/******************************************************************************
 * $Id$
 *
 * Copyright (c) 2005-2007 Transmission authors and contributors
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 *****************************************************************************/

#include <assert.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>

#include <glib.h>
#include <glib/gi18n.h>
#include <glib/gstdio.h>

#include <libtransmission/transmission.h>
#include <libtransmission/bencode.h>

#include "conf.h"
#include "util.h"

static char * gl_confdir = NULL;
static char * gl_lockpath = NULL;

/* errstr may be NULL, this might be called before GTK is initialized */
gboolean
cf_init(const char *dir, char **errstr)
{
    if( errstr != NULL )
        *errstr = NULL;

    gl_confdir = g_build_filename( dir, "gtk", NULL );

    if( mkdir_p(gl_confdir, 0755 ) )
        return TRUE;

    if( errstr != NULL )
        *errstr = g_strdup_printf( _("Failed to create the directory %s:\n%s"),
                                   gl_confdir, g_strerror(errno) );

    return FALSE;
}

/***
****
****  Lockfile
****
***/

/* errstr may be NULL, this might be called before GTK is initialized */
static int
lockfile(const char *file, char **errstr)
{
    int fd;
    struct flock lk;

    if( errstr )
        *errstr = NULL;

    fd = open( file, O_RDWR | O_CREAT, 0666 );
    if( fd < 0 )
    { 
        const int savederr = errno;
        if( errstr )
            *errstr = g_strdup_printf(
                          _("Failed to open the file %s for writing:\n%s"),
                          file, g_strerror( errno ) );
        errno = savederr;
        return -1;
    }

    memset( &lk, 0,  sizeof( lk ) );
    lk.l_start = 0;
    lk.l_len = 0;
    lk.l_type = F_WRLCK;
    lk.l_whence = SEEK_SET;
    if( -1 == fcntl( fd, F_SETLK, &lk ) )
    {
        const int savederr = errno;
        if( errstr )
            *errstr = ( errno == EAGAIN )
                ? g_strdup_printf( _( "Another copy of %s is already running." ),
                                   g_get_application_name( ) )
                : g_strdup_printf( _( "Failed to lock the file %s:\n%s" ),
                                  file, g_strerror( errno ) );
        close( fd );
        errno = savederr;
        return -1;
    }

    return fd;
}

static char*
getLockFilename( void )
{
    assert( gl_confdir != NULL );
    return g_build_filename( gl_confdir, "lock", NULL );
}

static void
cf_removelocks( void )
{
    g_unlink( gl_lockpath );
    g_free( gl_lockpath );
}

/* errstr may be NULL, this might be called before GTK is initialized */
gboolean
cf_lock( char ** errstr )
{
    char * path = getLockFilename( );
    int fd = lockfile( path, errstr );
    if( fd >= 0 )
        gl_lockpath = g_strdup( path );
    g_atexit( cf_removelocks );
    g_free( path );
    return fd >= 0;
}

char*
cf_sockname( void )
{
    assert( gl_confdir != NULL );
    return g_build_filename( gl_confdir, "socket", NULL );
}

/***
****
****  Preferences
****
***/

#define GROUP "general"

static char*
getPrefsFilename( void )
{
    assert( gl_confdir != NULL );
    return g_build_filename( gl_confdir, "prefs.ini", NULL );
}

static GKeyFile*
getPrefsKeyFile( void )
{
    static GKeyFile * myKeyFile = NULL;

    if( myKeyFile == NULL )
    {
        char * filename = getPrefsFilename( );
        myKeyFile = g_key_file_new( );
        g_key_file_load_from_file( myKeyFile, filename, 0, NULL );
        g_free( filename );
    }

    return myKeyFile;
}

int
pref_int_get( const char * key ) {
    return g_key_file_get_integer( getPrefsKeyFile( ), GROUP, key, NULL );
}
void
pref_int_set( const char * key, int value ) {
    g_key_file_set_integer( getPrefsKeyFile( ), GROUP, key, value );
}
void
pref_int_set_default( const char * key, int value ) {
    if( !g_key_file_has_key( getPrefsKeyFile( ), GROUP, key, NULL ) )
        pref_int_set( key, value );
}

gboolean
pref_flag_get ( const char * key ) {
    return g_key_file_get_boolean( getPrefsKeyFile( ), GROUP, key, NULL );
}
void
pref_flag_set( const char * key, gboolean value ) {
    g_key_file_set_boolean( getPrefsKeyFile( ), GROUP, key, value );
}
void
pref_flag_set_default( const char * key, gboolean value ) {
    if( !g_key_file_has_key( getPrefsKeyFile( ), GROUP, key, NULL ) )
        pref_flag_set( key, value );
}

