<?php

/**
 * @file
 * User Relationships API. Module shell.
 *
 * @author Jeff Smick (creator)
 * @author Alex Karshakevich (maintainer) http://drupal.org/user/183217
 */

define('UR_OK', 0x0);
define('UR_BANNED', 0x1);

function user_relationships_menu() {
  $items['admin/config/people/relationships'] = array(
    'title' => 'Relationships',
    'description' => 'Create relationship types',
    'access arguments' => array('administer user relationships'),
    'page callback' => 'user_relationships_admin_types_list_page',
    'file' => 'user_relationships.admin.inc',
  );
  $items['admin/config/people/relationships/list'] = array(
    'title' => 'List',
    'type' => MENU_DEFAULT_LOCAL_TASK,
    'page callback' => 'user_relationships_admin_types_list_page',
    'access arguments' => array('administer user relationships'),
    'file' => 'user_relationships.admin.inc',
  );
  $items['admin/config/people/relationships/add'] = array(
    'title' => 'Add relationship type',
    'type' => MENU_LOCAL_ACTION,
    'page callback' => 'drupal_get_form',
    'page arguments' => array('user_relationships_admin_type_edit'),
    'access arguments' => array('administer user relationships'),
    'file' => 'user_relationships.admin.inc',
  );
  $items['admin/config/people/relationships/%user_relationships_type/edit'] = array(
    'title' => 'Edit type',
    'type' => MENU_LOCAL_TASK,
    'page callback' => 'drupal_get_form',
    'page arguments' => array('user_relationships_admin_type_edit', 4),
    'access arguments' => array('administer user relationships'),
    'file' => 'user_relationships.admin.inc',
    'weight' => 5,
  );
  $items['admin/config/people/relationships/%user_relationships_type/delete'] = array(
    'title' => 'Delete type',
    'type' => MENU_LOCAL_TASK,
    'page callback' => 'drupal_get_form',
    'page arguments' => array('user_relationships_admin_type_delete', 4),
    'access arguments' => array('administer user relationships'),
    'file' => 'user_relationships.admin.inc',
    'weight' => 10,
  );
  $items['admin/config/people/relationships/settings'] = array(
    'title' => 'Settings',
    'type' => MENU_LOCAL_TASK,
    'page callback' => 'drupal_get_form',
    'page arguments' => array('user_relationships_admin_settings'),
    'access arguments' => array('administer user relationships'),
    'file' => 'user_relationships.admin.inc',
    'weight' => 20,
  );
  return $items;
}

/**
 * Helper function to generate the main and count queries from a list of parameters and options
 */
function _user_relationships_generate_query($param = array(), $options = array()) {
  extract($options, EXTR_SKIP);

  $twoway_reverse_clause = FALSE;//#479486
  // Turn the conditions into a query.
  $query = db_select('user_relationships', 'ur');
  $query->innerJoin('user_relationship_types', 'urt', 'urt.rtid = ur.rtid');
  foreach ($param as $key => $value) {
    if (!isset($value)) {
      continue;
    }

    switch ($key) {
    case 'between':
      $or = db_or()->condition(db_and()
          ->condition('ur.requester_id', $value[0])
          ->condition('ur.requestee_id', $value[1])
      );
      $and = db_and()
        ->condition('ur.requestee_id', $value[0])
        ->condition('ur.requester_id', $value[1]);
      //#479486 do not include reverse records of two-way relationships by default
      if (!isset($include_twoway_reverse)) {
        $and->condition(db_or()
          ->condition('ur.approved', 1, '<>')
          ->condition('urt.is_oneway', 0, '<>'));
        $twoway_reverse_clause = TRUE;
      }
      $or->condition($and);
      $query->condition($or);
      break;

    case 'user':
      //#479486 when showing all user's relationships, do not include reverse records of two-way relationships
      if (!isset($include_twoway_reverse)) {
        $query->condition(db_or()
          ->condition('ur.requester_id', $value)
          ->condition(db_and()
            ->condition(db_or()
              ->condition('ur.approved', 1, '<>')
              ->condition('urt.is_oneway', 0, '<>')
            )
            ->condition('ur.requestee_id', $value)
          )
        );
        $twoway_reverse_clause = TRUE;
      }
      else {
        $query->condition(db_or()
          ->condition('ur.requester_id', $value)
          ->condition('ur.requestee_id', $value)
        );
      }
      $arguments[] = $value;
      break;

