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

// Define the pins for the ultrasonic sensor, LED, relay module, and push button
#define TRIG_PIN 26
#define ECHO_PIN 25
#define LED_PIN 27
#define RELAY_PIN 27
#define BUTTON_PIN 32  // Push button pin

// Define the I2C address of the LCD display
#define LCD_ADDR 0x27

// Initialize the LCD display
LiquidCrystal_I2C lcd(LCD_ADDR, 16, 2);

// Variables to store the state of the button and the manual override
bool manualOverride = false;
bool buttonState;
bool lastButtonState = HIGH;
unsigned long lastDebounceTime = 0;
unsigned long debounceDelay = 50;
float lastDistance = 0;  // Track the last measured distance

void setup() {
  Serial.begin(9600);

  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  pinMode(LED_PIN, OUTPUT);
  pinMode(RELAY_PIN, OUTPUT);
  pinMode(BUTTON_PIN, INPUT_PULLUP);

  lcd.init();
  lcd.backlight();
  lcd.print("Water Level");
  delay(2000); // Display welcome message for 2 seconds
  lcd.clear();
}

void loop() {
  // Read the push button state with debounce
  bool reading = digitalRead(BUTTON_PIN);
  if (reading != lastButtonState) {
    lastDebounceTime = millis();
  }
  if ((millis() - lastDebounceTime) > debounceDelay) {
    if (reading != buttonState) {
      buttonState = reading;
      if (buttonState == LOW) {
        manualOverride = !manualOverride;
        Serial.println("Button Toggle");
        lcd.clear();
        lcd.print("Manual Toggle");
        delay(1000); // Display message for 1 second
      }
    }
  }
  lastButtonState = reading;

  // Send a trigger pulse to the ultrasonic sensor
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

  // Measure the time it takes for the echo pulse to return
  long duration = pulseIn(ECHO_PIN, HIGH);

  // Calculate the distance to the water surface
  float distance = duration * 0.034 / 2;

  // Automatically reset manual override if the water level crosses the threshold
  if ((lastDistance < 50 && distance >= 50) || (lastDistance >= 50 && distance < 50)) {
    manualOverride = false;
    Serial.println("Auto Reset");
  }
  lastDistance = distance;  // Update lastDistance for the next cycle

  // Update the LCD with the current distance
  lcd.clear();
  lcd.print("Dist: ");
  lcd.print(distance, 1);
  lcd.print("cm");

  // Automatic control based on water level
  if (!manualOverride) {
    if (distance < 50) {
      digitalWrite(LED_PIN, LOW); // Turn off LED
      digitalWrite(RELAY_PIN, HIGH); // Turn off motor
      lcd.setCursor(0, 1);
      lcd.print("Motor OFF");
    } else {
      digitalWrite(LED_PIN, HIGH); // Turn on LED
      digitalWrite(RELAY_PIN, LOW); // Turn on motor
      lcd.setCursor(0, 1);
      lcd.print("Motor ON");
    }
  } else {
    digitalWrite(LED_PIN, LOW); // Turn off LED
    digitalWrite(RELAY_PIN, HIGH); // Turn off motor
    lcd.setCursor(0, 1);
    lcd.print("Manual OFF");
  }

  // Wait for a second before taking the next measurement
  delay(1000);
}