file and moves it to new location. If the destination folder does not exist, it is created.
	 *
	 * @since 4.3.1
	 * @param string $old_file
	 * @param string $new_file
	 * @return boolean|WP_Error
	 */
	function avia_backend_rename_file( $old_file, $new_file )
	{
		$split = pathinfo( $new_file );

		$folder = $split['dirname'];
		if( ! avia_backend_create_folder( $folder, false ) )
		{
			return new WP_Error( 'filesystem', sprintf( __( 'Unable to create folder %s.', 'avia_framework' ), $folder ) );
		}

		if( file_exists( $new_file ) )
		{
			if( ! unlink( $new_file ) )
			{
				return new WP_Error( 'filesystem', sprintf( __( 'Unable to delete file %s.', 'avia_framework' ), $new_file ) );
			}
		}

		if( ! rename( $old_file, $new_file ) )
		{
			return new WP_Error( 'filesystem', sprintf( __( 'Unable to rename/move file %s to %s', 'avia_framework' ), $old_file, $new_file ) );
		}

		return true;
	}
}


if(!function_exists('av_backend_registered_sidebars'))
{
	function av_backend_registered_sidebars($sidebars = array(), $exclude = array())
	{
		//fetch all registered sidebars and save them to the sidebars array
		global $wp_registered_sidebars;

		foreach($wp_registered_sidebars as $sidebar)
		{
			if( !in_array($sidebar['name'], $exclude))
			{
				$sidebars[$sidebar['name']] = $sidebar['name'];
			}
		}

		return $sidebars;
	}
}

// ADMIN MENU
if( ! function_exists( 'avia_backend_admin_bar_menu' ) )
{
	add_action( 'admin_bar_menu', 'avia_backend_admin_bar_menu', 99 );

	/**
	 * Extend the admin bar
	 */
	function avia_backend_admin_bar_menu()
	{
		global $avia, $wp_admin_bar;

		if( ! current_user_can( 'manage_options' ) )
		{
			return;
		}

		$real_id  = is_admin() ? false : avia_get_the_ID();

		$meta_target_edit = array();
		$meta_target_dynamic = array();
		$meta_target_options = array();

		if( ! is_admin() )
		{
			/**
			 * Allow to change WP default behaviour to stay on same tab (also ADA complience).
			 *
			 * @used_by				currently unused
			 * @since 4.5.4
			 * @return string			anything different from '' sets value for target (e.g. "_blank")
			 */
			$target_edit = apply_filters( 'avf_admin_bar_link_target_frontend', '', 'edit_button' );
			$target_dynamic = apply_filters( 'avf_admin_bar_link_target_frontend', '', 'dynamic_template' );
			$target_options = apply_filters( 'avf_admin_bar_link_target_frontend', '', 'theme_options' );

			if( ! empty( $target_edit ) )
			{
				$meta_target_edit['target'] = $target_edit;
			}
			if( ! empty( $target_dynamic ) )
			{
				$meta_target_dynamic['target'] = $target_dynamic;
			}
			if( ! empty( $target_options ) )
			{
				$meta_target_options['target'] = $target_options;
			}
		}

		/**
		 * Replace WP edit link with Edit Frontpage message
		 */
		if( is_front_page() )
		{
			$front_id = avia_get_option( 'frontpage' );

			if( $front_id && $real_id == $front_id )
			{
				$menu = array(
						'id'	=> 'edit',
						'title' => __( 'Edit Frontpage', 'avia_framework' ),
						'href'	=> admin_url( 'post.php?post=' . $real_id . '&action=edit' ),
						'meta'	=> $target_edit
				);

				$wp_admin_bar->add_menu( $menu );
			}
		}

		/**
		 * dynamic template edit for current entry, in case a dynamic template is applied
		 */
		if( $real_id && $template = avia_is_dynamic_template() )
		{
			$safeSlug = avia_backend_safe_string( $template );

			$menu = array(
					'id'		=> 'avia_edit',
					'title'		=> __( 'Edit this entry', 'avia_framework' ),
					'href'		=> admin_url( 'post.php?post=' . $real_id . '&action=edit' ),
					'meta'		=> $meta_target_dynamic,
					'parent'	=> 'edit'
					);
			$wp_admin_bar->add_menu($menu);

