<?php
/*
 +--------------------------------------------------------------------+
 | CiviCRM version 4.6                                                |
 +--------------------------------------------------------------------+
 | Copyright CiviCRM LLC (c) 2004-2015                                |
 +--------------------------------------------------------------------+
 | This file is a part of CiviCRM.                                    |
 |                                                                    |
 | CiviCRM is free software; you can copy, modify, and distribute it  |
 | under the terms of the GNU Affero General Public License           |
 | Version 3, 19 November 2007 and the CiviCRM Licensing Exception.   |
 |                                                                    |
 | CiviCRM is distributed in the hope that it will be useful, but     |
 | WITHOUT ANY WARRANTY; without even the implied warranty of         |
 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.               |
 | See the GNU Affero General Public License for more details.        |
 |                                                                    |
 | You should have received a copy of the GNU Affero General Public   |
 | License and the CiviCRM Licensing Exception along                  |
 | with this program; if not, contact CiviCRM LLC                     |
 | at info[AT]civicrm[DOT]org. If you have questions about the        |
 | GNU Affero General Public License or the licensing of CiviCRM,     |
 | see the CiviCRM license FAQ at http://civicrm.org/licensing        |
 +--------------------------------------------------------------------+
 */

/**
 *
 * @package CRM
 * @copyright CiviCRM LLC (c) 2004-2015
 * $Id$
 *
 */

/**
 * This is the basic permission class wrapper
 */
class CRM_Core_Permission {

  /**
   * Static strings used to compose permissions.
   *
   * @const
   * @var string
   */
  const EDIT_GROUPS = 'edit contacts in ', VIEW_GROUPS = 'view contacts in ';

  /**
   * The various type of permissions.
   *
   * @var int
   */
  const EDIT = 1, VIEW = 2, DELETE = 3, CREATE = 4, SEARCH = 5, ALL = 6, ADMIN = 7;

  /**
   * A placeholder permission which always fails.
   */
  const ALWAYS_DENY_PERMISSION = "*always deny*";

  /**
   * A placeholder permission which always fails.
   */
  const ALWAYS_ALLOW_PERMISSION = "*always allow*";

  /**
   * Various authentication sources.
   *
   * @var int
   */
  const AUTH_SRC_UNKNOWN = 0, AUTH_SRC_CHECKSUM = 1, AUTH_SRC_SITEKEY = 2, AUTH_SRC_LOGIN = 4;

  /**
   * Get the current permission of this user.
   *
   * @return string
   *   the permission of the user (edit or view or null)
   */
  public static function getPermission() {
    $config = CRM_Core_Config::singleton();
    return $config->userPermissionClass->getPermission();
  }

  /**
   * Given a permission string or array, check for access requirements
   * @param mixed $permissions
   *   The permission to check as an array or string -see examples.
   *   arrays
   *
   *  Ex 1
   *
   *  Must have 'access CiviCRM'
   *  (string) 'access CiviCRM'
   *
   *
   *  Ex 2 Must have 'access CiviCRM' and 'access Ajax API'
   *   array('access CiviCRM', 'access Ajax API')
   *
   *  Ex 3 Must have 'access CiviCRM' or 'access Ajax API'
   *   array(
   *      array('access CiviCRM', 'access Ajax API'),
   *   ),
   *
   *  Ex 4 Must have 'access CiviCRM' or 'access Ajax API' AND 'access CiviEvent'
   *  array(
   *    array('access CiviCRM', 'access Ajax API'),
   *    'access CiviEvent',
   *   ),
   *
   *  Note that in permissions.php this is keyed by the action eg.
   *  (access Civi || access AJAX) && (access CiviEvent || access CiviContribute)
   *  'myaction' => array(
   *    array('access CiviCRM', 'access Ajax API'),
   *    array('access CiviEvent', 'access CiviContribute')
   *  ),
   *
   * @return bool
   *   true if yes, else false
   */
  public static function check($permissions) {
    $permissions = (array) $permissions;