    case 'exclude_rtids':
      $query->condition('ur.rtid', $value, 'NOT IN');
      break;

    case 'requester_id':
    case 'requestee_id':
      $twoway_reverse_clause = TRUE;//#479486 these columns automatically should exclude duplicates

    default:
      $types_cols = array('name', 'plural_name', 'is_oneway', 'is_reciprocal', 'requires_approval', 'expires_val');
      $prefix = !in_array($key, $types_cols) ? 'ur' : 'urt';
      $query->condition($prefix . '.' . $key, $value);
    }
  }

  //#479486 add a general clause that removed reverse direction from two-way relationship results, unless it's been addressed above
  if (!$twoway_reverse_clause && !isset($include_twoway_reverse)) {
    $query->condition(db_or()
      ->condition('urt.is_oneway', 0, '<>')
      ->condition('ur.approved', 1, '<>')
      ->where('ur.requester_id < ur.requestee_id')
    );
    $twoway_reverse_clause = TRUE;
  }

  if (!empty($only_count) || !empty($paging)) {
    $count = clone $query;
    $count->addExpression('COUNT(DISTINCT rid)', 'count');
  }
  $query
    ->distinct()
    ->fields('ur')
    ->fields('urt');

  if (isset($include_user_info) && $include_user_info) {
    $query->addField('requesters', 'name', 'requester_name');
    $query->addField('requesters', 'mail', 'requester_mail');
    $query->addField('requesters', 'data', 'requester_data');
    $query->addField('requesters', 'picture', 'requester_picture');
    $query->addField('requestees', 'name', 'requestee_name');
    $query->addField('requestees', 'mail', 'requestee_mail');
    $query->addField('requestees', 'data', 'requestee_data');
    $query->addField('requestees', 'picture', 'requestee_picture');

    $query->innerJoin('users', 'requesters', 'ur.requester_id = requesters.uid');
    $query->innerJoin('users', 'requestees', 'ur.requestee_id = requestees.uid');
  }
  if (!empty($order)) {
    if (is_array($order)) {
      $query->orderBy($order[0], $order[1]);
    }
    else {
      $query->orderBy($order);
    }
  }
  if (!empty($limit)) {
    $offset = !empty($offset) ? $offset : 0;
    $query->range($offset, $limit);
  }
  if (!empty($only_count)) {
    return $count;
  }
  if (!empty($paging)) {
    $query = $query
      ->extend('PagerDefault')
      ->limit($paging);
    $query->setCountQuery($count);
  }
  if (!empty($header)) {
    $query = $query
      ->extend('TableSort')
      ->orderByHeader($header);
  }
  return $query;
}


/**
 * hook_perm()
 */
function user_relationships_permission() {
  return array('can have relationships' => array(
    'title' => t('Can have relationships'),
    'description' => t('The user is allowed to have and accept relationships.'),
  ));
}


/**
 * hook_cron()
 */
function user_relationships_cron() {
  $now = REQUEST_TIME;

  // only expire relationships once a day
  $last_cron = variable_get('user_relationships_last_expire', 0);
  if ($now < $last_cron + 86400) {
    return FALSE;
  }

  $result = db_query(
    " SELECT ur.rid
      FROM {user_relationships} ur
        INNER JOIN {user_relationship_types} urt ON ur.rtid = urt.rtid
      WHERE ur.approved = 0
        AND urt.expires_val > 0
        AND ur.updated_at < (:now - (urt.expires_val * 86400))
      GROUP BY ur.rid", array(':now' => $now)
  );
  $expired_requests = $result->fetchCol();
  if (count($expired_requests)) {
    db_delete('user_relationships')
      ->condition('rid', $expired_requests)
      ->execute();
    //FIXME: this will trigger various hook_user_relationships() but will not pass a valid relationship object. E.g. in mailer.
    module_invoke_all('user_relationships_delete', $expired_requests);
  }

