/*****************************************************************************
 * file.c: configuration file handling
 *****************************************************************************
 * Copyright (C) 2001-2007 the VideoLAN team
 * $Id: 3cec0829d99beb012046dac234bbb75821dff177 $
 *
 * Authors: Gildas Bazin <gbazin@videolan.org>
 *
 * 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 Street, Fifth Floor, Boston MA 02110-1301, USA.
 *****************************************************************************/

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#include <errno.h>                                                  /* errno */
#include <assert.h>
#include <limits.h>
#include <fcntl.h>
#include <sys/stat.h>
#ifdef __APPLE__
#   include <xlocale.h>
#elif defined(HAVE_USELOCALE)
#include <locale.h>
#endif

#include <vlc_common.h>
#include "../libvlc.h"
#include <vlc_charset.h>
#include <vlc_fs.h>
#include "vlc_keys.h"

#include "configuration.h"
#include "modules/modules.h"

static inline char *strdupnull (const char *src)
{
    return src ? strdup (src) : NULL;
}

/**
 * Get the user's configuration file
 */
static char *config_GetConfigFile( vlc_object_t *obj )
{
    char *psz_file = var_CreateGetNonEmptyString( obj, "config" );
    var_Destroy( obj, "config" );
    if( psz_file == NULL )
    {
        char *psz_dir = config_GetUserDir( VLC_CONFIG_DIR );

        if( asprintf( &psz_file, "%s" DIR_SEP CONFIG_FILE, psz_dir ) == -1 )
            psz_file = NULL;
        free( psz_dir );
    }
    return psz_file;
}

static FILE *config_OpenConfigFile( vlc_object_t *p_obj )
{
    char *psz_filename = config_GetConfigFile( p_obj );
    if( psz_filename == NULL )
        return NULL;

    msg_Dbg( p_obj, "opening config file (%s)", psz_filename );

    FILE *p_stream = vlc_fopen( psz_filename, "rt" );
    if( p_stream == NULL && errno != ENOENT )
    {
        msg_Err( p_obj, "cannot open config file (%s): %m",
                 psz_filename );

    }
#if !( defined(WIN32) || defined(__APPLE__) || defined(SYS_BEOS) )
    else if( p_stream == NULL && errno == ENOENT )
    {
        /* This is the fallback for pre XDG Base Directory
         * Specification configs */
        char *home = config_GetUserDir(VLC_HOME_DIR);
        char *psz_old;

        if( home != NULL
         && asprintf( &psz_old, "%s/.vlc/" CONFIG_FILE,
                      home ) != -1 )
        {
            p_stream = vlc_fopen( psz_old, "rt" );
            if( p_stream )
            {
                /* Old config file found. We want to write it at the
                 * new location now. */
                msg_Info( p_obj->p_libvlc, "Found old config file at %s. "
                          "VLC will now use %s.", psz_old, psz_filename );
                char *psz_readme;
                if( asprintf(&psz_readme,"%s/.vlc/README",
                             home ) != -1 )
                {
                    FILE *p_readme = vlc_fopen( psz_readme, "wt" );
                    if( p_readme )
                    {
                        fprintf( p_readme, "The VLC media player "
                                 "configuration folder has moved to comply\n"
                                 "with the XDG Base Directory Specification "
                                 "version 0.6. Your\nconfiguration has been "
                                 "copied to the new location:\n%s\nYou can "
                                 "delete this directory and all its contents.",
                                  psz_filename);
                        fclose( p_readme );
                    }
                    free( psz_readme );
                }
                /* Remove the old configuration file so that --reset-config
                 * can work properly. Fortunately, Linux allows removing
                 * open files - with most filesystems. */
                unlink( psz_old );
            }
            free( psz_old );
        }
        free( home );
    }
#endif
    free( psz_filename );
    return p_stream;
}


static int strtoi (const char *str)
{
    char *end;
    long l;

    errno = 0;
    l = strtol (str, &end, 0);

    if (!errno)
    {
        if ((l > INT_MAX) || (l < INT_MIN))
            errno = ERANGE;
        if (*end)
            errno = EINVAL;
    }
    return (int)l;
}

#undef config_LoadConfigFile
/*****************************************************************************
 * config_LoadConfigFile: loads the configuration file.
 *****************************************************************************
 * This function is called to load the config options stored in the config
 * file.
 *****************************************************************************/
int config_LoadConfigFile( vlc_object_t *p_this, const char *psz_module_name )
{
    FILE *file;

    file = config_OpenConfigFile (p_this);
    if (file == NULL)
        return VLC_EGENERIC;

