<?php
// $Id: flag_friend_access.module,v 1.1.2.4 2010-03-24 15:18:35 sirkitree Exp $

/**
 * @file: provides access control for nodes. Allow only the users friends to
 * have access to it
 */

/**
 * Implementation of hook_node_grants().
 */
function flag_friend_access_node_grants($account, $op) {
  // module only controls view operations
  if ($op == 'view') {
    $friends = flag_friend_get_friends($account->uid);
    if (!empty($friends)) {
      $grants['flag_friend'] = array_keys($friends);
    }
    $grants['flag_friend'][] = $account->uid;
    return $grants;
  }
}

/**
 * Implementation of hook_node_access_records().
 */
function flag_friend_access_node_access_records($node) {
  if ($node->flag_friend_access) {
    return array(
      array(
        'realm' => 'flag_friend',
        'gid' => $node->uid,
        'grant_view' => 1,
        'grant_update' => 0,
        'grant_delete' => 0,
        'priority' => 5,
      ),
    );
  }
}

/**
 * Implementation of hook_form_alter().
 */
function flag_friend_access_form_alter(&$form, &$form_state, $form_id) {
  // add in a checkbox only if the 
  if (isset($form['#node']) && $form['#node']->type . '_node_form' == $form_id) {
    // We have a node form alter in our stuff.
    $form['flag_friend_control'] = array(
      '#type' => 'fieldset',
      '#title' => t('Friend Access Control'),
      '#collapsable' => FALSE,
    );
    $access_value = flag_friend_access_value($form['#node']->nid);
    $form['flag_friend_control']['flag_friend_access'] = array(
      '#type' => 'checkbox',
      '#title' => t('Only My Friends'),
      '#default_value' => !empty($access_value),
    );
  }
}

/**
 * Determine if we have an access entry already recorded.
 *
 * @param $nid
 *   Node id of the node to check.
 *
 * @param $reset = FALSE
 *  Whether or not to reset the static cache.
 *
 * @return
 *   User id.
 *
 */
function flag_friend_access_value($nid, $reset = FALSE) {
  static $nodes = array();

  if ($reset) {
    $nodes = array();
  }

  if (!isset($nodes[$nid])) {
    // db_result will return either FALSE or the result from the query.
    $nodes[$nid] = db_result(db_query('SELECT uid FROM {flag_friend_access} WHERE nid = %d', $nid));
  }

  return $nodes[$nid];
}

/**
 * Implementation of hook_nodeapi().
 */
function flag_friend_access_nodeapi(&$node, $op) {
  switch ($op) {
    case 'load':
      $node->flag_friend_access = flag_friend_access_value($node->nid);
      break;
    case 'insert':
      if ($node->flag_friend_access) {
        db_query('INSERT INTO {flag_friend_access} (uid, nid) VALUES (%d, %d)', $node->uid, $node->nid);
      }
      break;
    case 'update':
      $existing_access = flag_friend_access_value($node->nid);
      if (empty($node->flag_friend_access) && !empty($existing_access)) {
        db_query("DELETE FROM {flag_friend_access} WHERE nid = %d", $node->nid);
        node_access_acquire_grants($node);
      }
      elseif (!empty($node->flag_friend_access) && empty($existing_access)) {
        db_query('INSERT INTO {flag_friend_access} (uid, nid) VALUES (%d, %d)', $node->uid, $node->nid);
        node_access_acquire_grants($node);
      }
      break;
  }
}