  // remember when we last expired relationships
  variable_set('user_relationships_last_expire', $now);
  return TRUE;
}


/**
 * Implements hook_user_cancel().
 */
function user_relationships_user_cancel($edit, $account, $method) {
    db_delete('user_relationships')
      ->condition(db_or()
        ->condition('requester_id', $account->uid)
        ->condition('requestee_id', $account->uid)
      )
      ->execute();
}

/**
 * Wrapper function for tt() if i18nstrings enabled.
 */
function ur_tt($name, $string, $langcode = NULL, $update = FALSE) {
  if (module_exists('i18nstrings')) {
    return tt($name, $string, $langcode, $update);
  }
  else {
    return $string;
  }
}

/**
 * Implements hook_activity_info().
 */
function user_relationships_activity_info() {
  $info = new stdClass();
  $info->api = 2;
  $info->name = 'user_relationships';
  $info->object_type = 'user_relationships';
  $info->objects = array('Requester' => 'requester', 'Requestee' => 'requestee', 'Relationship' => 'relationship');
  $info->hooks = array('user_relationships' => array('approve', 'request'));
  foreach (user_relationships_types_load() as $type_obj) {
    $info->realms["user_relationships_" . $type_obj->rtid] = $type_obj->plural_name;
  }
  return $info;
}

/**
 * Public API for retrieving a specific relationship
 *
 * @param $param
 *    The rtid or an associative array of attributes to search for in selecting the
 *    relationship, such as rtid or name. Attributes must match column names
 *    in the user_relationship_types table.
 *
 * @param $reset
 *    a boolean that forces a reset of the internal static types list
 *
 * @return
 *    object of the requested relationship type
 *
 */
function user_relationships_type_load($param = array(), $reset = NULL) {
  $types = user_relationships_types_load($reset);

  if (!is_array($param)) {
    if (isset($types[$param])) {
      return $types[$param];
    }
    return FALSE;
  }

  foreach ($types as $type) {
    $found = TRUE;

    foreach ($param as $column => $value) {
      $column = strtolower($column);

      if ($column == 'name' || $column == 'plural_name') {
        $value = strtolower($value);
        $col_val = strtolower($type->$column);
      }
      else {
        $col_val = $type->$column;
      }

      // mismatch, move to the next type
      if ($col_val != $value) {
        $found = FALSE;
        break;
      }
    }

    if ($found) {
      return $type;
    }
  }
}


/**
 * Load all relationship types.
 *
 * @param $reset
 *   A boolean that forces a reset of the internal static types list
 *
 * @return
 *   Array of relationship_type objects
 */
function user_relationships_types_load($reset = FALSE) {
  static $relationship_types_list = NULL;

  if ($reset || !isset($relationship_types_list)) {
    // Clear the cached list, since some relationships may have disappeared.
    $relationship_types_list = db_query("SELECT * FROM {user_relationship_types}")->fetchAllAssoc('rtid');
    if (empty($relationship_types_list)) {
      // No relationships, avoid querying role permissions.
      return $relationship_types_list;
    }
    // Load role permissions for all types.
    $result = db_query('SELECT rtid, rid FROM {user_relationship_type_roles} WHERE rtid IN (:rtids) ORDER BY rtid, rid', array(':rtids' => array_keys($relationship_types_list)));
    foreach ($result as $mapping) {
      // roles is an associative array {role id} => {role id}.
      $relationship_types_list[$mapping->rtid]->roles[$mapping->rid] = $mapping->rid;//] = $mapping->name;
    }

    // Load role receive permissions for all types.
    $results = db_query('SELECT rtid, rid FROM {user_relationship_type_roles_receive} WHERE rtid IN (:rtids) ORDER BY rtid, rid', array(':rtids' => array_keys($relationship_types_list)));
    foreach ($results as $mapping) {
      // roles_receive is an associative array {role id} => {role id}.
      $relationship_types_list[$mapping->rtid]->roles_receive[$mapping->rid] = $mapping->rid;
    }
  }

  module_invoke_all('user_relationships_type_load', $relationship_types_list);

  return $relationship_types_list;
}


/**
 * Create or Update a User Relationship Type
 *
 * @param $rtype
 *   A User Relationship type object
 */
function user_relationships_type_save($rtype) {
  module_invoke_all('user_relationships_type_presave', $rtype);

