serial.println(apName);
+    Serial.print("  Config URL: http://");
+    Serial.println(WiFi.softAPIP());
+    Serial.println("========================================\n");
+}
+
+void WiFiService::stopAPMode() {
+    if (!apModeActive) return;
+
+    WiFi.softAPdisconnect(true);
+    WiFi.mode(WIFI_STA);
+    apModeActive = false;
+
+    Serial.println("Access Point stopped (WiFi connected)");
+}
+
+void WiFiService::connectToWiFi() {
+    if (!configService.isConfigured()) {
+        if (!apModeActive) {
+            startAPMode();
+        }
+        return;
+    }
+
+    if (WiFi.status() == WL_CONNECTED) {
+        if (!wifiConnected) {
+            wifiConnected = true;
+            wifiRetryCount = 0;
+            Serial.print("WiFi connected! IP: ");
+            Serial.println(WiFi.localIP());
+
+            deviceState.setWifiConnected(true, WiFi.localIP().toString());
+            stopAPMode();
+        }
+        return;
+    }
+
+    // WiFi not connected
+    if (wifiConnected) {
+        wifiConnected = false;
+        deviceState.setWifiConnected(false);
+        wifiRetryCount = 0;
+        Serial.println("WiFi disconnected!");
+        startAPMode();
+    }
+
+    // Don't spam connection attempts
+    if (millis() - lastWifiAttempt < WIFI_CONNECT_TIMEOUT) {
+        return;
+    }
+    lastWifiAttempt = millis();
+
+    // Cap retry count
+    if (wifiRetryCount < MAX_WIFI_RETRIES) {
+        wifiRetryCount++;
+    }
+
+    // Start AP mode after too many failed attempts
+    if (wifiRetryCount >= MAX_WIFI_RETRIES && !apModeActive) {
+        Serial.println("WiFi connection failed after multiple attempts");
+        Serial.println("Starting AP mode for reconfiguration...");
+
+        WiFi.mode(WIFI_AP_STA);
+        WiFi.softAPConfig(AP_IP, AP_GATEWAY, AP_SUBNET);
+        String apName = configService.getAPName();
+        WiFi.softAP(apName.c_str(), AP_PASSWORD);
+        apModeActive = true;
+
+        Serial.println("\n========================================");
+        Serial.println("Access Point Started");
+        Serial.print("  SSID: ");
+        Serial.println(apName);
+        Serial.print("  Config URL: http://");
+        Serial.println(WiFi.softAPIP());
+        Serial.println("========================================\n");
+
+        return;
+    }
+
+    Serial.print("Connecting to WiFi (attempt ");
+    Serial.print(wifiRetryCount);
+    Serial.print("/");
+    Serial.print(MAX_WIFI_RETRIES);
+    Serial.print("): ");
+    Serial.println(configService.getWifiSsid());
+
+    if (!apModeActive) {
+        WiFi.disconnect(false);
+        delay(100);
+    }
+
+    WiFi.begin(
+        configService.getWifiSsid().c_str(),
+        configService.getWifiPassword().c_str()
+    );
+}

