#include "dvlnet/packet.h"

namespace dvl {
namespace net {

static constexpr bool disable_encryption = false;

const buffer_t& packet::data()
{
	if (!have_decrypted || !have_encrypted)
		ABORT();
	return encrypted_buffer;
}

packet_type packet::type()
{
	if (!have_decrypted)
		ABORT();
	return m_type;
}

plr_t packet::src()
{
	if (!have_decrypted)
		ABORT();
	return m_src;
}

plr_t packet::dest()
{
	if (!have_decrypted)
		ABORT();
	return m_dest;
}

const buffer_t& packet::message()
{
	if (!have_decrypted)
		ABORT();
	if (m_type != PT_MESSAGE)
		throw packet_exception();
	return m_message;
}

turn_t packet::turn()
{
	if (!have_decrypted)
		ABORT();
	if (m_type != PT_TURN)
		throw packet_exception();
	return m_turn;
}

cookie_t packet::cookie()
{
	if (!have_decrypted)
		ABORT();
	if (m_type != PT_JOIN_REQUEST && m_type != PT_JOIN_ACCEPT)
		throw packet_exception();
	return m_cookie;
}

plr_t packet::newplr()
{
	if (!have_decrypted)
		ABORT();
	if (m_type != PT_JOIN_ACCEPT && m_type != PT_CONNECT
	    && m_type != PT_DISCONNECT)
		throw packet_exception();
	return m_newplr;
}

const buffer_t& packet::info()
{
	if (!have_decrypted)
		ABORT();
	if (m_type != PT_JOIN_REQUEST && m_type != PT_JOIN_ACCEPT)
		throw packet_exception();
	return m_info;
}

leaveinfo_t packet::leaveinfo()
{
	if (!have_decrypted)
		ABORT();
	if (m_type != PT_DISCONNECT)
		throw packet_exception();
	return m_leaveinfo;
}

void packet_in::create(buffer_t buf)
{
	if (have_encrypted || have_decrypted)
		ABORT();
	encrypted_buffer = std::move(buf);
	have_encrypted = true;
}

void packet_in::decrypt()
{
	if (!have_encrypted)
		ABORT();
	if (have_decrypted)
		return;
	if (!disable_encryption) {
		if (encrypted_buffer.size() < crypto_secretbox_NONCEBYTES
		    + crypto_secretbox_MACBYTES
		    + sizeof(packet_type) + 2*sizeof(plr_t))
			throw packet_exception();
		auto pktlen = (encrypted_buffer.size()
		               - crypto_secretbox_NONCEBYTES
		               - crypto_secretbox_MACBYTES);
		decrypted_buffer.resize(pktlen);
		if (crypto_secretbox_open_easy(decrypted_buffer.data(),
		                               encrypted_buffer.data()
		                               + crypto_secretbox_NONCEBYTES,
		                               encrypted_buffer.size()
		                               - crypto_secretbox_NONCEBYTES,
		                               encrypted_buffer.data(),
		                               key.data()))
			throw packet_exception();
	} else {
		if (encrypted_buffer.size() < sizeof(packet_type) + 2*sizeof(plr_t))
			throw packet_exception();
		decrypted_buffer = encrypted_buffer;
	}

	process_data();

	have_decrypted = true;
}

void packet_out::encrypt()
{
	if (!have_decrypted)
		ABORT();
	if (have_encrypted)
		return;

	process_data();

	if (!disable_encryption) {
		auto len_cleartext = encrypted_buffer.size();
		encrypted_buffer.insert(encrypted_buffer.begin(),
		                        crypto_secretbox_NONCEBYTES, 0);
		encrypted_buffer.insert(encrypted_buffer.end(),
		                        crypto_secretbox_MACBYTES, 0);
		randombytes_buf(encrypted_buffer.data(), crypto_secretbox_NONCEBYTES);
		if (crypto_secretbox_easy(encrypted_buffer.data()
		                          + crypto_secretbox_NONCEBYTES,
		                          encrypted_buffer.data()
		                          + crypto_secretbox_NONCEBYTES,
		                          len_cleartext,
		                          encrypted_buffer.data(),
		                          key.data()))
			ABORT();
	}
	have_encrypted = true;
}

packet_factory::packet_factory(std::string pw)
{
	if (sodium_init() < 0)
		ABORT();
	pw.resize(std::min<std::size_t>(pw.size(), crypto_pwhash_argon2id_PASSWD_MAX));
	pw.resize(std::max<std::size_t>(pw.size(), crypto_pwhash_argon2id_PASSWD_MIN), 0);
	std::string salt("devilution-salt 0.2.0");
	salt.resize(crypto_pwhash_argon2id_SALTBYTES, 0);
	if (crypto_pwhash(key.data(), crypto_secretbox_KEYBYTES,
	                  pw.data(), pw.size(),
	                  reinterpret_cast<const unsigned char *>(salt.data()),
	                  crypto_pwhash_argon2id_OPSLIMIT_INTERACTIVE,
	                  crypto_pwhash_argon2id_MEMLIMIT_INTERACTIVE,
	                  crypto_pwhash_ALG_ARGON2ID13))
		ABORT();
}

}  // namespace net
}  // namespace dvl