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

#define ECHO_PIN 4      // Echo pin of ultrasonic sensor
#define TRIG_PIN 5      // Trigger pin of ultrasonic sensor
#define ON_BUTTON_PIN 12 // Pin connected to the "Turn On" push button
#define OFF_BUTTON_PIN 14 // Pin connected to the "Turn Off" push button
#define RELAY_PIN 13     // Pin connected to the relay module
#define LED1_PIN 16      // Pin connected to LED1
#define LED2_PIN 17      // Pin connected to LED2
#define LED3_PIN 18      // Pin connected to LED3
#define LED4_PIN 19      // Pin connected to LED4

const int MIN_DISTANCE = 5;   // Minimum distance in cm
const int MAX_DISTANCE = 180; // Maximum distance in cm

bool relayState = LOW; // Initial state of the relay

LiquidCrystal_I2C lcd(0x27, 16, 2); // I2C address 0x27, 16 columns, 2 rows

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

  Serial.begin(115200);
  lcd.begin(16, 2);
  
  pinMode(ECHO_PIN, INPUT);
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ON_BUTTON_PIN, INPUT_PULLUP);
  pinMode(OFF_BUTTON_PIN, INPUT_PULLUP);
  pinMode(RELAY_PIN, OUTPUT);
  pinMode(LED1_PIN, OUTPUT);
  pinMode(LED2_PIN, OUTPUT);
  pinMode(LED3_PIN, OUTPUT);
  pinMode(LED4_PIN, OUTPUT);

  digitalWrite(RELAY_PIN, relayState);
}

void loop() {
  long duration, distance;

  // Trigger ultrasonic sensor
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

  // Measure the duration of the pulse from the echo pin
  duration = pulseIn(ECHO_PIN, HIGH);

  // Calculate distance in cm
  distance = constrain(duration * 0.034 / 2, MIN_DISTANCE, MAX_DISTANCE);

  // Scale the distance to a percentage (0-100)
  int percentage = map(distance, MAX_DISTANCE, MIN_DISTANCE, 0, 100);

  Serial.print("Distance: ");
  Serial.print(distance);
  Serial.print(" cm, Percentage: ");
  Serial.print(percentage);
  Serial.println("%");

  // Check if the "Turn On" button is pressed and the distance is greater than 5 cm
  if (digitalRead(ON_BUTTON_PIN) == LOW && distance > 5) {
    relayState = HIGH; // Water level is sufficient, turn on the relay
  }

  // Check if the "Turn Off" button is pressed or the distance is less than or equal to 5 cm
  if (digitalRead(OFF_BUTTON_PIN) == LOW || distance <= 5) {
    relayState = LOW; // Water level is low, turn off the relay
  }

  // Update relay state
  digitalWrite(RELAY_PIN, relayState);

  // Update LED indicators based on water level percentage
  updateLEDIndicators(percentage);

  // Display on LCD
  //lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Water Level: ");
  lcd.print(percentage);
  lcd.print("%");

  lcd.setCursor(0, 1);
  lcd.print("Relay: ");
  lcd.print(relayState == HIGH ? "ON" : "OFF");

  delay(1000); // Adjust the delay based on your needs
}

void updateLEDIndicators(int percentage) {
  if (percentage >= 25 && percentage < 25) {
    digitalWrite(LED1_PIN, HIGH);
    digitalWrite(LED2_PIN, LOW);
    digitalWrite(LED3_PIN, LOW);
    digitalWrite(LED4_PIN, LOW);
  } else if (percentage >= 25 && percentage < 50) {
    digitalWrite(LED1_PIN, HIGH);
    digitalWrite(LED2_PIN, HIGH);
    digitalWrite(LED3_PIN, LOW);
    digitalWrite(LED4_PIN, LOW);
  } else if (percentage >= 50 && percentage < 75) {
    digitalWrite(LED1_PIN, HIGH);
    digitalWrite(LED2_PIN, HIGH);
    digitalWrite(LED3_PIN, HIGH);
    digitalWrite(LED4_PIN, LOW);
  } else {
    digitalWrite(LED1_PIN, HIGH);
    digitalWrite(LED2_PIN, HIGH);
    digitalWrite(LED3_PIN, HIGH);
    digitalWrite(LED4_PIN, HIGH);
  }
}