    $tempPerm = CRM_Core_Config::singleton()->userPermissionTemp;

    foreach ($permissions as $permission) {
      if (is_array($permission)) {
        foreach ($permission as $orPerm) {
          if (self::check($orPerm)) {
            //one of our 'or' permissions has succeeded - stop checking this permission
            return TRUE;;
          }
        }
        //none of our our conditions was met
        return FALSE;
      }
      else {
        if (
          !CRM_Core_Config::singleton()->userPermissionClass->check($permission)
          && !($tempPerm && $tempPerm->check($permission))
        ) {
          //one of our 'and' conditions has not been met
          return FALSE;
        }
      }
    }
    return TRUE;
  }

  /**
   * Determine if any one of the permissions strings applies to current user.
   *
   * @param array $perms
   * @return bool
   */
  public static function checkAnyPerm($perms) {
    foreach ($perms as $perm) {
      if (CRM_Core_Permission::check($perm)) {
        return TRUE;
      }
    }
    return FALSE;
  }

  /**
   * Given a group/role array, check for access requirements
   *
   * @param array $array
   *   The group/role to check.
   *
   * @return bool
   *   true if yes, else false
   */
  public static function checkGroupRole($array) {
    $config = CRM_Core_Config::singleton();
    return $config->userPermissionClass->checkGroupRole($array);
  }

  /**
   * Get the permissioned where clause for the user.
   *
   * @param int $type
   *   The type of permission needed.
   * @param array $tables
   *   (reference ) add the tables that are needed for the select clause.
   * @param array $whereTables
   *   (reference ) add the tables that are needed for the where clause.
   *
   * @return string
   *   the group where clause for this user
   */
  public static function getPermissionedStaticGroupClause($type, &$tables, &$whereTables) {
    $config = CRM_Core_Config::singleton();
    return $config->userPermissionClass->getPermissionedStaticGroupClause($type, $tables, $whereTables);
  }

  /**
   * Get all groups from database, filtered by permissions
   * for this user
   *
   * @param string $groupType
   *   Type of group(Access/Mailing).
   * @param bool $excludeHidden
   *   exclude hidden groups.
   *
   *
   * @return array
   *   array reference of all groups.
   */
  public static function group($groupType, $excludeHidden = TRUE) {
    $config = CRM_Core_Config::singleton();
    return $config->userPermissionClass->group($groupType, $excludeHidden);
  }

  /**
   * @return bool
   */
  public static function customGroupAdmin() {
    $admin = FALSE;

    // check if user has all powerful permission
    // or administer civicrm permission (CRM-1905)
    if (self::check('access all custom data')) {
      return TRUE;
    }

    if (
      self::check('administer Multiple Organizations') &&
      self::isMultisiteEnabled()
    ) {
      return TRUE;
    }

    if (self::check('administer CiviCRM')) {
      return TRUE;
    }

    return FALSE;
  }

  /**
   * @param int $type
   * @param bool $reset
   *
   * @return array
   */
  public static function customGroup($type = CRM_Core_Permission::VIEW, $reset = FALSE) {
    $customGroups = CRM_Core_PseudoConstant::get('CRM_Core_DAO_CustomField', 'custom_group_id',
      array('fresh' => $reset));
    $defaultGroups = array();

    // check if user has all powerful permission
    // or administer civicrm permission (CRM-1905)
    if (self::customGroupAdmin()) {
      $defaultGroups = array_keys($customGroups);
    }

    return CRM_ACL_API::group($type, NULL, 'civicrm_custom_group', $customGroups, $defaultGroups);
  }

  /**
   * @param int $type
   * @param null $prefix
   * @param bool $reset
   *
   * @return string
   */
  public static function customGroupClause($type = CRM_Core_Permission::VIEW, $prefix = NULL, $reset = FALSE) {
    if (self::customGroupAdmin()) {
      return ' ( 1 ) ';
    }

    $groups = self::customGroup($type, $reset);
    if (empty($groups)) {
      return ' ( 0 ) ';
    }
    else {
      return "{$prefix}id IN ( " . implode(',', $groups) . ' ) ';
    }
  }

