#include <WiFi.h>
#include <FirebaseESP32.h>
#include <SoftwareSerial.h>
#include <string.h>

#define WIFI_SSID "YourWiFiSSID"
#define WIFI_PASSWORD "YourWiFiPassword"

#define FIREBASE_HOST "yourproject.firebaseio.com"
#define FIREBASE_AUTH "yourAuthenticationKey"

SoftwareSerial gsmSerial(2, 3);  // RX, TX pins of the GSM module
String mobileNumber;

FirebaseData firebaseData;

void setup() {
  Serial.begin(115200);
  
  gsmSerial.begin(9600);  // Initialize GSM module
  
  WiFi.begin(WIFI_SSID, WIFI_PASSWORD);
  while (WiFi.status() != WL_CONNECTED) {
    delay(1000);
    Serial.println("Connecting to WiFi...");
  }
  Serial.println("Connected to WiFi!");

  Firebase.begin(FIREBASE_HOST, FIREBASE_AUTH);
}

void loop() {
  if (Firebase.getJSON(firebaseData, "/mobileNumber")) {
    FirebaseJson &jsonObject = firebaseData.jsonObject();
    JsonObject::iterator it = jsonObject.begin();
    while (it != jsonObject.end()) {
      if (it->value.isNumeric()) {
        mobileNumber = String(it->value.asInt());
      } else {
        mobileNumber = it->value.asString();
      }
      Serial.print("Sending message to mobile number: ");
      Serial.println(mobileNumber);
      sendSMS(mobileNumber, "Hello from ESP32!"); // Send message to mobile number
      it++;
    }
  }
  delay(1000);
}

void sendSMS(String number, String message) {
  gsmSerial.println("AT+CMGF=1");  // Set SMS mode to text
  delay(1000);
  gsmSerial.print("AT+CMGS=\"");  // Send SMS command
  gsmSerial.print(number);
  gsmSerial.println("\"");
  delay(1000);
  gsmSerial.print(message);  // Send message
  delay(1000);
  gsmSerial.write(26);  // End message with ctrl+z
  delay(1000);
}