			$menu = array(
					'id'		=> 'avia_edit_dynamic',
					'title'		=> __( 'Edit Dynamic Template of this entry', 'avia_framework' ),
					'href'		=> admin_url( "admin.php?page=templates#goto_" . $safeSlug ),
					'meta'		=> $meta_target_dynamic,
					'parent'	=> 'edit'
					);

			$wp_admin_bar->add_menu($menu);
		}

		/**
		 * add all option pages
		 */
		if( empty( $avia->option_pages ) )
		{
			return;
		}

		$urlBase = admin_url( 'admin.php' );

		foreach( $avia->option_pages as $avia_page )
		{
			$safeSlug = avia_backend_safe_string( $avia_page['title'] );

			$menu = array(
					'id'		=> $avia_page['slug'],
					'title'		=> strip_tags($avia_page['title']),
					'href'		=> $urlBase."?page=".$avia_page['slug'],
					'meta'		=> $meta_target_options
				);

			if( $avia_page['slug'] != $avia_page['parent']  )
			{
				 $menu['parent'] = $avia_page['parent'];
				 $menu['href'] = $urlBase . "?page=" . $avia_page['parent'] . "#goto_" . $avia_page['slug'];
			}

            /* removed by tinabillinger - breaks theme option links in Safari */
		    // if(is_admin()) $menu['meta'] = array('onclick' => 'self.location.replace(encodeURI("'.$menu['href'].'")); window.location.reload(true);  ');

			$wp_admin_bar->add_menu( $menu );
		}
	}
}	//avia_backend_admin_bar_menu

if( ! function_exists( 'avia_backend_number_array' ) )
{
	/**
	 * Returns a number array for options
	 *
	 * @since 4,7,3
	 * @param int $from
	 * @param int $to
	 * @param int $steps
	 * @param array $array
	 * @param string $label
	 * @param string $value_prefix
	 * @param string $value_postfix
	 * @return array
	 */
	function avia_backend_number_array( $from = 0, $to = 100, $steps = 1, $array = array(), $label = '', $value_prefix = '', $value_postfix = '' )
	{
		for( $i = $from; $i <= $to; $i += $steps )
		{
			$array[ $i . $label ] = $value_prefix . $i . $value_postfix;
		}

		return $array;
	}

}

if( ! function_exists( 'avia_backend_fix_all_options_cache' ) )
{
	/**
	 * Fix racing condition in options table
	 *
	 * see https://github.com/pantheon-systems/wp-redis/issues/221
	 * see https://core.trac.wordpress.org/ticket/31245#comment:57
	 *
	 * @since 4.7.6.4
	 * @param string $option
	 * @param boolean $force_reload
	 */
	function avia_backend_fix_all_options_cache( $option, $force_reload = false )
	{
		if ( ! wp_installing() )
		{
			$alloptions = wp_load_alloptions(); //alloptions should be cached at this point

			if( isset( $alloptions[ $option ] ) || $force_reload )  //only if option is among alloptions
			{
				wp_cache_delete( 'alloptions', 'options' );
			}
		}
	}

}

if( ! function_exists( 'avia_backend_alb_color_option_palette' ) )
{
	/**
	 * Returns theme option or default (if empty default is returned).
	 * Does NOT check correctness of input !!
	 *
	 * @since 4.8.3
	 * @return array
	 */
	function avia_backend_alb_color_option_palette()
	{
		global $avia_config;

		if( 'alb_use_custom_colors' != avia_get_option( 'alb_use_custom_colors' ) )
		{
			return $avia_config['default_alb_color_palette'];
		}

		if( isset( $avia_config['alb_color_palette'] ) )
		{
			return $avia_config['alb_color_palette'];
		}

		$input = trim( avia_get_option( 'alb_custom_color_palette' ) );

		if( empty( $input ) )
		{
			$avia_config['alb_color_palette'] = $avia_config['default_alb_color_palette'];
		}
		else
		{
			$input = str_replace( "\r", "\n", $input );
			$input = explode( "\n", $input );
			$input = array_map( function ( $value ) { return trim( $value ); }, $input );
			$avia_config['alb_color_palette'] = array_filter( $input );
		}

		return $avia_config['alb_color_palette'];
	}
}