<?php
// $Id: og_field_access.module,v 1.1.2.15 2011-01-05 15:25:24 amitaibu Exp $

/**
 * @file
 * Provide field access based on group.
 */

/**
 * Implements hook_og_permission().
 *
 * Add view/ edit permissions to all existing fields.
 */
function og_field_access_og_permission() {
  $perms = array();
  foreach (field_info_instances() as $entity => $bundles) {
    foreach ($bundles as $bundle => $bundle_value) {
      if (!empty($bundle_value)) {
        foreach ($bundle_value as $field_name => $value) {
          $label = $value['label'];

          $perm = 'view ' . $field_name . ' field';
          $perms[$perm] = array(
              'title' => t('View @label field', array('@label' => $label)),
              'description' => t('View the @label field for existing groups.', array('@label' => $label)),
              'roles' => array(OG_ANONYMOUS_ROLE, OG_AUTHENTICATED_ROLE),
              'default role' => array(
                OG_ANONYMOUS_ROLE,
                OG_AUTHENTICATED_ROLE,
                OG_ADMINISTRATOR_ROLE,
              ),
              'module' => 'og_field_access',
            );

          $perm = 'update ' . $field_name . ' field';
          $perms[$perm] = array(
            'title' => t('Edit @label field', array('@label' => $label)),
            'description' => t('Edit the @label field for existing groups.', array('@label' => $label)),
            'roles' => array(OG_ANONYMOUS_ROLE, OG_AUTHENTICATED_ROLE),
            'default role' => array(OG_ADMINISTRATOR_ROLE),
            'module' => 'og_field_access',
          );
        }
      }
    }
  }
  return $perms;
}


/**
 * Implements hook_field_attach_form().
 *
 * Controls editing fields.
 */
function og_field_access_field_attach_form($entity_type, $entity, &$form, $form_state, $langcode) {
  // Make sure entity is a group or group content.
  if (isset($entity->{OG_AUDIENCE_FIELD}) || isset($entity->{OG_GROUP_FIELD})) {
    // Check field access permissions for the specific bundle.
    $fields = field_info_instances($entity_type, $form['#bundle']);
    if ($fields) {
      foreach ($fields as $field_name => $value) {
        og_field_access_check_access($entity_type, $entity, $form, $form_state, $langcode, $field_name, 'update');
      }
    }
  }
}

/**
 * Implements hook_field_attach_view_alter().
 *
 * Controls viewing fields.
 */
function og_field_access_field_attach_view_alter(&$result, $context) {
  $entity = $context['entity'];
  // Make sure entity is a group or group content.
  if (isset($entity->{OG_AUDIENCE_FIELD}) || isset($entity->{OG_GROUP_FIELD})) {
    // Copy the result to a new variable, so it won't be changed in
    // element_children().
    $fields = $result;
    if ($field_names = element_children($fields)) {
      foreach ($field_names as $field_name) {
        og_field_access_check_access($context['entity_type'], $entity, $result, array(), '', $field_name, 'view');
      }
    }
  }
}


/**
 * Helper function to check if a user has access to a field.
 *
 * @see hook_field_attach_form().

 * @param $entity_type
 * @param $entity
 * @param $form
 * @param $field_name
 *   The name of the field that the edit access is checked for.
 */
function og_field_access_check_access($entity_type, $entity, &$form, $form_state, $langcode, $field_name, $op) {
  global $user;

  // We might need to copy the bundle property from the form into the field.
  // This is because this function is called from the view and the edit
  // field attachers, and we want to deal with the access in a general way.
  if (!empty($form['#bundle'])) {
    $form[$field_name]['#bundle'] = $form['#bundle'];
  }
  if (!empty($form[$field_name]['#bundle'])) {
    $account = clone $user;
    list($id) = entity_extract_ids($entity_type, $entity);
    if (!empty($id)) {
      // Existing entity and the field exists.
      $access = FALSE;

      $perm = $op . ' ' . $field_name . ' field';

      // TODO: Remove hack, and see if we can get og_audience attached
      // to views' dummy objects.
      $entity = entity_load($entity_type, array($id));
      $entity = reset($entity);

      if (og_is_group_type($entity_type, $form[$field_name]['#bundle']) && $group = og_get_group($entity_type, $id)) {
        $access = og_user_access($group->gid, $perm);
      }
      // If there is no access, check if this is a group content.
      if (!$access && og_is_group_content_type($entity_type, $form[$field_name]['#bundle'])) {
        if ($gids = og_get_entity_groups($entity_type, $entity)) {
          foreach ($gids as $gid) {
            // TODO: Add "strict" mode.
            if (og_user_access($gid, $perm)) {
              $access = TRUE;
              break;
            }
          }
        }
        else {
          // This is an orphan group content.
          $access = TRUE;
        }
      }

      if ($op == 'update') {
        $element = &$form[$field_name][$langcode]['#access'];
      }
      else {
        $element = &$form[$field_name]['#access'];
      }
      $element = $access;
    }
  }
}