// Copyright (c) 2012 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.
//
// AudioInputRendererHost serves audio related requests from audio capturer
// which lives inside the render process and provide access to audio hardware.
//
// Create stream sequence (AudioInputController = AIC):
//
// AudioInputHostMsg_CreateStream -> OnCreateStream -> AIC::CreateLowLatency ->
//   <- AudioInputMsg_NotifyStreamCreated <- DoCompleteCreation <- OnCreated <-
//
// Close stream sequence:
//
// AudioInputHostMsg_CloseStream -> OnCloseStream -> AIC::Close ->
//
// This class is owned by BrowserRenderProcessHost and instantiated on UI
// thread. All other operations and method calls happen on IO thread, so we
// need to be extra careful about the lifetime of this object.
//
// To ensure low latency audio, a SyncSocket pair is used to signal buffer
// readiness without having to route messages using the IO thread.

#ifndef CONTENT_BROWSER_RENDERER_HOST_MEDIA_AUDIO_INPUT_RENDERER_HOST_H_
#define CONTENT_BROWSER_RENDERER_HOST_MEDIA_AUDIO_INPUT_RENDERER_HOST_H_

#include <map>
#include <string>

#include "base/compiler_specific.h"
#include "base/gtest_prod_util.h"
#include "base/memory/ref_counted.h"
#include "base/memory/scoped_ptr.h"
#include "base/memory/shared_memory.h"
#include "base/process/process.h"
#include "base/sequenced_task_runner_helpers.h"
#include "content/common/media/audio_messages.h"
#include "content/public/browser/browser_message_filter.h"
#include "content/public/browser/browser_thread.h"
#include "media/audio/audio_input_controller.h"
#include "media/audio/audio_io.h"
#include "media/audio/audio_logging.h"
#include "media/audio/simple_sources.h"

namespace media {
class AudioManager;
class AudioParameters;
class UserInputMonitor;
}

namespace content {
class AudioMirroringManager;
class MediaStreamManager;

class CONTENT_EXPORT AudioInputRendererHost
    : public BrowserMessageFilter,
      public media::AudioInputController::EventHandler {
 public:

  // Error codes to make native loggin more clear. These error codes are added
  // to generic error strings to provide a higher degree of details.
  // Changing these values can lead to problems when matching native debug
  // logs with the actual cause of error.
  enum ErrorCode {
    // An unspecified error occured.
    UNKNOWN_ERROR = 0,

    // Failed to look up audio intry for the provided stream id.
    INVALID_AUDIO_ENTRY,  // = 1

    // A stream with the specified stream id already exists.
    STREAM_ALREADY_EXISTS,  // = 2

    // The page does not have permission to open the specified capture device.
    PERMISSION_DENIED,  // = 3

    // Failed to create shared memory.
    SHARED_MEMORY_CREATE_FAILED,  // = 4

    // Failed to initialize the AudioInputSyncWriter instance.
    SYNC_WRITER_INIT_FAILED,  // = 5

    // Failed to create native audio input stream.
    STREAM_CREATE_ERROR,  // = 6

    // Renderer process handle is invalid.
    INVALID_PEER_HANDLE,  // = 7

    // Only low-latency mode is supported.
    INVALID_LATENCY_MODE,  // = 8

    // Failed to map and share the shared memory.
    MEMORY_SHARING_FAILED,  // = 9

    // Unable to prepare the foreign socket handle.
    SYNC_SOCKET_ERROR,  // = 10

    // This error message comes from the AudioInputController instance.
    AUDIO_INPUT_CONTROLLER_ERROR,  // = 11
  };

  // Called from UI thread from the owner of this object.
  // |user_input_monitor| is used for typing detection and can be NULL.
  AudioInputRendererHost(media::AudioManager* audio_manager,
                         MediaStreamManager* media_stream_manager,
                         AudioMirroringManager* audio_mirroring_manager,
                         media::UserInputMonitor* user_input_monitor);

  // BrowserMessageFilter implementation.
  void OnChannelClosing() override;
  void OnDestruct() const override;
  bool OnMessageReceived(const IPC::Message& message) override;