  /**
   * @param int $gid
   * @param int $type
   *
   * @return bool
   */
  public static function ufGroupValid($gid, $type = CRM_Core_Permission::VIEW) {
    if (empty($gid)) {
      return TRUE;
    }

    $groups = self::ufGroup($type);
    return !empty($groups) && in_array($gid, $groups) ? TRUE : FALSE;
  }

  /**
   * @param int $type
   *
   * @return array
   */
  public static function ufGroup($type = CRM_Core_Permission::VIEW) {
    $ufGroups = CRM_Core_PseudoConstant::get('CRM_Core_DAO_UFField', 'uf_group_id');

    $allGroups = array_keys($ufGroups);

    // check if user has all powerful permission
    if (self::check('profile listings and forms')) {
      return $allGroups;
    }

    switch ($type) {
      case CRM_Core_Permission::VIEW:
        if (self::check('profile view')) {
          return $allGroups;
        }
        break;

      case CRM_Core_Permission::CREATE:
        if (self::check('profile create')) {
          return $allGroups;
        }
        break;

      case CRM_Core_Permission::EDIT:
        if (self::check('profile edit')) {
          return $allGroups;
        }
        break;

      case CRM_Core_Permission::SEARCH:
        if (self::check('profile listings')) {
          return $allGroups;
        }
        break;
    }

    return CRM_ACL_API::group($type, NULL, 'civicrm_uf_group', $ufGroups);
  }

  /**
   * @param int $type
   * @param null $prefix
   * @param bool $returnUFGroupIds
   *
   * @return array|string
   */
  public static function ufGroupClause($type = CRM_Core_Permission::VIEW, $prefix = NULL, $returnUFGroupIds = FALSE) {
    $groups = self::ufGroup($type);
    if ($returnUFGroupIds) {
      return $groups;
    }
    elseif (empty($groups)) {
      return ' ( 0 ) ';
    }
    else {
      return "{$prefix}id IN ( " . implode(',', $groups) . ' ) ';
    }
  }

  /**
   * @param int $type
   * @param int $eventID
   * @param string $context
   *
   * @return array|null
   */
  public static function event($type = CRM_Core_Permission::VIEW, $eventID = NULL, $context = '') {
    if (!empty($context)) {
      if (CRM_Core_Permission::check($context)) {
        return TRUE;
      }
    }
    $events = CRM_Event_PseudoConstant::event(NULL, TRUE);
    $includeEvents = array();

    // check if user has all powerful permission
    if (self::check('register for events')) {
      $includeEvents = array_keys($events);
    }

    if ($type == CRM_Core_Permission::VIEW &&
      self::check('view event info')
    ) {
      $includeEvents = array_keys($events);
    }

    $permissionedEvents = CRM_ACL_API::group($type, NULL, 'civicrm_event', $events, $includeEvents);
    if (!$eventID) {
      return $permissionedEvents;
    }
    if (!empty($permissionedEvents)) {
      return array_search($eventID, $permissionedEvents) === FALSE ? NULL : $eventID;
    }
    return NULL;
  }

  /**
   * @param int $type
   * @param null $prefix
   *
   * @return string
   */
  public static function eventClause($type = CRM_Core_Permission::VIEW, $prefix = NULL) {
    $events = self::event($type);
    if (empty($events)) {
      return ' ( 0 ) ';
    }
    else {
      return "{$prefix}id IN ( " . implode(',', $events) . ' ) ';
    }
  }

