/***************************************************************************
 *   Copyright (C) 2008-2012 by Andrzej Rybczak                            *
 *   electricityispower@gmail.com                                          *
 *                                                                         *
 *   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.,                                       *
 *   51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.              *
 ***************************************************************************/

#include "charset.h"

#ifdef HAVE_ICONV_H

#include <iconv.h>
#include <cstdlib>
#include <cstring>
#include <fstream>
#include <iostream>
#include <stdexcept>

#include "settings.h"

namespace {//

bool is_utf8(const char *s)
{
	for (; *s; ++s)
	{
		if (*s & 0x80) // 1xxxxxxx
		{
			char c = 0x40;
			unsigned i = 0;
			while (c & *s)
				++i, c >>= 1;
			if (i < 1 || i > 3) // not 110xxxxx, 1110xxxx, 11110xxx
				return false;
			for (unsigned j = 0; j < i; ++j)
				if (!*++s || !(*s & 0x80) || *s & 0x40) // 10xxxxxx
					return false;
		}
	}
	return true;
}

bool has_non_ascii_chars(const char *s)
{
	for (; *s; ++s)
		if (*s & 0x80)
			return true;
	return false;
}

void charset_convert(const char *from, const char *to, const char *&inbuf,
                     bool delete_old, size_t len = 0)
{
	assert(inbuf);
	assert(from);
	assert(to);
	
	iconv_t cd = iconv_open(to, from);
	if (cd == iconv_t(-1))
	{
		std::cerr << "Error while executing iconv_open: " << strerror(errno) << "\n";
		return;
	}
	
	if (!len)
		len = strlen(inbuf);
	size_t buflen = len*MB_CUR_MAX+1;
	char *outbuf = static_cast<char *>(malloc(buflen));
	char *outstart = outbuf;
	const char *instart = inbuf;
	
	if (iconv(cd, const_cast<ICONV_CONST char **>(&inbuf), &len, &outbuf, &buflen) == size_t(-1))
	{
		std::cerr << "Error while executing iconv: " << strerror(errno) << "\n";
		inbuf = instart;
		delete [] outstart;
	}
	else
	{
		*outbuf = 0;
		if (delete_old)
			free(const_cast<char *>(instart));
		inbuf = outstart;
	}
	iconv_close(cd);
}

}

namespace IConv {//

void convertFromTo(const char *from, const char *to, std::string &s)
{
	const char *tmp = strdup(s.c_str());
	charset_convert(from, to, tmp, true, s.length());
	s = tmp;
	free(const_cast<char *>(tmp));
}

std::string utf8ToLocale(std::string s)
{
	utf8ToLocale_(s);
	return s;
}

void utf8ToLocale_(std::string &s)
{
	if (Config.system_encoding.empty() || !has_non_ascii_chars(s.c_str()))
		return;
	const char *tmp = strdup(s.c_str());
	charset_convert("utf-8", Config.system_encoding.c_str(), tmp, 1, s.length());
	s = tmp;
	free(const_cast<char *>(tmp));
}

std::string localeToUtf8(std::string s)
{
	localeToUtf8_(s);
	return s;
}

void localeToUtf8_(std::string &s)
{
	if (Config.system_encoding.empty() || !has_non_ascii_chars(s.c_str()) || is_utf8(s.c_str()))
		return;
	const char *tmp = strdup(s.c_str());
	charset_convert(Config.system_encoding.c_str(), "utf-8", tmp, 1, s.length());
	s = tmp;
	free(const_cast<char *>(tmp));
}

}

#endif // HAVE_ICONV_H