main.inc.php

<?php
/*
Plugin Name: Tag Groups
Version: auto
Description: Create groups of tags
Plugin URI: http://piwigo.org/ext/extension_view.php?eid=
Author: plg
Author URI: http://piwigo.org
*/

if (!defined('PHPWG_ROOT_PATH')) die('Hacking attempt!');

$render_tag_names = true;
if (defined('IN_ADMIN'))
{
  $render_tag_names = false;
}

if (script_basename() == 'tags')
{
  global $page, $conf;
  
  if (isset($_GET['display_mode']))
  {
    if ('groups' == $_GET['display_mode'])
    {
      $render_tag_names = false;
    }
  }
  elseif ('groups' == $conf['tags_default_display_mode'])
  {
    $render_tag_names = false;
  }

  $page['tg_display'] = !$render_tag_names;
}

if ($render_tag_names)
{
  add_event_handler('render_tag_name', 'tg_clean_tag_name');
}

function tg_clean_tag_name($tag_name)
{
  return preg_replace('/^[^:]*:/', '', $tag_name);
}

// file_get_contents('tags.tpl')

if (script_basename() == 'tags')
{
  add_event_handler('loc_begin_page_header', 'tg_groups_display');
}

function tg_groups_display()
{
  global $conf, $template, $user, $tags, $page;

  load_language('plugin.lang', PHPWG_PLUGINS_PATH . basename(dirname(__FILE__)) . '/');
  load_language('lang', PHPWG_ROOT_PATH.PWG_LOCAL_DIR, array('no_fallback'=>true, 'local'=>true) );

  $template->set_prefilter('tags', 'tg_add_display_link_prefilter');

  $template->assign('U_TAG_GROUPS', get_root_url().'tags.php?display_mode=groups');

  if ($page['tg_display'])
  {
    // echo __FILE__.'::'.__LINE__.' display_mode=groups<br>';
    $template->set_prefilter('tags', 'tg_groups_display_prefilter');

    $template->assign('display_mode', 'groups');

    // we want tags diplayed in alphabetic order
    usort($tags, 'tag_alpha_compare');

    $current_tag_group = null;
    $nb_tags = count($tags);
    $current_column = 1;
    $current_tag_idx = 0;
    
    $tag_group = array(
      'tags' => array()
      );
    
    foreach ($tags as $tag)
    {
      // if the tag belongs to no group, we don't show it on the "tag by
      // group" display mode
      if (strpos($tag['name'], ':') === false)
      {
        continue;
      }
      else
      {
        list($tag['group'], $tag['name']) = explode(':', $tag['name'], 2);
        $tag['group'] = preg_replace('/^[^=]*=/', '', $tag['group']);
      }

      if ($current_tag_idx == 0)
      {
        $current_tag_group = $tag['group'];
        $tag_group['TITLE'] = $tag['group'];
      }
      
      // new group?
      if ($tag['group'] !== $current_tag_group)
      {
        if ($current_column < $conf['tag_letters_column_number']
            and $current_tag_idx > $current_column*$nb_tags/$conf['tag_letters_column_number'] )
        {
          $tag_group['CHANGE_COLUMN'] = true;
          $current_column++;
        }
        
        $tag_group['TITLE'] = $current_tag_group;
        
        $template->append(
          'tag_groups',
          $tag_group
          );
        
        $current_tag_group = $tag['group'];
        $tag_group = array(
          'tags' => array()
          );
      }
      
      array_push(
        $tag_group['tags'],
        array_merge(
          $tag,
          array(
            'URL' => make_index_url(
              array(
                'tags' => array($tag),
                )
              ),
            )
          )
        );
      
      $current_tag_idx++;
    }
    
    // flush last group
    if (count($tag_group['tags']) > 0)
    {
      unset($tag_group['CHANGE_COLUMN']);
      $tag_group['TITLE'] = $current_tag_group;
      $template->append(
        'tag_groups',
        $tag_group
        );
    }
  }
}

function tg_groups_display_prefilter($content, &$smarty)
{
  $template_content = file_get_contents(PHPWG_PLUGINS_PATH.basename(dirname(__FILE__)).'/tags.tpl');
  
  $search = '#\{/if\}((\s*</div>\s*)+)<!-- content -->#mi';
  $replace = '{/if}'."\n".$template_content.'\1 <!-- content -->';

  return preg_replace($search, $replace, $content);
}

function tg_add_display_link_prefilter($content, &$smarty)
{
  $search = '#\{if \$display_mode == \'letters\'\}\s*<li>#mi';
  $replace = '{if $display_mode != \'cloud\'}<li>';
  $content = preg_replace($search, $replace, $content);

  $search = '#\{if \$display_mode == \'cloud\'\}\s*<li>#mi';
  $replace = '{if $display_mode != \'letters\'}<li>';
  $content = preg_replace($search, $replace, $content);

  $search = '<ul class="categoryActions">';
  $replace = '<ul class="categoryActions">
{if $display_mode != \'groups\'}<li>
  <li><a href="{$U_TAG_GROUPS}">{\'show tag groups\'|@translate}</a></li>
{/if}
';
  return str_replace($search, $replace, $content);
}
?>