<?php
/*
Plugin Name: Extended Table of Contents (with nextpage support)
Plugin URI: http://www.happybooking.de/wordpress/plugins/extended-toc
Description: This plugin automatically generates and inserts a table of contents (ToC) to your pages and posts, based on tags h1-h6. Whenever the plugin discovers more than a certain amount of headings (default: 3) the ToC is inserted at the top of the page. This plugin also can handle posts that are divided into pages by the nextpage-wordpress-tag. Any feedback or suggestions are welcome.  
Version: 0.7.0
Author: HappyBooking UG // Daniel Boldura
Author URI: http://www.happybooking.de/


/*  Copyright 2013 HappyBooking UG // Daniel Boldura (email: info at happybooking.de or daniel at boldura.de)

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

/**
 * Planed features and todos:
 * 
 * 1. Collision detection for anchors
 * 2. Header hierarchie
 * 3. Support markups for show or hide the ToC on single pages/posts
 * 4. Config the ToC within a markup e.g. [extoc start=5 headers=1,2,3 title="My table of contents"] oder [extoc start=5 headers=1,2,3 notitle]    
 */

define( 'EXTENDED_TOC_VERSION',  '0.7.0' );
define( 'EXTENDED_TOC_ID',       'extended_toc' );
define( 'EXTENDED_TOC_NAME',     'Extended-ToC' );
define( 'TOC_MIN_START',         2 );
define( 'TOC_MAX_START',         10 );

if( !class_exists('ExToC') ) {
	class ExToC 
  {
    private $path;
    private $content = "";
    private $fullcontent = "";
    private $pages = array(); 
    private $ID = 0;
    private $counter = array();
    private $totalHeadings = 0;
    
    public function __construct() {
      $this->path = plugins_url( '', __FILE__ );
      $this->exclude_post_types = array( 'attachment', 'revision', 'nav_menu_item', 'safecss' );
      
			// get options
			$defaults = array(		// default options
				'heading_text' => 'Contents',
				'start' => 3,
				'show_heading_text' => true,
        'auto_insert_post_types' => array('page', 'post'),
        'heading_levels' => array('1', '2', '3', '4', '5', '6'),
        'show_hierarchy' => true,
			);
			$options = get_option( EXTENDED_TOC_ID, $defaults );
			$this->options = wp_parse_args( $options, $defaults );
      
      add_action( 'plugins_loaded', array(&$this, 'plugins_loaded') );
      
      if( is_admin() ) {
        add_action('admin_init', array(&$this, 'admin_init'));
        add_action('admin_menu', array(&$this, 'admin_menu'));
      }
      else {
        /** Add the content filter and enqueue css **/
        add_filter( 'the_content', array(&$this, 'the_content'), 10 );
        add_action( 'wp_enqueue_scripts', array(&$this, 'wp_enqueue_scripts') );
      }
    }
    
		public function __destruct() {
		}

		public function admin_init() {
			wp_register_style( EXTENDED_TOC_ID, $this->path . '/admin-style.css', array(), EXTENDED_TOC_VERSION );
      wp_enqueue_style(EXTENDED_TOC_ID);
		}
    
    public function admin_menu() {
      // Create menu tab
			$page = add_submenu_page( 'plugins.php', EXTENDED_TOC_NAME, EXTENDED_TOC_NAME, 'manage_options', EXTENDED_TOC_ID, array(&$this, 'admin_options') );
    }
    
		private function save_admin_options()
		{
			global $post_id;

			// security check
			if ( !wp_verify_nonce( @$_POST[EXTENDED_TOC_ID], plugin_basename(__FILE__) ) )
				return false;
        
			// require an administrator level to save
			if ( !current_user_can( 'manage_options', $post_id ) )
				return false;
        
			$this->options = array_merge(
				$this->options,
				array(
					'heading_text' => stripslashes( trim($_POST['heading_text']) ),
          'auto_insert_post_types' => @(array)$_POST['auto_insert_post_types'],
          'start' => intval($_POST['start']),
          'show_heading_text' => (isset($_POST['show_heading_text']) && $_POST['show_heading_text']) ? true : false,
          'show_hierarchy' => (isset($_POST['show_hierarchy']) && $_POST['show_hierarchy']) ? true : false,
				)
			);
			
