/*
   Copyright (C) 2001-2006, William Joseph.
   All Rights Reserved.

   This file is part of GtkRadiant.

   GtkRadiant 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.

   GtkRadiant 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 GtkRadiant; if not, write to the Free Software
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

#include "environment.h"
#include "globaldefs.h"

#include "stream/textstream.h"
#include "string/string.h"
#include "stream/stringstream.h"
#include "debugging/debugging.h"
#include "os/path.h"
#include "os/file.h"
#include "cmdlib.h"

int g_argc;
char const** g_argv;

void args_init( int argc, char const* argv[] ){
	int i, j, k;

	for ( i = 1; i < argc; i++ )
	{
		for ( k = i; k < argc; k++ )
		{
			if ( argv[k] != 0 ) {
				break;
			}
		}

		if ( k > i ) {
			k -= i;
			for ( j = i + k; j < argc; j++ )
			{
				argv[j - k] = argv[j];
			}
			argc -= k;
		}
	}

	g_argc = argc;
	g_argv = argv;
}

char const *gamedetect_argv_buffer[1024];

void gamedetect_found_game( char const *game, char *path ){
	int argc;
	static char buf[128];

	if ( g_argv == gamedetect_argv_buffer ) {
		return;
	}

	globalOutputStream() << "Detected game " << game << " in " << path << "\n";

	sprintf( buf, "-%s-EnginePath", game );
	argc = 0;
	gamedetect_argv_buffer[argc++] = "-global-gamefile";
	gamedetect_argv_buffer[argc++] = game;
	gamedetect_argv_buffer[argc++] = buf;
	gamedetect_argv_buffer[argc++] = path;
	if ( (size_t) ( argc + g_argc ) >= sizeof( gamedetect_argv_buffer ) / sizeof( *gamedetect_argv_buffer ) - 1 ) {
		g_argc = sizeof( gamedetect_argv_buffer ) / sizeof( *gamedetect_argv_buffer ) - g_argc - 1;
	}
	memcpy( gamedetect_argv_buffer + 4, g_argv, sizeof( *gamedetect_argv_buffer ) * g_argc );
	g_argc += argc;
	g_argv = gamedetect_argv_buffer;
}

bool gamedetect_check_game( char const *gamefile, const char *checkfile1, const char *checkfile2, char *buf /* must have 64 bytes free after bufpos */, int bufpos ){
	buf[bufpos] = '/';

	strcpy( buf + bufpos + 1, checkfile1 );
	globalOutputStream() << "Checking for a game file in " << buf << "\n";
	if ( !file_exists( buf ) ) {
		return false;
	}

	if ( checkfile2 ) {
		strcpy( buf + bufpos + 1, checkfile2 );
		globalOutputStream() << "Checking for a game file in " << buf << "\n";
		if ( !file_exists( buf ) ) {
			return false;
		}
	}

	buf[bufpos + 1] = 0;
	gamedetect_found_game( gamefile, buf );
	return true;
}

void gamedetect(){
	// if we're inside a Nexuiz install
	// default to nexuiz.game (unless the user used an option to inhibit this)
	bool nogamedetect = false;
	int i;
	for ( i = 1; i < g_argc - 1; ++i )
	{
		if ( g_argv[i][0] == '-' ) {
			if ( !strcmp( g_argv[i], "-gamedetect" ) ) {
				nogamedetect = !strcmp( g_argv[i + 1], "false" );
			}
			++i;
		}
	}
	if ( !nogamedetect ) {
		static char buf[1024 + 64];
		strncpy( buf, environment_get_app_path(), sizeof( buf ) );
		buf[sizeof( buf ) - 1 - 64] = 0;
		if ( !strlen( buf ) ) {
			return;
		}

		char *p = buf + strlen( buf ) - 1; // point directly on the slash of get_app_path
		while ( p != buf )
		{
			// TODO add more games to this

			// try to detect Nexuiz installs
#if GDEF_OS_WINDOWS
			if ( gamedetect_check_game( "nexuiz.game", "data/common-spog.pk3", "nexuiz.exe", buf, p - buf ) )
#elif GDEF_OS_MACOS
			if ( gamedetect_check_game( "nexuiz.game", "data/common-spog.pk3", "Nexuiz.app/Contents/Info.plist", buf, p - buf ) )
#elif GDEF_OS_LINUX
			if ( gamedetect_check_game( "nexuiz.game", "data/common-spog.pk3", "nexuiz-linux-glx.sh", buf, p - buf ) )
#else
			if ( gamedetect_check_game( "nexuiz.game", "data/common-spog.pk3", NULL, buf, p - buf ) )
#endif
			{ return; }

			// try to detect Quetoo installs
			if ( gamedetect_check_game( "quetoo.game", "default/icons/quetoo.png", NULL, buf, p - buf ) ) {
				return;
			}

			// try to detect Warsow installs
			if ( gamedetect_check_game( "warsow.game", "basewsw/dedicated_autoexec.cfg", NULL, buf, p - buf ) ) {
				return;
			}

			// we found nothing
			// go backwards
			--p;
			while ( p != buf && *p != '/' && *p != '\\' )
				--p;
		}
	}
}

namespace
{
	// executable file path
	CopiedString app_filepath;
	// directory paths
	CopiedString home_path;
	CopiedString app_path;
	CopiedString lib_path;
	CopiedString data_path;
}

const char* environment_get_app_filepath(){
	return app_filepath.c_str();
}

const char* environment_get_home_path(){
	return home_path.c_str();
}

const char* environment_get_app_path(){
	return app_path.c_str();
}

const char *environment_get_lib_path()
{
	return lib_path.c_str();
}

const char *environment_get_data_path()
{
	return data_path.c_str();
}

bool portable_app_setup(){
	StringOutputStream confdir( 256 );
	confdir << app_path.c_str() << "settings/";
	if ( file_is_directory( confdir.c_str() ) ) {
		home_path = confdir.c_str();
		return true;
	}
	return false;
}

