// Copyright 2021 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.developer.ffx;

/// Contains information about the socket bound during mDNS setup.
type MdnsBindEvent = table {
    1: port uint16;
};

type MdnsEventType = strict union {
    /// Sent to subscribers when a new target is found on the network. This
    /// is only propagated when the target is either seen for the first time,
    /// or if the target has previously expired.
    1: target_found TargetInfo;
    /// Sent to subscribers when a target has been discovered after having
    /// alreaady been stored in the cache. This can often be treated the same
    /// as `target_found`.
    2: target_rediscovered TargetInfo;
    /// Sent to subscribers when a target has expired (the target has not been
    /// rediscovered after the TTL has been reached). The target can be
    /// rediscovered later. If this happens a `target_found` event will be sent.
    3: target_expired TargetInfo;
    /// An event propagated when the multicast listener is bound. Primarily
    /// for testing.
    4: socket_bound MdnsBindEvent;
};

@discoverable
protocol Mdns {
    /// Gets the next event from the protocol. There is only ever meant to be
    /// one event ready at a time on the service side, so it is important that
    /// the client call this frequently.
    GetNextEvent() -> (struct {
        event MdnsEventType:optional;
    });

    /// Gets full cache of targets. It is advised to call this before
    /// `GetNextEvent()`.
    GetTargets() -> (struct {
        targets vector<TargetInfo>:512;
    });
};