<?php
/**
 * @file
 * Vocabulary Permissions Per Role
 *
 * Allows adding to/editing terms of/removing terms from vocabularies per role.
 */

/**
 * Implements hook_menu_alter().
 */
function vppr_menu_alter(&$items) {
  // Taxonomy overview page.
  $items['admin/structure/taxonomy']['access callback'] = 'vppr_access_taxonomy';
  $items['admin/structure/taxonomy']['page callback'] = 'vppr_taxonomy_overview_vocabularies';
  $items['admin/structure/taxonomy']['file'] = 'vppr.admin.inc';
  $items['admin/structure/taxonomy']['file path'] = drupal_get_path('module', 'vppr');
  unset($items['admin/structure/taxonomy']['page arguments']);
  // Terms list.
  $items['admin/structure/taxonomy/%taxonomy_vocabulary_machine_name']['access callback'] = 'vppr_access_vocabulary_terms';
  $items['admin/structure/taxonomy/%taxonomy_vocabulary_machine_name']['access arguments'] = array(3);
  // Add terms.
  $items['admin/structure/taxonomy/%taxonomy_vocabulary_machine_name/add']['access callback'] = 'vppr_access_vocabulary_terms';
  $items['admin/structure/taxonomy/%taxonomy_vocabulary_machine_name/add']['access arguments'] = array(3);
  // Term edit.
  $items['taxonomy/term/%taxonomy_term/edit']['access callback'] = 'vppr_access_term_edit';
  $items['taxonomy/term/%taxonomy_term/edit']['access arguments'] = array(2);
}

/**
 * VPPR's access callback for taxonomy overview page (main entry point).
 *
 * Grants access to taxonomy overview page even if $user has access to any of
 * the vocabularies.
 */
function vppr_access_taxonomy() {
  if (user_access('administer taxonomy')) {
    return TRUE;
  }
  $perms = array_keys(vppr_permission());
  foreach ($perms as $perm) {
    if (user_access($perm)) {
      return TRUE;
    }
  }
  return FALSE;
}

/**
 * VPPR's access callback for terms list.
 */
function vppr_access_vocabulary_terms($vocabulary) {
  if (user_access('administer taxonomy') || user_access('administer ' . $vocabulary->machine_name . ' vocabulary terms')) {
    return TRUE;
  }
  return FALSE;
}

/**
 * Return edit access for a given term.
 */
function vppr_access_term_edit($term) {
  if (taxonomy_term_edit_access($term) || user_access('administer ' . $term->vocabulary_machine_name . ' vocabulary terms')) {
    return TRUE;
  }
  return FALSE;
}

/**
 * Return delete access for a given term.
 */
function vppr_access_term_delete($term) {
  if (user_access('administer taxonomy') || user_access("delete terms in $term->vid") || user_access('administer ' . $term->vocabulary_machine_name . ' vocabulary terms')) {
    return TRUE;
  }
  return FALSE;
}

/**
 * Implements hook_form_FORM_ID_alter().
 */
function vppr_form_taxonomy_form_term_alter(&$form, &$form_state) {
  if (isset($form['tid']['#value']) && isset($form['actions']['delete']['#access']) && isset($form['#term'])) {
    $form['actions']['delete']['#access'] = vppr_access_term_delete((object) $form['#term']);
  }
}

/**
 * Implements hook_permission().
 */
function vppr_permission() {
  $perms = array();
  $vocabularies = taxonomy_get_vocabularies();
  foreach ($vocabularies as $vocabulary) {
    $perms['administer ' . $vocabulary->machine_name . ' vocabulary terms'] = array(
      'title' => t('Administer %name vocabulary terms', array('%name' => $vocabulary->name)),
    );
  }
  return $perms;
}

/**
 * Implements hook_taxonomy_vocabulary_update().
 */
function vppr_taxonomy_vocabulary_update($vocabulary) {
  if ($vocabulary->old_machine_name != $vocabulary->machine_name) {
    db_update('role_permission')
      ->fields(array(
        'permission' => 'administer ' . $vocabulary->machine_name . ' vocabulary terms',
      ))
      ->condition('permission', 'administer ' . $vocabulary->old_machine_name . ' vocabulary terms')
      ->execute();

    // Clear the user access cache.
    drupal_static_reset('user_access');
    drupal_static_reset('user_role_permissions');
  }
}

/**
 * Implements hook_taxonomy_vocabulary_delete().
 */
function vppr_taxonomy_vocabulary_delete($vocabulary) {
  db_delete('role_permission')
    ->condition('permission', 'administer ' . $vocabulary->machine_name . ' vocabulary terms')
    ->execute();

  // Clear the user access cache.
  drupal_static_reset('user_access');
  drupal_static_reset('user_role_permissions');
}