			// update_option will return false if no changes were made
			update_option( EXTENDED_TOC_ID, $this->options );
			
			return true;
    }
    
    public function admin_options() {
      if( isset($_GET['update']) ) {       
				if( $this->save_admin_options() )
					$msg = '<div id="message" class="updated fade"><p>' . __('Options saved.', EXTENDED_TOC_ID) . '</p></div>';
				else
					$msg = '<div id="message" class="error fade"><p>' . __('Save failed.', EXTENDED_TOC_ID) . '</p></div>';
			}
?>
  <div class="wrap">
    <div id="icon-plugins" class="icon32">
      <br />
    </div>
      
    <h2><?=__("Extended Table of Contents", EXTENDED_TOC_ID)?></h2>
    
    <?=$msg?>

    <form method="post" action="<?php echo htmlentities('?page=' . $_GET['page'] . '&update'); ?>">
      <?php wp_nonce_field( plugin_basename(__FILE__), EXTENDED_TOC_ID ); ?>
      
      <div class="form_container">
        <table class="form-table">
          <tbody>
            <tr>
              <th><label for="show_heading_text"><?=__('Show heading text', EXTENDED_TOC_ID); ?></label></th>
              <td>
                <input id="show_heading_text" type="checkbox" name="show_heading_text" <?php if ( $this->options['show_heading_text'] ) echo ' checked="checked"'; ?> />
              </td>
            </tr>
            
            <tr>
              <th><label for="heading_text"><?=__('Heading text', EXTENDED_TOC_ID); ?></label></th>
              <td><input id="heading_text" type="text" class="regular-text" name="heading_text" value="<?=$this->options['heading_text']?>" /></td>
            </tr>
            
            <tr>
            	<th><?=__('Add table of contents to following content types', EXTENDED_TOC_ID); ?></th>
            	<td>
                <?php foreach( get_post_types() as $post_type ): ?>
                  <?php if( !in_array($post_type, $this->exclude_post_types) ): ?>
                    <input type="checkbox" value="<?=$post_type?>" id="auto_insert_post_types_<?=$post_type?>" name="auto_insert_post_types[]"<?=in_array($post_type, $this->options['auto_insert_post_types'])?' checked="checked"':''?> />
                    <label for="auto_insert_post_types_<?=$post_type?>"><?=$post_type?></label><br />
                  <?php endif; ?>
                <?php endforeach; ?>
              </td>
            </tr>
            
            <tr>
              <th><label for="start"><?=__('Show when', EXTENDED_TOC_ID); ?></label></th>
              <td>
            		<select name="start" id="start">
                <?php 
                for ($i = TOC_MIN_START; $i <= TOC_MAX_START; $i++) {
          				echo '<option value="' . $i . '"';
          				if ( $i == $this->options['start'] ) echo ' selected="selected"';
          				echo '>' . $i . '</option>' . "\n";
          			}
                ?>
            		</select>
                <span>or more headings are present</span>
              </td>
            </tr>
            
            <tr>
              <th><label for="show_hierarchy"><?=__('Show hierarchy', EXTENDED_TOC_ID); ?></label></th>
              <td>
                <input id="show_hierarchy" type="checkbox" name="show_hierarchy" <?php if ( $this->options['show_hierarchy'] ) echo ' checked="checked"'; ?> />
              </td>
            </tr>
          </tbody>
        </table>     
      </div>
      
      <p class="submit"><input class="button-primary" type="submit" value="<?=__("Save Options", EXTENDED_TOC_ID)?>" name="submit" /></p>
    </form>
  </div>                        
<?php
    }
    
    public function wp_enqueue_scripts() {
      wp_register_style(EXTENDED_TOC_ID, $this->path . '/style.css', array(), POWER_TOC_VERSION);
      wp_enqueue_style(EXTENDED_TOC_ID);
    }
    
    public function plugins_loaded() {
			load_plugin_textdomain( EXTENDED_TOC_ID, false, dirname(plugin_basename(__FILE__)) . '/locale/' );
		} 
    
    public function the_content($content) {
      global $post;
      
			if ( is_feed() ) 
        return $content;

      if( !in_array(get_post_type($post), $this->options['auto_insert_post_types'])|| is_search() || is_archive() || is_front_page() )
        return $content;
    
      /** Extract the content, and extract the part content if <!--nextpage--> was used **/
      $this->content = $content;
      $this->extract_full_post_content();
      
      $toc_content = "<div id=\"toc-np-container\">";
      
      if( $this->options['show_heading_text'] == true ) 
        $toc_content .= "<p id=\"toc-np-title\">" . $this->options["heading_text"] . "</p>";
      
