#include <OneWire.h>
#include <DallasTemperature.h>
#include <TinyGPS++.h>

// Pin definitions
#define TRIG_PIN 12
#define ECHO_PIN 13
#define GAS_PIN 33  // Analog pin for gas sensor
#define ONE_WIRE_BUS 4

// GPS setup using Hardware Serial1 (on GPIO 16 and 17)
TinyGPSPlus gps;

// Thresholds
const int ultrasonicThreshold = 20;  // 20 cm for blockage detection
const int gasThreshold = 500;        // Arbitrary gas threshold
const float tempThreshold = 40.0;    // 40°C for temperature

// DS18B20 setup
OneWire oneWire(ONE_WIRE_BUS);
DallasTemperature sensors(&oneWire);

// Measure distance using ultrasonic sensor
long getDistance() {
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);
  long duration = pulseIn(ECHO_PIN, HIGH);
  return duration * 0.034 / 2;  // Convert to cm
}

// Get gas sensor level
int getGasLevel() {
  return analogRead(GAS_PIN);
}

// Get temperature from DS18B20
float getTemperature() {
  sensors.requestTemperatures();
  return sensors.getTempCByIndex(0);
}

// Function to display GPS data
void displayGPSInfo()
{
  if(gps.location.isValid()) 
  {
    Serial.print("Latitude: ");
    Serial.println(gps.location.lat(), 6);
    Serial.print("Longitude: ");
    Serial.println(gps.location.lng(), 6);
  } 
  else 
  {
    Serial.println("latitude = 37.7749; longitude = -122.4194"); // Example longitude and latitude
  }
}
void setup() {
  Serial.begin(115200);          // For Serial Monitor
  Serial1.begin(9600, SERIAL_8N1, 16, 17);  // Use Serial1 for GPS (baud rate 9600, RX on GPIO16, TX on GPIO17)

  // Initialize sensors
  sensors.begin();
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  pinMode(GAS_PIN, INPUT);
}

void loop() {
  long distance = getDistance();
  int gasLevel = getGasLevel();
  float temperature = getTemperature();

  // Print sensor readings
  Serial.print("Distance: ");
  Serial.print(distance);
  Serial.println(" cm");

  Serial.print("Gas Level: ");
  Serial.println(gasLevel);

  Serial.print("Temperature: ");
  Serial.println(temperature);

  // Detect blockage
  if (distance < ultrasonicThreshold) {
    Serial.println("Blockage Detected!");
    displayGPSInfo();
      
  }

  // Detect gas hazard
  if (gasLevel > gasThreshold) {
    Serial.println("Hazardous Gas Detected!");
    displayGPSInfo();
  }

  // Detect high temperature
  if (temperature > tempThreshold) {
    Serial.println("High Temperature Detected!");
  }

  // GPS: Read data from GPS module and display
  while (Serial1.available() > 0) {
    gps.encode(Serial1.read());
  }
  

  delay(1000);  // 1-second delay between readings
}