#include <EEPROM.h>
#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27, 20, 4);

long duration, inches;
int set_val, percentage;
bool state, pump;

void setup() {
  lcd.begin(16, 2);
  lcd.print("WATER LEVEL:");
  lcd.setCursor(0, 1);
  lcd.print("PUMP: OFF MANUAL");

  pinMode(8, OUTPUT);
  pinMode(9, INPUT);
  pinMode(10, INPUT_PULLUP);
  pinMode(11, INPUT_PULLUP);
  pinMode(12, OUTPUT);

  set_val = EEPROM.read(0);
  if (set_val > 150) set_val = 150;
}

void loop() {
  digitalWrite(8, HIGH);  // Turn on the trigger pin
  delayMicroseconds(10);  // Wait for 10 microseconds
  digitalWrite(8, LOW);   // Turn off the trigger pin
  duration = pulseIn(9, HIGH);  // Measure the pulse duration
  inches = microsecondsToInches(duration);

  percentage = (set_val - inches) * 100 / set_val;

  lcd.setCursor(12, 0);
  if (percentage < 0) percentage = 0;
  lcd.print(percentage);
  lcd.print("%   ");

  if (percentage < 30 && digitalRead(11)) pump = 1;
  if (percentage > 99) pump = 0;
  digitalWrite(12, pump);

  lcd.setCursor(5, 1);
  if (pump == 1) lcd.print("ON  ");
  else if (pump == 0) lcd.print("OFF ");

  lcd.setCursor(9, 1);
  if (!digitalRead(11)) lcd.print("MANUAL");
  else lcd.print("AUTO   ");
}

long microsecondsToInches(long microseconds) {
  // Convert microseconds to inches using the speed of sound (approximately 74 microseconds per inch)
  return microseconds/74/2;
}