// Copyright 2013 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef EXTENSIONS_BROWSER_API_AUDIO_AUDIO_SERVICE_H_
#define EXTENSIONS_BROWSER_API_AUDIO_AUDIO_SERVICE_H_

#include <memory>
#include <string>
#include <vector>

#include "base/functional/callback.h"
#include "extensions/common/api/audio.h"

namespace extensions {

using DeviceIdList = std::vector<std::string>;
using DeviceInfoList = std::vector<api::audio::AudioDeviceInfo>;

class AudioDeviceIdCalculator;

class AudioService {
 public:
  class Observer {
   public:
    // Called when the sound level of an active audio device changes.
    virtual void OnLevelChanged(const std::string& id, int level) = 0;

    // Called when the mute state of audio input/output changes.
    virtual void OnMuteChanged(bool is_input, bool is_muted) = 0;

    // Called when the audio devices change, either new devices being added, or
    // existing devices being removed.
    virtual void OnDevicesChanged(const DeviceInfoList&) = 0;

   protected:
    virtual ~Observer() = default;
  };

  using Ptr = std::unique_ptr<AudioService>;

  // Creates a platform-specific AudioService instance.
  static Ptr CreateInstance(AudioDeviceIdCalculator* id_calculator);

  AudioService(const AudioService&) = delete;
  AudioService& operator=(const AudioService&) = delete;

  virtual ~AudioService() = default;

  // Called by listeners to this service to add/remove themselves as observers.
  virtual void AddObserver(Observer* observer) = 0;
  virtual void RemoveObserver(Observer* observer) = 0;

  // Retrieves list of audio devices that satisfy |filter|.
  // Passes devices list into a |callback|.
  // If |filter->is_active| is set, |devices_out| will contain only devices
  // whose is-active state matches |filter->is_active| value.
  // If |filter->stream_types| is set, |devices_out| will contain only devices
  // whose stream type (INPUT for input devices, OUTPUT for output devices) is
  // contained in |filter->stream_types|.
  // Returns whether the list of devices was successfully retrieved.
  virtual void GetDevices(
      const api::audio::DeviceFilter* filter,
      base::OnceCallback<void(bool, DeviceInfoList)> callback) = 0;

  // Sets set of active inputs to devices defined by IDs in |input_devices|,
  // and set of active outputs to devices defined by IDs in |output_devices|.
  // If either of |input_devices| or |output_devices| is not set, associated
  // set of active devices will remain unchanged.
  // If either list is empty, all active devices of associated type will be
  // deactivated.
  // Returns whether the operation succeeded into a |callback| - on failure
  // there will be no changes to active devices.
  // Note that device ID lists should contain only existing device ID of
  // appropriate type in order for the method to succeed.
  virtual void SetActiveDeviceLists(
      const DeviceIdList* input_devices,
      const DeviceIdList* output_devives,
      base::OnceCallback<void(bool)> callback) = 0;

  // Set the sound level properties (volume or gain) of a device.
  // Passes if operation succeeded into a |callback|.
  virtual void SetDeviceSoundLevel(const std::string& device_id,
                                   int level_value,
                                   base::OnceCallback<void(bool)> callback) = 0;

  // Sets mute property for audio input (if |is_input| is true) or output (if
  // |is_input| is false). Passes if operation succeeded into a |callback|.
  virtual void SetMute(bool is_input,
                       bool value,
                       base::OnceCallback<void(bool)> callback) = 0;

  // Gets mute property for audio input (if |is_input| is true) or output (if
  // |is_input| is false).
  // The mute value is passed into a |callback|.
  // First bool indicates if operation succeeded.
  // Second bool is the mute value.
  virtual void GetMute(bool is_input,
                       base::OnceCallback<void(bool, bool)> callback) = 0;

 protected:
  AudioService() = default;
};

}  // namespace extensions

#endif  // EXTENSIONS_BROWSER_API_AUDIO_AUDIO_SERVICE_H_