<?php

/**
 * Validates shorthand CSS property background.
 * @warning Does not support url tokens that have internal spaces.
 */
class HTMLPurifier_AttrDef_CSS_Background extends HTMLPurifier_AttrDef {
	
	/**
	 * Local copy of component validators.
	 * @type HTMLPurifier_AttrDef[]
	 * @note See HTMLPurifier_AttrDef_Font::$info for a similar impl.
	 */
	protected $info;
	
	/**
	 *
	 * @param HTMLPurifier_Config $config        	
	 */
	public function __construct($config) {
		$def = $config->getCSSDefinition ();
		$this->info ['background-color'] = $def->info ['background-color'];
		$this->info ['background-image'] = $def->info ['background-image'];
		$this->info ['background-repeat'] = $def->info ['background-repeat'];
		$this->info ['background-attachment'] = $def->info ['background-attachment'];
		$this->info ['background-position'] = $def->info ['background-position'];
	}
	
	/**
	 *
	 * @param string $string        	
	 * @param HTMLPurifier_Config $config        	
	 * @param HTMLPurifier_Context $context        	
	 * @return bool|string
	 */
	public function validate($string, $config, $context) {
		// regular pre-processing
		$string = $this->parseCDATA ( $string );
		if ($string === '') {
			return false;
		}
		
		// munge rgb() decl if necessary
		$string = $this->mungeRgb ( $string );
		
		// assumes URI doesn't have spaces in it
		$bits = explode ( ' ', $string ); // bits to process
		
		$caught = array ();
		$caught ['color'] = false;
		$caught ['image'] = false;
		$caught ['repeat'] = false;
		$caught ['attachment'] = false;
		$caught ['position'] = false;
		
		$i = 0; // number of catches
		
		foreach ( $bits as $bit ) {
			if ($bit === '') {
				continue;
			}
			foreach ( $caught as $key => $status ) {
				if ($key != 'position') {
					if ($status !== false) {
						continue;
					}
					$r = $this->info ['background-' . $key]->validate ( $bit, $config, $context );
				} else {
					$r = $bit;
				}
				if ($r === false) {
					continue;
				}
				if ($key == 'position') {
					if ($caught [$key] === false) {
						$caught [$key] = '';
					}
					$caught [$key] .= $r . ' ';
				} else {
					$caught [$key] = $r;
				}
				$i ++;
				break;
			}
		}
		
		if (! $i) {
			return false;
		}
		if ($caught ['position'] !== false) {
			$caught ['position'] = $this->info ['background-position']->validate ( $caught ['position'], $config, $context );
		}
		
		$ret = array ();
		foreach ( $caught as $value ) {
			if ($value === false) {
				continue;
			}
			$ret [] = $value;
		}
		
		if (empty ( $ret )) {
			return false;
		}
		return implode ( ' ', $ret );
	}
}

// vim: et sw=4 sts=4