<?php

/**
 * Validates shorthand CSS property font.
 */
class HTMLPurifier_AttrDef_CSS_Font extends HTMLPurifier_AttrDef {
	
	/**
	 * Local copy of validators
	 * @type HTMLPurifier_AttrDef[]
	 * @note If we moved specific CSS property definitions to their own
	 * classes instead of having them be assembled at run time by
	 * CSSDefinition, this wouldn't be necessary. We'd instantiate
	 * our own copies.
	 */
	protected $info = array ();
	
	/**
	 *
	 * @param HTMLPurifier_Config $config        	
	 */
	public function __construct($config) {
		$def = $config->getCSSDefinition ();
		$this->info ['font-style'] = $def->info ['font-style'];
		$this->info ['font-variant'] = $def->info ['font-variant'];
		$this->info ['font-weight'] = $def->info ['font-weight'];
		$this->info ['font-size'] = $def->info ['font-size'];
		$this->info ['line-height'] = $def->info ['line-height'];
		$this->info ['font-family'] = $def->info ['font-family'];
	}
	
	/**
	 *
	 * @param string $string        	
	 * @param HTMLPurifier_Config $config        	
	 * @param HTMLPurifier_Context $context        	
	 * @return bool|string
	 */
	public function validate($string, $config, $context) {
		static $system_fonts = array (
				'caption' => true,
				'icon' => true,
				'menu' => true,
				'message-box' => true,
				'small-caption' => true,
				'status-bar' => true 
		);
		
		// regular pre-processing
		$string = $this->parseCDATA ( $string );
		if ($string === '') {
			return false;
		}
		
		// check if it's one of the keywords
		$lowercase_string = strtolower ( $string );
		if (isset ( $system_fonts [$lowercase_string] )) {
			return $lowercase_string;
		}
		
		$bits = explode ( ' ', $string ); // bits to process
		$stage = 0; // this indicates what we're looking for
		$caught = array (); // which stage 0 properties have we caught?
		$stage_1 = array (
				'font-style',
				'font-variant',
				'font-weight' 
		);
		$final = ''; // output
		
		for($i = 0, $size = count ( $bits ); $i < $size; $i ++) {
			if ($bits [$i] === '') {
				continue;
			}
			switch ($stage) {
				case 0 : // attempting to catch font-style, font-variant or font-weight
					foreach ( $stage_1 as $validator_name ) {
						if (isset ( $caught [$validator_name] )) {
							continue;
						}
						$r = $this->info [$validator_name]->validate ( $bits [$i], $config, $context );
						if ($r !== false) {
							$final .= $r . ' ';
							$caught [$validator_name] = true;
							break;
						}
					}
					// all three caught, continue on
					if (count ( $caught ) >= 3) {
						$stage = 1;
					}
					if ($r !== false) {
						break;
					}
				case 1 : // attempting to catch font-size and perhaps line-height
					$found_slash = false;
					if (strpos ( $bits [$i], '/' ) !== false) {
						list ( $font_size, $line_height ) = explode ( '/', $bits [$i] );
						if ($line_height === '') {
							// ooh, there's a space after the slash!
							$line_height = false;
							$found_slash = true;
						}
					} else {
						$font_size = $bits [$i];
						$line_height = false;
					}
					$r = $this->info ['font-size']->validate ( $font_size, $config, $context );
					if ($r !== false) {
						$final .= $r;
						// attempt to catch line-height
						if ($line_height === false) {
							// we need to scroll forward
							for($j = $i + 1; $j < $size; $j ++) {
								if ($bits [$j] === '') {
									continue;
								}
								if ($bits [$j] === '/') {
									if ($found_slash) {
										return false;
									} else {
										$found_slash = true;
										continue;
									}
								}
								$line_height = $bits [$j];
								break;
							}
						} else {
							// slash already found
							$found_slash = true;
							$j = $i;
						}
						if ($found_slash) {
							$i = $j;
							$r = $this->info ['line-height']->validate ( $line_height, $config, $context );
							if ($r !== false) {
								$final .= '/' . $r;
							}
						}
						$final .= ' ';
						$stage = 2;
						break;
					}
					return false;
				case 2 : // attempting to catch font-family
					$font_family = implode ( ' ', array_slice ( $bits, $i, $size - $i ) );
					$r = $this->info ['font-family']->validate ( $font_family, $config, $context );
					if ($r !== false) {
						$final .= $r . ' ';
						// processing completed successfully
						return rtrim ( $final );
					}
					return false;
			}
		}
		return false;
	}
}

// vim: et sw=4 sts=4