src/api/hr_variation.py

@@ -0,0 +1,159 @@
+"""Heart rate variation manager - smooth realistic HR simulation."""
+
+import asyncio
+import math
+import random
+from dataclasses import dataclass, field
+
+
+@dataclass
+class HRDeviceState:
+    """State for a single device's HR variation."""
+    target: int = 70
+    float_hr: float = 70.0
+    phase: float = field(default_factory=lambda: random.random() * math.pi * 2)
+    enabled: bool = False
+    task: asyncio.Task | None = field(default=None, repr=False)
+
+
+class HRVariationManager:
+    """Manages smooth HR variation for multiple devices."""
+
+    def __init__(self):
+        self._devices: dict[str, HRDeviceState] = {}
+        self._mqtt_manager = None
+        self._device_registry = None
+        self._ws_broadcast = None
+
+    def set_dependencies(self, mqtt_manager, device_registry, ws_broadcast=None):
+        """Set required dependencies after initialization."""
+        self._mqtt_manager = mqtt_manager
+        self._device_registry = device_registry
+        self._ws_broadcast = ws_broadcast
+
+    def get_state(self, device_id: str) -> dict:
+        """Get current HR variation state for a device."""
+        if device_id not in self._devices:
+            return {"enabled": False, "target": 70, "current": 70}
+
+        state = self._devices[device_id]
+        return {
+            "enabled": state.enabled,
+            "target": state.target,
+            "current": round(state.float_hr),
+        }
+
+    async def set_target(self, device_id: str, target: int):
+        """Set HR target for a device."""
+        if device_id not in self._devices:
+            self._devices[device_id] = HRDeviceState(target=target, float_hr=float(target))
+        else:
+            self._devices[device_id].target = target
+
+        # If variation not enabled, send value directly
+        if not self._devices[device_id].enabled:
+            await self._send_hr(device_id, target)
+
+    async def enable(self, device_id: str, target: int | None = None):
+        """Enable HR variation for a device."""
+        if device_id not in self._devices:
+            initial_target = target or 70
+            self._devices[device_id] = HRDeviceState(
+                target=initial_target,
+                float_hr=float(initial_target)
+            )
+        elif target is not None:
+            self._devices[device_id].target = target
+
+        state = self._devices[device_id]
+
+        if state.enabled and state.task and not state.task.done():
+            return  # Already running
+
+        state.enabled = True
+        state.task = asyncio.create_task(self._variation_loop(device_id))
+
+    async def disable(self, device_id: str):
+        """Disable HR variation for a device."""
+        if device_id not in self._devices:
+            return
+
+        state = self._devices[device_id]
+        state.enabled = False
+
+        if state.task and not state.task.done():
+            state.task.cancel()
+            try:
+                await state.task
+            except asyncio.CancelledError:
+                pass
+            state.task = None
+
+    async def stop_all(self):
+        """Stop all variation tasks (for shutdown)."""
+        for device_id in list(self._devices.keys()):
+            await self.disable(device_id)
+
+    async def _variation_loop(self, device_id: str):
+        """Run smooth HR variation for a device."""
+        state = self._devices[device_id]
+        last_sent = None
+
+        try:
+            while state.enabled:
+                # Advance phase (completes cycle in ~30 seconds)
+                state.phase += 0.2
+
+                # Smooth sinusoidal base variation (±2 BPM)
+                sine_variation = math.sin(state.phase) * 2
+
+                # Small random walk component
+                random_walk = (random.random() - 0.5) * 0.6
+
+                # Calculate ideal HR
+                ideal_hr = state.target + sine_variation + random_walk
+
+                # Smooth transition (30% toward ideal each tick)
+                state.float_hr += (ideal_hr - state.float_hr) * 0.3
+
+                # Clamp to ±3 of target
+                state.float_hr = max(
+                    state.target - 3,
+                    min(state.target + 3, state.float_hr)
+                )
+
+                # Round for transmission
+                current_hr = round(max(30, min(220, state.float_hr)))
+
+                # Only send if changed
+                if current_hr != last_sent:
+                    last_sent = current_hr
+                    await self._send_hr(device_id, current_hr)
+
+                await asyncio.sleep(1)
+
+        except asyncio.CancelledError:
+            pass
+
+    async def _send_hr(self, device_id: str, hr: int):
+        """Send HR value to device via MQTT and update registry."""
+        if self._mqtt_manager and self._mqtt_manager.is_connected:
+            await self._mqtt_manager.publish(
+                f"ble-sim/{device_id}/set",
+                {"heart_rate": hr}
+            )
+
+        if self._device_registry:
+            self._device_registry.update_device(device_id, {"values": {"heart_rate": hr}})
+
+        # Broadcast to WebSocket clients
+        if self._ws_broadcast:
+            await self._ws_broadcast({
+                "type": "hr_update",
+                "device_id": device_id,
+                "heart_rate": hr
+            })
+
+
+# Global instance
+hr_variation_manager = HRVariationManager()

src/api/main.py

@@ -5,7 +5,7 @@ from contextlib import asynccontextmanager
 from fastapi import FastAPI, WebSocket, WebSocketDisconnect
 
