/*
   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 ) )
#else
            if (gamedetect_check_game("nexuiz.game", "data/common-spog.pk3", "nexuiz-linux-glx.sh", 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 {
    CopiedString home_path;
    CopiedString app_path;
}

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

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

bool portable_app_setup()
{
    StringOutputStream confdir(256);
    confdir << app_path.c_str() << "settings/";
    if (file_exists(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 OSX
"/proc/curproc/file"
#endif
;

/// brief Returns the filename of the executable belonging to the current process, or 0 if not found.
char const *getexename(char *buf)
{
    /* Now read the symbolic link */
    int ret = readlink(LINK_NAME, buf, PATH_MAX);

    if (ret == -1) {
        globalOutputStream() << "getexename: falling back to argv[0]: " << makeQuoted(g_argv[0]);
        const char *path = realpath(g_argv[0], buf);
        if (path == 0) {
            /* In case of an error, leave the handling up to the caller */
            return "";
        }
    }

    /* Ensure proper NUL termination */
    buf[ret] = 0;

    /* 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_path = getexename(real);
        ASSERT_MESSAGE(!string_empty(app_path.c_str()), "failed to deduce app path");
    }

    if (!portable_app_setup()) {
        StringOutputStream home(256);
        home << DirectoryCleaned(g_get_user_config_dir()) << "netradiant/";
        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];
        GetModuleFileName( 0, filename, MAX_PATH );
        char* last_separator = strrchr( filename, '\\' );
        if ( last_separator != 0 ) {
            *( last_separator + 1 ) = '\0';
        }
        else
        {
            filename[0] = '\0';
        }
        StringOutputStream app( 256 );
        app << PathCleaned( filename );
        app_path = app.c_str();
    }

    if ( !portable_app_setup() ) {
        char *appdata = getenv( "APPDATA" );
        StringOutputStream home( 256 );
        if ( !appdata || string_empty( appdata ) ) {
            ERROR_MESSAGE( "Application Data folder not available.\n"
                           "Radiant will use C:\\ for user preferences.\n" );
            home << "C:";
        }
        else
        {
            home << PathCleaned( appdata );
        }
        home << "/NetRadiantSettings/";
        Q_mkdir( home.c_str() );
        home_path = home.c_str();
    }
    gamedetect();
}

#else
#error "unsupported platform"
#endif