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

LiquidCrystal_I2C lcd(0x27, 20, 4);  // Adjust the I2C address if needed

const int buttonUpPin = 2;   // Pin for the up button
const int buttonDownPin = 3; // Pin for the down button
const int solenoidPin = 13;  // Pin connected to the solenoid

int frequency;           // Frequency in Hz
unsigned long pulseDuration = 500;  // Pulse duration in milliseconds
unsigned long period;
unsigned long lastPulseTime = 0;

// Define states for button debouncing
#define IDLE 0
#define PRESSED 1

int buttonUpState = IDLE;
int buttonDownState = IDLE;

void setup() {
  pinMode(buttonUpPin, INPUT_PULLUP);
  pinMode(buttonDownPin, INPUT_PULLUP);
  pinMode(solenoidPin, OUTPUT);

  lcd.begin(20, 4);  // Initialize the LCD with 20 columns and 4 rows
  lcd.print("Frequency: ");
  
  // Read frequency from EEPROM
  frequency = EEPROM.read(0);
  if (frequency == 255 || frequency < 1) {
    frequency = 1;  // Default value if EEPROM is not initialized or less than 1
  }

  period = 1000 / frequency;
  
  lcd.setCursor(12, 0);
  lcd.print(frequency);
  lcd.print(" Hz");
}

void loop() {
  // Check for button presses
  if (digitalRead(buttonUpPin) == LOW) {
    if (buttonUpState == IDLE) {
      frequency = min(6, frequency + 1);  // Limit to 10 Hz
      updateLCD();
      saveFrequencyToEEPROM();
      buttonUpState = PRESSED;
    }
  } else {
    buttonUpState = IDLE;
  }

  if (digitalRead(buttonDownPin) == LOW) {
    if (buttonDownState == IDLE) {
      frequency = max(1, frequency - 1);  // Limit to 1 Hz
      updateLCD();
      saveFrequencyToEEPROM();
      buttonDownState = PRESSED;
    }
  } else {
    buttonDownState = IDLE;
  }

  // Generate pulse
  unsigned long currentTime = millis();
  if (currentTime - lastPulseTime >= period) {
    lastPulseTime = currentTime;
    digitalWrite(solenoidPin, HIGH);
    delay(pulseDuration);
    digitalWrite(solenoidPin, LOW);
  }
}

void updateLCD() {
  period = 1000 / frequency;
  lcd.setCursor(12, 0);
  lcd.print("    ");  // Clear previous frequency value
  lcd.setCursor(12, 0);
  lcd.print(frequency);
  lcd.print(" Hz");
}

void saveFrequencyToEEPROM() {
  EEPROM.write(0, frequency);
  // EEPROM.commit(); // Not needed for the built-in EEPROM in Arduino
}