/*
    PIP - Platform Independent Primitives
    Cryptographic class using lib Sodium
    Copyright (C) 2016 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 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 General Public License for more details.

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

#include "picrypt.h"
#ifdef PIP_CRYPT
#  include "sodium.h"
#endif


const char hash_def_key[] = "_picrypt_";


PICrypt::PICrypt() {
#ifdef PIP_CRYPT
	if (!sodium_init()) piCout << "[PICrypt]" << "Error while initialize sodium!";
	nonce_.resize(crypto_secretbox_NONCEBYTES);
	key_.resize(crypto_secretbox_KEYBYTES);
	randombytes_buf(key_.data(), key_.size());
	randombytes_buf(nonce_.data(), nonce_.size());
#else
	piCout << "[PICrypt]" << "Warning: PICrypt is disabled, to enable install libsodium-dev library and build pip with -DCRYPT=1";
#endif
}


bool PICrypt::setKey(const PIByteArray & _key) {
	if (_key.size() != key_.size()) return false;
	key_ = _key;
	return true;
}


PIByteArray PICrypt::setKey(const PIString & secret) {
	PIByteArray hash;
#ifdef PIP_CRYPT
	hash.resize(crypto_generichash_BYTES);
	PIByteArray s(secret.data(), secret.size());
	crypto_generichash(hash.data(), hash.size(), s.data(), s.size(), (const uchar*)hash_def_key, sizeof(hash_def_key) - 1);
	hash.resize(key_.size());
	setKey(hash);
#endif
	return hash;
}


PIByteArray PICrypt::crypt(const PIByteArray & data) {
	PIByteArray ret;
#ifdef PIP_CRYPT
	ret.resize(data.size() + crypto_secretbox_MACBYTES);
	randombytes_buf(nonce_.data(), nonce_.size());
	crypto_secretbox_easy(ret.data(), data.data(), data.size(), nonce_.data(), key_.data());
	ret.append(nonce_);
#endif
	return ret;
}


PIByteArray PICrypt::crypt(const PIByteArray & data, PIByteArray key) {
	PIByteArray retba;
#ifdef PIP_CRYPT
	if (key.size() != crypto_secretbox_KEYBYTES)
		key.resize(crypto_secretbox_KEYBYTES, ' ');
		//return PIByteArray();
	if (!sodium_init()) return retba;
	PIByteArray n;
	retba.resize(data.size() + crypto_secretbox_MACBYTES);
	n.resize(crypto_secretbox_NONCEBYTES);
	randombytes_buf(n.data(), n.size());
	crypto_secretbox_easy(retba.data(), data.data(), data.size(), n.data(), key.data());
	retba.append(n);
#else
	piCout << "[PICrypt]" << "Warning: PICrypt is disabled, to enable install sodium library and build pip with -DCRYPT=1";
#endif
	return retba;
}


PIByteArray PICrypt::decrypt(const PIByteArray & crypt_data, bool *ok) {
	PIByteArray ret;
#ifdef PIP_CRYPT
	if (crypt_data.size() < nonce_.size() + crypto_secretbox_MACBYTES) {
		if (ok) *ok = false;
		return PIByteArray();
	}
	ret.resize(crypt_data.size() - nonce_.size() - crypto_secretbox_MACBYTES);
	memcpy(nonce_.data(), crypt_data.data(crypt_data.size() - nonce_.size()), nonce_.size());
	if (crypto_secretbox_open_easy(ret.data(), crypt_data.data(), crypt_data.size() - nonce_.size(), nonce_.data(), key_.data()) != 0) {
		if (ok) *ok = false;
		//			piCout << "[PICrypt]" << "bad key_";
		return PIByteArray();
	}
#endif
	if (ok) *ok = true;
	return ret;
}


