#include <Wire.h>
#include <MPU6050.h>
#include <SoftwareSerial.h> // For GSM and GPS communication
#include <TinyGPS++.h>      // For GPS processing

MPU6050 mpu;
TinyGPSPlus gps;
SoftwareSerial gsm(7, 8); // RX, TX for GSM module
SoftwareSerial gpsSerial(3, 4); // RX, TX for GPS module

const int BUZZER_PIN = 2;
const int ALCOHOL_SENSOR_PIN = A0;
const float TILT_THRESHOLD_X = 20.0; // 20-degree tilt threshold
const int ALCOHOL_THRESHOLD = 300;   // Adjust based on calibration

void setup() {
  Serial.begin(9600); // Initialize Serial for debugging
  gsm.begin(9600);    // Initialize GSM serial communication
  gpsSerial.begin(9600); // Initialize GPS serial communication
  
  Wire.begin();
  mpu.initialize();
  
  pinMode(BUZZER_PIN, OUTPUT);
  
  if (!mpu.testConnection()) {
    Serial.println("MPU6050 connection failed");
    while (1); // Halt program if MPU6050 is not detected
  }
  
  gsm.println("AT+CMGF=1"); // Set GSM module to text mode
}

void loop() {
  int16_t ax, ay, az;
  mpu.getAcceleration(&ax, &ay, &az);
  
  // Convert raw accelerometer data to g's
  float x = ax / 16384.0;
  float y = ay / 16384.0;
  float z = az / 16384.0;
  
  // Calculate the forward/backward tilt angle in degrees
  float angle_x = atan2(x, sqrt(y * y + z * z)) * (180.0 / M_PI);
  
  // Read alcohol level from the sensor
  int alcohol_level = analogRead(ALCOHOL_SENSOR_PIN);
  
  // Check if the tilt angle or alcohol level exceeds the threshold
  if (angle_x > TILT_THRESHOLD_X || alcohol_level > ALCOHOL_THRESHOLD) {
    digitalWrite(BUZZER_PIN, HIGH); // Activate buzzer
    
    // Wait for a valid GPS location
    while (gpsSerial.available() > 0) {
      gps.encode(gpsSerial.read());
      if (gps.location.isUpdated()) {
        // Prepare the SMS message
        String latitude = String(gps.location.lat(), 6);
        String longitude = String(gps.location.lng(), 6);
        String message = "ALERT! Driver in danger. Location: " + latitude + ", " + longitude;
        
        // Send SMS with GPS location
        gsm.println("AT+CMGS=\"+91XXXXXXXXXX\""); // Replace with recipient's phone number
        gsm.print(message);
        gsm.write(26); // ASCII code for Ctrl+Z to send the SMS
      }
    }
  } else {
    digitalWrite(BUZZER_PIN, LOW); // Deactivate buzzer if conditions are normal
  }

  delay(100); // Short delay for sensor reading stability
}