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

#define I2C_ADDR 0x27
#define LCD_COLUMNS 20
#define LCD_LINES 4

LiquidCrystal_I2C lcd(I2C_ADDR, LCD_COLUMNS, LCD_LINES);

#define LEDGreen  2
#define LEDRed    3
#define Buzzer    4

#define DHT_PIN   6
#define DHT_TYPE  DHT22

#define sensorMIN  0
#define sensorMAX  512
#define Threshold  300

#define BUTTON_ON  10
#define BUTTON_OFF 11

#define echo 8
#define trig 9

DHT dht(DHT_PIN, DHT_TYPE);

int value = 0; //variable to store the sensor value
int level = 0; //variable to store the water level
bool programOn = false; // variable to store the program state

void setup() {
  lcd.init();
  lcd.backlight();

  Serial.begin(115200);
  pinMode(Buzzer, OUTPUT);
  pinMode(LEDGreen, OUTPUT);
  pinMode(LEDRed, OUTPUT);
  pinMode(BUTTON_ON, INPUT_PULLUP);
  pinMode(BUTTON_OFF, INPUT_PULLUP);
  pinMode(trig, OUTPUT);
  pinMode(echo, INPUT);
  digitalWrite(LEDGreen, LOW);
  digitalWrite(LEDRed, LOW);

  dht.begin();

  lcd.setCursor(6, 0);
  lcd.print("Welcome");
  lcd.setCursor(2, 1);
  lcd.print("TEMPT. & HUMIDITY");
  lcd.setCursor(5, 2);
  lcd.print("ULTRASONIC");
  lcd.setCursor(7, 3);
  lcd.print("SENSOR");

  delay(4000);
  lcd.clear();
}

float readDistance() {
  digitalWrite(trig, LOW);
  delayMicroseconds(2);
  digitalWrite(trig, HIGH);
  delayMicroseconds(10);
  digitalWrite(trig, LOW);
  int duration = pulseIn(echo, HIGH);
  return duration * 0.034 / 2;
}

void loop() {
  if (digitalRead(BUTTON_ON) == LOW) {
    programOn = true;
    lcd.clear();
  }
  if (digitalRead(BUTTON_OFF) == LOW) {
    programOn = false;
    lcd.clear();
    lcd.setCursor(6, 0);
    lcd.print("System Off");
  }

  if (programOn) {
    delay(1000);
    //START
    noTone(Buzzer);
    digitalWrite(LEDGreen, LOW);
    digitalWrite(LEDRed, LOW);

    value = analogRead(DHT_PIN);
    digitalWrite(DHT_PIN, LOW);
    delay(1000);

    float temperature = dht.readTemperature();
    float humidity = dht.readHumidity();
    float distance = readDistance();

    if (temperature < 25 && humidity < 25) {
      noTone(Buzzer);
      digitalWrite(LEDGreen, HIGH);
      digitalWrite(LEDRed, LOW);

      Serial.print("ATTENTION!!! LOW TEMPERATURE");

      lcd.setCursor(1, 3);
      lcd.print("LOW TEMPERATURE ");
    } else if (temperature > 35 || humidity > 35) {
      tone(Buzzer, 1000, 500); // Play a high-pitched tone for 500 ms
      digitalWrite(LEDGreen, LOW);
      digitalWrite(LEDRed, HIGH);

      Serial.print("ATTENTION!!! TEMPERATURE TOO HIGH. ");

      lcd.setCursor(5, 3);
      lcd.print("TEMP. TOO HIGH");
    } else {
      level = map(value, sensorMIN, sensorMAX, 0, 10); // to be 10 levels
      tone(Buzzer, 500, 500); // Play a medium-pitched tone for 500 ms
    }

    Serial.print("TEMPERATURE DETECTED: ");
    Serial.print(temperature);
    Serial.print(" HUMIDITY: ");
    Serial.println(humidity);

    lcd.setCursor(0, 0);
    lcd.print("TEMPERATURE: ");
    lcd.setCursor(13, 0);
    lcd.print(temperature);

    lcd.setCursor(0, 1);
    lcd.print("HUMIDITY   : ");
    lcd.setCursor(13, 1);
    lcd.print(humidity);

    if (distance < 50) {
      digitalWrite(LEDRed, HIGH);
      digitalWrite(LEDGreen, LOW);
    } else {
      digitalWrite(LEDRed, LOW);
      digitalWrite(LEDGreen, HIGH);
    }

    Serial.print("Distance: ");
    Serial.println(distance);
    lcd.setCursor(0, 2);
    lcd.print("DISTANCE: ");
    lcd.setCursor(10, 2);
    lcd.print(distance);
    lcd.print(" cm");

  } else {
    noTone(Buzzer);
    digitalWrite(LEDGreen, LOW);
    digitalWrite(LEDRed, LOW);
  }
}