#include "dns.h"

int dns_parse_packet ( char* _buffer, int _bufflen, struct dns_message* _msg )
{
	if ( !_buffer || !_bufflen || !_msg )
		return 1; //Invalid input

	if ( _bufflen < 12 )
		return 1; //Too short to contain a DNS header
	
	//TODO test
	_msg->header.id = *( (uint16_t*) _buffer );	
	_msg->header.QR =  ( 0x80 & *( (uint8_t*) (_buffer + 2)) ) >> 7;
	_msg->header.OPCODE = (0x78 & *( (uint8_t*) (_buffer + 2))) >> 3;
	_msg->header.AA = (0x04 & *( (uint8_t*) (_buffer + 2))) >> 2;
	_msg->header.TC = (0x02 & *( (uint8_t*) (_buffer + 2))) >> 1;
	_msg->header.RD = (0x01 & *( (uint8_t*) (_buffer + 2)));
	_msg->header.RA = (0x80 & *( (uint8_t*) (_buffer + 3))) >> 7;
	_msg->header.Z  = (0x70 & *( (uint8_t*) (_buffer + 3))) >> 4;
	_msg->header.RCODE = (0x0F & *( (uint8_t*) (_buffer + 3)));
	_msg->header.question_count	= (*((uint8_t*) (_buffer + 4)) << 8) | *((uint8_t*) (_buffer + 5));
	_msg->header.answer_count	= (*((uint8_t*) (_buffer + 6)) << 8) | *((uint8_t*) (_buffer + 7));
	_msg->header.authorative_count	= (*((uint8_t*) (_buffer + 8)) << 8) | *((uint8_t*) (_buffer + 9));
	_msg->header.additional_count	= (*((uint8_t*) (_buffer + 10)) << 8) | *((uint8_t*) (_buffer + 11));

	printf("ANSWER %i\n", _msg->header.answer_count);
	printf("QUESTI %i\n", _msg->header.question_count);
	printf("AUTHOR %i\n", _msg->header.authorative_count);
	printf("ADDITI %i\n", _msg->header.additional_count);
	
	return 1;
}

int fqdn_to_qname( char* _source, int _sourcelen, char* _sink ,int _sinklen )
{
	int i;
	int lastdot = 0;

	if (_sourcelen < 1 || _sinklen < 1)
		return -1;

	_sink[0] = ' '; //Set to known value

	for(i = 0; ((i < _sourcelen) && (i < (_sinklen - 1))); i++) { //Copy offset 1
		if(! _source[i])
			break;
		_sink[i+1] = _source[i];
	}

	if( _source[i] ) // _source not terminated, thus no valid string
		return -1;

	for (int o = 0; o < i; o++) {
		if( _sink[o] == '.') {
			_sink[lastdot] = o - lastdot - 1;
			lastdot = o;
		}
	}

	_sink[lastdot] = i - lastdot;
	_sink[i + 1] = 0;

	return i+2; 
}


int qname_to_fqdn( char* _source, int _sourcelen, char* _sink, int _sinklen )
{
	if ( !_sourcelen || !_sinklen ) {
		return -1;
	}

	unsigned int next_dot = _source[0] + 1;
	int i = 1;
	for(i = 1; i < _sourcelen; i++) {
		if( i > _sinklen){ //Output too small. Not >= bc sink[i-1] is used
			return -1;
		}
		if ( !_source[i] ) {
			_sink[i-1] = '\0';
			break;
		} else if (i == next_dot) {
			_sink[i-1]='.';
			next_dot = _source[i] + i + 1;
		} else {
			_sink[i-1] = _source[i];
		}

	}

	return i-1;
}