#include "DHTesp.h"

// ---------------- PIN DEFINITIONS ----------------
#define DHT_PIN 4       // DHT22 data -> GPIO 4 (D4)
#define MQ2_PIN 34      // MQ2 analog output -> GPIO 34 (D34)

// DHT22 sensor
DHTesp dhtSensor;

void setup() {
  Serial.begin(115200);

  // Start DHT22
  dhtSensor.setup(DHT_PIN, DHTesp::DHT22);

  Serial.println("================================");
  Serial.println(" AI AIR QUALITY MONITORING SYSTEM");
  Serial.println(" ESP32 IoT SENSOR NODE");
  Serial.println("================================");
  Serial.println();
}

void loop() {

  // -------- READ DHT22 --------
  TempAndHumidity data = dhtSensor.getTempAndHumidity();

  float temperature = data.temperature;
  float humidity = data.humidity;

  // -------- READ MQ2 --------
  int gasValue = analogRead(MQ2_PIN);

  // -------- SIMULATED AIR QUALITY --------
  // Convert MQ2 reading into a simple 0-500 AQI-like value
  int aqi = map(gasValue, 0, 4095, 0, 500);
  aqi = constrain(aqi, 0, 500);

  // -------- DETERMINE AIR QUALITY STATUS --------
  String status;

  if (aqi <= 50) {
    status = "Good";
  }
  else if (aqi <= 100) {
    status = "Moderate";
  }
  else if (aqi <= 150) {
    status = "Unhealthy for Sensitive Groups";
  }
  else if (aqi <= 200) {
    status = "Unhealthy";
  }
  else if (aqi <= 300) {
    status = "Very Unhealthy";
  }
  else {
    status = "Hazardous";
  }

  // -------- DISPLAY DATA --------
  Serial.println("--------------------------------");

  Serial.print("Temperature : ");
  Serial.print(temperature, 1);
  Serial.println(" °C");

  Serial.print("Humidity    : ");
  Serial.print(humidity, 1);
  Serial.println(" %");

  Serial.print("Gas Sensor  : ");
  Serial.println(gasValue);

  Serial.print("AQI Value   : ");
  Serial.println(aqi);

  Serial.print("Air Quality : ");
  Serial.println(status);

  Serial.println("--------------------------------");
  Serial.println();

  delay(2000);
}