    /* Look for the selected module, if NULL then save everything */
    module_t **list = module_list_get (NULL);

    /* Look for UTF-8 Byte Order Mark */
    char * (*convert) (const char *) = strdupnull;
    char bom[3];

    if ((fread (bom, 1, 3, file) != 3)
     || memcmp (bom, "\xEF\xBB\xBF", 3))
    {
        convert = FromLocaleDup;
        rewind (file); /* no BOM, rewind */
    }

    module_t *module = NULL;
    char line[1024], section[1022];
    section[0] = '\0';

    /* Ensure consistent number formatting... */
    locale_t loc = newlocale (LC_NUMERIC_MASK, "C", NULL);
    locale_t baseloc = uselocale (loc);

    vlc_rwlock_wrlock (&config_lock);
    while (fgets (line, 1024, file) != NULL)
    {
        /* Ignore comments and empty lines */
        switch (line[0])
        {
            case '#':
            case '\n':
            case '\0':
                continue;
        }

        if (line[0] == '[')
        {
            char *ptr = strchr (line, ']');
            if (ptr == NULL)
                continue; /* syntax error; */
            *ptr = '\0';

            /* New section ( = a given module) */
            strcpy (section, line + 1);
            module = NULL;

            if ((psz_module_name == NULL)
             || (strcmp (psz_module_name, section) == 0))
            {
                for (int i = 0; list[i]; i++)
                {
                    module_t *m = list[i];

                    if ((strcmp (section, m->psz_object_name) == 0)
                     && (m->i_config_items > 0)) /* ignore config-less modules */
                    {
                        module = m;
                        if (psz_module_name != NULL)
                            msg_Dbg (p_this,
                                     "loading config for module \"%s\"",
                                     section);
                        break;
                    }
                }
            }

            continue;
        }

        if (module == NULL)
            continue; /* no need to parse if there is no matching module */

        char *ptr = strchr (line, '\n');
        if (ptr != NULL)
            *ptr = '\0';

        /* look for option name */
        const char *psz_option_name = line;

        ptr = strchr (line, '=');
        if (ptr == NULL)
            continue; /* syntax error */

        *ptr = '\0';
        const char *psz_option_value = ptr + 1;

        /* try to match this option with one of the module's options */
        for (size_t i = 0; i < module->confsize; i++)
        {
            module_config_t *p_item = module->p_config + i;

            if ((p_item->i_type & CONFIG_HINT)
             || strcmp (p_item->psz_name, psz_option_name))
                continue;

            /* We found it */
            errno = 0;

            switch( p_item->i_type )
            {
                case CONFIG_ITEM_BOOL:
                case CONFIG_ITEM_INTEGER:
                {
                    long l = strtoi (psz_option_value);
                    if (errno)
                        msg_Warn (p_this, "Integer value (%s) for %s: %m",
                                  psz_option_value, psz_option_name);
                    else
                        p_item->saved.i = p_item->value.i = (int)l;
                    break;
                }

                case CONFIG_ITEM_FLOAT:
                    if( !*psz_option_value )
                        break;                    /* ignore empty option */
                    p_item->value.f = (float)atof (psz_option_value);
                    p_item->saved.f = p_item->value.f;
                    break;

                case CONFIG_ITEM_KEY:
                    if( !*psz_option_value )
                        break;                    /* ignore empty option */
                    p_item->value.i = ConfigStringToKey(psz_option_value);
                    p_item->saved.i = p_item->value.i;
                    break;

                default:
                    /* free old string */
                    free( (char*) p_item->value.psz );
                    free( (char*) p_item->saved.psz );

                    p_item->value.psz = convert (psz_option_value);
                    p_item->saved.psz = strdupnull (p_item->value.psz);
                    break;
            }
            break;
        }
    }
    vlc_rwlock_unlock (&config_lock);

    if (ferror (file))
    {
        msg_Err (p_this, "error reading configuration: %m");
        clearerr (file);
    }
    fclose (file);

    module_list_free (list);
    if (loc != (locale_t)0)
    {
        uselocale (baseloc);
        freelocale (loc);
    }
    return 0;
}

