<?php
/**
 * @file
 * Use tac_lite to control which terms can be used when creating new
 * content.  Unlike tac_lite.module, which relies on Drupal's node_access
 * features, this module uses hook_form_alter to change which terms are
 * presented by the taxonomy module.
 *
 * Original implementation by markDrupal http://drupal.org/user/93970.
 */

/**
 * Implementation of hook_form_alter().
 */
function tac_lite_create_form_alter(&$form, $form_state, $form_id) {
  if (strpos($form_id, 'node_form') !== FALSE) {
    global $user;

    if (user_access('administer tac_lite')) {
      // no need to restrict based on update permission in this cases
      return;
    }

    // the vocabularies containing protected info.
    $vids = variable_get('tac_lite_categories', array(0));

    // the terms this user is allowed to edit
    $tids = array();
    for ($i = 1; $i <= variable_get('tac_lite_schemes', 1); $i++) {
      $config = _tac_lite_config($i);
      if ((isset($config['tac_lite_create']) && $config['tac_lite_create']) ||
        in_array('grant_update', $config['perms'])) {
        $tids = array_merge($tids, _tac_lite_user_tids($user, $i));
      }
    }

    if (isset($form['taxonomy'])) {
      foreach ($form['taxonomy'] as $vid => $data) {
        if (!is_numeric($vid) || !in_array($vid, $vids)) {
          // Not a vid, or not controlled by tac_lite.
          continue;
        }
        foreach ($data['#options'] as $num => $term) {
          if (!is_numeric($num)) {
            continue;
          }
          if (!in_array(key($term->option), $tids)) {
            if (!in_array(key($term->option), $form['taxonomy'][$vid]['#default_value'])) {
              // The term is not the default value, and user is not allowed to create with it.
              unset($form['taxonomy'][$vid]['#options'][$num]);
            }
          }
        }

        if (count($form['taxonomy'][$vid]['#options']) == 0 && $form['taxonomy'][$vid]['#required'] == TRUE) {
          drupal_set_message(t('You have no permissions to add content to the required %name vocabulary. Please contact the site administrator if you believe you should have permission to add content.', array('%name' => $form['taxonomy'][$vid]['#title'])));
          drupal_access_denied();
          exit();
        }
        
        if (count($form['taxonomy'][$vid]['#options']) <= 1) {
          // Don't show if the only option left is <none>.
          unset($form['taxonomy'][$vid]);
        }
        if (isset($form['taxonomy'][$vid]['#size']) &&
          $form['taxonomy'][$vid]['#size'] > count($form['taxonomy'][$vid]['#options'])) {
          $form['taxonomy'][$vid]['#size'] = count($form['taxonomy'][$vid]['#options']);
        }
      }
    }
  }
  elseif ($form_id == 'tac_lite_admin_scheme_form') {
    $config = $form['#tac_lite_config'];
    $scheme = $form['#parameters'][2];

    $form['tac_lite_config_scheme_' . $scheme]['tac_lite_create'] = array(
      '#type' => 'checkbox',
      '#title' => 'Visibility on create and edit forms',
      '#default_value' => isset($config['tac_lite_create']) ? $config['tac_lite_create'] : FALSE,
      '#description' => t('Show terms when creating content.  This <strong>does not</strong> control which users can create a given content type. This <strong>does</strong> control which terms appear on the node edit forms.  <br/>Note that schemes granting <em>update</em> permission (above) imply <em>visibility on forms</em> as well.'),
    );
  }
}