 # Version info
-__version__ = "1.1.2"
+__version__ = "1.3.0"
 from fastapi.middleware.cors import CORSMiddleware
 from fastapi.staticfiles import StaticFiles
 from fastapi.responses import FileResponse
@@ -14,6 +14,7 @@ import os
 from .routes import router
 from .mqtt_client import mqtt_manager
 from .device_registry import device_registry
+from .hr_variation import hr_variation_manager
 
 
 class ConnectionManager:
@@ -62,6 +63,7 @@ async def handle_device_status(topic: str, payload: str):
                 "ble_started": data.get("ble_started", False),
                 "ip": data.get("ip"),
                 "firmware_version": data.get("firmware_version"),
+                "bt_mac": data.get("bt_mac"),
             }
             device_registry.update_device(device_id, update_data)
             print(f"Device {device_id} status updated: {data}")
@@ -97,9 +99,16 @@ async def handle_device_values(topic: str, payload: str):
 
 @asynccontextmanager
 async def lifespan(app: FastAPI):
-    """Manage application lifecycle - connect/disconnect MQTT."""
+    """Manage application lifecycle - connect/disconnect MQTT and HR variation."""
     await mqtt_manager.connect()
+    # Wire up HR variation manager dependencies
+    hr_variation_manager.set_dependencies(
+        mqtt_manager=mqtt_manager,
+        device_registry=device_registry,
+        ws_broadcast=ws_manager.broadcast
+    )
     yield
+    await hr_variation_manager.stop_all()
     await mqtt_manager.disconnect()
 
 

src/api/mqtt_client.py

@@ -102,7 +102,7 @@ class MQTTManager:
             return func
         return decorator
 
-    async def publish(self, topic: str, payload: dict | str):
+    async def publish(self, topic: str, payload: dict | str, retain: bool = False):
         """Publish a message to MQTT."""
         if not self._connected or not self.client:
             raise RuntimeError("MQTT not connected")
@@ -110,7 +110,13 @@ class MQTTManager:
         if isinstance(payload, dict):
             payload = json.dumps(payload)
 
-        await self.client.publish(topic, payload)
+        await self.client.publish(topic, payload, retain=retain)
+
+    async def clear_retained(self, topic: str):
+        """Clear a retained message by publishing empty payload with retain flag."""
+        if not self._connected or not self.client:
+            return
+        await self.client.publish(topic, "", retain=True)
 
     async def configure_device(self, device_id: str, device_type: str):
         """Send configuration command to a device."""

src/api/routes.py

@@ -5,6 +5,7 @@ from pydantic import BaseModel, Field
 
 from .mqtt_client import mqtt_manager
 from .device_registry import device_registry
+from .hr_variation import hr_variation_manager
 
 router = APIRouter()
 
@@ -21,6 +22,14 @@ class DeviceValues(BaseModel):
     incline: float | None = Field(None, ge=-10, le=40)  # percent
     cadence: int | None = Field(None, ge=0, le=300)  # rpm
     power: int | None = Field(None, ge=0, le=2000)  # watts
+    battery: int | None = Field(None, ge=0, le=100)  # battery percentage
+    distance: int | None = Field(None, ge=0)  # distance in meters
+
+
+class HRVariationConfig(BaseModel):
+    """HR variation configuration."""
+    enabled: bool
+    target: int | None = Field(None, ge=30, le=220)
 
 
 @router.get("/devices")
@@ -40,6 +49,29 @@ async def get_device(device_id: str):
     return device
 
 
+@router.delete("/devices/{device_id}")
+async def delete_device(device_id: str):
+    """Remove a device from the registry and clear its retained MQTT messages."""
+    device = device_registry.get_device(device_id)
+    if not device:
+        raise HTTPException(status_code=404, detail="Device not found")
+
+    # Stop any HR variation for this device
+    await hr_variation_manager.disable(device_id)
+
+    # Clear retained MQTT messages so device doesn't reappear on restart
+    try:
+        await mqtt_manager.clear_retained(f"ble-sim/{device_id}/status")
+        await mqtt_manager.clear_retained(f"ble-sim/{device_id}/values")
+    except Exception:
+        pass  # MQTT might not be connected
+
+    # Remove from registry
+    device_registry.remove_device(device_id)
+
+    return {"status": "ok", "device_id": device_id, "message": "Device removed"}
+
+
 @router.post("/devices/{device_id}/configure")
 async def configure_device(device_id: str, config: DeviceConfig):
     """Configure a device's type."""
@@ -67,3 +99,43 @@ async def set_device_values(device_id: str, values: DeviceValues):
     device_registry.update_device(device_id, {"values": values_dict})
 