/*****************************************************************************
 * config_CreateDir: Create configuration directory if it doesn't exist.
 *****************************************************************************/
int config_CreateDir( vlc_object_t *p_this, const char *psz_dirname )
{
    if( !psz_dirname || !*psz_dirname ) return -1;

    if( vlc_mkdir( psz_dirname, 0700 ) == 0 )
        return 0;

    switch( errno )
    {
        case EEXIST:
            return 0;

        case ENOENT:
        {
            /* Let's try to create the parent directory */
            char psz_parent[strlen( psz_dirname ) + 1], *psz_end;
            strcpy( psz_parent, psz_dirname );

            psz_end = strrchr( psz_parent, DIR_SEP_CHAR );
            if( psz_end && psz_end != psz_parent )
            {
                *psz_end = '\0';
                if( config_CreateDir( p_this, psz_parent ) == 0 )
                {
                    if( !vlc_mkdir( psz_dirname, 0700 ) )
                        return 0;
                }
            }
        }
    }

    msg_Warn( p_this, "could not create %s: %m", psz_dirname );
    return -1;
}

static int
config_Write (FILE *file, const char *desc, const char *type,
              bool comment, const char *name, const char *fmt, ...)
{
    va_list ap;
    int ret;

    if (desc == NULL)
        desc = "?";

    if (fprintf (file, "# %s (%s)\n%s%s=", desc, vlc_gettext (type),
                 comment ? "#" : "", name) < 0)
        return -1;

    va_start (ap, fmt);
    ret = vfprintf (file, fmt, ap);
    va_end (ap);
    if (ret < 0)
        return -1;

    if (fputs ("\n\n", file) == EOF)
        return -1;
    return 0;
}


static int config_PrepareDir (vlc_object_t *obj)
{
    char *psz_configdir = config_GetUserDir (VLC_CONFIG_DIR);
    if (psz_configdir == NULL)
        return -1;

    int ret = config_CreateDir (obj, psz_configdir);
    free (psz_configdir);
    return ret;
}

/*****************************************************************************
 * config_SaveConfigFile: Save a module's config options.
 *****************************************************************************
 * This will save the specified module's config options to the config file.
 * If psz_module_name is NULL then we save all the modules config options.
 * It's no use to save the config options that kept their default values, so
 * we'll try to be a bit clever here.
 *
 * When we save we mustn't delete the config options of the modules that
 * haven't been loaded. So we cannot just create a new config file with the
 * config structures we've got in memory.
 * I don't really know how to deal with this nicely, so I will use a completly
 * dumb method ;-)
 * I will load the config file in memory, but skipping all the sections of the
 * modules we want to save. Then I will create a brand new file, dump the file
 * loaded in memory and then append the sections of the modules we want to
 * save.
 * Really stupid no ?
 *****************************************************************************/
static int SaveConfigFile( vlc_object_t *p_this, const char *psz_module_name,
                           bool b_autosave )
{
    module_t *p_parser;
    FILE *file = NULL;
    char *permanent = NULL, *temporary = NULL;
    char p_line[1024], *p_index2;
    unsigned long i_sizebuf = 0;
    char *p_bigbuffer = NULL, *p_index;
    bool b_backup;
    int i_index;

    if( config_PrepareDir( p_this ) )
    {
        msg_Err( p_this, "no configuration directory" );
        goto error;
    }

    file = config_OpenConfigFile( p_this );
    if( file != NULL )
    {
        struct stat st;

        /* Some users make vlcrc read-only to prevent changes.
         * The atomic replacement scheme breaks this "feature",
         * so we check for read-only by hand. */
        if (fstat (fileno (file), &st)
         || !(st.st_mode & S_IWUSR))
        {
            msg_Err (p_this, "configuration file is read-only");
            goto error;
        }
        i_sizebuf = ( st.st_size < LONG_MAX ) ? st.st_size : 0;
    }

    p_bigbuffer = p_index = malloc( i_sizebuf+1 );
    if( !p_bigbuffer )
        goto error;
    p_bigbuffer[0] = 0;

    /* List all available modules */
    module_t **list = module_list_get (NULL);

    /* backup file into memory, we only need to backup the sections we won't
     * save later on */
    b_backup = false;
    while( file && fgets( p_line, 1024, file ) )
    {
        if( (p_line[0] == '[') && (p_index2 = strchr(p_line,']')))
        {

