/*
	(c) Copyright  2012 - 2018 Anton Sviridenko
	https://picapica.im

	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, version 3.

	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 <https://www.gnu.org/licenses/>.
*/
#include "dhparam.h"
#include <QFile>
#include <QDir>


DHParam *DHParam::dhparamgenerator = NULL;
QString DHParam::current_dhparam_file;

DHParam::DHParam(QObject *parent) :
	QObject(parent)
{
}


bool DHParam::VerifyDefault(QString *errormsg)
{
	if (!QFile::exists(config_defaultDHParam))
	{
		if (errormsg)
			*errormsg =
			    QString(tr("Diffie-Hellman parameters file \"%1\" does not exist"))
			    .arg(config_defaultDHParam);

		return false;
	}

	return true;
}

bool DHParam::VerifyGenerated(QString *errormsg)
{
	if (!QFile::exists(config_dir + QDir::separator() + PICA_CLIENT_DHPARAMFILE))
		return false;

	return true;
}

bool DHParam::UseDefault()
{
	return QFile::copy(config_defaultDHParam, config_dir + QDir::separator() + PICA_CLIENT_DHPARAMFILE);
}

bool DHParam::StartNewDHParamGeneration(QString *errormsg)
{
	if (dhparamgenerator)
	{
		if (errormsg)
			*errormsg = QString(tr("Diffie-Hellman parameter generation process is already running"));
		return false;
	}

	dhparamgenerator = new DHParam();

	if (!dhparamgenerator)
		return false;

	QString tempdhfile = config_dir + QDir::separator() + PICA_CLIENT_DHPARAMFILE + ".temp";

	if (QFile::exists(tempdhfile))
		QFile::remove(tempdhfile);

	return dhparamgenerator -> osslt.GenDHParamSignal(PICA_CLIENT_DHPARAMBITS,
	        tempdhfile, dhparamgenerator, SLOT(DHParamGenFinished(int)));
}

QString DHParam::GetDHParamFilename()
{
	if (current_dhparam_file.isEmpty())
	{
		if (QFile::exists(config_dir + QDir::separator() + PICA_CLIENT_DHPARAMFILE))
			current_dhparam_file = config_dir + QDir::separator() + PICA_CLIENT_DHPARAMFILE;
		else
			current_dhparam_file = config_defaultDHParam;
	}

	return current_dhparam_file;
}

void DHParam::DHParamGenFinished(int retval)
{
	if (retval == 0)
	{
		if (QFile::exists(config_dir + QDir::separator() + PICA_CLIENT_DHPARAMFILE))
			QFile::remove(config_dir + QDir::separator() + PICA_CLIENT_DHPARAMFILE);

		QFile::rename(config_dir + QDir::separator() + PICA_CLIENT_DHPARAMFILE + ".temp",
		              config_dir + QDir::separator() + PICA_CLIENT_DHPARAMFILE);

		current_dhparam_file = config_dir + QDir::separator() + PICA_CLIENT_DHPARAMFILE;

		/*
		 * deleteLater, not delete: we are inside a slot the generator's own
		 * OpenSSLLib member is emitting to, and it still has to return
		 * through it.
		 */
		dhparamgenerator->deleteLater();

		dhparamgenerator = NULL;
	}
}