<?php
// $Id$

/**
 * @file
 * Allows users with proper permissions to alter the taxonomy of a
 * parent node inside of a comment.
 */

/**
 * Implementation of hook_perm().
 */
function comment_alter_taxonomy_perm() {
  $perms = array();
  $types = node_get_types();
  foreach ($types as $type) {
    $name = check_plain($type->type);
    $perms[] = "alter taxonomy on $name content";
  }

  return $perms;
}

/**
 * Implementation of hook_menu().
 */
function comment_alter_taxonomy_menu() {
  $items = array();

  $items[] = array(
    'path' => 'admin/settings/comment_alter_taxonomy',
    'title' => t('Comment alter taxonomy'),
    'description' => t('Enable/disable vocabularies that users may alter from their comments.'),
    'callback' => 'drupal_get_form',
    'callback arguments' => array('comment_alter_taxonomy_admin_settings'),
  );

  return $items;
}

/**
 * Administration settings form.
 */
function comment_alter_taxonomy_admin_settings() {
  $options = array();

  // Get a list of all vocabularies in the system.
  $vocabularies = taxonomy_get_vocabularies();
  foreach ($vocabularies as $vid => $vocabulary) {
    $options[$vid] = check_plain($vocabulary->name);
  }

  $form['comment_alter_taxonomy_vocabularies'] = array(
    '#type' => 'checkboxes',
    '#title' => t('Vocabularies that may be altered'),
    '#options' => $options,
    '#default_value' => variable_get('comment_alter_taxonomy_vocabularies', array()),
  );

  return system_settings_form($form);
}

/**
 * Implementation of hook_form_alter().
 */
function comment_alter_taxonomy_form_alter($form_id, &$form) {
  // Only fire on comment forms.
  if ($form_id == 'comment_form') {

    // Prepare some variables for later checking.
    $node = node_load($form['nid']['#value']);
    $type = check_plain($node->type);
    $access = "alter taxonomy on $type content";

    $vocabularies = taxonomy_get_vocabularies($type);
    $enabled = array_keys($vocabularies);
    $allowed = variable_get('comment_alter_taxonomy_vocabularies', array());
    $intersect = array_intersect($enabled, $allowed);

    // Only proceed if user has access to alter tags on this node type, and if
    // node type has vocabularies enabled on it which can be altered.
    if (user_access($access) && !empty($intersect)) {

      // Display the edit form for each qualifying vocabulary.
      foreach ($intersect as $vid) {
       _comment_alter_taxonomy_vocabulary_form($vocabularies[$vid], $node, $form);
       }

      // Add custom submit handler.
      $form['#submit']['comment_taxonomy_alter_submit'] = array();
    }
  }
}

/**
 * Submit handler for taxonomy alter form.
 */
function comment_taxonomy_alter_submit($form_id, $form_values) {
  taxonomy_node_save($form_values['nid'], $form_values['taxonomy']);
}

/**
 * Generate taxonomy forms for a given set of vocabulary IDs.
 *
 * This is kind of nasty (it is indeed!!); mostly a copy/paste of taxonomy_form_alter, which is
 * a big glop of stuff.
 */
function _comment_alter_taxonomy_vocabulary_form($vocabulary, $node, &$form) {
  // Determine existing term assignments, if any.
  if (!isset($node->taxonomy)) {
    if ($node->nid) {
      $terms = taxonomy_node_get_terms($node->nid);
    }
    else {
      $terms = array();
    }
  }
  else {
    $terms = $node->taxonomy;
  }

  if ($vocabulary->tags) {
    // Handle free-tagging vocabularies.
    $typed_terms = array();
    foreach ($terms as $term) {
      // Extract terms belonging to the vocabulary in question.
      if ($term->vid == $vocabulary->vid) {

        // Commas and quotes in terms are special cases, so encode 'em.
        if (strpos($term->name, ',') !== FALSE || strpos($term->name, '"') !== FALSE) {
          $term->name = '"'.str_replace('"', '""', $term->name).'"';
        }

