<?php

/**
 * Requirements.
 */
require_once 'includes/node_view_permissions.api.inc';

/**
 * Implements hook_menu().
 */
function node_view_permissions_menu() {
  $items = array();

  $items['admin/config/content/node-view-permissions'] = array(
    'title' => 'Node view permissions',
    'description' => t('Adds extra permissions "View own content" and "View any content" for each content type.'),
    'page callback' => 'drupal_get_form',
    'page arguments' => array('node_view_permissions_settings_page_form'),
    'file' => 'includes/pages/node_view_permissions.settings.inc',
    'access arguments' => array('administer site configuration'),
  );

  return $items;
}

/**
 * Implements hook_permission().
 */
function node_view_permissions_permission() {
  $perms = array();

  foreach (node_view_permissions_get_configured_types() as $type) {
    $info = node_type_get_type($type);

    $perms += array(
      "view own $type content" => array(
        'title' => t('%type_name: View own content', array('%type_name' => $info->name)),
      ),
      "view any $type content" => array(
        'title' => t('%type_name: View any content', array('%type_name' => $info->name)),
      ),
    );
  }

  return $perms;
}

/**
 * Implements hook_node_access().
 */
function node_view_permissions_node_access($node, $op, $account) {
  $type = is_string($node) ? $node : $node->type;

  if (node_view_permissions_check_node_type_activation($type)) {
    if ($op == 'view') {
      if (user_access('view any ' . $type . ' content', $account) || (user_access('view own ' . $type . ' content', $account) && ($account->uid == $node->uid))) {
        if (!$node->status && !(user_access('view own unpublished content') && ($account->uid == $node->uid))) {
          return NODE_ACCESS_DENY;
        } 
        return NODE_ACCESS_ALLOW;
      }
      if (!count(module_implements('node_grants'))) {
        return NODE_ACCESS_DENY;
      }
    }
  }

  return NODE_ACCESS_IGNORE;
}

/**
 * Implements hook_node_access_records().
 */
function node_view_permissions_node_access_records($node) {
  if (!count(module_implements('node_grants'))) {
    return array();
  }

  $grants = array();

  if (node_view_permissions_check_node_type_activation($node->type)) {
    $grants[] = array(
      'realm' => 'all',
      'gid' => 0,
      'grant_view' => 0,
      'grant_update' => 0,
      'grant_delete' => 0,
      'priority' => 0,
    );
  }

  return $grants;
}

/**
 * Implements hook_query_TAG_alter().
 */
function node_view_permissions_query_node_access_alter(QueryAlterableInterface $query) {
   global $user;
  // Read meta-data from query, if provided.
  if (!$account = $query->getMetaData('account')) {
    $account = $user;
  }
  if (!$op = $query->getMetaData('op')) {
    $op = 'view';
  }

  // If $account can bypass node access, or there are no node access modules,
  // or the operation is 'view' and the $acount has a global view grant (i.e.,
  // a view grant for node ID 0), we don't need to alter the query.
  if (user_access('bypass node access', $account)) {
    return;
  }

  //if viewing the node, deny access if the type is a configured type and no node grants allow access
  if ($op == 'view') {
    $tables = $query->getTables();
    // @see _node_query_node_access_alter().
    $node_table_alias = FALSE;
    foreach ($tables as $alias => $table) {
      if ($table['table'] == 'node') {
        $node_table_alias = $alias;
        break;
      }
    }
    
    if (!$node_table_alias) {
      //The array internal pointer should be reset before getting the first key bacause it can be NULL here.
      reset($tables);
      // If the query has 'node_access' meta tag, we can assume that there should be a nid field.
      $query->join('node', 'n', 'n.nid = ' . key($tables) . '.nid');
      $node_table_alias = 'n';
    }
    
    if ($node_table_alias) {
      $alias = $node_table_alias;
      foreach (node_view_permissions_get_configured_types() as $type) {
        if (user_access('view any ' . $type . ' content', $account)) {
          //user can view any of these nodes, don't worry about altering the query
          continue;
        }
        if (user_access('view own ' . $type . ' content', $account)) {
          //user can view their own type of this node, add condition ($account->uid == $node->uid) to db query
          $or = db_or();
          $or->condition("$alias.type", $type, '<>');
          $or->condition("$alias.uid", $account->uid, '=');
          $query->condition($or);
          continue;
        }
        if (!count(module_implements('node_grants'))) {
          //user doesn't have access permissions on this type, set a condtion that prevents this type from being seen
          $query->condition("$alias.type", $type, '<>');
        }
      }
    }
  }

}