<?php

// This is the entry point of the plugin (Right after Wordpress is done

// processing the user request, setting up `$wp_query` etc, and right before the

// template renders the HTML output.

add_action('template_redirect', 'wp_geshi_main');

function wp_geshi_main() {

    global $wp_geshi_codesnipmatch_arrays;

    global $wp_geshi_run_token;

    // Generate unique token. Code snippets will be replaced by it (+snip ID)

    // temporarily during the action of this plugin.

    $wp_geshi_run_token = md5(uniqid(rand())); // from Ryan McGeary

    // Filter all post/comment text and save and replace code snippets.

    wp_geshi_filter_and_replace_code_snippets();

    // If we did not find any code snippets, it's time to leave...

    if (!count($wp_geshi_codesnipmatch_arrays)) return;

    // `$wp_geshi_codesnipmatch_arrays` is populated. Work on it: it's now

    // GeSHi's part: highlight the code an generate CSS code.

    wp_geshi_highlight_and_generate_css();

    // Now, `$wp_geshi_css_code` and `$wp_geshi_highlighted_matches` are set.

    // Add action to add CSS code to HTML header.

    add_action('wp_head', 'wp_geshi_add_css_to_head');

    // Add low priority filter to replace unique identifiers with highlighted

    // code.

    add_filter('the_content', 'wp_geshi_insert_highlighted_code_filter', 99);

    add_filter('the_excerpt', 'wp_geshi_insert_highlighted_code_filter', 99);

    add_filter('comment_text', 'wp_geshi_insert_highlighted_code_filter', 99);

    }

// Parse all post texts and comment texts (the latter only in case of single

// pages). While iterating over these texts, do the following:

// - detect <pre args> code code code </ pre> parts.

// - save these parts in a global variable.

// - modify post/comment texts: replace code parts by a unique token.

function wp_geshi_filter_and_replace_code_snippets() {

    global $wp_query;

    // Iterate over all posts in this query.

    foreach ($wp_query->posts as $post) {

        // Extract code snippets from the content. Replace them.

        $post->post_content = wp_geshi_filter_replace_code($post->post_content);

        if (is_single()) {

            $comments_array = get_approved_comments($post->ID);

            // Iterate over all approved comments belonging to this post.

            // Filter them, too.

            foreach ($comments_array as $comment) {

                $comment->comment_content = wp_geshi_filter_replace_code(

                    $comment->comment_content);

                }

            }

        }

    }

// Search for all <pre args>code</ pre> occurrences. Save them in a global var.

// Replace them with unambiguous identifiers.

// `wp_geshi_substitute($match)` is called for each match.

// A `$match` is an array, following the sub-pattern of the regex:

// 0: all

// 1: language

// 2: line

// 3: escaped

// 4: cssfile

// 5: code

function wp_geshi_filter_replace_code($s) {

    return preg_replace_callback(

        "/\s*<pre(?:lang=[\"']([\w-]+)[\"']|line=[\"'](\d*)[\"']"

        ."|escaped=[\"'](true|false)?[\"']|cssfile=[\"']([\S]+)[\"']|\s)+>".

        "(.*)<\/pre>\s*/siU",

        "wp_geshi_store_and_substitute",

        $s

        );

    }

// Store code snippet data. Return unambiguous identifier for this code snippet.

function wp_geshi_store_and_substitute($match_array) {

    global $wp_geshi_run_token, $wp_geshi_codesnipmatch_arrays;

    // count() returns 0 if the variable is not set already.

    // We need this index for the identifier of this code snippet.

    $match_index = count($wp_geshi_codesnipmatch_arrays);

    // Elements of $match_array are strings matching the sub-expressions in the

    // big regular expression searching <pre args>code</ pre>. They contain

    // the arguments of <pre> tag and the code snippet itself.

    // Store this array for later usage. Before, store the match index as last

    // array element to `$match_array`.

    $match_array[] = $match_index;

    $wp_geshi_codesnipmatch_arrays[$match_index] = $match_array;

    // Return a string that is unambiguously to identify during another filter

    // run. This string replaces the <pre args>code</ pre> code snippet for now.

    return "\n<p>".$wp_geshi_run_token."_".

        sprintf("%06d",$match_index)."</p>\n"; // from Ryan McGeary

    }

// Iterate over all match arrays in `$wp_geshi_codesnipmatch_arrays`.

// Perform syntax highlighting and store the resulting string back in e.g.

// `$wp_geshi_highlighted_matches[$match_index]`.

// Generate CSS code and append it to global `$wp_geshi_css_code`.

function wp_geshi_highlight_and_generate_css() {

    global $wp_geshi_codesnipmatch_arrays;

    global $wp_geshi_css_code;

    global $wp_geshi_highlighted_matches;

    global $wp_geshi_requested_css_files;

    // When we're here, code was found.

