#include <BLEDevice.h>
#include <BLEServer.h>
#include <BLEUtils.h>
#include <BLE2902.h>

// --------------------
// Pin definition / Definición de pines
// --------------------
#define BUTTON1 D4
#define BUTTON2 D6

// --------------------
// BLE UUIDs (custom service and characteristic)
// UUIDs BLE (servicio y característica personalizados)
// --------------------
#define SERVICE_UUID        "12345678-1234-1234-1234-1234567890ab"
#define CHARACTERISTIC_UUID "abcdefab-1234-1234-1234-abcdefabcdef"

// Pointer to the BLE characteristic / Puntero a la característica BLE
BLECharacteristic *pCharacteristic;

// Flag to know if a device is connected / Flag para saber si hay dispositivo conectado
bool deviceConnected = false;

// Previous states for edge detection / Estados anteriores para detectar cambios
int lastState1 = HIGH;
int lastState2 = HIGH;

// --------------------
// BLE connection callbacks / Callbacks de conexión BLE
// --------------------
class MyServerCallbacks : public BLEServerCallbacks {
  void onConnect(BLEServer* pServer) {
    deviceConnected = true;
    Serial.println("iPhone connected / iPhone conectado");
  }

  void onDisconnect(BLEServer* pServer) {
    deviceConnected = false;
    Serial.println("iPhone disconnected / iPhone desconectado");

    // Restart advertising so it can reconnect
    // Reiniciar advertising para permitir reconexión
    BLEDevice::startAdvertising();
    Serial.println("Advertising restarted / Advertising reiniciado");
  }
};

// --------------------
// Function to send BLE message / Función para enviar mensaje BLE
// --------------------
void sendBLEMessage(const char *message) {
  Serial.print("Sending: / Enviando: ");
  Serial.println(message);

  // Set the value of the characteristic
  // Asignar valor a la característica
  pCharacteristic->setValue(message);

  // Send notification if device is connected
  // Enviar notificación si hay dispositivo conectado
  if (deviceConnected) {
    pCharacteristic->notify();
  }
}

// --------------------
// Setup / Configuración inicial
// --------------------
void setup() {
  Serial.begin(115200);
  delay(1000);

  // Configure buttons with internal pull-up
  // Configurar botones con resistencia pull-up interna
  pinMode(BUTTON1, INPUT_PULLUP);
  pinMode(BUTTON2, INPUT_PULLUP);

  // --------------------
  // BLE initialization / Inicialización BLE
  // --------------------
  BLEDevice::init("XIAO-ESP32C6-BLE");

  // Create BLE server / Crear servidor BLE
  BLEServer *pServer = BLEDevice::createServer();
  pServer->setCallbacks(new MyServerCallbacks());

  // Create BLE service / Crear servicio BLE
  BLEService *pService = pServer->createService(SERVICE_UUID);

  // Create BLE characteristic with READ + NOTIFY
  // Crear característica BLE con READ + NOTIFY
  pCharacteristic = pService->createCharacteristic(
    CHARACTERISTIC_UUID,
    BLECharacteristic::PROPERTY_READ |
    BLECharacteristic::PROPERTY_NOTIFY
  );

  // Add descriptor so phone can enable notifications
  // Añadir descriptor para que el móvil pueda activar notificaciones
  pCharacteristic->addDescriptor(new BLE2902());

  // Initial value / Valor inicial
  pCharacteristic->setValue("Waiting...");

  // Start service / Iniciar servicio
  pService->start();

  // Start advertising / Iniciar advertising
  BLEAdvertising *pAdvertising = BLEDevice::getAdvertising();
  pAdvertising->addServiceUUID(SERVICE_UUID);
  pAdvertising->start();

  Serial.println("BLE ready / BLE listo");
  Serial.println("Device name: XIAO-ESP32C6-BLE");
}

// --------------------
// Loop / Bucle principal
// --------------------
void loop() {
  // Read current button states
  // Leer estado actual de los botones
  int currentState1 = digitalRead(BUTTON1);
  int currentState2 = digitalRead(BUTTON2);

  // Detect press on Button 1 (HIGH → LOW)
  // Detectar pulsación en botón 1 (HIGH → LOW)
  if (lastState1 == HIGH && currentState1 == LOW) {
    sendBLEMessage("BUTTON 1");
    delay(200); // simple debounce / anti-rebote
  }

  // Detect press on Button 2 (HIGH → LOW)
  // Detectar pulsación en botón 2 (HIGH → LOW)
  if (lastState2 == HIGH && currentState2 == LOW) {
    sendBLEMessage("BUTTON 2");
    delay(200); // simple debounce / anti-rebote
  }

  // Update last states
  // Actualizar estados anteriores
  lastState1 = currentState1;
  lastState2 = currentState2;

  delay(20);
}