     return {"status": "ok", "device_id": device_id, "values": values_dict}
+
+
+@router.get("/devices/{device_id}/hr-variation")
+async def get_hr_variation(device_id: str):
+    """Get HR variation state for a device."""
+    return hr_variation_manager.get_state(device_id)
+
+
+@router.post("/devices/{device_id}/hr-variation")
+async def set_hr_variation(device_id: str, config: HRVariationConfig):
+    """Enable or disable HR variation for a device."""
+    if config.enabled:
+        await hr_variation_manager.enable(device_id, config.target)
+    else:
+        await hr_variation_manager.disable(device_id)
+        # If target provided, set it directly
+        if config.target is not None:
+            await hr_variation_manager.set_target(device_id, config.target)
+
+    return {
+        "status": "ok",
+        "device_id": device_id,
+        **hr_variation_manager.get_state(device_id)
+    }
+
+
+class HRTargetRequest(BaseModel):
+    """HR target request."""
+    target: int = Field(ge=30, le=220)
+
+
+@router.post("/devices/{device_id}/hr-target")
+async def set_hr_target(device_id: str, request: HRTargetRequest):
+    """Set HR target (works with or without variation enabled)."""
+    await hr_variation_manager.set_target(device_id, request.target)
+    return {
+        "status": "ok",
+        "device_id": device_id,
+        **hr_variation_manager.get_state(device_id)
+    }

src/web/static/index.html

@@ -258,6 +258,28 @@
             color: var(--text-dim);
         }
 
+        .device-mac {
+            color: var(--text-dim);
+            font-family: monospace;
+            font-size: 0.75rem;
+        }
+
+        .delete-btn {
+            background: var(--error);
+            color: white;
+            border: none;
+            border-radius: 4px;
+            width: 20px;
+            height: 20px;
+            font-size: 14px;
+            cursor: pointer;
+            margin-left: 0.5rem;
+            line-height: 1;
+        }
+        .delete-btn:hover {
+            opacity: 0.8;
+        }
+
         /* WebSocket connection status */
         .connection-status {
             display: flex;
@@ -289,7 +311,7 @@
     <div class="header">
         <div>
             <h1>pyBTMCP</h1>
-            <p class="subtitle">BLE Device Simulator &bull; UI v1.2.3 &bull; API <span id="backendVersion"></span></p>
+            <p class="subtitle">BLE Device Simulator &bull; UI v1.4.0 &bull; API <span id="backendVersion"></span></p>
         </div>
         <div class="header-buttons">
             <div class="connection-status">
@@ -424,6 +446,16 @@
             } else if (message.type === 'device_update') {
                 // Single device updated - update UI efficiently
                 updateDeviceInUI(message.device_id, message.data);
+            } else if (message.type === 'hr_update') {
+                // HR value update from server-side variation
+                updateHrDisplay(message.device_id, message.heart_rate);
+            }
+        }
+
+        function updateHrDisplay(deviceId, hr) {
+            const display = document.getElementById(`hr-display-${deviceId}`);
+            if (display) {
+                display.textContent = `${hr} BPM`;
             }
         }
 
@@ -449,18 +481,39 @@
             if (dot) dot.className = `status-dot ${deviceData.online ? '' : 'offline'}`;
             if (text) text.textContent = deviceData.online ? 'Online' : 'Offline';
 
