/* Copyright (C) 2009 Wildfire Games.
 * This file is part of 0 A.D.
 *
 * 0 A.D. 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.
 *
 * 0 A.D. 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 0 A.D.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "precompiled.h"
#include "Paths.h"

#include "lib/path_util.h"
#include "lib/utf8.h"
#include "lib/sysdep/filesystem.h"	// wrealpath
#include "lib/sysdep/sysdep.h"	// sys_get_executable_name
#if OS_WIN
# include "lib/sysdep/os/win/wutil.h"	// wutil_AppdataPath
#endif


Paths::Paths(const CmdLineArgs& args)
{
	m_root = Root(wstring_from_utf8(args.GetArg0()));
	m_rdata = m_root/L"data/";
	const wchar_t* subdirectoryName = args.Has("writableRoot")? 0 : L"0ad";

	// everything is a subdirectory of the root
	if(!subdirectoryName)
	{
		m_data = m_rdata;
		m_config = m_data/L"config/";
		m_cache = m_data/L"cache/";
		m_logs = m_root/L"logs/";
	}
	else
	{
#if OS_WIN
		const fs::wpath appdata = AddSlash(wutil_AppdataPath()/subdirectoryName);
		m_data = appdata/L"data/";
		m_config = appdata/L"config/";
		m_cache = appdata/L"cache/";
		m_logs = appdata/L"logs/";
#else
		const char* envHome = getenv("HOME");
		debug_assert(envHome);
		const fs::wpath home(wstring_from_utf8(envHome));
		const fs::wpath xdgData = XDG_Path("XDG_DATA_HOME", home, home/L".local/share/")/subdirectoryName;
		const fs::wpath xdgConfig = XDG_Path("XDG_CONFIG_HOME", home, home/L".config/")/subdirectoryName;
		const fs::wpath xdgCache = XDG_Path("XDG_CACHE_HOME", home, home/L".cache/")/subdirectoryName;
		m_data = AddSlash(xdgData);
		m_cache = AddSlash(xdgCache);
		m_config = AddSlash(xdgConfig/L"config");
		m_logs = AddSlash(xdgConfig/L"logs");
#endif
	}
}


/*static*/ fs::wpath Paths::Root(const std::wstring& argv0)
{
	// get full path to executable
	fs::wpath pathname;
	// .. first try safe, but system-dependent version
	if(sys_get_executable_name(pathname) != INFO::OK)
	{
		// .. failed; use argv[0]
		wchar_t pathname_buf[PATH_MAX];
		errno = 0;
		if(!wrealpath(argv0.c_str(), pathname_buf))
			WARN_ERR(LibError_from_errno(false));
		pathname = pathname_buf;
	}

	// make sure it's valid
	if(!fs::exists(pathname))
		WARN_ERR(LibError_from_errno(false));

	for(size_t i = 0; i < 3; i++)	// remove "system/name.exe"
		pathname.remove_leaf();
	return pathname;
}


/*static*/ fs::wpath Paths::XDG_Path(const char* envname, const fs::wpath& home, const fs::wpath& defaultPath)
{
	const char* path = getenv(envname);
	if(path)
	{
		if(path[0] != '/')	// relative to $HOME
			return AddSlash(home/wstring_from_utf8(path));
		return AddSlash(fs::wpath(wstring_from_utf8(path)));
	}
	return AddSlash(defaultPath);
}