  $op = (isset($rtype->rtid) && $rtype->rtid) ? 'update' : 'insert';

  // find a relationship type with the name we're trying to save
  // if it's an update action check to see that the rtypes match
  // otherwise it's just invalid
  if (
    ($found_rt = user_relationships_type_load(array('name' => $rtype->name))) &&
    ($op == 'update' ? $found_rt->rtid != $rtype->rtid : TRUE)
  ) {
    return FALSE;
  }

  // ensure "expires_val" is numeric and not negative
  if (!is_numeric($rtype->expires_val) || $rtype->expires_val < 0) {
    $rtype->expires_val = 0;
  }

  drupal_write_record('user_relationship_types', $rtype, ($op == 'update' ? 'rtid' : array()));

  module_invoke_all('user_relationships_type_' . $op, $rtype);
}


/**
 * Delete a User Relationship Type
 *
 * @param $rtid
 *   A User Relationship type ID
 */
function user_relationships_type_delete($rtid) {
  $rtype = user_relationships_type_load($rtid);

  db_delete('user_relationship_types')
    ->condition('rtid', $rtid)
    ->execute();
  db_delete('user_relationships')
    ->condition('rtid', $rtid)
    ->execute();
  db_delete('user_relationship_type_roles')
    ->condition('rtid', $rtid)
    ->execute();
  db_delete('user_relationship_type_roles_receive')
    ->condition('rtid', $rtid)
    ->execute();

  module_invoke_all('user_relationships_type_delete', $rtype);
}


/**
 * Request a new user relationship
 *
 * @param $requester
 *   object or UID of the requester
 * @param $requestee
 *   object  or UID of the requestee
 * @param $type
 *   object or RTID of the relationship type
 * @param $approved
 *    boolean status of the relationship
 *
 * @return
 *    object of the newly created relationship
 */
function user_relationships_request_relationship($requester, $requestee = NULL, $type = NULL, $approved = FALSE) {
  //#578372 check if this is a "new" type of invocation, where first argument is a relationship object
  if (is_object($requester) && isset($requester->requester) && isset($requester->requestee) && isset($requester->type)) {
    $relationship = $requester;
    $requester = $relationship->requester;
    $requestee = $relationship->requestee;
    $type = $relationship->type;
    if (isset($relationship->approved)) {
      $approved = $relationship->approved;
    }
  }
  else {
    $relationship = new stdClass;
  }
  // translate an ID into an object
  foreach (array('requester' => $requester, 'requestee' => $requestee, 'type' => $type) as $key => $value) {
    if (!is_object($value)) {
      $$key = $key == 'type' ? user_relationships_type_load($value) : user_load($value);
    }
  }

  //check requester is allowed to create this rtype
  if (!user_relationships_can_request($requester, $type)) {
    watchdog('user_relationships', 'User %user has no suitable roles to request a %rtype relationship', array('%user' => format_username($requester), '%rtype' => $type->name), WATCHDOG_WARNING);
    //it would be good to return a reason why save is denied, but it's the API portion, it does not expose anything user-visible
    return FALSE;
  }

  //check requestee is allowed to receive this rtype
  if (!user_relationships_can_receive($requestee, $type)) {
    watchdog('user_relationships', 'User %user has no suitable roles to receive a %rtype relationship', array('%user' => format_username($requestee), '%rtype' => $type->name), WATCHDOG_WARNING);
    //it would be good to return a reason why save is denied, but it's the API portion, it does not expose anything user-visible
    return FALSE;
  }

