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

// Define pins
const int lowerTankPin = 2;  // Lower tank float sensor
const int upperTankFullPin = 3;  // Upper tank full-level float sensor
const int upperTankMidPin = 4;   // Upper tank middle-level float sensor
const int pumpPin = 8;       // Pump relay

// Display
LiquidCrystal_I2C lcd(0x27, 16, 2);

void setup() {
  pinMode(lowerTankPin, INPUT_PULLUP);      // Lower tank sensor as input
  pinMode(upperTankFullPin, INPUT_PULLUP);  // Upper tank full sensor as input
  pinMode(upperTankMidPin, INPUT_PULLUP);   // Upper tank middle sensor as input
  pinMode(pumpPin, OUTPUT);                 // Pump relay as output

  lcd.init();
  lcd.backlight();
  lcd.print("Water System");
  delay(2000);
  lcd.clear();
}

void loop() {
  bool lowerTankEmpty = digitalRead(lowerTankPin) == LOW;        // LOWER tank empty
  bool upperTankFull = digitalRead(upperTankFullPin) == LOW;     // UPPER tank full
  bool upperTankMidLow = digitalRead(upperTankMidPin) == LOW;    // UPPER tank middle-level low

  // Pump control logic
  if (!lowerTankEmpty && upperTankMidLow && !upperTankFull) {
    // Start the pump if lower tank has water, upper tank is not full, and middle sensor is low
    digitalWrite(pumpPin, HIGH);
    lcd.setCursor(0, 0);
    lcd.print("Pumping...");
  } else if (upperTankFull || lowerTankEmpty) {
    // Stop the pump if upper tank is full or lower tank is empty
    digitalWrite(pumpPin, LOW);
    lcd.setCursor(0, 0);
    lcd.print("Pump Off     ");
  }

  // Display status
  lcd.setCursor(0, 1);
  if (upperTankFull) {
    lcd.print("Upper Full   ");
  } else if (lowerTankEmpty) {
    lcd.print("Lower Empty  ");
  } else if (upperTankMidLow) {
    lcd.print("Mid Low      ");
  } else {
    lcd.print("Idle         ");
  }

  delay(500); // Small delay for stability
}