/*

Miranda NG: the free IM client for Microsoft* Windows*

Copyright (c) 2012-18 Miranda NG team (https://miranda-ng.org)
all portions of this codebase are copyrighted to the people
listed in contributors.txt.

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 2
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, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
*/

#include "stdafx.h"

/////////////////////////////////////////////////////////////////////////////////////////

char DBKey_Crypto_Provider[] = "Provider";
char DBKey_Crypto_Key[] = "Key";
char DBKey_Crypto_IsEncrypted[] = "EncryptedDB";

CRYPTO_PROVIDER* CDbxMDBX::SelectProvider()
{
	CRYPTO_PROVIDER **ppProvs, *pProv;
	int iNumProvs;
	Crypto_EnumProviders(&iNumProvs, &ppProvs);

	if (iNumProvs == 0)
		return nullptr;

	bool bTotalCrypt = false;

	if (iNumProvs > 1) {
		CSelectCryptoDialog dlg(ppProvs, iNumProvs);
		dlg.DoModal();
		pProv = dlg.GetSelected();
		bTotalCrypt = dlg.TotalSelected();
	}
	else pProv = ppProvs[0];

	{
		txn_ptr trnlck(StartTran());
		MDBX_val key = { DBKey_Crypto_Provider, sizeof(DBKey_Crypto_Provider) }, value = { pProv->pszName, mir_strlen(pProv->pszName) + 1 };
		if (mdbx_put(trnlck, m_dbCrypto, &key, &value, 0) != MDBX_SUCCESS)
			return nullptr;

		key.iov_len = sizeof(DBKey_Crypto_IsEncrypted); key.iov_base = DBKey_Crypto_IsEncrypted; value.iov_len = sizeof(bool); value.iov_base = &bTotalCrypt;
		if (mdbx_put(trnlck, m_dbCrypto, &key, &value, 0) != MDBX_SUCCESS)
			return nullptr;

		if (trnlck.commit() != MDBX_SUCCESS)
			return nullptr;
	}

	DBFlush();
	return pProv;
}

int CDbxMDBX::InitCrypt()
{
	CRYPTO_PROVIDER *pProvider;

	txn_ptr_ro txn(m_txn_ro);

	MDBX_val key = { DBKey_Crypto_Provider, sizeof(DBKey_Crypto_Provider) }, value;
	if (mdbx_get(txn, m_dbCrypto, &key, &value) == MDBX_SUCCESS) {
		pProvider = Crypto_GetProvider((const char*)value.iov_base);
		if (pProvider == nullptr)
			pProvider = SelectProvider();
	}
	else pProvider = SelectProvider();

	if (pProvider == nullptr)
		return 1;

	if ((m_crypto = pProvider->pFactory()) == nullptr)
		return 3;

	key.iov_len = sizeof(DBKey_Crypto_Key); key.iov_base = DBKey_Crypto_Key;
	if (mdbx_get(txn, m_dbCrypto, &key, &value) == MDBX_SUCCESS && (value.iov_len == m_crypto->getKeyLength())) {
		if (!m_crypto->setKey((const BYTE*)value.iov_base, value.iov_len)) {
			DlgChangePassParam param = { this };
			CEnterPasswordDialog dlg(&param);
			while (true) {
				if (-128 != dlg.DoModal())
					return 4;
				m_crypto->setPassword(pass_ptrA(mir_utf8encodeW(param.newPass)));
				if (m_crypto->setKey((const BYTE*)value.iov_base, value.iov_len)) {
					m_bUsesPassword = true;
					SecureZeroMemory(&param, sizeof(param));
					break;
				}
				param.wrongPass++;
			}
		}
	}
	else {
		if (!m_crypto->generateKey())
			return 6;
		StoreKey();
	}

	key.iov_len = sizeof(DBKey_Crypto_IsEncrypted); key.iov_base = DBKey_Crypto_IsEncrypted;

	if (mdbx_get(txn, m_dbCrypto, &key, &value) == MDBX_SUCCESS)
		m_bEncrypted = *(const bool*)value.iov_base;
	else
		m_bEncrypted = false;

	InitDialogs();
	return 0;
}

void CDbxMDBX::StoreKey()
{
	size_t iKeyLength = m_crypto->getKeyLength();
	BYTE *pKey = (BYTE*)_alloca(iKeyLength);
	m_crypto->getKey(pKey, iKeyLength);
	{
		txn_ptr trnlck(StartTran());
		MDBX_val key = { DBKey_Crypto_Key, sizeof(DBKey_Crypto_Key) }, value = { pKey, iKeyLength };
		int rc = mdbx_put(trnlck, m_dbCrypto, &key, &value, 0);
		if (rc == MDBX_SUCCESS)
			rc = trnlck.commit();
		/* FIXME: throw an exception */
		assert(rc == MDBX_SUCCESS);
		UNREFERENCED_PARAMETER(rc);
	}