-            // Update IP and version if present
+            // Update IP, MAC, and version if present
             const infoDiv = existingCard.querySelector('.device-info');
             if (infoDiv) {
                 let infoHtml = '';
                 if (deviceData.ip) {
                     infoHtml += `<a href="http://${deviceData.ip}" target="_blank" class="device-link">Admin: ${deviceData.ip}</a>`;
                 }
+                if (deviceData.bt_mac) {
+                    infoHtml += `<span class="device-mac">BT: ${deviceData.bt_mac}</span>`;
+                }
                 if (deviceData.firmware_version) {
                     infoHtml += `<span class="device-version">v${deviceData.firmware_version}</span>`;
                 }
                 infoDiv.innerHTML = infoHtml;
             }
+
+            // Update values if present
+            const values = deviceData.values || {};
+            if (values.heart_rate !== undefined) {
+                updateHrDisplay(deviceId, values.heart_rate);
+            }
+            if (values.speed !== undefined) {
+                const speedDisplay = document.getElementById(`speed-display-${deviceId}`);
+                if (speedDisplay) speedDisplay.textContent = formatSpeed(values.speed);
+            }
+            if (values.distance !== undefined) {
+                const distDisplay = document.getElementById(`distance-display-${deviceId}`);
+                if (distDisplay) distDisplay.textContent = `${values.distance} m`;
+            }
+            if (values.battery !== undefined) {
+                const battDisplay = document.getElementById(`battery-display-${deviceId}`);
+                if (battDisplay) battDisplay.textContent = `${values.battery}%`;
+            }
         }
 
         // Settings (persisted to localStorage)
@@ -469,11 +522,8 @@
             hrVariation: true
         };
 
-        // HR variation state per device
+        // Track active devices (for UI state only - business logic is server-side)
-        let hrVariationIntervals = {};
+        let activeDevices = new Set();
-        let currentHrTargets = {};
-        let currentHrValues = {};
-        let activeDevices = new Set(); // Track devices being actively controlled
 
         // Treadmill presets (stored in metric - km/h)
         const treadmillPresets = [
@@ -515,18 +565,25 @@
             loadDevices(); // Re-render with new units
         }
 
-        function toggleHrVariation() {
+        async function toggleHrVariation() {
             settings.hrVariation = document.getElementById('hrVariationToggle').checked;
             saveSettings();
             updateSettingsDisplay();
 
-            // Stop or start variation for all HR devices
+            // Update all HR devices via API
-            Object.keys(hrVariationIntervals).forEach(deviceId => {
+            const devices = document.querySelectorAll('.device-card[data-type="heart_rate"]');
-                if (!settings.hrVariation) {
+            for (const card of devices) {
-                    clearInterval(hrVariationIntervals[deviceId]);
+                const deviceId = card.dataset.id;
-                    delete hrVariationIntervals[deviceId];
+                try {
+                    await fetch(`${API_BASE}/devices/${deviceId}/hr-variation`, {
+                        method: 'POST',
+                        headers: { 'Content-Type': 'application/json' },
+                        body: JSON.stringify({ enabled: settings.hrVariation })
+                    });
+                } catch (error) {
+                    console.error('Failed to toggle HR variation:', error);
                 }
-            });
+            }
         }
 
         function updateSettingsDisplay() {
@@ -605,11 +662,13 @@
                             <div class="device-status">
                                 <span class="status-dot ${device.online ? '' : 'offline'}"></span>
                                 <span class="status-text">${device.online ? 'Online' : 'Offline'}</span>
+                                <button class="delete-btn" onclick="deleteDevice('${device.id}')" title="Remove device">×</button>
                             </div>
                         </div>
 
                         <div class="device-info">
                             ${device.ip ? `<a href="http://${device.ip}" target="_blank" class="device-link">Admin: ${device.ip}</a>` : ''}
+                            ${device.bt_mac ? `<span class="device-mac">BT: ${device.bt_mac}</span>` : ''}
                             ${device.firmware_version ? `<span class="device-version">v${device.firmware_version}</span>` : ''}
                         </div>
 
@@ -627,11 +686,10 @@
                     </div>
                 `).join('');
 
-                // Setup HR variation for new HR devices
+                // Enable HR variation for new HR devices if setting is on
                 devices.forEach(device => {
-                    if (device.type === 'heart_rate' && settings.hrVariation && !hrVariationIntervals[device.id]) {
+                    if (device.type === 'heart_rate' && settings.hrVariation) {
-                        const startHr = currentHrValues[device.id] || device.values?.heart_rate || 70;
+                        enableHrVariationForDevice(device.id, device.values?.heart_rate || 70);
-                        setupHrVariation(device.id, startHr);
                     }
                 });
             } else {
@@ -653,25 +711,19 @@
             const values = device.values || {};
 