  // AudioInputController::EventHandler implementation.
  void OnCreated(media::AudioInputController* controller) override;
  void OnRecording(media::AudioInputController* controller) override;
  void OnError(media::AudioInputController* controller,
               media::AudioInputController::ErrorCode error_code) override;
  void OnData(media::AudioInputController* controller,
              const media::AudioBus* data) override;
  void OnLog(media::AudioInputController* controller,
             const std::string& message) override;

 private:
  // TODO(henrika): extend test suite (compare AudioRenderHost)
  friend class BrowserThread;
  friend class TestAudioInputRendererHost;
  friend class base::DeleteHelper<AudioInputRendererHost>;

  struct AudioEntry;
  typedef std::map<int, AudioEntry*> AudioEntryMap;

  ~AudioInputRendererHost() override;

  // Methods called on IO thread ----------------------------------------------

  // Audio related IPC message handlers.

  // For ChromeOS: Checks if the stream should contain keyboard mic, if so
  // registers to AudioInputDeviceManager. Then calls DoCreateStream.
  // For non-ChromeOS: Just calls DoCreateStream.
  void OnCreateStream(int stream_id,
                      int render_view_id,
                      int session_id,
                      const AudioInputHostMsg_CreateStream_Config& config);

  // Creates an audio input stream with the specified format whose data is
  // consumed by an entity in the render view referenced by |render_view_id|.
  // |session_id| is used to find out which device to be used for the stream.
  // Upon success/failure, the peer is notified via the
  // NotifyStreamCreated message.
  void DoCreateStream(int stream_id,
                      int render_view_id,
                      int session_id,
                      const AudioInputHostMsg_CreateStream_Config& config);

  // Record the audio input stream referenced by |stream_id|.
  void OnRecordStream(int stream_id);

  // Close the audio stream referenced by |stream_id|.
  void OnCloseStream(int stream_id);

  // Set the volume of the audio stream referenced by |stream_id|.
  void OnSetVolume(int stream_id, double volume);

  // Complete the process of creating an audio input stream. This will set up
  // the shared memory or shared socket in low latency mode and send the
  // NotifyStreamCreated message to the peer.
  void DoCompleteCreation(media::AudioInputController* controller);

  // Send a state change message to the renderer.
  void DoSendRecordingMessage(media::AudioInputController* controller);

  // Handle error coming from audio stream.
  void DoHandleError(media::AudioInputController* controller,
      media::AudioInputController::ErrorCode error_code);

  // Log audio level of captured audio stream.
  void DoLog(media::AudioInputController* controller,
             const std::string& message);

  // Send an error message to the renderer.
  void SendErrorMessage(int stream_id, ErrorCode error_code);

  // Delete all audio entry and all audio streams
  void DeleteEntries();

  // Closes the stream. The stream is then deleted in DeleteEntry() after it
  // is closed.
  void CloseAndDeleteStream(AudioEntry* entry);

  // Delete an audio entry and close the related audio stream.
  void DeleteEntry(AudioEntry* entry);

  // Delete audio entry and close the related audio input stream.
  void DeleteEntryOnError(AudioEntry* entry, ErrorCode error_code);

  // A helper method to look up a AudioEntry identified by |stream_id|.
  // Returns NULL if not found.
  AudioEntry* LookupById(int stream_id);

  // Search for a AudioEntry having the reference to |controller|.
  // This method is used to look up an AudioEntry after a controller
  // event is received.
  AudioEntry* LookupByController(media::AudioInputController* controller);

  // If ChromeOS and |config|'s layout has keyboard mic, unregister in
  // AudioInputDeviceManager.
  void MaybeUnregisterKeyboardMicStream(
      const AudioInputHostMsg_CreateStream_Config& config);

  // Used to create an AudioInputController.
  media::AudioManager* audio_manager_;

  // Used to access to AudioInputDeviceManager.
  MediaStreamManager* media_stream_manager_;

  AudioMirroringManager* audio_mirroring_manager_;

  // A map of stream IDs to audio sources.
  AudioEntryMap audio_entries_;

  // Raw pointer of the UserInputMonitor.
  media::UserInputMonitor* user_input_monitor_;

  scoped_ptr<media::AudioLog> audio_log_;

  DISALLOW_COPY_AND_ASSIGN(AudioInputRendererHost);
};

}  // namespace content

#endif  // CONTENT_BROWSER_RENDERER_HOST_MEDIA_AUDIO_INPUT_RENDERER_HOST_H_