#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <SD.h>
#include <DHT.h>

#define CS_PIN 5
#define SENSOR_PIN 4 // Change to the pin corresponding to the DHT sensor
#define GAS_SENSOR_PIN 13

File root;
File dataFile;

DHT dht(SENSOR_PIN, DHT22);

LiquidCrystal_I2C lcd(0x27, 16, 2);

bool isFirstSlide = true;

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

  Serial.print("Initializing SD card... ");
  if (!SD.begin(CS_PIN)) {
    Serial.println("Card initialization failed!");
    while (true);
  }

  Serial.println("Initialization done.");

  Serial.println("Files in the card:");
  root = SD.open("/");
  printDirectory(root, 0);
  Serial.println("");

  dataFile = SD.open("/wokwi.txt", FILE_WRITE);
  if (dataFile) {
    Serial.println("wokwi.txt opened for writing.");
    dataFile.println("Time,Temperature (C),Humidity (%RH),Air Quality,Gas Sensor");
  } else {
    Serial.println("Error opening wokwi.txt for writing!");
  }

  pinMode(GAS_SENSOR_PIN, INPUT);

  dht.begin();

  lcd.init();
  lcd.backlight();
  lcd.setCursor(0, 0);
  lcd.print("Air Quality Sensor");
  lcd.setCursor(0, 1);
  lcd.print("Initialization...");
  delay(2000);
  lcd.clear();
}

void loop() {
  float temperature = dht.readTemperature();
  float humidity = dht.readHumidity();

  // Add a condition for air quality
  String airQualityStatus;
  if (temperature > 25.0 && humidity > 70.0) {
    airQualityStatus = "Poor (high temperature and humidity)";
  } else if (temperature < 20.0 && humidity < 30.0) {
    airQualityStatus = "Poor (low temperature and humidity)";
  } else {
    airQualityStatus = "Normal";
  }

  int airQualityValue = analogRead(SENSOR_PIN);
  int gasSensorValue = digitalRead(GAS_SENSOR_PIN);

  Serial.print("Temperature: ");
  if (!isnan(temperature)) {
    Serial.print(temperature);
    Serial.println(" °C");
  } else {
    Serial.println("Failed to read temperature!");
  }

  Serial.print("Humidity: ");
  if (!isnan(humidity)) {
    Serial.print(humidity);
    Serial.println(" %RH");
  } else {
    Serial.println("Failed to read humidity!");
  }

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

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

  // Display data on the LCD
  lcd.clear();
  if (isFirstSlide) {
    lcd.setCursor(0, 0);
    lcd.print("Temp: ");
    if (!isnan(temperature)) {
      lcd.print(temperature);
      lcd.print(" C");
    } else {
      lcd.print("Error");
    }
    lcd.setCursor(0, 1);
    lcd.print("Humidity: ");
    if (!isnan(humidity)) {
      lcd.print(humidity);
      lcd.print(" %RH");
    } else {
      lcd.print("Error");
    }
    isFirstSlide = false;
  } else {
    lcd.setCursor(0, 0);
    lcd.print("AirQual: ");
    lcd.print(airQualityStatus);  // Display air quality status instead of the raw value
    lcd.setCursor(0, 1);
    lcd.print("Gas: ");
    lcd.print(gasSensorValue);
    isFirstSlide = true;
  }

  // Log data to SD card
  if (dataFile) {
    dataFile.print(millis()); // Time stamp
    dataFile.print(",");
    dataFile.print(temperature);
    dataFile.print(",");
    dataFile.print(humidity);
    dataFile.print(",");
    dataFile.print(airQualityValue);
    dataFile.print(",");
    dataFile.print(gasSensorValue);
    dataFile.print(",");
    dataFile.println(airQualityStatus);
    dataFile.flush();
  }

  delay(10000);
}

void printDirectory(File dir, int numTabs) {
  while (true) {
    File entry = dir.openNextFile();
    if (!entry) {
      break;
    }
    for (uint8_t i = 0; i < numTabs; i++) {
      Serial.print('\t');
    }
    Serial.print(entry.name());
    if (entry.isDirectory()) {
      Serial.println("/");
      printDirectory(entry, numTabs + 1);
    } else {
      Serial.print("\t\t");
      Serial.println(entry.size(), DEC);
    }
    entry.close();
  }
}