  // check whether this relationship aleady exists
  if (!$type->is_oneway || !$type->is_reciprocal) {
    $existing = user_relationships_load(array('between' => array($requester->uid, $requestee->uid), 'rtid' => $type->rtid), array('count' => TRUE));
  }
  else {
    $existing = user_relationships_load(array('requester_id' => $requester->uid, 'requestee_id' => $requestee->uid, 'rtid' => $type->rtid), array('count' => TRUE));
  }

  if (!$existing) {
    $relationship->requester_id = $requester->uid;
    $relationship->requestee_id = $requestee->uid;
    $relationship->approved = $approved || !$type->requires_approval || (!empty($requestee->data['user_relationships_ui_auto_approve']) && !empty($requestee->data['user_relationships_ui_auto_approve'][$type->rtid]));
    $relationship->rtid = $type->rtid;

    return user_relationships_save_relationship($relationship);
  }
}


/**
 * Create or update a user relationship.
 *
 * @param $relationship
 *   Object of the current relationship.
 * @param $action
 *   The reason for the update (request, approve, update).
 *
 * @return
 *   Object of the updated relationship or FALSE if the relationship wasn't
 *   able to save
 */
function user_relationships_save_relationship($relationship, $action = 'request') {
  //set basic info if it doesn't already exist
	if (!isset($relationship->flags)) {
    $relationship->flags = UR_OK;
  }
  if (!isset($relationship->created_at)) {
    $relationship->created_at = REQUEST_TIME;
  }
  $relationship->updated_at = REQUEST_TIME;

  if ($action == 'approve') {
    $relationship->approved = 1;
  }

  // Start a transaction so that we can roll back in case of an error.
  $transaction = db_transaction();
  try {
    module_invoke_all('user_relationships_presave', $relationship);
	$keys = array();
    if (isset($relationship->rid)) {
      // Delete possible requests coming the other direction
      $relationship_type = user_relationships_type_load($relationship->rtid);
      function user_relationships_save_relationship($relationship, $action = 'request'
           ->condition('requestee_id', $relationship->requester_id)
           ->execute();
       }
     $keys = array('rid');
    }

  else {
     // For a new entry, get a new id.
     $relationship->rid = db_next_id(db_query('SELECT MAX(rid) FROM {user_relationships}')->fetchField());
    }
    // #454680 make sure that an update is performed if this is an existing
    // relationship.
    if (drupal_write_record('user_relationships', $relationship, $keys)) {
      // If the relationship has been approved and is two-way we need
      // to do a double entry for DB efficiency.
      $relationship_type = user_relationships_type_load($relationship->rtid);
      if ($relationship->approved && !$relationship_type->is_oneway) {
        $reversed_relationship = clone $relationship;
        $reversed_relationship->requestee_id = $relationship->requester_id;
        $reversed_relationship->requester_id = $relationship->requestee_id;
        drupal_write_record('user_relationships', $reversed_relationship, $keys);
      }
    }

    // Don't execute a different hook for update/insert since that is not
    // relevant. The $action is important if someone needs to differentiate.
    module_invoke_all('user_relationships_save', $relationship, $action);
    return $relationship;
  }
  catch (Exception $e) {
    $transaction->rollback();
    watchdog_exception('user_relationships', $e);
    return FALSE;
  }
}


/**
 * Public API for deleting a relationship.
 *
 * @param $relationship
 *    object of the relationship
 * @param $deleted_by
 *    object of the user that initiated the delete command
 * @param $action
 *    string reason for removal ('cancel','disapprove','remove')
 */
function user_relationships_delete_relationship($relationship, $deleted_by, $action = 'remove') {
  $relationship->deleted_by = $deleted_by;
  db_delete('user_relationships')
    ->condition('rid', $relationship->rid)
    ->execute();