  /**
   * @param $module
   * @param bool $checkPermission
   *
   * @return bool
   */
  public static function access($module, $checkPermission = TRUE) {
    $config = CRM_Core_Config::singleton();

    if (!in_array($module, $config->enableComponents)) {
      return FALSE;
    }

    if ($checkPermission) {
      if ($module == 'CiviCase') {
        return CRM_Case_BAO_Case::accessCiviCase();
      }
      else {
        return CRM_Core_Permission::check("access $module");
      }
    }

    return TRUE;
  }

  /**
   * Check permissions for delete and edit actions.
   *
   * @param string $module
   *   Component name.
   * @param int $action
   *   Action to be check across component.
   *
   *
   * @return bool
   */
  public static function checkActionPermission($module, $action) {
    //check delete related permissions.
    if ($action & CRM_Core_Action::DELETE) {
      $permissionName = "delete in $module";
    }
    else {
      $editPermissions = array(
        'CiviEvent' => 'edit event participants',
        'CiviMember' => 'edit memberships',
        'CiviPledge' => 'edit pledges',
        'CiviContribute' => 'edit contributions',
        'CiviGrant' => 'edit grants',
        'CiviMail' => 'access CiviMail',
        'CiviAuction' => 'add auction items',
      );
      $permissionName = CRM_Utils_Array::value($module, $editPermissions);
    }

    if ($module == 'CiviCase' && !$permissionName) {
      return CRM_Case_BAO_Case::accessCiviCase();
    }
    else {
      //check for permission.
      return CRM_Core_Permission::check($permissionName);
    }
  }

  /**
   * @param $args
   * @param string $op
   *
   * @return bool
   */
  public static function checkMenu(&$args, $op = 'and') {
    if (!is_array($args)) {
      return $args;
    }
    foreach ($args as $str) {
      $res = CRM_Core_Permission::check($str);
      if ($op == 'or' && $res) {
        return TRUE;
      }
      elseif ($op == 'and' && !$res) {
        return FALSE;
      }
    }
    return ($op == 'or') ? FALSE : TRUE;
  }

  /**
   * @param $item
   *
   * @return bool|mixed
   * @throws Exception
   */
  public static function checkMenuItem(&$item) {
    if (!array_key_exists('access_callback', $item)) {
      CRM_Core_Error::backtrace();
      CRM_Core_Error::fatal();
    }

    // if component_id is present, ensure it is enabled
    if (isset($item['component_id']) &&
      $item['component_id']
    ) {
      $config = CRM_Core_Config::singleton();
      if (is_array($config->enableComponentIDs) &&
        in_array($item['component_id'], $config->enableComponentIDs)
      ) {
        // continue with process
      }
      else {
        return FALSE;
      }
    }

    // the following is imitating drupal 6 code in includes/menu.inc
    if (empty($item['access_callback']) ||
      is_numeric($item['access_callback'])
    ) {
      return (boolean ) $item['access_callback'];
    }

    // check whether the following Ajax requests submitted the right key
    // FIXME: this should be integrated into ACLs proper
    if (CRM_Utils_Array::value('page_type', $item) == 3) {
      if (!CRM_Core_Key::validate($_REQUEST['key'], $item['path'])) {
        return FALSE;
      }
    }

    // check if callback is for checkMenu, if so optimize it
    if (is_array($item['access_callback']) &&
      $item['access_callback'][0] == 'CRM_Core_Permission' &&
      $item['access_callback'][1] == 'checkMenu'
    ) {
      $op = CRM_Utils_Array::value(1, $item['access_arguments'], 'and');
      return self::checkMenu($item['access_arguments'][0], $op);
    }
    else {
      return call_user_func_array($item['access_callback'], $item['access_arguments']);
    }
  }

  /**
   * @param bool $all
   * @param bool $descriptions
   *   whether to return descriptions
   *
   * @return array
   */
  public static function &basicPermissions($all = FALSE, $descriptions = FALSE) {
    if ($descriptions) {
      static $permissionsDesc = NULL;

      if (!$permissionsDesc) {
        $permissionsDesc = self::assembleBasicPermissions($all, $descriptions);
      }

      return $permissionsDesc;
    }
    else {
      static $permissions = NULL;

      if (!$permissions) {
        $permissions = self::assembleBasicPermissions($all, $descriptions);
      }

      return $permissions;
    }
  }

  /**
   * @param bool $all
   * @param bool $descriptions
   *   whether to return descriptions
   *
   * @return array
   */
  public static function assembleBasicPermissions($all = FALSE, $descriptions = FALSE) {
    $config = CRM_Core_Config::singleton();
    $prefix = ts('CiviCRM') . ': ';
    $permissions = self::getCorePermissions($descriptions);