        $typed_terms[] = $term->name;
      }
    }
    $typed_string = implode(', ', $typed_terms) . (array_key_exists('tags', $terms) ? $terms['tags'][$vocabulary->vid] : NULL);

    if ($vocabulary->help) {
      $help = $vocabulary->help;
    }
    else {
      $help = t('A comma-separated list of terms describing this content. Example: funny, bungee jumping, "Company, Inc.".');
    }
    $form['taxonomy']['tags'][$vocabulary->vid] = array('#type' => 'textfield',
      '#title' => $vocabulary->name,
      '#description' => $help,
      '#required' => $vocabulary->required,
      '#default_value' => $typed_string,
      '#autocomplete_path' => 'taxonomy/autocomplete/'. $vocabulary->vid,
      '#weight' => $vocabulary->weight,
      '#maxlength' => 255,
      '#tree' => TRUE,
    );
  }
  else {
    // Extract terms belonging to the vocabulary in question.
    $default_terms = array();
    foreach ($terms as $term) {
      if ($term->vid == $vocabulary->vid) {
        $default_terms[$term->tid] = $term;
      }
    }
    $form['taxonomy'][$vocabulary->vid] = taxonomy_form($vocabulary->vid, array_keys($default_terms), $vocabulary->help);
    $form['taxonomy'][$vocabulary->vid]['#weight'] = $vocabulary->weight;
    $form['taxonomy'][$vocabulary->vid]['#required'] = $vocabulary->required;
    $form['taxonomy'][$vocabulary->vid]['#tree'] = TRUE;
  }

  if (is_array($form['taxonomy']) && !empty($form['taxonomy'])) {
    if (count($form['taxonomy']) > 1) { // Add fieldset only if form has more than 1 element.
      $form['taxonomy'] += array(
        '#type' => 'fieldset',
        '#title' => t('Categories'),
        '#collapsible' => TRUE,
        '#collapsed' => FALSE,
      );
    }
    $form['taxonomy']['#weight'] = -3;
    $form['taxonomy']['#tree'] = TRUE;
  }
}

/**
 * Implementation of hook_followup_metadata_changes
 *
 * Handles the diffing of taxonomy terms in project_issue comments.
 */
function comment_alter_taxonomy_followup_metadata_changes($old_data, $new_data) {
  global $project_issue_comment_changes_array;

  if (!in_array('taxonomy', $project_issue_comment_changes_array['changes_keys'])) {
    return;
  }
  $old_taxonomy = unserialize($project_issue_comment_changes_array['old']['taxonomy']);
  $new_taxonomy = unserialize($project_issue_comment_changes_array['new']['taxonomy']);

  // Process changeserences in free tagging vocabularies.
  $vids = array();
  if (!empty($old_taxonomy['tags'])) {
    $vids = array_keys($old_taxonomy['tags']);
  }
  if (!empty($new_taxonomy['tags'])) {
    $vids += array_keys($new_taxonomy['tags']);
  }
  $vids = array_unique($vids);

  foreach ($vids as $vid) {
    if (isset($old_taxonomy['tags'][$vid]) && isset($new_taxonomy['tags'][$vid])) {
      if ($old_taxonomy['tags'][$vid] != $new_taxonomy['tags'][$vid]) {
        $project_issue_comment_changes_array['old']["taxonomy_vid_$vid"] = $old_taxonomy['tags'][$vid];
        $project_issue_comment_changes_array['new']["taxonomy_vid_$vid"] = $new_taxonomy['tags'][$vid];
        $project_issue_comment_changes_array['changes_keys'][] = 'taxonomy_vid_'. $vid;
        $vocabulary = taxonomy_get_vocabulary($vid);
        $project_issue_comment_changes_array['label_array']["taxonomy_vid_$vid"] = check_plain($vocabulary->name);
      }
    }
    elseif ($old_taxonomy['tags'][$vid]) {
      $project_issue_comment_changes_array['old']["taxonomy_vid_$vid"] = $old_taxonomy['tags'][$vid];
      $project_issue_comment_changes_array['new']["taxonomy_vid_$vid"] = '';
      $project_issue_comment_changes_array['changes_keys'][] = 'taxonomy_vid_'. $vid;
      $vocabulary = taxonomy_get_vocabulary($vid);
      $project_issue_comment_changes_array['label_array']["taxonomy_vid_$vid"] = check_plain($vocabulary->name);
    }
    else {
      $project_issue_comment_changes_array['old']["taxonomy_vid_$vid"] = '';
      $project_issue_comment_changes_array['new']["taxonomy_vid_$vid"] = $new_taxonomy['tags'][$vid];
      $project_issue_comment_changes_array['changes_keys'][] = 'taxonomy_vid_'. $vid;
      $vocabulary = taxonomy_get_vocabulary($vid);
      $project_issue_comment_changes_array['label_array']["taxonomy_vid_$vid"] = check_plain($vocabulary->name);
    }
  }
}

/**
 * @return
 *  An array with each value representing one vid present in $taxonomy.
 */
function _comment_alter_taxonomy_get_vid_array($taxonomy) {
  $vid_array = array_keys($taxonomy);
  if (!empty($taxonomy) && array_key_exists('tags', $taxonomy)) {

    $tag_vids = array_keys($taxonomy['tags']);
    $vid_array = array_merge($vid_array, $tag_vids);
  }
  return $vid_array;
}