  module_invoke_all('user_relationships_delete', $relationship, $action);
}


/**
  * Load relationship objects from the database.
  *
  * @param $param
  *   an array of parameters with the key being the column. columns from both the user_relationships and user_relationship_types tables will work
  *     columns from user_relationships: rid, requester_id, requestee_id, rtid, approved, created_at, updated_at, flags
  *     columns from user_relationship_types: name, plural_name, is_oneway, requires_approval, expires_val
  *   There are two special keys:
  *     1) array("between" => array($uid1, $uid2)) will return all relationships between the two user ids.
  *     2) array("user" => $uid) will return all relationships for the specified uid
  *
  *   arguments will process operators as well using the syntax: array(col => '> {value}').
  *     example: show all relationships created in 2007
  *       $start_time = mktime(0,0,0,0,0,2007);
  *       $end_time = mktime(0,0,0,0,0,2008);
  *       user_relationships_load(array('created_at' => ">= {$start_time}", 'created_at' => '< {$end_time'}));
  *
  *   each parameter may be an array, if you wish to pass several values
  *     example: user_relationships_load(array('rtid' => array(2, 3), 'between' => array($uid1, $uid2)))
  *       will load all relationships of types 2 or 3 between uid1 and uid2 (query will have an IN clause)
  *
  * @param @options
  *   An array keyed by the option
  *   count
  *     a boolean stating whether or not the return value should be the number of relationships found
  *
  *   sort
  *     a string containing a valid column name which will become the key for the returned array of relationships
  *     default is 'rid'
  *
  *   order
  *     a string containing SQL stating the column and direction of the sort (ex. "requester_id ASC, rtid DESC")
  *
  *   limit
  *     a string containing SQL stating the limit (ex "10" or "10, 5")
  *
  *   include_user_info
  *     a boolean that will load basic user info without having to call user_load
  *     columns: uid, name, mail, data, picture
  *
  *   include_twoway_reverse (not used unless there is a specific need)
  *     a boolean that, if present, and if sort is set to other than 'rid', will include records for both directions for
  *     two-way relationships. Normally for a two-way relationship only one entry is returned, although in the database there
  *     are two records. This flag has no effect if sort is 'rid'
  *
  * @param $reset
  *   a boolean that will reset the internal static $relationships variable to ensure programatic relationship insertion works
  *
  * @return
  *   an array of relationships
  *   if the key is "rid" the array will be a single dimention: array($rid => $relationship, $rid => $relationship)
  *   otherwise it'll be multidimentional: array($rtid => array($relationship, $relationship))
  *
  *   each relationship will have the user's name, mail, and data attached as requester_name, requester_mail, requester_data
  *   or requestee_name, requestee_mail, requestee_data
 */
function user_relationships_load($param = array(), $options = array(), $reset = FALSE) {
  static $relationships = array();

  $default_options = array(
    'sort' => 'rid',
  );
  $options = array_merge($default_options, $options);
  extract($options, EXTR_SKIP);

  $arguments = array();
  if (is_numeric($param)) {
    if (!$reset && isset($relationships[$param])) {
      return is_object($relationships[$param]) ? clone $relationships[$param] : $relationships[$param];
    }
    $rid = $param;
    $param = array('rid' => $param);
  }

  $options['only_count'] = !empty($count);

  $query = _user_relationships_generate_query($param, $options);

  if (!empty($count)) {
    return (int)$query->execute()->fetchField();
  }

  $relationships = array();
  foreach ($query->execute() as $relationship) {
    if (isset($include_user_info)) {
      user_relationships_translate_user_info($relationship);
    }

    if ($sort == 'rid') {
      $relationships[$relationship->$sort] = $relationship;
    }
    else {
      $relationships[$relationship->$sort][] = $relationship;
    }
  }

  if (isset($rid) && !isset($relationships[$rid])) {
    return FALSE;
  }

  // Always call the hook with an array, even though there is only single entry.
  if (isset($rid)) {
    $return = $relationships[$rid];
    module_invoke_all('user_relationships_load', array($rid => $return));
  }
  else {
    $return = $relationships;
    // Only execute the hook if the array is not empty.
    if (!empty($return)) {
      module_invoke_all('user_relationships_load', $return);
    }
  }
  return $return;
}


/**
 * Used when the "include_user_info" option is set on user_relationships_load
 * to translate the retrieved user fields into actual user objects. This allows us
 * to pull the basic user data without having to run user_load
 *
 * @param $relationship
 *    The relationship object with pulled user info
 */
function user_relationships_translate_user_info(&$relationship) {
  if ($relationship->requester_name) {
    foreach (array('requester', 'requestee') as $user_type) {
      $relationship->{$user_type} = new stdClass();
      foreach (array('name', 'mail', 'data', 'picture') as $field) {
        $db_field = "{$user_type}_{$field}";
        $relationship->{$user_type}->{$field} = $relationship->{$db_field};

        unset($relationship->{$db_field});
      }
      $user_type_id = "{$user_type}_id";
      $relationship->{$user_type}->uid = $relationship->{$user_type_id};
      $relationship->{$user_type}->data = unserialize($relationship->{$user_type}->data);
    }
  }
}

