#include <Keypad.h>
#include <LiquidCrystal.h>

// Keypad setup
const byte ROWS = 4; //four rows
const byte COLS = 4; //four columns

char keys[ROWS][COLS] ={
  {'1','2','3','A'},
  {'4','5','6','B'},
  {'7','8','9','C'},
  {'*','0','#','D'}
};

byte rowPins[ROWS] = {14, 15, 18, 13}; //connect to the row pinouts of the keypad
byte colPins[COLS] =  {10, 19, 8, 7}; //connect to the column pinouts of the keypad

//Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);
Keypad keypad = Keypad( makeKeymap(keys), rowPins, colPins, ROWS, COLS);

const int rs = 12, en = 11, d4 = 5, d5 = 4, d6 = 3, d7 = 2;
LiquidCrystal lcd(rs, en, d4, d5, d6, d7);

// LED setup
const int ledPin = A2;

// Codes
const char codeA[] = "12345678"; // Countdown
const char codeB[] = "87654321"; // Lock
const char codeC[] = "11223344"; // Unlock

// Variables
char enteredCode[9];
int codeIndex = 0;

enum States { ATTESA, COUNTDOWN, LOCKED, BOOM };
States currentState = ATTESA;

unsigned long countdownStartTime;

unsigned long countdownDuration = 1800000UL; // 30 minutes in milliseconds

void setup() {
  Serial.begin(9600);
  lcd.begin(16, 2);
  pinMode(ledPin, OUTPUT);
  digitalWrite(ledPin, LOW);
  displayState();
  Serial.println("board resettata");
  Serial.println(countdownDuration);
  keypad.setDebounceTime(10);
}

void loop() {
  char key = keypad.getKey();
  if (key) {
    if (key == '#') {
      checkCode();
    } else if (key == '*') {
      clearCode();
      displayState();
    } else {
      enteredCode[codeIndex++] = key;
      displayEnteredCode();
    }
  }

  if (currentState == COUNTDOWN) {
    updateCountdown();
  }
}

void checkCode() {
  if (currentState == LOCKED) {
    if (strcmp(enteredCode, codeC) == 0) {
      currentState = ATTESA;
      displayMessage("Unlocked");
      delay(1000);
      clearCode();
      displayState();
    } else {
        displayMessage("Locked");
        delay(1000);
        clearCode();
        displayState();
    }
    return;
  }

  if (strcmp(enteredCode, codeA) == 0 && currentState == IDLE) {
    startCountdown();
  } else if (strcmp(enteredCode, codeB) == 0) {
      currentState = LOCKED;
      countdownStartTime = 0; //reset countdown
      displayMessage("Locked");
      delay(1000);
      clearCode();
      displayState();
  } else if (currentState == COUNTDOWN && strcmp(enteredCode, codeB) == 0) {
      currentState = LOCKED;
      displayMessage("Locked");
      delay(1000);
      clearCode();
      displayState();
  } else {
      displayMessage("Invalid Code");
      delay(1000);
      clearCode();
      displayState();
  }
}

void startCountdown() {
  // metto in countdownStartTime il momento in millisecondi in cui e' stato avviato il timer
  countdownStartTime = millis();
  currentState = COUNTDOWN;
  displayState();
  clearCode();
}

void updateCountdown() {
  //Serial.print(countdownDuration);
  //Serial.println();
  //Serial.print(countdownStartTime);
  //Serial.println();
  //long remainingMillis = countdownDuration - (millis() - countdownStartTime);
  unsigned long remainingMillis = countdownDuration - (millis() - countdownStartTime);
  Serial.print(remainingMillis);
  Serial.println();

  //if (remainingMillis <= 0) {
  if (remainingMillis >=  countdownDuration) {

    digitalWrite(ledPin, HIGH);
    displayMessage(">> IGNITION <<");
    currentState = BOOM;
    delay(5000);
    digitalWrite(ledPin, LOW);
    displayState();
  } else {
    unsigned long remainingSeconds = remainingMillis / 1000;
    unsigned long minutes = remainingSeconds / 60;
    unsigned long seconds = remainingSeconds % 60;

    lcd.setCursor(16 - 5, 0); // Right-aligned
    if (minutes < 10) lcd.print("0");
    lcd.print(minutes);
    lcd.print(":");
    if (seconds < 10) lcd.print("0");
    lcd.print(seconds);
    lcd.print(" ");
  }
}

void clearCode() {
  codeIndex = 0;
  memset(enteredCode, 0, sizeof(enteredCode));
}

void displayEnteredCode() {
  //lcd.clear();
  lcd.setCursor(0,1);
  for (int i = 0; i < 15; i++) {
        lcd.print("");
  }
  lcd.setCursor(0,1);
  lcd.print("Code: ");
  for (int i = 0; i < codeIndex; i++) {
    lcd.print(enteredCode[i]);
  }
}

void displayMessage(const char* message) {
  lcd.clear();
  lcd.print(message);
}

void displayState() {
  lcd.clear();
  switch (currentState) {
    case IDLE:
      lcd.print("ENTER CODE:");
      break;
    case COUNTDOWN:
      lcd.print("COUNTDOWN:");
      break;
    case LOCKED:
      lcd.print("SYSTEM LOCKED");
      break;
    case BOOM:
      lcd.print("LANCIO ESEGUITO");
      break;
  }
}