    if (self::isMultisiteEnabled()) {
      $permissions['administer Multiple Organizations'] = array($prefix . ts('administer Multiple Organizations'));
    }

    if (!$descriptions) {
      foreach ($permissions as $name => $attr) {
        $permissions[$name] = array_shift($attr);
      }
    }
    if (!$all) {
      $components = CRM_Core_Component::getEnabledComponents();
    }
    else {
      $components = CRM_Core_Component::getComponents();
    }

    foreach ($components as $comp) {
      $perm = $comp->getPermissions(FALSE, $descriptions);
      if ($perm) {
        $info = $comp->getInfo();
        foreach ($perm as $p => $attr) {

          if (!is_array($attr)) {
            $attr = array($attr);
          }

          $attr[0] = $info['translatedName'] . ': ' . $attr[0];

          if ($descriptions) {
            $permissions[$p] = $attr;
          }
          else {
            $permissions[$p] = $attr[0];
          }
        }
      }
    }

    // Add any permissions defined in hook_civicrm_permission implementations.
    $module_permissions = $config->userPermissionClass->getAllModulePermissions($descriptions);
    $permissions = array_merge($permissions, $module_permissions);
    return $permissions;
  }

  /**
   * @return array
   */
  public static function getAnonymousPermissionsWarnings() {
    static $permissions = array();
    if (empty($permissions)) {
      $permissions = array(
        'administer CiviCRM',
      );
      $components = CRM_Core_Component::getComponents();
      foreach ($components as $comp) {
        if (!method_exists($comp, 'getAnonymousPermissionWarnings')) {
          continue;
        }
        $permissions = array_merge($permissions, $comp->getAnonymousPermissionWarnings());
      }
    }
    return $permissions;
  }

  /**
   * @param $anonymous_perms
   *
   * @return array
   */
  public static function validateForPermissionWarnings($anonymous_perms) {
    return array_intersect($anonymous_perms, self::getAnonymousPermissionsWarnings());
  }

