<?php

// must be called POST validation

/**
 * Adds rel="nofollow" to all outbound links.
 * This transform is
 * only attached if Attr.Nofollow is TRUE.
 */
class HTMLPurifier_AttrTransform_Nofollow extends HTMLPurifier_AttrTransform {
	/**
	 * @type HTMLPurifier_URIParser
	 */
	private $parser;
	public function __construct() {
		$this->parser = new HTMLPurifier_URIParser ();
	}
	
	/**
	 *
	 * @param array $attr        	
	 * @param HTMLPurifier_Config $config        	
	 * @param HTMLPurifier_Context $context        	
	 * @return array
	 */
	public function transform($attr, $config, $context) {
		if (! isset ( $attr ['href'] )) {
			return $attr;
		}
		
		// XXX Kind of inefficient
		$url = $this->parser->parse ( $attr ['href'] );
		$scheme = $url->getSchemeObj ( $config, $context );
		
		if ($scheme->browsable && ! $url->isLocal ( $config, $context )) {
			if (isset ( $attr ['rel'] )) {
				$rels = explode ( ' ', $attr ['rel'] );
				if (! in_array ( 'nofollow', $rels )) {
					$rels [] = 'nofollow';
				}
				$attr ['rel'] = implode ( ' ', $rels );
			} else {
				$attr ['rel'] = 'nofollow';
			}
		}
		return $attr;
	}
}

// vim: et sw=4 sts=4