#include <Wire.h>
#include <WiFi.h>
#include <LiquidCrystal_I2C.h>
#include <DHT.h>
#include "ThingSpeak.h"

#define DHTPIN 2     // Digital pin connected to the DHT sensor
#define DHTTYPE DHT11 // DHT 11

#define MQ_PIN 4          // Analog pin connected to the MQ-135 sensor
#define BUZZER_PIN 12      // Digital pin connected to the buzzer

#define LCD_ADDRESS 0x27  // I2C address of the LCD
#define LCD_COLS 16       // Number of columns on the LCD
#define LCD_ROWS 2        // Number of rows on the LCD

const char* WIFI_NAME = "Wokwi-GUEST";
const char* WIFI_PASSWORD = "";
const int myChannelNumber = 2319977;
const char* myApiKey = "HD66D1WA9P9FW64C";
const char* server = "api.thingspeak.com";

LiquidCrystal_I2C lcd(LCD_ADDRESS, LCD_COLS, LCD_ROWS);
DHT dht(DHTPIN, DHTTYPE);
const int aqi_ppm = 0;

WiFiClient client;

void setup() {
  Serial.begin(9600);
  lcd.init();
  lcd.backlight();
  dht.begin();
  pinMode(BUZZER_PIN, OUTPUT);
  
  // Connect to Wi-Fi
  WiFi.begin(WIFI_NAME, WIFI_PASSWORD);
  while (WiFi.status() != WL_CONNECTED){
    delay(1000);
    Serial.println("Wifi not connected");
  }
  Serial.println("Wifi connected !");
  Serial.println("Local IP: " + String(WiFi.localIP()));

  // Initialize ThingSpeak
  WiFi.mode(WIFI_STA);
  ThingSpeak.begin(client);

}

void loop() {
   lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("AIR QUALITY");
   lcd.setCursor(0, 1);
  lcd.print("MONITORING SYSTEM");
  float temperature = dht.readTemperature();  // Read temperature
  float humidity = dht.readHumidity();        // Read humidity
  float airQuality = analogRead(MQ_PIN);      // Read air quality value

  // Convert analog reading to voltage
  float voltage = airQuality * (5.0 / 1023.0);

  // Convert voltage to ppm using the sensitivity of the MQ-135 sensor
  float aqi_ppm = 116.6020682 * pow(voltage, -2.769034857);
   
  // Update ThingSpeak fields
  ThingSpeak.setField(1, temperature); // Field for temperature data on ThingSpeak
  ThingSpeak.setField(2, humidity);    // Field for humidity data on ThingSpeak
  ThingSpeak.setField(2, AirQuality );    // Field for humidity data on ThingSpeak

  int x = ThingSpeak.writeFields(myChannelNumber, myApiKey);

  // Display values on the LCD
 
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Temp: ");
  lcd.print(temperature);
  lcd.print(" C");
  lcd.setCursor(0, 1);
  lcd.print("Humidity: ");
  lcd.print(humidity);
  lcd.print(" %");
  delay(100);

  // Check for sensor reading errors
  if (isnan(temperature) || isnan(humidity) || isnan(airQuality)) {
    Serial.println("Failed to read from sensor!");
    lcd.clear();
    lcd.setCursor(0,0);
    lcd.print("Sensor error!");
    tone(BUZZER_PIN, 1000, 500); // Sound the buzzer for half a second to indicate an error
  } else {
    // Determine air quality status and control buzzer
    if ((aqi_ppm >= 0) && (aqi_ppm <= 50)) {
      lcd.print("AQI Good");
      digitalWrite(BUZZER_PIN, LOW); // Turn off the buzzer
    } else if ((aqi_ppm > 50) && (aqi_ppm <= 100)) {
      lcd.print("AQI Moderate");
      tone(BUZZER_P IN, 1000, 200); // Sound the buzzer for moderate air quality
    } else if ((aqi_ppm > 100) && (aqi_ppm <= 200)) {
      lcd.print("AQI Unhealthy");
      tone(BUZZER_PIN, 1000, 200); // Sound the buzzer for unhealthy air quality
    } else if ((aqi_ppm > 200) && (aqi_ppm <= 300)) {
      lcd.print("AQI V.Unhealthy");
      tone(BUZZER_PIN, 1000, 200); // Sound the buzzer for very unhealthy air quality
    } else {
      lcd.print("Hazardous");
      tone(BUZZER_PIN, 1000, 200); // Sound the buzzer for hazardous air quality
    }
  }

  // Wait for 1 second

  // Print sensor readings and AQI to serial monitor
  Serial.print("Temperature: ");
  Serial.print(temperature);
  Serial.println(" C");
  Serial.print("Humidity: ");
  Serial.print(humidity);
  Serial.println(" %");
  Serial.print("Air Quality: ");
  Serial.print(aqi_ppm);
  Serial.println(" ppm");
  
  delay(2000);  // Wait for 2 seconds before taking the next reading
}