Content parser

<?php

require_once( dirname(dirname(__FILE__)).'/thirdparty/simple_html_dom.php' );

// Transforms the content area of the page
// Usage:
// $Content.Parse(ContentParser)

class ContentParser extends TextParser {

	public function parse() {
		$html = str_get_html($this->content);

		if ( !$html ) {
			return $this->content;
		}

		// Add 'responsive' class to tables
		$tables = $html->find('table');
		foreach($tables as $table ) {
			$table->class = trim($table->class . ' responsive');
		}

		// Add anchors and back to top links before H3 elements - linked to by sidebar
		$headings = $html->find('h3');
		foreach( $headings as $Pos => $heading ) {
			$Pos = $Pos + 1; // $Pos is 1-indexed
			$newOuterText = '<a name="heading-'.$Pos.'"></a>' . $heading->outertext;
			// If there are 2 or more headings, add back to top before each one (but not the top one)
			if ( count($headings) >= 2 && $Pos != 1 ) {
				$newOuterText = '<p class="back-to-top"><a href="#top">Back to top</a></p>' . $newOuterText;
			}
			$heading->outertext = $newOuterText;
		}

		// IMG elements need a bunch of stuff, can be tricky!
		$imgs = $html->find('img');
		foreach( $imgs as $img ) {
			$target = $img;
			$src = '/' . $img->src;
			$alt = $img->alt;
			$title = $img->title;

			$class = ( $img->class == 'right' ? 'span3 build-figure-portrait build-figure-right' : 'build-figure-landscape' );
			$orientation = ($img->class == 'right' ? 'Portrait' : 'Landscape' );
			
			$imgAltSpan = $img->parent()->find('span', 0);
			if ($imgAltSpan) $imgAltText = $imgAltSpan->plaintext; else $imgAltText = $alt;
		}

		// Youtube video divs need the 'build-content-video' class added
		$iframes = $html->find('iframe');
		foreach( $iframes as $iframe ) {
			$parent = $iframe->parent();
			if ( $parent->tag == 'div' && strpos($parent->class, 'thumbnail=') !== false ) {
				$parent->class = trim($parent->class . ' build-content-video');
			}
		}

		$string = $html->save();
		
		// Add a final back to top link if there are 2 or more headings
		if ( count($headings) >= 2 ) {
			$string = $string . '<p class="back-to-top"><a href="#top">Back to top</a></p>';
		}

		return $string;
	}
	
}