    // Time to get the highlight machine running...

    include_once("geshi/geshi.php");

    $wp_geshi_css_code = "";

    foreach($wp_geshi_codesnipmatch_arrays as $match_index => $match) {

            // process the match details. the correspondence is explained at

            // function `wp_geshi_filter_replace_code()`.

            $language = strtolower(trim($match[1]));

            $line = trim($match[2]);

            $escaped = trim($match[3]);

            $cssfile = trim($match[4]);

            $code = wp_geshi_code_trim($match[5]);

            if ($escaped == "true")

                $code = htmlspecialchars_decode($code); // from Ryan McGeary

            // set up GeSHi

            $geshi = new GeSHi($code, $language);

            $geshi->enable_keyword_links(false);

            $geshi->enable_classes();

            if ($line) {

                $geshi->enable_line_numbers(GESHI_NORMAL_LINE_NUMBERS);

                $geshi->start_line_numbers_at($line);

                }

            $geshi->set_header_type(GESHI_HEADER_PRE_VALID);

            $wp_geshi_css_code .= $geshi->get_stylesheet();

            $output = "";

            // cssfile "none" means no wrapping styling at all!

            if ("$cssfile" != "none") {

                if (empty($cssfile))

                    // for this code snippet we need the default css file!

                    $cssfile = "wp-geshi-highlight";

                // append "the css file" to the array..

                $wp_geshi_requested_css_files[] = $cssfile;

                $output .= "\n\n".'<div class="'.$cssfile.'-wrap5">'.

                           '<div class="'.$cssfile.'-wrap4">'.

                           '<div class="'.$cssfile.'-wrap3">'.

                           '<div class="'.$cssfile.'-wrap2">'.

                           '<div class="'.$cssfile.'-wrap">'.      

                           '<div class="'.$cssfile.'">';

                }

            $output .= $geshi->parse_code();

            if ("$cssfile" != "none")

                $output .= '</div></div></div></div></div></div>'."\n\n";

            $wp_geshi_highlighted_matches[$match_index] = $output;  

        }

    // At this point all code snippets are parsed. highlighted code is stored.

    // CSS code is generated. Delete what's not necessary anymore.

    unset($wp_geshi_codesnipmatch_arrays);

    }

function wp_geshi_insert_highlighted_code_filter($content){

    global $wp_geshi_run_token;

    return preg_replace_callback(

        "/<p>\s*".$wp_geshi_run_token."_(\d{6})\s*<\/p>/si",

        "wp_geshi_get_highlighted_code",

        $content

        ); // from Ryan McGeary

    }

function wp_geshi_get_highlighted_code($match) {

    global $wp_geshi_highlighted_matches;

    // Found a unique identifier. Extract code snippet match index.

    $match_index = intval($match[1]);

    // Return corresponding highlighted code.

    return $wp_geshi_highlighted_matches[$match_index];

    }

function wp_geshi_code_trim($code) {

    // Special ltrim b/c leading whitespace matters on 1st line of content.

    $code = preg_replace("/^\s*\n/siU", "", $code); // from Ryan McGeary

    $code = rtrim($code); // from Ryan McGeary

    return $code;

    }

function wp_geshi_add_css_to_head() {

    global $wp_geshi_css_code;

    global $wp_geshi_requested_css_files;

    echo "\n<!-- WP-GeSHi-Highlight plugin by ".

         "Jan-Philip Gehrcke: http://gehrcke.de -->\n";

    // set up paths and names

    $csspathpre = WP_PLUGIN_DIR."/wp-geshi-highlight/";

    $cssurlpre = WP_PLUGIN_URL."/wp-geshi-highlight/";

    $csssfx = ".css";

    // echo all required CSS files

    // delete duplicates

    $wp_geshi_requested_css_files = array_unique($wp_geshi_requested_css_files);

    foreach($wp_geshi_requested_css_files as $cssfile)

        wp_geshi_echo_cssfile($csspathpre.$cssfile.$csssfx,

            $cssurlpre.$cssfile.$csssfx);

    // echo GeSHi CSS code if given

    if (strlen($wp_geshi_css_code) > 0)

        echo '<style type="text/css"><!--'.

            $wp_geshi_css_code."//--></style>\n";

    }

function wp_geshi_echo_cssfile($path, $url) {

    if (file_exists($path)) {

        echo '<link rel="stylesheet" href="'.$url.

             '" type="text/css" media="screen" />'."\n";

        }

    }

// Set allowed attributes for pre tags. For more info see wp-includes/kses.php

// credits: wp-syntax (Ryan McGeary)

if (!CUSTOM_TAGS) {

    $allowedposttags['pre'] = array(

        'lang' => array(),

        'line' => array(),

        'escaped' => array(),

        'cssfile' => array()

    );

  //Allow plugin use in comments

    $allowedtags['pre'] = array(

        'lang' => array(),

        'line' => array(),

        'escaped' => array(),

        'cssfile' => array()

    );

}

?>