// Copyright 2019 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

library fuchsia.auth.oldtokens;

/// The id of a user linked to this device, alongside the current access token
/// to make requests on the user's behalf.
table Credential {
  /// Opaque id for the user with which this credential is associated. It is
  /// stable across reconnections to the CredentialsProducer protocol.
  1: string user_id;

  /// OAuth2 access token for this user.
  2: string access_token;
};

/// Clients can connect to this protocol to subscribe to changes in the set of
/// users linked to this device, as well as the OAuth2 access token associated
/// with each.
///
/// This protocol won't be supported on the majority of devices, and shouldn't
/// be used without permission from its maintainers.
[Discoverable]
protocol CredentialsProducer {
  /// Get the set of users linked to this device, and their corresponding access
  /// tokens. While the connection to the service remains uninterrumpted, the
  /// method call hangs if it would return the same response as the previous
  /// time it was called by this client. In other words, if the client already
  /// has the most up-to-date credentials, the method acts as a hanging get and
  /// only returns when there's an update to report.
  GetUpdatedCredentials() -> (vector<Credential> credentials);
};