PIByteArray PICrypt::decrypt(const PIByteArray & crypt_data, PIByteArray key, bool *ok) {
	PIByteArray retba;
#ifdef PIP_CRYPT
	if (key.size() != crypto_secretbox_KEYBYTES)
		key.resize(crypto_secretbox_KEYBYTES, ' ');
		/*if (ok) *ok = false;
		return PIByteArray();
	}*/
	if (crypt_data.size() < crypto_secretbox_NONCEBYTES + crypto_secretbox_MACBYTES) {
		if (ok) *ok = false;
		return PIByteArray();
	}
	if (!sodium_init()) return retba;
	PIByteArray n;
	n.resize(crypto_secretbox_NONCEBYTES);
	retba.resize(crypt_data.size() - n.size() - crypto_secretbox_MACBYTES);
	memcpy(n.data(), crypt_data.data(crypt_data.size() - n.size()), n.size());
	if (crypto_secretbox_open_easy(retba.data(), crypt_data.data(), crypt_data.size() - n.size(), n.data(), key.data()) != 0) {
		if (ok) *ok = false;
		//			piCout << "[PICrypt]" << "bad key_";
		return PIByteArray();
	}
#else
	piCout << "[PICrypt]" << "Warning: PICrypt is disabled, to enable install sodium library and build pip with -DCRYPT=";
#endif
	if (ok) *ok = true;
	return retba;
}


PIByteArray PICrypt::hash(const PIString & secret) {
	PIByteArray hash;
#ifdef PIP_CRYPT
	if (!sodium_init()) return hash;
	hash.resize(crypto_generichash_BYTES);
	PIByteArray s(secret.data(), secret.size());
	crypto_generichash(hash.data(), hash.size(), s.data(), s.size(), (const uchar*)hash_def_key, sizeof(hash_def_key) - 1);
#else
	piCout << "[PICrypt]" << "Warning: PICrypt is disabled, to enable install sodium library and build pip with -DCRYPT=";
#endif
	return hash;
}


ullong PICrypt::shorthash(const PIString& s, PIByteArray key) {
	ullong hash = 0;
#ifdef PIP_CRYPT
	if (crypto_shorthash_BYTES != sizeof(hash)) piCout << "[PICrypt]" << "internal error: bad hash size";
	if (!sodium_init()) return hash;
	if (key.size() != crypto_shorthash_KEYBYTES) {
		piCout << "[PICrypt]" << "invalid key size" << key.size() << ", shoud be" << crypto_shorthash_KEYBYTES << ", filled zeros";
		key.resize(crypto_shorthash_KEYBYTES, 0);
	}
	PIByteArray in(s.data(), s.size());
	crypto_shorthash((uchar *)&hash, in.data(), in.size(), key.data());
#else
	piCout << "[PICrypt]" << "Warning: PICrypt is disabled, to enable install sodium library and build pip with -DCRYPT=";
#endif
	return hash;
}


PIByteArray PICrypt::generateKey() {
	PIByteArray hash;
#ifdef PIP_CRYPT
	if (!sodium_init()) return hash;
	hash.resize(crypto_secretbox_KEYBYTES);
	randombytes_buf(hash.data(), hash.size());
#else
	piCout << "[PICrypt]" << "Warning: PICrypt is disabled, to enable install sodium library and build pip with -DCRYPT=";
#endif
	return hash;
}


size_t PICrypt::sizeKey() {
#ifdef PIP_CRYPT
	return crypto_secretbox_KEYBYTES;
#else
	piCout << "[PICrypt]" << "Warning: PICrypt is disabled, to enable install sodium library and build pip with -DCRYPT=";
#endif
	return 0;
}


size_t PICrypt::sizeCrypt() {
#ifdef PIP_CRYPT
	return crypto_secretbox_MACBYTES + crypto_secretbox_NONCEBYTES;
#else
	piCout << "[PICrypt]" << "Warning: PICrypt is disabled, to enable install sodium library and build pip with -DCRYPT=";
#endif
	return 0;
}