<?php

/**
 * Zend Framework
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 *
 * @category   Zend
 * @package    Zend_Uri
 * @copyright  Copyright (c) 2005-2008 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 * @version    $Id: Uri.php 8064 2008-02-16 10:58:39Z thomas $
 */

/**
 * @see Zend_Loader
 */
require_once 'external/Zend/Loader.php';

/**
 * @category   Zend
 * @package    Zend_Uri
 * @copyright  Copyright (c) 2005-2008 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */
abstract class Zend_Uri {
  /**
   * Scheme of this URI (http, ftp, etc.)
   * @var string
   */
  protected $_scheme = '';

  /**
   * Return a string representation of this URI.
   *
   * @see     getUri()
   * @return  string
   */
  public function __toString() {
    return $this->getUri();
  }

  /**
   * Convenience function, checks that a $uri string is well-formed
   * by validating it but not returning an object.  Returns TRUE if
   * $uri is a well-formed URI, or FALSE otherwise.
   *
   * @param string $uri
   * @return boolean
   */
  public static function check($uri) {
    try {
      $uri = self::factory($uri);
    } catch (Exception $e) {
      return false;
    }
    
    return $uri->valid();
  }

  /**
   * Create a new Zend_Uri object for a URI.  If building a new URI, then $uri should contain
   * only the scheme (http, ftp, etc).  Otherwise, supply $uri with the complete URI.
   *
   * @param string $uri
   * @throws Zend_Uri_Exception
   * @return Zend_Uri
   */
  public static function factory($uri = 'http') {
    /**
     * Separate the scheme from the scheme-specific parts
     * @link http://www.faqs.org/rfcs/rfc2396.html
     */
    $uri = explode(':', $uri, 2);
    $scheme = strtolower($uri[0]);
    $schemeSpecific = isset($uri[1]) ? $uri[1] : '';
    
    if (! strlen($scheme)) {
      require_once 'external/Zend/Uri/Exception.php';
      throw new Zend_Uri_Exception('An empty string was supplied for the scheme');
    }
    
    // Security check: $scheme is used to load a class file, so only alphanumerics are allowed.
    if (! ctype_alnum($scheme)) {
      require_once 'external/Zend/Uri/Exception.php';
      throw new Zend_Uri_Exception('Illegal scheme supplied, only alphanumeric characters are permitted');
    }
    
    /**
     * Create a new Zend_Uri object for the $uri. If a subclass of Zend_Uri exists for the
     * scheme, return an instance of that class. Otherwise, a Zend_Uri_Exception is thrown.
     */
    switch ($scheme) {
      case 'http':
      case 'https':
        $className = 'Zend_Uri_Http';
        break;
      case 'mailto':
      // @todo
      default:
        require_once 'external/Zend/Uri/Exception.php';
        throw new Zend_Uri_Exception("Scheme \"$scheme\" is not supported");
    }
    Zend_Loader::loadClass($className);
    return new $className($scheme, $schemeSpecific);
  
  }

  /**
   * Get the URI's scheme
   *
   * @return string|false Scheme or false if no scheme is set.
   */
  public function getScheme() {
    if (! empty($this->_scheme)) {
      return $this->_scheme;
    } else {
      return false;
    }
  }

  /******************************************************************************
   * Abstract Methods
   *****************************************************************************/
  
  /**
   * Zend_Uri and its subclasses cannot be instantiated directly.
   * Use Zend_Uri::factory() to return a new Zend_Uri object.
   */
  abstract protected function __construct($scheme, $schemeSpecific = '');

  /**
   * Return a string representation of this URI.
   *
   * @return string
   */
  abstract public function getUri();

  /**
   * Returns TRUE if this URI is valid, or FALSE otherwise.
   *
   * @return boolean
   */
  abstract public function valid();
}
