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

  #include "PN532.h"

  #include <PN532_SPI/PN532_SPI.h>

  #define __SCREEN_DEBUG__
  
  #ifdef __SCREEN_DEBUG__
  #define	MODEL_QUERY			'A'
  #define	SERIAL_ERROR		'G'
  #define	NFC_TAGQUERY		'C'
  #define	NFC_TAGQUERY_UID	'H'
  #define	NFC_ARDUINO			'B'
  #define	NFC_NOTAG			'D'
  #define	NFC_TYPE_PROFESSOR	'E'
  #define	NFC_TYPE_STUDENT	'F'
  #else

  #define	MODEL_QUERY			0x80
  #define	SERIAL_ERROR		0x55
  #define	NFC_TAGQUERY		0x82
  #define	NFC_TAGQUERY_UID	0x84
  #define	NFC_ARDUINO			0x02
  #define	NFC_NOTAG			0x81

  #define	NFC_TYPE_PROFESSOR	0x04

  #define	NFC_TYPE_STUDENT	0x01

  #endif
  

  #define	CPU_FREQ			16000000L

  #define	SERIAL_SPEED		19200

  boolean	tagDetected = false;

  boolean	tagType;
  

  PN532_SPI pn532spi(SPI, 10);
  PN532 nfc(pn532spi);
  

  void init_serial(int speed)
  {
  	UBRR0 = CPU_FREQ/(((unsigned long int)speed)<<4)-1;
  	UCSR0B = (1<<TXEN0 | 1<<RXEN0);
  	UCSR0C = (1<<UCSZ01 | 1<<UCSZ00);
  	UCSR0A &= ~(1 << U2X0);
  }
  
  void send_serial(unsigned char c)
  {
  	loop_until_bit_is_set(UCSR0A, UDRE0);
  	UDR0 = c;
  }
  
  unsigned char get_serial(void)
  {
  	loop_until_bit_is_set(UCSR0A, RXC0);
  	return UDR0;
  }
  
  

  void setup(void)
  {
  	int ser;
  

  	init_serial(SERIAL_SPEED);

  	nfc.begin();
  

  	uint32_t versiondata = nfc.getFirmwareVersion();

  	if(!versiondata)

  	{

  		send_serial(SERIAL_ERROR);

  		while (1);

  	}  
  

  	nfc.SAMConfig();
    

  	do
  	{

  		ser = get_serial();

  		if(ser == MODEL_QUERY)

  			send_serial(NFC_ARDUINO);

  		else

  			send_serial(SERIAL_ERROR);

  	}while(ser != MODEL_QUERY);

  }
  

  uint8_t success;
  uint8_t uid[] = { 0, 0, 0, 0, 0, 0, 0 };
  uint8_t uidLength;
  uint8_t data1[16];
  uint8_t data2[16];
  char  professorTag[7];
  char  studentTag[9] = {'0', '1', '2', '3', '4', '5', '6', '7'};
  int ser;

  
  void loop(void)
  {

  	success = nfc.readPassiveTargetID(PN532_MIFARE_ISO14443A, uid, &uidLength);

  
  	if(success && !tagDetected)

  	{

  		if(uidLength == 4)
  		{

  			uint8_t keya[6] = { 0xA0, 0xA1, 0xA2, 0xA3, 0xA4, 0xA5 };

  			success = nfc.mifareclassic_AuthenticateBlock(uid, uidLength, 44, 0, keya);  

  			if(success)
  			{

  				success = nfc.mifareclassic_ReadDataBlock(44, data1);

  
  				//_delay_ms(50);
  

  				if(success)
  				{

  					success = nfc.mifareclassic_ReadDataBlock(45, data2);
  
  					if(success)
  					{
  						tagDetected = true;
  						if(data1[4] == data1[15] &&
  						data1[5] == data2[0] &&
  						data1[6] == data2[1] &&
  						data1[7] == data2[2] &&
  						data1[8] == data2[3] &&
  						data1[9] == data2[4])
  						{

  							//send_serial('M');

  							tagType = NFC_TYPE_PROFESSOR;

  							professorTag[0] = data1[4];
  							professorTag[1] = data1[5];
  							professorTag[2] = data1[6];
  							professorTag[3] = data1[7];
  							professorTag[4] = data1[8];
  							professorTag[5] = data1[9];

  						}
  						else
  						{

  							//send_serial('N');

  							tagType = NFC_TYPE_STUDENT;

  							studentTag[0] = data1[15];
  							studentTag[1] = data2[0];
  							studentTag[2] = data2[1];
  							studentTag[3] = data2[2];
  							studentTag[4] = data2[3];
  							studentTag[5] = data2[4];
  							studentTag[6] = data2[5];
  							studentTag[7] = data2[6];

  						}
  					}

  					//else
  						//send_serial('L');

  				}

  				//else
  					//send_serial('K');

  			}

  			//else
  				//send_serial('J');

  		}

  		//else
  			//send_serial('I');

  	}
  	else if(tagDetected)
  	{

  		ser = get_serial();

  		if(ser == NFC_TAGQUERY)

  			send_serial(tagType);

  		else if(ser == NFC_TAGQUERY_UID)

  		{

                      if(tagType == NFC_TYPE_STUDENT)

                      {
                          send_serial(studentTag[0]);
  						_delay_ms(50);
  						send_serial(studentTag[1]);
  						_delay_ms(50);
                          send_serial(studentTag[2]);
  						_delay_ms(50);
  						send_serial(studentTag[3]);
  						_delay_ms(50);
                          send_serial(studentTag[4]);
  						_delay_ms(50);
  						send_serial(studentTag[5]);
  						_delay_ms(50);
  	                    send_serial(studentTag[6]);
  						_delay_ms(50);
  						send_serial(studentTag[7]);
  						_delay_ms(50);

                      }
                      else
                      {
                          send_serial(professorTag[0]);

                          send_serial(professorTag[1]);
                          send_serial(professorTag[2]);
                          send_serial(professorTag[3]);
                          send_serial(professorTag[4]);
                          send_serial(professorTag[5]);

                      }
  		    tagDetected = false;

  			_delay_ms(5000);

  		}

  		else

  			send_serial(SERIAL_ERROR);

  	}
  	else
  	{

  		if(get_serial() == NFC_TAGQUERY)
  			send_serial(NFC_NOTAG);

  		else
  			send_serial(SERIAL_ERROR);

  	}
  }

  
  int main(void)
  {
  	setup();
  
  	while(1)

  		loop();

  
  	return 0;
  }