// 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.ui.policy;

using fuchsia.ui.input;

/// Service for exposing state and events of devices, such as media buttons.
@discoverable
protocol DeviceListenerRegistry {
    // TODO(fxbug.dev/41384): Remove when no longer used.
    /// Registers a listener to receive media button related events, such as
    /// changes from volume buttons and mute switches.
    @deprecated("Use RegisterListener() ")
    RegisterMediaButtonsListener(resource struct {
        listener client_end:MediaButtonsListener;
    });

    /// Registers a listener to receive media button related events, such as
    /// changes from volume buttons and mute switches.
    /// On registration, the `listener` receives the last media button event that
    /// occurred, if one exists, and all media button events going forward.
    @transitional
    RegisterListener(resource struct {
        listener client_end:MediaButtonsListener;
    }) -> ();
};

/// A listener for media buttons events. `DeviceListenerRegistry.RegisterMediaButtonsListener`
/// will consume this listener interface and call `OnMediaButtonsEvent` when the
/// registered media buttons event occurs.
protocol MediaButtonsListener {
    // TODO(fxbug.dev/41384): Remove when no longer used.
    @deprecated("Use OnEvent() ")
    OnMediaButtonsEvent(struct {
        event fuchsia.ui.input.MediaButtonsEvent;
    });

    @transitional
    OnEvent(struct {
        event fuchsia.ui.input.MediaButtonsEvent;
    }) -> ();
};