#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27, 16, 2);

#define NUM_BUTTONS 6
#define NUM_MOSFETS 5
#define NUM_LIMIT_SWITCHES 5

int buttons[] = {3, 4, 5, 6, 7, 8};
int mosfets[] = {9, 10, 11, 12, 13};
int limitSwitches[] = {A0, A1, A2, A3, A6};
int buzzerPin = A7;
int coinSlot = 2;

int pulse;
bool buttonPressed;

int itemAmounts[] = {5, 10, 15, 20, 25};

void setup() {
  lcd.init();
  lcd.backlight();
  displayMessage("SPLOOP! SANITARY", "Vending Machine!");
  delay(2000);
  displayMessage("PLEASE", "SELECT YOUR ITEM");

  setupPins();
}

void loop() {
  for (int i = 0; i < NUM_BUTTONS; i++) {
    if (digitalRead(buttons[i]) == LOW) {
      buttonPressed = true;
      displaySelectedItem(i);
    }
  }

  if (buttonPressed) {
    insertCoins();
  }
}

void displayMessage(const char* line1, const char* line2) {
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print(line1);
  lcd.setCursor(0, 1);
  lcd.print(line2);
}

void displaySelectedItem(int index) {
  displayMessage("You've selected", ("Item: Napkin " + String(index + 1)).c_str());
  delay(2000);
  displayMessage("PLEASE", "INSERT COINS");
}

void setupPins() {
  for (int i = 0; i < NUM_BUTTONS; i++) {
    pinMode(buttons[i], INPUT_PULLUP);
  }

  for (int i = 0; i < NUM_MOSFETS; i++) {
    pinMode(mosfets[i], OUTPUT);
  }

  for (int i = 0; i < NUM_LIMIT_SWITCHES; i++) {
    pinMode(limitSwitches[i], INPUT_PULLUP);
  }

  pinMode(coinSlot, INPUT_PULLUP);
  pinMode(buzzerPin, OUTPUT);
}

void insertCoins() {
  if (digitalRead(coinSlot) == LOW) {
    displayMessage("COINS INSERTED", ("Bal. PHP " + String(++pulse) + ".00").c_str());
    delay(30);
  }
}