            /* we found a section, check if we need to do a backup */
            for( i_index = 0; (p_parser = list[i_index]) != NULL; i_index++ )
            {
                if( ((p_index2 - &p_line[1])
                       == (int)strlen(p_parser->psz_object_name) )
                    && !memcmp( &p_line[1], p_parser->psz_object_name,
                                strlen(p_parser->psz_object_name) ) )
                {
                    if( !psz_module_name )
                        break;
                    else if( !strcmp( psz_module_name,
                                      p_parser->psz_object_name ) )
                        break;
                }
            }

            if( list[i_index] == NULL )
            {
                /* we don't have this section in our list so we need to back
                 * it up */
                *p_index2 = 0;
#if 0
                msg_Dbg( p_this, "backing up config for unknown module \"%s\"",
                                 &p_line[1] );
#endif
                *p_index2 = ']';

                b_backup = true;
            }
            else
            {
                b_backup = false;
            }
        }

        /* save line if requested and line is valid (doesn't begin with a
         * space, tab, or eol) */
        if( b_backup && (p_line[0] != '\n') && (p_line[0] != ' ')
            && (p_line[0] != '\t') )
        {
            strcpy( p_index, p_line );
            p_index += strlen( p_line );
        }
    }
    if( file )
        fclose( file );
    file = NULL;

    /*
     * Save module config in file
     */
    permanent = config_GetConfigFile (p_this);
    if (!permanent)
    {
        module_list_free (list);
        goto error;
    }

    if (asprintf (&temporary, "%s.%u", permanent, getpid ()) == -1)
    {
        temporary = NULL;
        module_list_free (list);
        goto error;
    }

    /* Configuration lock must be taken before vlcrc serializer below. */
    vlc_rwlock_rdlock (&config_lock);

    /* The temporary configuration file is per-PID. Therefore SaveConfigFile()
     * should be serialized against itself within a given process. */
    static vlc_mutex_t lock = VLC_STATIC_MUTEX;
    vlc_mutex_lock (&lock);

    int fd = vlc_open (temporary, O_CREAT|O_WRONLY|O_TRUNC, S_IRUSR|S_IWUSR);
    if (fd == -1)
    {
        vlc_rwlock_unlock (&config_lock);
        vlc_mutex_unlock (&lock);
        module_list_free (list);
        goto error;
    }
    file = fdopen (fd, "wt");
    if (file == NULL)
    {
        vlc_rwlock_unlock (&config_lock);
        close (fd);
        vlc_mutex_unlock (&lock);
        module_list_free (list);
        goto error;
    }

    fprintf( file,
        "\xEF\xBB\xBF###\n"
        "###  "PACKAGE_NAME" "PACKAGE_VERSION"\n"
        "###\n"
        "\n"
        "###\n"
        "### lines beginning with a '#' character are comments\n"
        "###\n"
        "\n" );

    /* Ensure consistent number formatting... */
    locale_t loc = newlocale (LC_NUMERIC_MASK, "C", NULL);
    locale_t baseloc = uselocale (loc);

    /* We would take the config lock here. But this would cause a lock
     * inversion with the serializer above and config_AutoSaveConfigFile().
    vlc_rwlock_rdlock (&config_lock);*/

    /* Look for the selected module, if NULL then save everything */
    for( i_index = 0; (p_parser = list[i_index]) != NULL; i_index++ )
    {
        module_config_t *p_item, *p_end;

        if( psz_module_name && strcmp( psz_module_name,
                                       p_parser->psz_object_name ) )
            continue;

        if( !p_parser->i_config_items )
            continue;

        if( psz_module_name )
            msg_Dbg( p_this, "saving config for module \"%s\"",
                     p_parser->psz_object_name );

        fprintf( file, "[%s]", p_parser->psz_object_name );
        if( p_parser->psz_longname )
            fprintf( file, " # %s\n\n", p_parser->psz_longname );
        else
            fprintf( file, "\n\n" );

        for( p_item = p_parser->p_config, p_end = p_item + p_parser->confsize;
             p_item < p_end;
             p_item++ )
        {
            if ((p_item->i_type & CONFIG_HINT) /* ignore hint */
             || p_item->b_removed              /* ignore deprecated option */
             || p_item->b_unsaveable)          /* ignore volatile option */
                continue;