  /**
   * Get core permissions.
   *
   * @return array
   */
  public static function getCorePermissions() {
    $prefix = ts('CiviCRM') . ': ';
    $permissions = array(
      'add contacts' => array(
        $prefix . ts('add contacts'),
        ts('Create a new contact record in CiviCRM'),
      ),
      'view all contacts' => array(
        $prefix . ts('view all contacts'),
        ts('View ANY CONTACT in the CiviCRM database, export contact info and perform activities such as Send Email, Phone Call, etc.'),
      ),
      'edit all contacts' => array(
        $prefix . ts('edit all contacts'),
        ts('View, Edit and Delete ANY CONTACT in the CiviCRM database; Create and edit relationships, tags and other info about the contacts'),
      ),
      'view my contact' => array(
        $prefix . ts('view my contact'),
      ),
      'edit my contact' => array(
        $prefix . ts('edit my contact'),
      ),
      'delete contacts' => array(
        $prefix . ts('delete contacts'),
      ),
      'access deleted contacts' => array(
        $prefix . ts('access deleted contacts'),
        ts('Access contacts in the trash'),
      ),
      'import contacts' => array(
        $prefix . ts('import contacts'),
        ts('Import contacts and activities'),
      ),
      'import SQL datasource' => array(
        $prefix . ts('import SQL datasource'),
        ts('When importing, consume data directly from a SQL datasource'),
      ),
      'edit groups' => array(
        $prefix . ts('edit groups'),
        ts('Create new groups, edit group settings (e.g. group name, visibility...), delete groups'),
      ),
      'administer CiviCRM' => array(
        $prefix . ts('administer CiviCRM'),
        ts('Perform all tasks in the Administer CiviCRM control panel and Import Contacts'),
      ),
      'skip IDS check' => array(
        $prefix . ts('skip IDS check'),
        ts('IDS system is bypassed for users with this permission. Prevents false errors for admin users.'),
      ),
      'access uploaded files' => array(
        $prefix . ts('access uploaded files'),
        ts('View / download files including images and photos'),
      ),
      'profile listings and forms' => array(
        $prefix . ts('profile listings and forms'),
        ts('Access the profile Search form and listings'),
      ),
      'profile listings' => array(
        $prefix . ts('profile listings'),
      ),
      'profile create' => array(
        $prefix . ts('profile create'),
        ts('Use profiles in Create mode'),
      ),
      'profile edit' => array(
        $prefix . ts('profile edit'),
        ts('Use profiles in Edit mode'),
      ),
      'profile view' => array(
        $prefix . ts('profile view'),
      ),
      'access all custom data' => array(
        $prefix . ts('access all custom data'),
        ts('View all custom fields regardless of ACL rules'),
      ),
      'view all activities' => array(
        $prefix . ts('view all activities'),
        ts('View all activities (for visible contacts)'),
      ),
      'delete activities' => array(
        $prefix . ts('Delete activities'),
      ),
      'access CiviCRM' => array(
        $prefix . ts('access CiviCRM'),
        ts('Master control for access to the main CiviCRM backend and API'),
      ),
      'access Contact Dashboard' => array(
        $prefix . ts('access Contact Dashboard'),
        ts('View Contact Dashboard (for themselves and visible contacts)'),
      ),
      'translate CiviCRM' => array(
        $prefix . ts('translate CiviCRM'),
        ts('Allow User to enable multilingual'),
      ),
      'administer reserved groups' => array(
        $prefix . ts('administer reserved groups'),
        ts('Edit and disable Reserved Groups (Needs Edit Groups)'),
      ),
      'administer Tagsets' => array(
        $prefix . ts('administer Tagsets'),
      ),
      'administer reserved tags' => array(
        $prefix . ts('administer reserved tags'),
      ),
      'administer dedupe rules' => array(
        $prefix . ts('administer dedupe rules'),
        ts('Create and edit rules, change the supervised and unsupervised rules'),
      ),
      'merge duplicate contacts' => array(
        $prefix . ts('merge duplicate contacts'),
        ts('Delete Contacts must also be granted in order for this to work.'),
      ),
      'view debug output' => array(
        $prefix . ts('view debug output'),
        ts('View results of debug and backtrace'),
      ),
      'view all notes' => array(
        $prefix . ts('view all notes'),
        ts("View notes (for visible contacts) even if they're marked admin only"),
      ),
      'access AJAX API' => array(
        $prefix . ts('access AJAX API'),
        ts('Allow API access even if Access CiviCRM is not granted'),
      ),
      'access contact reference fields' => array(
        $prefix . ts('access contact reference fields'),
        ts('Allow entering data into contact reference fields'),
      ),
      'create manual batch' => array(
        $prefix . ts('create manual batch'),
        ts('Create an accounting batch (with Access to CiviContribute and View Own/All Manual Batches)'),
      ),
      'edit own manual batches' => array(
        $prefix . ts('edit own manual batches'),
        ts('Edit accounting batches created by user'),
      ),
      'edit all manual batches' => array(
        $prefix . ts('edit all manual batches'),
        ts('Edit all accounting batches'),
      ),
      'view own manual batches' => array(
        $prefix . ts('view own manual batches'),
        ts('View accounting batches created by user (with Access to CiviContribute)'),
      ),
      'view all manual batches' => array(
        $prefix . ts('view all manual batches'),
        ts('View all accounting batches (with Access to CiviContribute)'),
      ),
      'delete own manual batches' => array(
        $prefix . ts('delete own manual batches'),
        ts('Delete accounting batches created by user'),
      ),
      'delete all manual batches' => array(
        $prefix . ts('delete all manual batches'),
        ts('Delete all accounting batches'),
      ),
      'export own manual batches' => array(
        $prefix . ts('export own manual batches'),
        ts('Export accounting batches created by user'),
      ),
      'export all manual batches' => array(
        $prefix . ts('export all manual batches'),
        ts('Export all accounting batches'),
      ),
      'administer payment processors' => array(
        $prefix . ts('administer payment processors'),
        ts('Add, Update, or Disable Payment Processors'),
      ),
      'edit message templates' => array(
        $prefix . ts('edit message templates'),
      ),
      'view my invoices' => array(
        $prefix . ts('view my invoices'),
        ts('Allow users to view/ download their own invoices'),
      ),
      'edit api keys' => array(
        $prefix . ts('edit api keys'),
        ts('Edit API keys'),
      ),
      'edit own api keys' => array(
        $prefix . ts('edit own api keys'),
        ts('Edit user\'s own API keys'),
      ),
    );

