#include "LiquidCrystal_I2C.h"

#define I2C_ADDR 0x27
#define LCD_COLUMNS 16
#define LCD_LINES 2

#define WATER_SENSOR A0

LiquidCrystal_I2C lcd(I2C_ADDR, LCD_COLUMNS, LCD_LINES);

void setup() {
  delay(100);

  lcd.init();
  lcd.backlight();

  pinMode(WATER_SENSOR, INPUT);
}

void loop() {

  // Read potentiometer/water sensor
  int sensorValue = analogRead(WATER_SENSOR);

  // Convert ADC reading to percentage (0-100%)
  int waterLevel = map(sensorValue, 0, 1023, 0, 100);

  // Limit value between 0 and 100
  waterLevel = constrain(waterLevel, 0, 100);

  lcd.clear();

  // First line: Display water level
  lcd.setCursor(0, 0);
  lcd.print("Level: ");
  lcd.print(waterLevel);
  lcd.print("%");

  // Second line: Display status
  lcd.setCursor(0, 1);

  if (waterLevel <= 20) {
    lcd.print("LOW WATER!");
  }
  else if (waterLevel <= 80) {
    lcd.print("WATER LEVEL OK");
  }
  else if (waterLevel < 100) {
    lcd.print("TANK NEAR FULL");
  }
  else {
    lcd.print("TANK FULL!");
  }

  delay(500);
}