#include <LiquidCrystal.h>
#include "DHT.h"

#define DHT_PIN A1                    
#define DHT_TYPE DHT22                  

LiquidCrystal lcd(8, 9, 10, 11, 12, 13); 
DHT dht(DHT_PIN, DHT_TYPE);            

const int echoPin = 4;                   
const int trigPin = 5;                  

const int greenLED = 2;
const int yellowLED = 3;                
const int redLED = 6;                    
const int buzzer = 7;

void setup() {
  Serial.begin(115200);                 
  lcd.begin(16, 2);                      
  pinMode(echoPin, INPUT);
  pinMode(trigPin, OUTPUT);
  pinMode(greenLED, OUTPUT);
  pinMode(yellowLED, OUTPUT);
  pinMode(redLED, OUTPUT);
  pinMode(buzzer, OUTPUT);

  dht.begin();                           
  digitalWrite(greenLED, LOW);
  digitalWrite(yellowLED, LOW);
  digitalWrite(redLED, LOW);
  digitalWrite(buzzer, LOW);
  
  lcd.setCursor(0, 0);
  lcd.print("Flood Detection");
  lcd.setCursor(0, 1);
  lcd.print("Initializing...");
  delay(3000);                          
  lcd.clear();
}

void loop() {
  float temperature = dht.readTemperature();
  float humidity = dht.readHumidity();
  
  if (isnan(temperature) || isnan(humidity)) { 
    lcd.print("Sensor Error");
    return;
  }

  long duration, distance, levelPercent;
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  duration = pulseIn(echoPin, HIGH);
  distance = (duration * 0.034) / 2;
  
  levelPercent = map(distance, 15, 2, 0, 100);

  if(levelPercent < 0) levelPercent = 0;
  if(levelPercent > 100) levelPercent = 100;

  lcd.setCursor(0, 0);
  lcd.print("Temp:");
  lcd.print(temperature);
  lcd.setCursor(0, 1);
  lcd.print("Humidity:");
  lcd.print(humidity);
  delay(1000);
  
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Water Level:");
  lcd.print(levelPercent);
  lcd.print("%");

  if (distance <= 4) {                
    lcd.setCursor(0, 1);
    lcd.print("Critical Alert! ");
    digitalWrite(redLED, HIGH);
    digitalWrite(greenLED, LOW);
    digitalWrite(yellowLED, LOW);
    tone(buzzer, 1000, 1500);            
    delay(2000);
  } 
  else if (distance <= 12) {            
    lcd.setCursor(0, 1);
    lcd.print("Caution!       ");
    digitalWrite(yellowLED, HIGH);
    digitalWrite(redLED, LOW);
    digitalWrite(greenLED, LOW);
    tone(buzzer, 800, 1000);           
    delay(3000);
  } 
  else {
    lcd.setCursor(0, 1);
    lcd.print("All Safe!      ");
    digitalWrite(greenLED, HIGH);
    digitalWrite(yellowLED, LOW);
    digitalWrite(redLED, LOW);
    noTone(buzzer);                      
  }

  delay(2000);                          
}