	SecureZeroMemory(pKey, iKeyLength);
	DBFlush();
}

void CDbxMDBX::SetPassword(const wchar_t *ptszPassword)
{
	if (ptszPassword == nullptr || *ptszPassword == 0) {
		m_bUsesPassword = false;
		m_crypto->setPassword(nullptr);
	}
	else {
		m_bUsesPassword = true;
		m_crypto->setPassword(pass_ptrA(mir_utf8encodeW(ptszPassword)));
	}
	UpdateMenuItem();
}

/////////////////////////////////////////////////////////////////////////////////////////

int CDbxMDBX::EnableEncryption(bool bEncrypted)
{
	if (m_bEncrypted == bEncrypted)
		return 0;

	{
		txn_ptr_ro txnro(m_txn_ro);

		MDBX_stat st;
		mdbx_dbi_stat(txnro, m_dbEvents, &st, sizeof(st));

		std::vector<MEVENT> lstEvents;
		lstEvents.reserve(st.ms_entries);
		{
			cursor_ptr_ro cursor(m_curEvents);
			MDBX_val key, data;
			while (mdbx_cursor_get(cursor, &key, &data, MDBX_NEXT) == MDBX_SUCCESS) {
				const MEVENT hDbEvent = *(const MEVENT*)key.iov_base;
				lstEvents.push_back(hDbEvent);
			}
		}

		do {
			size_t portion = min(lstEvents.size(), 1000);

			txn_ptr trnlck(StartTran());
			for (size_t i = 0; i < portion; i++) {
				MEVENT &hDbEvent = lstEvents[i];
				MDBX_val key = { &hDbEvent, sizeof(MEVENT) }, data;
				int rc = mdbx_get(txnro, m_dbEvents, &key, &data);
				/* FIXME: throw an exception */
				assert(rc == MDBX_SUCCESS);
				(void)rc;

				const DBEvent *dbEvent = (const DBEvent*)data.iov_base;
				const BYTE    *pBlob = (BYTE*)(dbEvent + 1);

				if (((dbEvent->flags & DBEF_ENCRYPTED) != 0) != bEncrypted) {
					mir_ptr<BYTE> pNewBlob;
					size_t nNewBlob;
					uint32_t dwNewFlags;

					if (dbEvent->flags & DBEF_ENCRYPTED) {
						pNewBlob = (BYTE*)m_crypto->decodeBuffer(pBlob, dbEvent->cbBlob, &nNewBlob);
						dwNewFlags = dbEvent->flags & (~DBEF_ENCRYPTED);
					}
					else {
						pNewBlob = m_crypto->encodeBuffer(pBlob, dbEvent->cbBlob, &nNewBlob);
						dwNewFlags = dbEvent->flags | DBEF_ENCRYPTED;
					}

					data.iov_len = sizeof(DBEvent) + nNewBlob;
					mir_ptr<BYTE> pData((BYTE*)mir_alloc(data.iov_len));
					data.iov_base = pData.get();

					DBEvent *pNewDBEvent = (DBEvent *)data.iov_base;
					*pNewDBEvent = *dbEvent;
					pNewDBEvent->cbBlob = (uint16_t)nNewBlob;
					pNewDBEvent->flags = dwNewFlags;
					memcpy(pNewDBEvent + 1, pNewBlob, nNewBlob);

					if (mdbx_put(trnlck, m_dbEvents, &key, &data, 0) != MDBX_SUCCESS)
						return 1;
				}
			}

			lstEvents.erase(lstEvents.begin(), lstEvents.begin()+portion);
			if (trnlck.commit() != MDBX_SUCCESS)
				return 1;
		}
			while (lstEvents.size() > 0);
	}

	txn_ptr trnlck(StartTran());
	MDBX_val key = { DBKey_Crypto_IsEncrypted, sizeof(DBKey_Crypto_IsEncrypted) }, value = { &bEncrypted, sizeof(bool) };
	if (mdbx_put(trnlck, m_dbCrypto, &key, &value, 0) != MDBX_SUCCESS)
		return 1;
	if (trnlck.commit() != MDBX_SUCCESS)
		return 1;

	DBFlush();
	m_bEncrypted = bEncrypted;
	return 0;
}