#include <Wire.h> // библиотека для управления устройствами по I2C 
#include <LiquidCrystal_I2C.h> // подключаем библиотеку для QAPASS 1602
#include <Keypad.h>
#include <EEPROM.h>

#define CORRECT_PASS_ADDR 0
#define CORRECT_PASS_INITED_FLAG_ADDR 255
#define DEFAULT_PASSWORD "1234"

const uint8_t KEYPAD_ROWS = 4;
const uint8_t KEYPAD_COLS = 3;
const char OK_KEY = '*';
const char RESET_KEY = '#';
const size_t MAX_PASSWORD_LENGTH = 16;

char keypadInputText[17];
char currentInputPosition = 0;

char correctPassword[] = "";

char keypadKeys[KEYPAD_ROWS][KEYPAD_COLS] = {
  { '1', '2', '3' },
  { '4', '5', '6' },
  { '7', '8', '9' },
  { OK_KEY, '0', RESET_KEY }
};

uint8_t keypadColPins[KEYPAD_COLS] = { 5, 4, 3 }; // Pins connected to C1, C2, C3
uint8_t keypadRowPins[KEYPAD_ROWS] = { 9, 8, 7, 6 }; // Pins connected to R1, R2, R3, R4

Keypad keypad = Keypad(makeKeymap(keypadKeys), keypadRowPins, keypadColPins, KEYPAD_ROWS, KEYPAD_COLS);
LiquidCrystal_I2C LCD(0x27,16,2);

void setup() {
  Serial.begin(9600);

  prepareCorrectPass();

  LCD.init();
  LCD.backlight();
   
  lcdClear();
}

void loop() {
  char key = keypad.getKey();

  if (key != NO_KEY && currentInputPosition < MAX_PASSWORD_LENGTH) {
    if (key == OK_KEY) {
      handleInputComplete();
      reset();
      debugPrint("OK complete");
    } else if (key == RESET_KEY) {
      reset();
      debugPrint("Reset complete!");
    } else {
      keypadInputText[currentInputPosition] = key;
      currentInputPosition++;
      lcdPrint(keypadInputText, 1);
    }
  }

  delay(100);
}

void lcdPrint(char stringToWrite[], int lineNo) {
  LCD.setCursor(0, lineNo);
  LCD.print(stringToWrite);
}

void lcdClear() {
  LCD.clear();
  lcdPrint("Enter number:", 0);
}

void debugPrint(char stringToWrite[]) {
  Serial.println(stringToWrite);
}

void debugPrint(int stringToWrite) {
  Serial.println(stringToWrite);  
}

void reset() {
  currentInputPosition = 0;
  memset(keypadInputText, '\0', sizeof(keypadInputText));
  lcdClear();
}

void handleInputComplete() {
  debugPrint("---------------");
  debugPrint("Correct pass: ");
  debugPrint(correctPassword);
  debugPrint("Entered pass: ");
  debugPrint(keypadInputText);

  if (strcmp(correctPassword, keypadInputText) == 0) {
    debugPrint("Match");
  } else {
    debugPrint("Not Match");
  }

  debugPrint("OK handleInput");
}

void prepareCorrectPass() {
  bool isPasswordSet = false;
  byte passwordSetFlagValue;
  EEPROM.get(CORRECT_PASS_INITED_FLAG_ADDR, passwordSetFlagValue);

  isPasswordSet = passwordSetFlagValue == 1;

  if (!isPasswordSet) {
    initPassword();
  }

  debugPrint("prepareCorrectPass");
  debugPrint(passwordSetFlagValue);

  debugPrint(DEFAULT_PASSWORD);
  debugPrint(sizeof(DEFAULT_PASSWORD));
  debugPrint("rom dump");
  byte romByte;
  for (size_t i = 0; i != 5; ++i) {
    EEPROM.get(i, romByte);
    debugPrint(romByte);
  }
}

void initPassword() {
  for (size_t i = 0; i != sizeof(DEFAULT_PASSWORD); ++i) {
    EEPROM.put(CORRECT_PASS_ADDR + i, DEFAULT_PASSWORD[i]);
  }
}