<?php

// must be called POST validation

/**
 * Transform that supplies default values for the src and alt attributes
 * in img tags, as well as prevents the img tag from being removed
 * because of a missing alt tag.
 * This needs to be registered as both
 * a pre and post attribute transform.
 */
class HTMLPurifier_AttrTransform_ImgRequired extends HTMLPurifier_AttrTransform {
	
	/**
	 *
	 * @param array $attr        	
	 * @param HTMLPurifier_Config $config        	
	 * @param HTMLPurifier_Context $context        	
	 * @return array
	 */
	public function transform($attr, $config, $context) {
		$src = true;
		if (! isset ( $attr ['src'] )) {
			if ($config->get ( 'Core.RemoveInvalidImg' )) {
				return $attr;
			}
			$attr ['src'] = $config->get ( 'Attr.DefaultInvalidImage' );
			$src = false;
		}
		
		if (! isset ( $attr ['alt'] )) {
			if ($src) {
				$alt = $config->get ( 'Attr.DefaultImageAlt' );
				if ($alt === null) {
					// truncate if the alt is too long
					$attr ['alt'] = substr ( basename ( $attr ['src'] ), 0, 40 );
				} else {
					$attr ['alt'] = $alt;
				}
			} else {
				$attr ['alt'] = $config->get ( 'Attr.DefaultInvalidImageAlt' );
			}
		}
		return $attr;
	}
}

// vim: et sw=4 sts=4