    return $permissions;
  }

  /**
   * Validate user permission across.
   * edit or view or with supportable acls.
   *
   * @return bool
   */
  public static function giveMeAllACLs() {
    if (CRM_Core_Permission::check('view all contacts') ||
      CRM_Core_Permission::check('edit all contacts')
    ) {
      return TRUE;
    }

    $session = CRM_Core_Session::singleton();
    $contactID = $session->get('userID');

    //check for acl.
    $aclPermission = self::getPermission();
    if (in_array($aclPermission, array(
      CRM_Core_Permission::EDIT,
      CRM_Core_Permission::VIEW,
    ))
    ) {
      return TRUE;
    }

    // run acl where hook and see if the user is supplying an ACL clause
    // that is not false
    $tables = $whereTables = array();
    $where = NULL;

    CRM_Utils_Hook::aclWhereClause(CRM_Core_Permission::VIEW,
      $tables, $whereTables,
      $contactID, $where
    );
    return empty($whereTables) ? FALSE : TRUE;
  }

  /**
   * Get component name from given permission.
   *
   * @param string $permission
   *
   * @return null|string
   *   the name of component.
   */
  public static function getComponentName($permission) {
    $componentName = NULL;
    $permission = trim($permission);
    if (empty($permission)) {
      return $componentName;
    }

    static $allCompPermissions = array();
    if (empty($allCompPermissions)) {
      $components = CRM_Core_Component::getComponents();
      foreach ($components as $name => $comp) {
        //get all permissions of each components unconditionally
        $allCompPermissions[$name] = $comp->getPermissions(TRUE);
      }
    }

    if (is_array($allCompPermissions)) {
      foreach ($allCompPermissions as $name => $permissions) {
        if (array_key_exists($permission, $permissions)) {
          $componentName = $name;
          break;
        }
      }
    }

    return $componentName;
  }

  /**
   * Get all the contact emails for users that have a specific permission.
   *
   * @param string $permissionName
   *   Name of the permission we are interested in.
   *
   * @return string
   *   a comma separated list of email addresses
   */
  public static function permissionEmails($permissionName) {
    $config = CRM_Core_Config::singleton();
    return $config->userPermissionClass->permissionEmails($permissionName);
  }

  /**
   * Get all the contact emails for users that have a specific role.
   *
   * @param string $roleName
   *   Name of the role we are interested in.
   *
   * @return string
   *   a comma separated list of email addresses
   */
  public static function roleEmails($roleName) {
    $config = CRM_Core_Config::singleton();
    return $config->userRoleClass->roleEmails($roleName);
  }

  /**
   * @return bool
   */
  public static function isMultisiteEnabled() {
    return CRM_Core_BAO_Setting::getItem(CRM_Core_BAO_Setting::MULTISITE_PREFERENCES_NAME,
      'is_enabled'
    ) ? TRUE : FALSE;
  }

  /**
   * Verify if the user has permission to get the invoice.
   *
   * @return bool
   *   TRUE if the user has download all invoices permission or download my
   *   invoices permission and the invoice author is the current user.
   */
  public static function checkDownloadInvoice() {
    global $user;
    $cid = CRM_Core_BAO_UFMatch::getContactId($user->uid);
    if (CRM_Core_Permission::check('access CiviContribute') ||
      (CRM_Core_Permission::check('view my invoices') && $_GET['cid'] == $cid)
    ) {
      return TRUE;
    }
    return FALSE;
  }

}