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

LiquidCrystal_I2C lcd(0x27, 16, 2);

char password[4]; // 1234
char initial_password[4], new_password[4];
int i = 0;
int relay_pin = 11;
char key_pressed = 0;
#define setupDelay 5000
#define setupDelay 200

const byte rows = 4;
const byte columns = 4;

char hexaKeys[rows][columns] = {
  {'1', '2', '3', 'A'},
  {'4', '5', '6', 'B'},
  {'7', '8', '9', 'C'},
  {'*', '0', '#', 'D'}
};
// byte row_pins[rows] = {7, 8, 9, 10};
// byte column_pins[columns] = {3, 4, 5, 6};
byte row_pins[rows] = {5, 4, 3, 2};
byte column_pins[columns] = {A3, A2, A1, A0};
Keypad keypad_key = Keypad( makeKeymap(hexaKeys), row_pins, column_pins, rows, columns);

void setup() {
  lcd.init();
  lcd.backlight();
  pinMode(relay_pin, OUTPUT);
  digitalWrite(relay_pin, HIGH); // LOCK

  lcd.setCursor(5, 0);
  lcd.print("B & F");
  lcd.setCursor(2, 1);
  lcd.print("ELECTRONICS");
  delay(setupDelay);
  lcd.clear();

  lcd.setCursor(4, 0);
  lcd.print("WELCOME");
  delay(setupDelay);
  lcd.clear();

  lcd.setCursor(0, 0);
  lcd.print("ELECTRIC VEHICLE");
  lcd.setCursor(0, 1);
  lcd.print("CHARGING STATION");
  delay(setupDelay);
  lcd.clear();

  lcd.setCursor(1, 0);
  lcd.print("PLEASE CONNECT");
  lcd.setCursor(1, 1);
  lcd.print("CHARGING CABLE");
  delay(setupDelay);
  lcd.clear();

  lcd.setCursor(4, 0);
  lcd.print("TO YOUR");
  lcd.setCursor(0, 1);
  lcd.print("ELECTRIC VEHICLE");
  delay(setupDelay);
  lcd.clear();

  lcd.setCursor(0, 0);
  lcd.print("AFTER CONNECTION");
  lcd.setCursor(0, 1);
  lcd.print("ENTER YOUR PIN");
  delay(setupDelay);
  lcd.clear();

  lcd.print(" Enter Password");
  lcd.setCursor(6, 1);
  initialpassword();
}

void loop() {
  digitalWrite(relay_pin, HIGH); // LOCK

  key_pressed = keypad_key.getKey();
  if (key_pressed == '#')
    change();
  if (key_pressed)
  {
    password[i++] = key_pressed;
    lcd.print('*');
  }
  if (i == 4)
  {
    delay(200);
    for (int j = 0; j < 4; j++)
      initial_password[j] = EEPROM.read(j);
    if (!(strncmp(password, initial_password, 4))) {
      lcd.clear();

      lcd.setCursor(2, 0);
      lcd.print("PASSWORD IS");
      lcd.setCursor(4, 1);
      lcd.print("CORRECT");
      digitalWrite(relay_pin, LOW); // OPEN
      delay(8000);

      lcd.setCursor(0, 0);
      lcd.print("to set new pin");
      lcd.setCursor(0, 1);
      lcd.print("Press >#< button");
      delay(5000);
      lcd.clear();
      lcd.print(" Enter Password");
      lcd.setCursor(0, 1);
      i = 0;
    }
    else {
      digitalWrite(relay_pin, HIGH); // LOCK
      lcd.clear();

      lcd.setCursor(1, 0);
      lcd.print("Wrong Password");
      lcd.setCursor(3, 1);
      lcd.print("Try Again");

      delay(2000);

      lcd.setCursor(0, 0);
      lcd.print("Press >#< button");
      lcd.setCursor(0, 1);
      lcd.print("to set new pin");
      delay(2000);
      lcd.clear();
      lcd.print(" Enter Password");
      lcd.setCursor(0, 1);
      i = 0;
    }
  }
}

void change() {
  int j = 0;
  lcd.clear();
  lcd.print("Current Password");
  lcd.setCursor(0, 1);
  while (j < 4) {
    char key = keypad_key.getKey();
    if (key)
    {
      new_password[j++] = key;
      lcd.print(key);
    }
    key = 0;
  }
  delay(500);

  if ((strncmp(new_password, initial_password, 4))) {
    lcd.clear();
    lcd.print("Wrong Password");
    lcd.setCursor(0, 1);
    lcd.print("Try Again");
    delay(1000);
  }

  else {
    j = 0;
    lcd.clear();
    lcd.print("New Password");
    lcd.setCursor(0, 1);

    while (j < 4) {
      char key = keypad_key.getKey();
      if (key)
      {
        initial_password[j] = key;
        lcd.print(key);
        EEPROM.write(j, key);
        j++;
      }
    }
    lcd.print("PIN is Changed");
    delay(1000);
  }

  lcd.clear();
  lcd.print(" Enter Password");
  lcd.setCursor(0, 1);
  key_pressed = 0;
}

void initialpassword() {
  int j;
  for (j = 0; j < 4; j++)
    EEPROM.write(j, j + 49);
  for (j = 0; j < 4; j++)
    initial_password[j] = EEPROM.read(j);
}

/*

      +-----------------------------------+
      |  +---|EXT|--------|USB|---+       |  +---------------+
      |  |    PWR          A5/SCL |-------|--| SCL  LCD 1602 |
      |  |                 A4/SDA |-------|--| SDA           |       +-----+
      |  |          UNO      AREF |    +--|--| GND           |  +----|LOCK+|
      |  |                    GND |----+  +--| VCC           |  | +--|LOCK-|
      |  | IOREF          SCK/D13 |    |  |  +---------------+  | |  +-----+
      |  | RST             DI/D12 |    |  |  +---------------+  | |  +-----+
      |  | 3V3             DO/D11~|----|--|--|SIG  RELAY  N/C|--+ +--| PS- |
      +--| +5V                D10~|    |  +--|VCC         COM|-------| PS+ |
         | GND                 D9~|    +-----|GND         N/O|       +-----+
         | GND                 D8 |          +---------------+          ||
         | Vin                 D7 |          +---------------+          ++===(mains)
         |                     D6~|          |        KEYPAD |
+--------| A0                  D5~|--------R4| 1   2   3   A |
| +------| A1                  D4 |--------R3| 4   5   6   B |
| | +----| A2             INT1/D3 |--------R2| 7   8   9   C |
| | | +--| A3             INT0/D2~|--------R1| *   0   #   D |
| | | |  | A4/DA  RS CK DI  TX>D1 |          +---------------+
| | | |  | A5/CL  GD D0 5V  RX<D0 |              C  C  C  C
| | | |  +------------------------+              1  2  3  4
| | | |                                          |  |  |  |
| | | +------------------------------------------+  |  |  |
| | +-----------------------------------------------+  |  |
| +----------------------------------------------------+  |
+---------------------------------------------------------+

*/