#include <avr/io.h>
#include <util/delay.h>

#define F_CPU 16000000UL

uint8_t column[2] = {0,64};
const char password[4] = {'9','9','8','9'};
char entered_password[4] = {0};
uint8_t currentindex = 0;

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

#define row1 PD0
#define row2 PD1
#define row3 PD2
#define row4 PD3
#define col1 PD4
#define col2 PD5
#define col3 PD6
#define col4 PD7

#define rs PC0
#define en PC1
#define D4 PC2
#define D5 PC3
#define D6 PC4
#define D7 PC5

void ports_init(void)
{
  DDRD &= ~((1 << row1) | (1 << row2) | (1 << row3) | (1 << row4));
  PORTD |= (1 << row1) | (1 << row2) | (1 << row3) | (1 << row4);

  DDRD |= (1 << col1) | (1 << col2) | (1 << col3) | (1 << col4);
  PORTD |= (1 << col1) | (1 << col2) | (1 << col3) | (1 << col4);

  lcd_init();
  timer_init();
  send_string("enter password =");
  set_cursor(0,1);
}

void timer_init(void)
{
  DDRB = (1 << PB1);
  TCCR1A |= (1 << COM1A1) | (1 << WGM11);
  TCCR1B |= (1 << WGM13) | (1 << WGM12) | (1 << CS11);
  ICR1 = 39999;
}

void set_servo_position(uint16_t position)
{
  if(position < 1000) position = 1000;
  if(position > 2000) position = 2000;
  OCR1A = position * 2;
}

char scan_keypad(void)
{
  for(uint8_t col = 0;col < 4;col++)
  {
    PORTD &= ~(1 << (col1 + col));

    for(uint8_t row=0;row < 4;row++)
    {
      if(!(PIND & (1 << (row1 + row))))
      {
        _delay_ms(20);
        while(!(PIND & (1 << (row1 + row))));
        PORTD |= (1 << (col1 + col));
        return keymap[row][col];
      }
    }
    PORTD |= (1 << (col1 + col));
  }
  return '\0';
}

void lcd_clear(void)
{
  send_command(0x01);
  _delay_ms(2);
}

uint8_t checkpassword(void)
{
  for(uint8_t i=0;i<4;i++)
  {
    if(entered_password[i] != password[i])
    {
      return 0;
    }
  }
  return 1;
}

void lock_open(void)
{
  servo_open();
  lcd_clear();
  send_string("access granted");
  set_cursor(0,1);
  send_string("lock open");
  _delay_ms(3000);
  lcd_clear();
  send_string("enter password = ");
  set_cursor(0,1);
}

void servo_open(void)
{
  set_servo_position(2000);
  _delay_ms(5000);
  set_servo_position(1000);
}

void wrongpassword(void)
{
  lcd_clear();
  send_string("access denied");
  set_cursor(0,1);
  send_string("please try again");
  _delay_ms(3000);
  lcd_clear();
  send_string("enter password = ");
  set_cursor(0,1);
}

void lcd_init(void)
{
  DDRC |= (1 << rs) | (1 << en) | (1 << D4) | (1 << D5) | (1 << D6) | (1 << D7);
  _delay_ms(20);
  send_command(0x33);
  send_command(0x32);
  send_command(0x28);
  send_command(0x0E);
  send_command(0x06);
  send_command(0x01);
  _delay_ms(2);
}

void send_command(unsigned char command)
{
  PORTC = ((PORTC & 0x03) | ((command & 0xF0) >> 2));
  PORTC &= ~(1 << rs);
  PORTC |= (1 << en);
  _delay_ms(2);
  PORTC &= ~(1 << en);
  _delay_ms(200);
  PORTC = ((PORTC & 0x03) | (command & 0x0F) << 2);
  PORTC |= (1 << en);
  _delay_ms(2);
  PORTC &= ~(1 << en);
  _delay_ms(2);
}

void send_data(unsigned char data)
{
  PORTC = ((PORTC & 0x03) | ((data & 0xF0) >> 2));
  PORTC |= (1 << rs);
  PORTC |= (1 << en);
  _delay_ms(2);
  PORTC &= ~(1 << en);
  _delay_ms(200);
  PORTC = ((PORTC & 0x03) | (data & 0x0F) << 2);
  PORTC |= (1 << en);
  _delay_ms(2);
  PORTC &= ~(1 << en);
  _delay_ms(2);
}

void set_cursor(uint8_t x,uint8_t y)
{
  send_command(0x80 + x + column[y]);
}

void send_string(char *string)
{
  while(*string != '\0')
  {
    send_data(*string++);
  }
}

int main(void)
{
  ports_init();
  set_servo_position(1000);

  while(1)
  {
    char key = scan_keypad();

    if(key != '\0')
    {
      if(key == '#')
      {
        if(currentindex == 4)
        {
          if(checkpassword())
          {
            lock_open();
          }
          else
          {
            set_servo_position(1000);
            wrongpassword();
          }
        }
        else
        {
          set_servo_position(1000);
          wrongpassword();
        }
        currentindex = 0;
      }
      else if(key == '*')
      {
        currentindex = 0;
        set_cursor(0,1);
        send_string("                ");
        set_cursor(0,1);
        _delay_ms(200);
      }
      else if(currentindex < 4)
      {
        entered_password[currentindex++] = key;
        send_data('*');
      }
    }
  }
  return 0;
}