             if (device.type === 'heart_rate') {
-                const hr = currentHrValues[device.id] || values.heart_rate || 70;
+                const hr = values.heart_rate || 70;
-                if (!currentHrTargets[device.id]) currentHrTargets[device.id] = hr;
-                if (!currentHrValues[device.id]) currentHrValues[device.id] = hr;
                 return `
                     <div class="presets">
                         ${hrPresets.map(p => `
                             <button class="preset-btn"
-                                    onclick="applyHrPresetGradual('${device.id}', ${p.hr})"
+                                    onclick="setHrTarget('${device.id}', ${p.hr})">${p.name}</button>
-                                    ondblclick="applyHrPresetImmediate('${device.id}', ${p.hr})">${p.name}</button>
                         `).join('')}
                     </div>
-                    <p style="font-size: 0.75rem; color: var(--text-dim); margin-bottom: 1rem;">
-                        Click = gradual transition | Double-click = instant
-                    </p>
                     <div class="control-group">
                         <label>Heart Rate Target</label>
                         <div class="slider-container">
-                            <input type="range" min="30" max="220" value="${currentHrTargets[device.id]}"
+                            <input type="range" min="30" max="220" value="${hr}"
-                                   oninput="updateHrTarget('${device.id}', this.value)">
+                                   oninput="setHrTargetDebounced('${device.id}', this.value)">
                             <span class="value-display" id="hr-display-${device.id}">${hr} BPM</span>
                         </div>
                     </div>
@@ -747,135 +799,53 @@
             return '';
         }
 
-        // HR variation - smooth realistic human heart rate simulation
+        // HR control functions - business logic is server-side
-        const hrVariationState = {};  // Store per-device state
+        const hrTargetDebounceTimers = {};
 
