<?php
	/**
    This file is part of WideImage.
		
    WideImage is free software; you can redistribute it and/or modify
    it under the terms of the GNU Lesser General Public License as published by
    the Free Software Foundation; either version 2.1 of the License, or
    (at your option) any later version.
		
    WideImage 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 Lesser General Public License for more details.
		
    You should have received a copy of the GNU Lesser General Public License
    along with WideImage; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  **/
	
	class wiUnsupportedFormatException extends wiException {}
	
	abstract class wiFileMapperFactory
	{
		static protected $mappers = array();
		
		static function selectMapper($uri, $format = null)
		{
			$format = self::determineFormat($uri, $format);
			
			if (array_key_exists($format, self::$mappers))
				return self::$mappers[$format];
			
			$mapperClassName = 'wi' . 'ImageFileMapper_' . $format;
			if (!class_exists($mapperClassName))
			{
				$mapperFileName = WI_LIB_PATH . 'mappers/' . 'ImageFileMapper_' . $format . '.class.php';
				if (file_exists($mapperFileName))
					require_once($mapperFileName);
			}
			
			if (class_exists($mapperClassName))
			{
				self::$mappers[$format] = new $mapperClassName();
				return self::$mappers[$format];
			}
			
			throw new wiUnsupportedFormatException("Format '{$format}' is not supported.");
		}
		
		static function determineFormat($uri, $format = null)
		{
			if ($format == null)
				$format = self::extractExtension($uri);
			
			$format = strtoupper(preg_replace('/[^a-z0-9_-]/i', '', $format));
			if ($format == 'JPG')
				$format = 'JPEG';
			
			return $format;
		}
		
		static function extractExtension($uri)
		{
			$p = strrpos($uri, '.');
			if ($p === false)
				return '';
			else
				return substr($uri, $p + 1);
		}
	}
?>