define( 'UPLOADS', ''.'image' );

// Allow gpx, kml, and kmz files

function my_myme_types($mime_types){
    $mime_types['gpx'] = 'application/gpx+xm'; //Adding gpx extension
    $mime_types['kml'] = 'application/vnd.google-earth.kml+xml'; //Adding kml extension
    $mime_types['kmz'] = 'application/vnd.google-earth.kmz'; //Adding kmz files
    return $mime_types;
}
add_filter('upload_mimes', 'my_myme_types', 1, 1);

define('ALLOW_UNFILTERED_UPLOADS', true);

// Generate folders based on postname to organize media
    add_filter('wp_handle_upload_prefilter', 'wpse_25894_handle_upload_prefilter');
    add_filter('wp_handle_upload', 'wpse_25894_handle_upload');

function wpse_25894_handle_upload_prefilter( $file )
{
    add_filter('upload_dir', 'wpse_25894_custom_upload_dir');
    return $file;
}

function wpse_25894_handle_upload( $fileinfo )
{
    remove_filter('upload_dir', 'wpse_25894_custom_upload_dir');
    return $fileinfo;
}

function wpse_25894_custom_upload_dir($path)
{
    /*
     * Determines if uploading from inside a post/page/cpt - if not, default Upload folder is used
     */

    $use_default_dir = ( isset($_REQUEST['post_id'] ) && $_REQUEST['post_id'] == 0 ) ? true : false;
    if( !empty( $path['error'] ) || $use_default_dir )
        return $path; //error or uploading not from a post/page/cpt

     //Save uploads in SLUG/alias based folders

     $the_post = get_post($_REQUEST['post_id']);
     $customdir = '/' . $the_post->post_name;

    /*
     * Save uploads in FILETYPE based folders
     * when using this method, you may want to change the check for $use_default_dir
     *
     */

     $extension = substr( strrchr( $_POST['name'], '.' ), 1 );
     switch( $extension )
     {
        case 'jpg':
        case 'png':
        case 'gif':
            define( 'UPLOADS', ''.'image' );
            $customdir = '';
            break;

        case 'mp4':
        case 'm4v':
            define( 'UPLOADS', ''.'videos' );
            $customdir = '';
            break;

        case 'txt':
        case 'doc':
        case 'pdf':
            define( 'UPLOADS', ''.'documents' );
            $customdir = '';
            break;

        case 'gpx':
        case 'kml':
        case 'kmz':
            define( 'UPLOADS', ''.'map' );
            $customdir = '';
            break;

        default:
            define( 'UPLOADS', ''.'file' );
            $customdir = '';
            break;
     }
    // end mime type upload folder method


    //$path['path']    = str_replace($path['subdir'], '', $path['path']); //remove default subdir (year/month)
    $path['url']     = str_replace($path['subdir'], '', $path['url']);
    $path['subdir']  = $customdir;
    $path['path']   .= $customdir;
    $path['url']    .= $customdir;

    return $path;
}