char*
pref_string_get( const char * key ) {
    return g_key_file_get_string( getPrefsKeyFile( ), GROUP, key, NULL );
}
void
pref_string_set( const char * key, const char * value ) {
    g_key_file_set_string( getPrefsKeyFile( ), GROUP, key, value );
}
void
pref_string_set_default( const char * key, const char * value ) {
    if( !g_key_file_has_key( getPrefsKeyFile( ), GROUP, key, NULL ) )
        pref_string_set( key, value );
}

void
pref_save(char **errstr)
{
    gsize datalen;
    GError * err = NULL;
    char * data;
    char * filename;
    char * path;

    filename = getPrefsFilename( );
    path = g_path_get_dirname( filename );
    mkdir_p( path, 0755 );

    data = g_key_file_to_data( getPrefsKeyFile(), &datalen, &err );
    if( !err ) {
        GIOChannel * out = g_io_channel_new_file( filename, "w+", &err );
        g_io_channel_write_chars( out, data, datalen, NULL, &err );
        g_io_channel_unref( out );
    }

    if( errstr != NULL )
        *errstr = err ? g_strdup( err->message ) : NULL;

    g_clear_error( &err );
    g_free( data );
    g_free( path );
    g_free( filename );
}

/***
****
***/

#if !GLIB_CHECK_VERSION(2,8,0)
static void
tr_file_set_contents( const char * filename, const void * out, size_t len, GError* unused UNUSED )
{
    FILE * fp = fopen( filename, "wb+" );
    if( fp != NULL ) {
        fwrite( out, 1, len, fp );
        fclose( fp );
    }
}
#define g_file_set_contents tr_file_set_contents
#endif

static char*
getCompat08PrefsFilename( void )
{
    assert( gl_confdir != NULL );
    return g_build_filename( gl_confdir, "prefs", NULL );
}

static void
translate_08_to_09( const char* oldfile, const char* newfile )
{
    static struct pref_entry {
	const char* oldkey;
	const char* newkey;
    } pref_table[] = {
	{ "add-behavior-ipc",       "add-behavior-ipc"},
	{ "add-behavior-standard",  "add-behavior-standard"},
	{ "download-directory",     "default-download-directory"},
	{ "download-limit",         "download-limit"},
	{ "use-download-limit",     "download-limit-enabled" },
	{ "listening-port",         "listening-port"},
	{ "use-nat-traversal",      "nat-traversal-enabled"},
	{ "use-peer-exchange",      "pex-enabled"},
	{ "ask-quit",               "prompt-before-exit"},
	{ "ask-download-directory", "prompt-for-download-directory"},
	{ "use-tray-icon",          "system-tray-icon-enabled"},
	{ "upload-limit",           "upload-limit"},
	{ "use-upload-limit",       "upload-limit-enabled"}
    };

    GString * out = g_string_new( NULL );
    gchar * contents = NULL;
    gsize contents_len = 0;
    benc_val_t top;

    memset( &top, 0, sizeof(benc_val_t) );

    if( g_file_get_contents( oldfile, &contents, &contents_len, NULL )
        && !tr_bencLoad( contents, contents_len, &top, NULL )
        && top.type==TYPE_DICT )
    {
        unsigned int i;
        g_string_append( out, "\n[general]\n" );
        for ( i=0; i<G_N_ELEMENTS(pref_table); ++i ) {
            const benc_val_t * val = tr_bencDictFind( &top, pref_table[i].oldkey );
            if( val != NULL ) {
                const char * valstr = val->val.s.s;
                if( !strcmp( valstr, "yes" ) ) valstr = "true";
                if( !strcmp( valstr, "no" ) ) valstr = "false";
                g_string_append_printf( out, "%s=%s\n", pref_table[i].newkey, valstr );
            }
        }
    }

    g_file_set_contents( newfile, out->str, out->len, NULL );
    g_string_free( out, TRUE );
    g_free( contents );
}

void
cf_check_older_configs( void )
{
    char * cfn = getPrefsFilename( );
    char * cfn08 = getCompat08PrefsFilename( );

    if( !g_file_test( cfn,   G_FILE_TEST_IS_REGULAR )
      && g_file_test( cfn08, G_FILE_TEST_IS_REGULAR ) )
        translate_08_to_09( cfn08, cfn );

    g_free( cfn08 );
    g_free( cfn );
}