/********************************************************************\
 * gnc-locale-utils.cpp -- provide a default locale for C++         *
 * Copyright (C) 2019 John Ralls <jralls@ceridwen.us                *
 *                                                                  *
 * 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, contact:                        *
 *                                                                  *
 * Free Software Foundation           Voice:  +1-617-542-5942       *
 * 51 Franklin Street, Fifth Floor    Fax:    +1-617-542-2652       *
 * Boston, MA  02110-1301,  USA       gnu@gnu.org                   *
\********************************************************************/
extern "C"
{
#include <glib.h>
}
#include <clocale>
#include <boost/locale.hpp>
#include "gnc-locale-utils.hpp"

/** Cache the UI locale
 *
 * We don't want to set the default locale because we need
 * std::locale::classic for consistency in stored data. We also don't
 * want to call std::locale("") more than once, it's slow... and we
 * don't want to call it on MinGW32 at all because that supports only
 * std::locale::classic and throws if you try to construct anything
 * else. Boost::locale doesn't support std::locale::facet required by
 * boost::datetime (go figure).
 *
 * @return a copy of std::locale::classic() on MinGW32 and a copy of
 * the cached result of std::locale("") otherwise.
 */
const std::locale&
gnc_get_locale()
{
#ifdef __MINGW32__
    return std::locale::classic(); // Nothing else supported.
#else
    static std::locale cached;
    static bool tried_already = false;
    if (!tried_already)
    {
	tried_already = true;
	try
	{
	    cached = std::locale("");
	}
	catch (const std::runtime_error& err)
	{
	    char* locale = g_strdup(setlocale(LC_ALL, ""));

	    g_log(G_LOG_DOMAIN, G_LOG_LEVEL_WARNING,
		  "Failed to create C++ default locale from"
		  "%s because %s. Using the 'C' locale for C++.",
		  locale, err.what());
	    g_free(locale);
	    cached = std::locale::classic();
	}
    }
    return cached;
#endif
}