/**
 * Check whether a user is allowed to request a certain relationship type
 *
 * @param $requester requesting user object or uid
 * @param $relationship_type loaded relationship type object or rtid
 * @return TRUE iff requester is allowed to request this type of relationship
 */
function user_relationships_can_request($requester, $relationship_type) {
  //validate arguments
  if (is_numeric($requester)) {
    $requester = user_load($requester);
  }
  if (is_numeric($relationship_type)) {
    $relationship_type = user_relationships_type_load($relationship_type);
  }
  if (!is_object($requester) || !is_object($relationship_type)) {
    return FALSE;
  }
  if ($requester->uid == 1) {
    return TRUE;
  }
  //if no roles have been set, any user can request
  if (!isset($relationship_type->roles) || !count($relationship_type->roles)) {
    return TRUE;
  }
  //check user has at least one required role
  foreach ($relationship_type->roles as $role_id) {
    if (isset($requester->roles[$role_id])) {
      return TRUE;
    }
  }
  return FALSE;
}

/**
 * Check whether a user is allowed to receive a certain relationship type
 *
 * @param $requestee requesting user object or uid
 * @param $relationship_type loaded relationship type object or rtid
 * @return TRUE iff receiver is allowed to request this type of relationship
 */
function user_relationships_can_receive($requestee, $relationship_type) {
  //validate arguments
  if (is_numeric($relationship_type)) {
    $relationship_type = user_relationships_type_load($relationship_type);
  }
  if (is_numeric($requestee)) {
    $requestee = user_load($requestee);
  }
  if (!is_object($requestee) || !is_object($relationship_type)) {
    return FALSE;
  }
  //if no roles have been set to receive the relationship, any user can receive it
  if (!isset($relationship_type->roles_receive) || !count($relationship_type->roles_receive)) {
    return TRUE;
  }
  //check user has at least one required role
  foreach ($relationship_type->roles_receive as $role_id) {
    if (isset($requestee->roles[$role_id])) {
      return TRUE;
    }
  }
  return FALSE;
}

/**
 * Public API for getting the set or default message
 *
 * Use the relationship message system. This is set up to retrieve the admin's set messages or fall back on the default
 * if those aren't set. It'll automatically replace specific tokens with information from $relationship. If you need to provide
 * additional tokens, they can be sent through $replacements.
 *
 * @param $key
 *   Message name, see _user_relationships_ui_default_messages() for the
 *   keys and default messages attached to those keys.
 * @param $replacements
 *    Replaceable tokens to append or replace default tokens.
 *
 * @return
 *   Formatted message.
 */
function user_relationships_get_message($key, $relationship = NULL, $replacements = array()) {
  $msg = variable_get("user_relationships_msg_{$key}", NULL);

  if ($relationship) {
    if (!isset($relationship->requester)) {
      $relationship->requester = user_load($relationship->requester_id);
    }
    if (!isset($relationship->requestee)) {
      $relationship->requestee = user_load($relationship->requestee_id);
    }
    if (!(isset($relationship->name) || isset($relationship->type))) {
      $relationship->type = user_relationships_type_load($relationship->rtid);
    }