-        function setupHrVariation(deviceId, startHr) {
+        async function enableHrVariationForDevice(deviceId, startHr) {
-            if (hrVariationIntervals[deviceId]) {
-                clearInterval(hrVariationIntervals[deviceId]);
-            }
-            if (!settings.hrVariation) return;
-
-            // Only set target if not already set (don't overwrite user's target)
-            if (!currentHrTargets[deviceId]) {
-                currentHrTargets[deviceId] = startHr;
-            }
-            // Use existing value if we have one, otherwise start at startHr
-            if (!currentHrValues[deviceId]) {
-                currentHrValues[deviceId] = startHr;
-            }
-
-            // Initialize smooth variation state
-            if (!hrVariationState[deviceId]) {
-                hrVariationState[deviceId] = {
-                    phase: Math.random() * Math.PI * 2,  // Random start phase
-                    floatHr: currentHrValues[deviceId]   // Floating point HR for smooth transitions
-                };
-            }
-
-            hrVariationIntervals[deviceId] = setInterval(() => {
-                const target = currentHrTargets[deviceId];
-                const state = hrVariationState[deviceId];
-
-                // Slowly advance phase (completes cycle in ~30 seconds)
-                state.phase += 0.2;
-
-                // Smooth sinusoidal base variation (±2 BPM)
-                const sineVariation = Math.sin(state.phase) * 2;
-
-                // Small random walk component (±0.3 per tick, smooths out)
-                const randomWalk = (Math.random() - 0.5) * 0.6;
-
-                // Calculate ideal HR with smooth variation
-                const idealHr = target + sineVariation + randomWalk;
-
-                // Smooth transition toward ideal (move 30% of the way each tick)
-                state.floatHr += (idealHr - state.floatHr) * 0.3;
-
-                // Clamp to ±3 of target
-                state.floatHr = Math.max(target - 3, Math.min(target + 3, state.floatHr));
-
-                // Round for display/transmission
-                const currentHr = Math.round(Math.max(30, Math.min(220, state.floatHr)));
-
-                // Only send if value changed
-                if (currentHr !== currentHrValues[deviceId]) {
-                    currentHrValues[deviceId] = currentHr;
-                    sendHrValue(deviceId, currentHr);
-
-                    const display = document.getElementById(`hr-display-${deviceId}`);
-                    if (display) {
-                        display.textContent = `${currentHr} BPM`;
-                    }
-                }
-            }, 1000);
-        }
-
-        // Gradual transition - just change target, let variation do the work
-        function applyHrPresetGradual(deviceId, targetHr) {
-            currentHrTargets[deviceId] = targetHr;
-
-            // Update slider to show target
-            const card = document.querySelector(`[data-id="${deviceId}"]`);
-            const slider = card?.querySelector('input[type="range"]');
-            if (slider) slider.value = targetHr;
-
-            // Ensure variation is running
-            if (!hrVariationIntervals[deviceId] && settings.hrVariation) {
-                const startHr = currentHrValues[deviceId] || targetHr;
-                setupHrVariation(deviceId, startHr);
-            }
-
-            // If variation is off, just send the value
-            if (!settings.hrVariation) {
-                currentHrValues[deviceId] = targetHr;
-                sendHrValue(deviceId, targetHr);
-                const display = document.getElementById(`hr-display-${deviceId}`);
-                if (display) display.textContent = `${targetHr} BPM`;
-            }
-        }
-
-        // Immediate jump - set both current and target immediately
-        function applyHrPresetImmediate(deviceId, targetHr) {
-            currentHrTargets[deviceId] = targetHr;
-            currentHrValues[deviceId] = targetHr;
-
-            // Update slider
-            const card = document.querySelector(`[data-id="${deviceId}"]`);
-            const slider = card?.querySelector('input[type="range"]');
-            if (slider) slider.value = targetHr;
-
-            // Update display
-            const display = document.getElementById(`hr-display-${deviceId}`);
-            if (display) display.textContent = `${targetHr} BPM`;
-
-            // Send immediately
-            sendHrValue(deviceId, targetHr);
-        }
-
-        function updateHrTarget(deviceId, value) {
-            const hr = parseInt(value);
-            currentHrTargets[deviceId] = hr;
-
-            if (!settings.hrVariation) {
-                sendHrValue(deviceId, hr);
-                const display = document.getElementById(`hr-display-${deviceId}`);
-                if (display) display.textContent = `${hr} BPM`;
-            }
-        }
-
-        async function sendHrValue(deviceId, hr) {
             try {
-                await fetch(`${API_BASE}/devices/${deviceId}/values`, {
+                await fetch(`${API_BASE}/devices/${deviceId}/hr-variation`, {
                     method: 'POST',
                     headers: { 'Content-Type': 'application/json' },
-                    body: JSON.stringify({ heart_rate: hr })
+                    body: JSON.stringify({ enabled: true, target: startHr })
+                });
+            } catch (error) {
+                console.error('Failed to enable HR variation:', error);
+            }
+        }
+
+        async function setHrTarget(deviceId, targetHr) {
+            // Update slider UI immediately
+            const card = document.querySelector(`[data-id="${deviceId}"]`);
+            const slider = card?.querySelector('input[type="range"]');
+            if (slider) slider.value = targetHr;
+
+            try {
+                await fetch(`${API_BASE}/devices/${deviceId}/hr-target`, {
+                    method: 'POST',
+                    headers: { 'Content-Type': 'application/json' },
+                    body: JSON.stringify({ target: targetHr })
                 });
             } catch (error) {
                 console.error('Failed to send HR:', error);
             }
         }
 
+        function setHrTargetDebounced(deviceId, value) {
+            const hr = parseInt(value);
+            // Update display immediately
+            const display = document.getElementById(`hr-display-${deviceId}`);
+            if (display) display.textContent = `${hr} BPM`;
+
+            // Debounce the API call
+            if (hrTargetDebounceTimers[deviceId]) {
+                clearTimeout(hrTargetDebounceTimers[deviceId]);
+            }
+            hrTargetDebounceTimers[deviceId] = setTimeout(() => {
+                setHrTarget(deviceId, hr);
+            }, 100);
+        }
+
         function updateSpeed(deviceId, displayValue) {
             const metricSpeed = displayToMetric(parseFloat(displayValue));
             const display = document.getElementById(`speed-display-${deviceId}`);
@@ -952,6 +922,18 @@
             }
         }
 
+        async function deleteDevice(deviceId) {
+            if (!confirm(`Remove device ${deviceId} from the list?`)) return;
+            try {
+                await fetch(`${API_BASE}/devices/${deviceId}`, {
+                    method: 'DELETE'
+                });
+                loadDevices();
+            } catch (error) {
+                console.error('Failed to delete device:', error);
+            }
+        }
+
         let updateTimeouts = {};
         function updateValueDebounced(deviceId, key, value) {
             const timeoutKey = `${deviceId}-${key}`;