      $toc_content .= "<ul class=\"no-bullets\">";
      $toc_content .= $this->extract_toc();
      $toc_content .= "</ul></div>";

      if( $this->totalHeadings >= $this->options['start'] )
        return $toc_content . $this->content;
      else
        return $this->content; 
    }
    
    private function check_for_first_toc_position() {
    }
    
    /** Extract the full unshortened content from the post **/
    private function extract_full_post_content() {
      global $post;
      $this->fullcontent = $post->post_content;  
      $this->ID = $post->ID; 
    }
    
    private function extract_toc() {
      /** check within the full content how many pages exists */
      $this->extract_pages();
    
      $headers = "";
      
      /** Extract headings from every pages */
      for( $pagenum = 1; $pagenum <= count($this->pages); $pagenum++ ) {
        $headers .= $this->exctract_headings($pagenum);   
      }
      
      return $headers;
    }
    
    private function extract_pages() {
      /** Split the content by "nextpage"-tags if some exists */
      $this->pages = preg_split("/<!--nextpage-->/msuU", $this->fullcontent); 
    }
    
    private function exctract_headings($pagenum) {
      /** find all header tags within the page **/
      preg_match_all('/(<h([1-6]{1})[^>]*>).*<\/h\2>/msuU', $this->pages[$pagenum-1], $matches, PREG_SET_ORDER);
 
			/** Check the headings that are desired */
			if( count($this->options['heading_levels']) != 6 ) {
				$new_matches = array();
				for ($i = 0; $i < count($matches); $i++) {
					if ( in_array($matches[$i][2], $this->options['heading_levels']) )
						$new_matches[] = $matches[$i];
				}
				$matches = $new_matches;
			}
          
      $items = "";
      
      /** Take first h-level as baseline */
      $minLevel       =   $matches[0][2];          // lowest level e.g. h3
      $currentLevel   =   $minLevel;

    	for( $i = 0; $i < count($matches); $i++ ) {
    		/** get anchor and add to find and replace arrays **/
    		$anchor = $this->url_encode_anchor($matches[$i][0]);
    		$find[] = $matches[$i][0];
    		$this->content = str_replace(
    			array(
    				$matches[$i][1],				// start of heading
    				'</h' . $matches[$i][2] . '>'	// end of heading
    			),
    			array(
    				$matches[$i][1] . '<span id="' . $anchor . '">',
    				'</span></h' . $matches[$i][2] . '>'
    			),
    			$this->content
    		); 

        /** Check if header lower current header, then add level and update current header */
        if( $matches[$i][2] > $currentLevel && $this->options['show_hierarchy'] == true) {
          $currentLevel = $matches[$i][2];
          $this->counter[$currentLevel] = 1;
        }
        else if( $matches[$i][2] < $currentLevel && $matches[$i][2] >= $minLevel && $this->options['show_hierarchy'] == true) {
          $currentLevel = $matches[$i][2];
          $this->counter[$currentLevel] += 1;
        }
        else
          $this->counter[$currentLevel] += 1;
          
    		/** build html */
        $items .= '<li class="header-level-' . ($currentLevel - $minLevel + 1) . '">';
    		$items .= '<a href="?p='.$this->ID.($pagenum>1?'&page='.$pagenum:'').'#' . $anchor . '">';
        $items .= "<span class=\"toc-np-number\">";
        
        if( $this->options['show_hierarchy'] == true ) {
          for( $j = $minLevel; $j < $currentLevel; $j++ ) {
              $items = $items . $this->counter[$j] . ".";
          }
        }
        $items = $items . $this->counter[$currentLevel];
        
        $items .= "</span>";
    		$items .= strip_tags($matches[$i][0]) . '</a>';
        $items .= '</li>';
        
        $this->totalHeadings++;
    	}  
      
      return $items;
    }
    
    private function url_encode_anchor($anchor)
    {
    	$return = false;
    	
    	if(!empty($anchor) ) {
        /** Remove tags */
        $return = trim( strip_tags($anchor) );
        
        /** remove &amp; */
    		$return = str_replace( '&amp;', '', $return );
        
        /** remove all unknown chars **/
        $return = preg_replace("/[^0-9a-zA-Z \-_]+/", "", $return);
        
        /** Remove backspace etc */
        $return = preg_replace("/[\s]+/", "-", $return);

        /** If we now start or end with a - or _ remove it */
        $return = preg_replace("/^[-_]/", "", $return);
        $return = preg_replace("/[-_]$/", "", $return);
    	}
    	
    	return $return;
    }
  }
}  

/** Initialise the class */
$tocPlugin = new ExToC();

?>