    $replaceables = array(
      '!requester'                => theme('username', array('account' => $relationship->requester)),
      '!requestee'                => theme('username', array('account' => $relationship->requestee)),
      '%relationship_name'        => isset($relationship->name)
                                     ? ur_tt("user_relationships:rtid:$relationship->rtid:name", $relationship->name)
                                     : ur_tt("user_relationships:rtid:$relationship->rtid:name", $relationship->type->name),
      '%relationship_plural_name' => isset($relationship->plural_name)
                                     ? ur_tt("user_relationships:rtid:$relationship->rtid:plural_name", $relationship->plural_name)
                                     : ur_tt("user_relationships:rtid:$relationship->rtid:plural_name", $relationship->type->plural_name),
    );
    $replacements = array_merge($replaceables, $replacements);
  }

  if (is_null($msg)) {
    $messages = _user_relationships_default_messages($replacements);
    $msg      = _user_relationships_get_from_array($key, $messages);
  }
  else {
    $msg = t($msg, $replacements);
  }

  return $msg;
}

/**
 * Returns a nested array of default messages.
 * When adding any keys, add translations in
 * _user_relationships_default_message_key_translations().
 */
function _user_relationships_default_messages($replacements) {
  return array(
    'informational' => array(
      'submitted'     => t('Your %relationship_name request has been sent to !requestee.', $replacements),
      'accepted'      => t("!requester's %relationship_name request has been approved.", $replacements),
      'disapproved'   => t("!requester has declined your %relationship_name request.", $replacements),
      'disapprove'   => t("!requester's %relationship_name request has been declined.", $replacements),
      'cancel'        => t('Your %relationship_name request to !requestee has been canceled.', $replacements),
      'default'       => t('No action has been taken.'),
      'removed'       => t('The %relationship_name relationship between !requester and !requestee has been deleted.', $replacements),
      'pending'       => t('!requester has requested to be your %relationship_name. View your !pending_relationship_requests to approve or decline.', $replacements),
      'pre_approved'  => t("You are !requestee's newest %relationship_name.", $replacements),
    ),
    'error' => array(
      'too_many_relationships'  => t('You are not permitted to create any more relationships with this user.'),
      'existing_request'        => t('There is already an earlier %relationship_name request sent to !requestee.', $replacements),
      'existing_relationship'   => t('There is already an existing %relationship_name relationship with !requestee.', $replacements),
      'not_accepting_requests'  => t('This user does not accept relationship requests.'),
      'self_request'            => t('You cannot create a relationship with yourself.'),
      'non_existent_user'       => t('This user does not exist.'),
      'non_existent_type'       => t('This relationship type does not exist.'),
      'unknown_error'           => t('An error has occurred. Please contact the site administrator.'),
      'relationship_type_not_set' => t('Please choose the type of relationship.'),
      'relationship_type_not_allowed' => t('You may not create %relationship_name relationships.', $replacements),
    ),
  );
}

/**
 * Returns translations of message keys, used on the admin settings form. #515338
 */
function _user_relationships_default_message_key_translations() {
  return array(
    'informational' => t('Informational Messages'),
    'submitted'     => t('Submitted'),
    'accepted'      => t('Accepted'),
    'disapproved'   => t('Declined'),
    'disapprove'   => t('Decline'),
    'cancel'        => t('Cancel'),
    'default'       => t('Default'),
    'removed'       => t('Removed'),
    'pending'       => t('Pending'),
    'pre_approved'  => t('Pre-approved'),
    'error'         => t('Error Messages'),
    'too_many_relationships'  => t('Too many relationships'),
    'existing_request'        => t('Existing request'),
    'existing_relationship'   => t('Existing relationship'),
    'not_accepting_requests'  => t('Not accepting requests'),
    'self_request'            => t('Self request'),
    'non_existent_user'       => t('Non-existent user'),
    'non_existent_type'       => t('Non-existent type'),
    'unknown_error'           => t('Unknown error'),
    'relationship_type_not_set' => t('Relationship type not set'),
    'relationship_type_not_allowed' => t('Relationship type not allowed'),
  );
}

/**
 * Recursively search an array for a key and return the value attached to it
 */
function _user_relationships_get_from_array($needle, &$haystack) {
  foreach ($haystack as $key => $value) {
    if ($key == $needle) {
      return $value;
    }
    elseif (is_array($value)) {
      if ($msg = _user_relationships_get_from_array($needle, $value)) {
        return $msg;
      }
    }
  }
}

/**
 * Implementation of hook_locale().
 */
function user_relationships_ui_locale($op = 'groups') {
  switch ($op) {
    case 'groups':
      return array('user_relationships' => t('User Relationships'));
  }
}