            /* Do not save the new value in the configuration file
             * if doing an autosave, and the item is not an "autosaved" one. */
            bool b_retain = b_autosave && !p_item->b_autosave;

            if (IsConfigIntegerType (p_item->i_type))
            {
                int val = b_retain ? p_item->saved.i : p_item->value.i;
                if (p_item->i_type == CONFIG_ITEM_KEY)
                {
                    char *psz_key = ConfigKeyToString (val);
                    config_Write (file, p_item->psz_text, N_("key"),
                                  val == p_item->orig.i,
                                  p_item->psz_name, "%s",
                                  psz_key ? psz_key : "");
                    free (psz_key);
                }
                else
                    config_Write (file, p_item->psz_text,
                                  (p_item->i_type == CONFIG_ITEM_BOOL)
                                      ? N_("boolean") : N_("integer"),
                                  val == p_item->orig.i,
                                  p_item->psz_name, "%d", val);
                p_item->saved.i = val;
            }
            else
            if (IsConfigFloatType (p_item->i_type))
            {
                float val = b_retain ? p_item->saved.f : p_item->value.f;
                config_Write (file, p_item->psz_text, N_("float"),
                              val == p_item->orig.f,
                              p_item->psz_name, "%f", val);
                p_item->saved.f = val;
            }
            else
            {
                const char *psz_value = b_retain ? p_item->saved.psz
                                                 : p_item->value.psz;
                bool modified;

                assert (IsConfigStringType (p_item->i_type));

                if (b_retain && (psz_value == NULL)) /* FIXME: hack */
                    psz_value = p_item->orig.psz;

                modified =
                    (psz_value != NULL)
                        ? ((p_item->orig.psz != NULL)
                            ? (strcmp (psz_value, p_item->orig.psz) != 0)
                            : true)
                        : (p_item->orig.psz != NULL);

                config_Write (file, p_item->psz_text, N_("string"),
                              !modified, p_item->psz_name, "%s",
                              psz_value ? psz_value : "");

                if ( !b_retain )
                {

                    free ((char *)p_item->saved.psz);
                    if( (psz_value && p_item->orig.psz &&
                         strcmp( psz_value, p_item->orig.psz )) ||
                        !psz_value || !p_item->orig.psz)
                        p_item->saved.psz = strdupnull (psz_value);
                    else
                        p_item->saved.psz = NULL;
                }
            }

            if (!b_retain)
                p_item->b_dirty = false;
        }
    }
    vlc_rwlock_unlock (&config_lock);

    module_list_free (list);
    if (loc != (locale_t)0)
    {
        uselocale (baseloc);
        freelocale (loc);
    }

    /*
     * Restore old settings from the config in file
     */
    fputs( p_bigbuffer, file );
    free( p_bigbuffer );

    /*
     * Flush to disk and replace atomically
     */
    fflush (file); /* Flush from run-time */
#ifndef WIN32
#ifdef __APPLE__
    fsync (fd); /* Flush from OS */
#else
    fdatasync (fd); /* Flush from OS */
#endif
    /* Atomically replace the file... */
    if (vlc_rename (temporary, permanent))
        vlc_unlink (temporary);
    /* (...then synchronize the directory, err, TODO...) */
    /* ...and finally close the file */
    vlc_mutex_unlock (&lock);
#endif
    fclose (file);
#ifdef WIN32
    /* Windows cannot remove open files nor overwrite existing ones */
    vlc_unlink (permanent);
    if (vlc_rename (temporary, permanent))
        vlc_unlink (temporary);
    vlc_mutex_unlock (&lock);
#endif

    free (temporary);
    free (permanent);
    return 0;

error:
    if( file )
        fclose( file );
    free (temporary);
    free (permanent);
    free( p_bigbuffer );
    return -1;
}

int config_AutoSaveConfigFile( vlc_object_t *p_this )
{
    int ret = VLC_SUCCESS;
    bool save = false;

    assert( p_this );

    /* Check if there's anything to save */
    module_t **list = module_list_get (NULL);
    vlc_rwlock_rdlock (&config_lock);
    for (size_t i_index = 0; list[i_index] && !save; i_index++)
    {
        module_t *p_parser = list[i_index];
        module_config_t *p_item, *p_end;

        if( !p_parser->i_config_items ) continue;

        for( p_item = p_parser->p_config, p_end = p_item + p_parser->confsize;
             p_item < p_end && !save;
             p_item++ )
        {
            save = p_item->b_autosave && p_item->b_dirty;
        }
    }

    if (save)
        /* Note: this will get the read lock recursively. Ok. */
        ret = SaveConfigFile (p_this, NULL, true);
    vlc_rwlock_unlock (&config_lock);

    module_list_free (list);
    return ret;
}

#undef config_SaveConfigFile
int config_SaveConfigFile( vlc_object_t *p_this, const char *psz_module_name )
{
    return SaveConfigFile( p_this, psz_module_name, false );
}
