// 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.settings;

using fuchsia.media;

/// Settings related to audio.
///
/// Supported SettingsEpitaph enums:
/// REQUEST_NOT_SUPPORTED, INTERNAL_SERVICE_ERROR, PERSISTENT_STORAGE_ERROR
[Discoverable]
protocol Audio {
    /// Gets the current [AudioSettings]. Returns immediately on first call;
    /// subsequent calls return when the value changes.
    ///
    /// If this call fails, it is considered a fatal error and the channel
    /// will be closed.
    Watch() -> (AudioSettings settings);

    /// Sets audio settings. Any field not explicitly set in the table performs a
    /// no-op, and will not make any changes.
    Set(AudioSettings settings) -> () error Error;
};

/// The source of the volume settings. The volume is set according to the source.
enum AudioStreamSettingSource {

    /// The volume is set by the user. When the `source` in AudioStreamSettings is
    /// set to this, the audio volume is set to `user_volume`.
    USER = 0;

    /// The system takes control of the volume. This is used when the system constantly
    /// calculates and changes the volume. The volume is not stored for this source.
    SYSTEM = 1;
};

table Volume {
    /// The volume level ranged [0.0, 1.0]. The level maps to a dbfs value from a volume
    /// curve in the setting service.
    1: float32 level;

    /// True if the volume should be muted. If this is true, then the volume is silent,
    /// regardless of `level`.
    2: bool muted;
};

table AudioStreamSettings {
    /// The audio stream which the settings are applying to.
    1: fuchsia.media.AudioRenderUsage stream;

    /// The volume of `stream` is set according to the volume settings from `source`.
    2: AudioStreamSettingSource source;

    /// User level volume setting. If the `source` is USER, then the volume is set to
    /// `user_volume`.
    3: Volume user_volume;
};

table AudioSettings {
    /// Contains the volume setting for all audio stream settings. There should only be
    /// one AudioStreamSettings for each fuchsia.media.AudioRenderUsage.
    1: vector<AudioStreamSettings>:5 streams;

    /// To be deprecated in favor of fuchsia.settings.InputDeviceSettings.
    2: AudioInput input;
};

table AudioInput {
    /// Whether the audio input is muted. Takes into consideration the hardware state.
    1: bool muted;
};