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

LiquidCrystal_I2C lcd(0x27, 16, 2);
DHT dht(15, DHT22);

const int echoPin = 18;
const int trigPin = 19;
const int green = 14;
const int orange = 13;
const int red = 12;
const int buzz = 16;

unsigned long previousMillis = 0;
const long interval = 2000;  // Interval for sensor readings (2 seconds)

void setup() {
  lcd.init();
  lcd.backlight();
  lcd.display();
  lcd.setCursor(0, 0);
  lcd.print("Flood Monitoring");
  lcd.setCursor(0, 1);
  lcd.print("Alerting System");
  delay(5000);
  lcd.clear();
  
  pinMode(echoPin, INPUT);
  pinMode(trigPin, OUTPUT);
  pinMode(green, OUTPUT);
  pinMode(orange, OUTPUT);
  pinMode(red, OUTPUT);
  pinMode(buzz, OUTPUT);
  
  digitalWrite(green, LOW);
  digitalWrite(orange, LOW);
  digitalWrite(red, LOW);
  digitalWrite(buzz, LOW);
}

void loop() {
  unsigned long currentMillis = millis();

  if (currentMillis - previousMillis >= interval) {
    previousMillis = currentMillis;

    float temperature = dht.readTemperature();
    int humidity = dht.readHumidity();

    if (isnan(temperature)) {
      Serial.println("Failed to read from DHT sensor!");
      return;
    }

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

    unsigned long duration;
    float distance;
    int percentage;
    int percent;

    digitalWrite(trigPin, LOW);
    delayMicroseconds(2);
    digitalWrite(trigPin, HIGH);
    delayMicroseconds(10);
    digitalWrite(trigPin, LOW);
    duration = pulseIn(echoPin, HIGH);
    distance = duration * 0.034 / 2;
    percentage = (distance / 400) * 100;
    percent = 99 - percentage;
    percent = constrain(percent, 0, 100);
    lcd.setCursor(0, 0);
    lcd.print("Water Level:");
    lcd.print(percent);
    lcd.print("%  ");

    lcd.setCursor(0, 1);
    lcd.print("Temp:");
    lcd.print(temperature);
    lcd.print("*C");

    if (percent > 66) {
      digitalWrite(red, HIGH);
      digitalWrite(green, LOW);
      digitalWrite(orange, LOW);
      tone(buzz, 1000, 1000);
    } else if (percent > 33 && temperature <= 27 || humidity >= 90) {
      tone(buzz, 1000, 1000);
      digitalWrite(orange, HIGH);
      digitalWrite(red, LOW);
      digitalWrite(green, LOW);
      noTone(buzz);
    } else {
      digitalWrite(green, HIGH);
      digitalWrite(orange, LOW);
      digitalWrite(red, LOW);
      noTone(buzz);
    }
  }
}