#include <Wire.h>
#include <MPU6050.h>
  //#include <NMEAGPS.h>     // Include NeoGPS library for handling GPS data
//#include <GPSport.h>       // Include your GPS port configuration file

MPU6050 mpu;
NMEAGPS gps;              // Create a GPS object
gps_fix fix;              // Create a fix object to store the GPS data

const int buzzerPin = 2;  // Pin for the buzzer
const float angleThreshold = 60.0;  // Threshold angle for detecting a fall
const float netAccelThreshold = 1.1;  // Threshold for net acceleration (in g's, adjust as necessary)
const float k = 0.1;  // Steepness of the curve for logistic regression

void setup() {
  Serial.begin(115200);
  Wire.begin();
  mpu.initialize();
  gpsPort.begin(9600);    // Initialize GPS port at 9600 baud

  pinMode(buzzerPin, OUTPUT);  // Initialize the buzzer pin as an output

  // Check MPU6050 connection
  if (!mpu.testConnection()) {
    Serial.println("MPU6050 connection failed");
    while (1);
  }
  Serial.println("MPU6050 connection successful");
}

void loop() {
  // Get angle data from MPU6050
  int16_t ax, ay, az;
  mpu.getAcceleration(&ax, &ay, &az);

  // Convert raw accelerometer data to 'g' (assuming 16-bit data with range ±2g)
  float ax_g = ax / 16384.0;
  float ay_g = ay / 16384.0;
  float az_g = az / 16384.0;

  // Calculate pitch (angle in degrees)
  float angle = atan2(ax_g, sqrt(ay_g * ay_g + az_g * az_g)) * 180.0 / PI;

  // Calculate net acceleration (in g's)
  float netAccel = sqrt(ax_g * ax_g + ay_g * ay_g + az_g * az_g);

  // Calculate fall probability using a simple logistic regression approximation
  float fallProbability = calculateFallProbability(angle);

  // Print the angle, net acceleration, and probability
  Serial.print("Angle: ");
  Serial.print(angle);
  Serial.print(" degrees, Net Acceleration: ");
  Serial.print(netAccel);
  Serial.print(" g, Fall Probability: ");
  Serial.println(fallProbability);

  // Trigger an alert if the probability exceeds 60% and net acceleration threshold is met
  if (fallProbability > 0.6 && netAccel > netAccelThreshold) {
    Serial.println("Fall detected! Triggering alert...");
    triggerBuzzer();
    getGPSData();  // Call function to read GPS data
  } else {
    digitalWrite(buzzerPin, LOW);
  }

  delay(5000);  // Delay for 5 seconds
}

float calculateFallProbability(float angle) {
  // Using a simple logistic regression approximation
  float probability = 1.0 / (1.0 + exp(-k * (angle - angleThreshold)));
  return probability; 
}

void triggerBuzzer() {
  digitalWrite(buzzerPin, HIGH);
  delay(500);
  digitalWrite(buzzerPin, LOW);
  delay(500);
}

void getGPSData() {
  if (gps.available(gpsPort)) {  // Check if GPS data is available
    fix = gps.read();  // Read the GPS data

    // Check if GPS fix is valid
    if (fix.valid.location) {
      Serial.print("Latitude: ");
      Serial.println(fix.latitude(), 6);  // Print latitude with 6 decimal places
      Serial.print("Longitude: ");
      Serial.println(fix.longitude(), 6); // Print longitude with 6 decimal places
    } else {
      Serial.println("GPS fix not available.");
    }
  } else {
    Serial.println("No GPS data available.");
  }
}