/* using http://sourceforge.net/projects/libserial/
 */


#include "SmsPdu.h"

#include <string>
#include <sstream>

#include <time.h>
#include <stdlib.h> 


#include "util.h"


using namespace std;


namespace SmsPdu
{


vector<unsigned char> BcdEncode(string input)
{
	char buf[2] = " ";
	vector<unsigned char> result;

	unsigned char current;
	for (unsigned int i=0; i<input.length(); ++i)
	{
		buf[0] = input.at(i);
		unsigned char tmp = atoi(buf);

		if ( (i%2) == 0)
		{
			current = tmp;
		}
		else
		{
			current |= (tmp<<4);
			result.push_back(current);
		}
	}

	if ((input.length() % 2) == 1)
	{
		current |= 0xF0;
		result.push_back(current);
	}

	return result;
}

string HexformatVector(vector<unsigned char> vec)
{
	ostringstream os;

	for (unsigned int i=0; i<vec.size(); ++i)
	{
		os.width(2);
		os.fill('0');
		os << hex << uppercase << static_cast<unsigned int>(vec.at(i));
	}


	return os.str();
}

std::string Encode8to7bit(vector<unsigned char> vec)
{
	string result;

	return result;
}

vector<unsigned char> Encode7to8bit(std::string str)
{
	vector<unsigned char> buf;

	int shift = 0;
	for (unsigned int i=0; i<str.size(); ++i)
	{
		unsigned char current = str.at(i) & 0x7F;
		unsigned char next = ( (i+1)<str.size()) ? str.at(i+1) : 0;
		next &= 0x7F;

		current >>= shift;
		next <<= (7-shift);

		unsigned char byte = current | next;
		buf.push_back(byte);

		if (shift == 6)
			i++;

		shift = (shift+1) % 7;

	}

	return buf;
}

vector<PduInfo> CreateSmsPdu(string to, string message, bool allowMultipart)
{
	bool multipart = allowMultipart && message.length() > 160;

	const unsigned char UDHI = multipart ? 0x40 : 0;

	srand(time(0));
	unsigned char csms_ref = rand() % 128;

	int part_count;

	const int PDU_LEN = 153;

	if (multipart)
	{
		part_count = message.length() / PDU_LEN;
		if (message.length() % PDU_LEN)
			part_count++;
	}
	else
	{
		part_count = 1;
	}

	vector<PduInfo> result;
	for (int partnr = 0; partnr < part_count; ++partnr)
	{
		vector<unsigned char> pdu;

		pdu.push_back(0x00); // use SMSC from phone
		pdu.push_back( 0x01|UDHI ); // first octet -- no timeout
		pdu.push_back(0x00); // TP-MR message reference
		pdu.push_back(to.length() ); //length of phone nr
		pdu.push_back(0x91); // type of address (international nr  + ISDN/telephone range) - else try 0x81

		vector<unsigned char> phone = BcdEncode(to);
		pdu.insert( pdu.end(), phone.begin(), phone.end());

		pdu.push_back(0x00); // Protocol identifier
		pdu.push_back(0x00); // Data coding scheme 

		string message_part;
		if (multipart)
		{
			message_part = message.substr(0, PDU_LEN);
			message.erase(0, PDU_LEN);

			pdu.push_back( message_part.length()+ 7 );  //UserDataLength
			pdu.push_back( 0x06 ); // UDH Len
			pdu.push_back( 0x00 ); // UDH Element Identifier
			pdu.push_back( 0x03 ); // UDH element length
			pdu.push_back( csms_ref ); // csms_ref reference
			pdu.push_back( part_count );
			pdu.push_back( partnr+1 );
			pdu.push_back( 0x00);

		}
		else
		{
			message_part = message.substr(0,160); //truncate to 160

			pdu.push_back( message_part.length() ); //UserDataLength
		}

		vector<unsigned char> userData = Encode7to8bit(message_part);

		pdu.insert( pdu.end(), userData.begin(), userData.end());

		PduInfo info;
		info.len = pdu.size()-1;
		info.pdu = HexformatVector(pdu);
		result.push_back(info);

	}
	return result;
}

}