/*
    PIP - Platform Independent Primitives
    Simple packet wrap aroud any PIIODevice
    Ivan Pelipenko peri4ko@yandex.ru, Andrey Bychkov work.a.b@yandex.ru

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU Lesser General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#ifdef __GNUC__
#  pragma GCC diagnostic push
#  pragma GCC diagnostic ignored "-Wnonnull"
#endif
#include "pistreampacker.h"

#include "piiodevice.h"
#ifdef __GNUC__
#  pragma GCC diagnostic pop
#endif

/** \class PIStreamPacker
 * \brief Simple packet wrap aroud any PIIODevice
 *
 * \section PIStreamPacker_synopsis Synopsis
 * %PIStreamPacker provides simple pack/unpack logic for any data packets.
 *
 * When you call \a send() function data splited into several
 * parts, \a packetSign() prepended to first part and \a sendRequest()
 * event raised several times.
 *
 * When your device receive some data, call \a received() function.
 * \a packetReceiveEvent() event will be raised when packet will be
 * collected.
 *
 * Use \a assignDevice() to connect device to this %PIStreamPacker.
 *
 */


PIStreamPacker::PIStreamPacker(PIIODevice * dev): PIObject() {
	crypt_frag = crypt_size = false;
	aggressive_optimization = true;
	packet_size             = -1;
	size_crypted_size       = sizeof(int);
	crypt_frag_size         = 1024 * 1024;
	max_packet_size         = 1400;
	packet_sign             = 0xAFBE;
	assignDevice(dev);
}


void PIStreamPacker::setCryptSizeEnabled(bool on) {
	crypt_size = on;
	if (crypt_size) {
		PIByteArray ba;
		ba << int(0);
		size_crypted_size = cryptData(ba).size_s();
	} else
		size_crypted_size = sizeof(int);
}


void PIStreamPacker::clear() {
	packet.clear();
	packet_size = -1;
	stream.clear();
}


void PIStreamPacker::send(const PIByteArray & data) {
	if (data.isEmpty()) return;
	PIByteArray cd;
	if (crypt_frag) {
		int fcnt = (data.size_s() - 1) / crypt_frag_size + 1, fst = 0;
		// piCout << "crypt_frag send" << fcnt << "frags";
		PIByteArray frag;
		for (int i = 0; i < fcnt; ++i) {
			if (i == fcnt - 1)
				frag = PIByteArray(data.data(fst), data.size_s() - fst);
			else
				frag = PIByteArray(data.data(fst), crypt_frag_size);
			fst += crypt_frag_size;
			cd << cryptData(frag);
		}
	} else {
		cd = cryptData(data);
	}
	// piCout << "crypt" << data.size() << "->" << cd.size() << key().size();
	PIByteArray hdr, part;
	hdr << packet_sign;
	if (crypt_size) {
		PIByteArray crsz;
		crsz << int(cd.size_s());
		hdr.append(cryptData(crsz));
	} else
		hdr << int(cd.size_s());
	cd.insert(0, hdr);
	int pcnt = (cd.size_s() - 1) / max_packet_size + 1, pst = 0;
	for (int i = 0; i < pcnt; ++i) {
		if (i == pcnt - 1)
			part = PIByteArray(cd.data(pst), cd.size_s() - pst);
		else
			part = PIByteArray(cd.data(pst), max_packet_size);
		// piCout << "send" << part.size();
		sendRequest(part);
		pst += max_packet_size;
	}
}


void PIStreamPacker::received(const uchar * readed, ssize_t size) {
	received(PIByteArray(readed, size));
}


void PIStreamPacker::received(const PIByteArray & data) {
	stream.append(data);
	// piCout << "rec" << data.size();
	while (!stream.isEmpty()) {
		int hdr_size = sizeof(packet_sign) + size_crypted_size;
		if (packet_size < 0) {
			if (stream.size_s() < hdr_size) return;
			ushort sign(0);
			memcpy(&sign, stream.data(), 2);
			if (sign != packet_sign) {
				if (aggressive_optimization)
					stream.clear();
				else
					stream.pop_front();
				continue;
			}
			int sz = -1;
			if (crypt_size) {
				PIByteArray crsz((uint)size_crypted_size);
				memcpy(crsz.data(), stream.data(2), size_crypted_size);
				crsz = decryptData(crsz);
				if (crsz.size() < sizeof(sz)) {
					if (aggressive_optimization)
						stream.clear();
					else
						stream.pop_front();
					continue;
				}
				crsz >> sz;
			} else {
				memcpy(&sz, stream.data(2), size_crypted_size);
			}
			if (sz < 0) {
				if (aggressive_optimization)
					stream.clear();
				else
					stream.pop_front();
				continue;
			}
			stream.remove(0, hdr_size);
			packet.clear();
			packet_size = sz;
			if (packet_size == 0) packet_size = -1;
			continue;
		} else {
			int ps = piMini(stream.size_s(), packet_size - packet.size_s());
			packet.append(stream.data(), ps);
			stream.remove(0, ps);
			if (packet.size_s() == packet_size) {
				PIByteArray cd;
				if (crypt_frag) {
					// piCout << "decrypt frags ..." << packet_size;
					while (packet.size_s() >= 4) {
						// piCout << "decrypt frags take data ...";
						PIByteArray frag;
						// piCout << "decrypt frags take data done" << frag.size_s();
						packet >> frag;
						if (frag.isEmpty()) {
							// piCout << "decrypt frags corrupt, break";
							cd.clear();
							break;
						}
						cd.append(decryptData(frag));
						// piCout << "decrypt frags add" << frag.size_s();
					}
					// piCout << "decrypt frags done" << cd.size();
				} else {
					cd = decryptData(packet);
				}
				// piCout << "decrypt" << packet.size() << "->" << cd.size() << key().size();
				if (!cd.isEmpty()) {
					packetReceived(cd);
					packetReceiveEvent(cd);
				}
				packet.clear();
				packet_size = -1;
			}
		}
	}
}


void PIStreamPacker::assignDevice(PIIODevice * dev) {
	if (!dev) return;
	if (!dev->infoFlags()[PIIODevice::Reliable]) {
		piCoutObj << "Warning! Not recommended to use with non-reliable" << dev;
	}
	CONNECT2(void, const uchar *, ssize_t, dev, threadedReadEvent, this, received);
	CONNECT1(void, PIByteArray, this, sendRequest, dev, write);
}