// Copyright 2018 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

module chromeos.assistant.mojom;

import "ui/accessibility/mojom/ax_assistant_structure.mojom";
import "ui/gfx/geometry/mojo/geometry.mojom";
import "url/mojom/url.mojom";
import "mojo/public/mojom/base/string16.mojom";
import "mojo/public/mojom/base/time.mojom";

// Interface to communicate with assistant backend.
interface Assistant {
  // Starts a cached screen context interaction. Results related to the screen
  // context will be returned through the |AssistantInteractionSubscriber|
  // interface to registered subscribers. It is illegal to call this method
  // without having first cached screen context (see CacheScreenContext()).
  StartCachedScreenContextInteraction();

  // Starts a metalayer interaction for the selected screen |region|. Results
  // related to the selected region will be returned through the
  // |AssistantInteractionSubscriber| interface to registered subscribers.
  StartMetalayerInteraction(gfx.mojom.Rect region);

  // Starts a new Assistant voice interaction.
  StartVoiceInteraction();

  // Stops the active Assistant interaction. If there is no active interaction,
  // this method is a no-op.
  StopActiveInteraction();

  // Send text query to assistant. Result will be returned through registered
  // |AssistantInteractionSubscriber|.
  SendTextQuery(string query);

  // Registers assistant interaction event subscriber. Subscribers'
  // implementation is responsible for selecting events of interest.
  AddAssistantInteractionSubscriber(AssistantInteractionSubscriber subscriber);

  // Registers assistant notification event subscriber. Subscribers'
  // implementation is responsible for selecting events of interest.
  AddAssistantNotificationSubscriber(
      AssistantNotificationSubscriber subscriber);

  // Retrieves a notification. A voiceless interaction will be sent to server to
  // retrieve the notification payload, which can trigger other assistant's
  // events such as OnTextResponse to show the result in the UI. The reteived
  // notification will be removed from the UI.
  RetrieveNotification(AssistantNotification notification, int32 action_index);

  // Dismisses a notification.
  DismissNotification(AssistantNotification notification);

  // Caches screen context, made up of view hierarchy and screenshot data.
  // Screen context is used to provide additional context alongside text and
  // voice queries, and may also be used in standalone screen context
  // interactions (see StartCachedScreenContextInteraction()).
  CacheScreenContext() => ();
};

// Subscribes to assistant's interaction event. These events are server driven
// in response to the user's direct interaction with the assistant. Responses
// from the assistant may contain untrusted third-party content. Subscriber
// implementations must be sure to handle the response data appropriately.
interface AssistantInteractionSubscriber {
  // Assistant interaction has started. In the event of a voice interaction,
  // |is_voice_interaction| will be true. This implies that the mic is open.
  OnInteractionStarted(bool is_voice_interaction);

  // Assistant interaction has ended with the specified |resolution|.
  OnInteractionFinished(AssistantInteractionResolution resolution);

  // Assistant got Html response from server.
  OnHtmlResponse(string response);

  // Assistant got suggestions response from server.
  OnSuggestionsResponse(array<AssistantSuggestion> response);

  // Assistant got text response from server.
  OnTextResponse(string response);

  // Assistant got open URL response from server.
  OnOpenUrlResponse(url.mojom.Url url);

  // Assistant speech recognition has started.
  OnSpeechRecognitionStarted();

  // Assistant speech recognition intermediate result is available.
  OnSpeechRecognitionIntermediateResult(string high_confidence_text,
                                        string low_confidence_text);

  // Assistant speech recognition detected end of utterance.
  OnSpeechRecognitionEndOfUtterance();

  // Assistant speech recognition final result is available.
  OnSpeechRecognitionFinalResult(string final_result);

  // Assistant got an instantaneous speech level update in dB.
  OnSpeechLevelUpdated(float speech_level);

  // Assistant has started speaking. When TTS is started due to an error that
  // occurred during the interaction, |due_to_error| is true.
  OnTtsStarted(bool due_to_error);
};

// Subscribes to assistant's notification event. These events are server
// driven and pertain to push notifications.
interface AssistantNotificationSubscriber {
  // Assistant got notification from server.
  OnShowNotification(AssistantNotification notification);

  // Notifies UI to remove the notification with the |grouping_key|.
  // If |grouping_key| is empty, remove all notifications.
  OnRemoveNotification(string grouping_key);
};

// Interface for browser to bind and start assistant.
interface AssistantPlatform {
  // Initiates assistant and provides interfaces for assistant to call into the
  // browser.
  Init(Client assistant_client_interface,
       DeviceActions device_actions_interface);
};

// Interface for assistant to call into client.
interface Client {
  // Notifies assistant client that assistant running status has changed.
  OnAssistantStatusChanged(bool running);

  // Request context of current window from browser.
  RequestAssistantStructure() => (
    ax.mojom.AssistantExtra? extra,
    ax.mojom.AssistantTree? structure);
};

// Interface for assistant to call into browser for audio input related
// functions.
interface AudioInput {
  // Registers audio input observer. We assume dual-channel, 16kHz and signed
  // 32-bit int interleaved format. Audio stream starts recording as soon as
  // the first observer is added. And will stop recording if last observer is
  // closed.
  AddObserver(AudioInputObserver observer);
};

// Observer for assistant to receive audio input data.
interface AudioInputObserver {
  // Notifies that audio frames are available.
  // TODO(muyuanli): Use data pipe.
  OnAudioInputFramesAvailable(array<int32> buffer, uint32 frame_count,
                              mojo_base.mojom.TimeTicks timestamp);
  // Notifies that audio input stream is closed.
  OnAudioInputClosed();
};

// Interface for assistant to call into browser to perform device actions.
interface DeviceActions {
  // Enables or disables WiFi.
  SetWifiEnabled(bool enabled);

  // Enables or disables Bluetooth.
  SetBluetoothEnabled(bool enabled);
};

// Enumeration of possible completions for an Assistant interaction.
enum AssistantInteractionResolution {
  // Assistant interaction completed normally.
  kNormal,
  // Assistant interaction completed due to barge in or cancellation.
  kInterruption,
  // Assistant interaction completed due to error.
  kError,
  // Assistant interaction completed due to mic timeout.
  kMicTimeout,
  // Assistant interaction completed due to multi-device hotword loss.
  kMultiDeviceHotwordLoss,
};

// Models an Assistant suggestion.
struct AssistantSuggestion {
  // Display text. e.g. "Cancel".
  string text;
  // Optional URL for icon. e.g. "https://www.gstatic.com/icon.png".
  url.mojom.Url icon_url;
  // Optional URL for action. e.g.
  // "https://www.google.com/search?query=action".
  url.mojom.Url action_url;
};

// Models an Assistant notification.
struct AssistantNotification {
  // Title of the notification.
  string title;

  // Body text of the notification.
  string message;

  // URL to open when the tap action is invoked on the notification.
  url.mojom.Url action_url;

  // An id that uniquely identifies a notification.
  string notification_id;

  // Used to fetch notification contents.
  string consistency_token;
  string opaque_token;

  // Key that can be used to group multiple notifications together.
  string grouping_key;

  // Obfuscated Gaia id of the intended recipient of the user.
  string obfuscated_gaia_id;
};