#if GDEF_OS_POSIX

#include <stdlib.h>
#include <pwd.h>
#include <unistd.h>

#include <glib.h>

const char* LINK_NAME =
#if GDEF_OS_LINUX
	"/proc/self/exe"
#else // FreeBSD and macOS
	"/proc/curproc/file"
#endif
;

/// brief Returns the filename of the executable belonging to the current process, or empty string if not found.
char const* getexename( char *buf ){
	/* Now read the symbolic link */
	const int ret = readlink( LINK_NAME, buf, PATH_MAX );

	if ( ret == -1 ) {
		globalOutputStream() << "getexename: falling back to argv[0]: " << makeQuoted( g_argv[0] );
		if( realpath( g_argv[0], buf ) == 0 ) {
			/* In case of an error, leave the handling up to the caller */
			*buf = '\0';
		}
	}
	else {
		/* Ensure proper NUL termination */
		buf[ret] = 0;
	}

	return buf;
}

char const* getexepath( char *buf ) {
	/* delete the program name */
	*( strrchr( buf, '/' ) ) = '\0';

	// NOTE: we build app path with a trailing '/'
	// it's a general convention in Radiant to have the slash at the end of directories
	if ( buf[strlen( buf ) - 1] != '/' ) {
		strcat( buf, "/" );
	}

	return buf;
}

void environment_init( int argc, char const* argv[] ){
	// Give away unnecessary root privileges.
	// Important: must be done before calling gtk_init().
	char *loginname;
	struct passwd *pw;
	seteuid( getuid() );
	if ( geteuid() == 0 && ( loginname = getlogin() ) != 0 &&
		 ( pw = getpwnam( loginname ) ) != 0 ) {
		setuid( pw->pw_uid );
	}

	args_init( argc, argv );

	{
		char real[PATH_MAX];
		app_filepath = getexename( real );
		ASSERT_MESSAGE( !string_empty( app_filepath.c_str() ), "failed to deduce app path" );

		strncpy( real, app_filepath.c_str(), strlen( app_filepath.c_str() ) );
		app_path = getexepath( real );
	}

	{
#if defined(RADIANT_FHS_INSTALL)
		StringOutputStream buffer;
	#if defined(RADIANT_ADDONS_DIR)
		buffer << RADIANT_ADDONS_DIR << "/";
	#else
		buffer << app_path.c_str() << "../lib/";
		buffer << RADIANT_LIB_ARCH << "/";
		buffer << RADIANT_BASENAME << "/";
	#endif
		lib_path = buffer.c_str();
#else
		lib_path = app_path.c_str();
#endif
	}

	{
#if defined(RADIANT_FHS_INSTALL)
		StringOutputStream buffer;
	#if defined(RADIANT_DATA_DIR)
		buffer << RADIANT_DATA_DIR << "/";
	#else
		buffer << app_path.c_str() << "../share/";
		buffer << RADIANT_BASENAME << "/";
	#endif
		data_path = buffer.c_str();
#else
		data_path = app_path.c_str();
#endif
	}

	if ( !portable_app_setup() ) {
		StringOutputStream home( 256 );
#if GDEF_OS_MACOS
		/* This is used on macOS, this will produce
		~/Library/Application Support/NetRadiant folder. */
		home << DirectoryCleaned( g_get_home_dir() );
		Q_mkdir( home.c_str() );
		home << "Library/";
		Q_mkdir( home.c_str() );
		home << "Application Support/";
		Q_mkdir( home.c_str() );
		home << RADIANT_NAME << "/";
#else // if GDEF_OS_XDG
		/* This is used on both Linux and FreeBSD,
		this will produce ~/.config/netradiant folder
		when environment has default settings, the
		XDG_CONFIG_HOME variable modifies it. */
		home << DirectoryCleaned( g_get_user_config_dir() );
		Q_mkdir( home.c_str() );
		home << RADIANT_BASENAME << "/";
#endif // ! GDEF_OS_MACOS
		Q_mkdir( home.c_str() );
		home_path = home.c_str();
	}

	gamedetect();
}

#elif GDEF_OS_WINDOWS

#include <windows.h>

void environment_init( int argc, char const* argv[] ){
	args_init( argc, argv );

	{
		// get path to the editor
		char filename[MAX_PATH + 1];
		StringOutputStream app_filepath_stream( 256 );
		StringOutputStream app_path_stream( 256 );

		GetModuleFileName( 0, filename, MAX_PATH );
		
		app_filepath_stream << PathCleaned( filename );
		app_filepath = app_filepath_stream.c_str();

		char* last_separator = strrchr( filename, '\\' );
		if ( last_separator != 0 ) {
			*( last_separator + 1 ) = '\0';
		}
		else
		{
			filename[0] = '\0';
		}

		app_path_stream << PathCleaned( filename );
		app_path = app_path_stream.c_str();

		lib_path = app_path;
		data_path = app_path;
	}

	if ( !portable_app_setup() ) {
		char *appdata = getenv( "APPDATA" );

		StringOutputStream home( 256 );
		home << PathCleaned( appdata );
		home << "/";
		home << RADIANT_NAME;
		home << "/";

		Q_mkdir( home.c_str() );
		home_path = home.c_str();
	}
	gamedetect();
}

#else
#error "unsupported platform"
#endif