// 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.

#ifndef CEF_LIBCEF_BROWSER_MEDIA_CAPTURE_DEVICES_DISPATCHER_H_
#define CEF_LIBCEF_BROWSER_MEDIA_CAPTURE_DEVICES_DISPATCHER_H_

#include "base/callback.h"
#include "base/memory/scoped_ptr.h"
#include "base/memory/singleton.h"
#include "base/observer_list.h"
#include "content/public/browser/media_observer.h"
#include "content/public/common/media_stream_request.h"

class PrefRegistrySimple;
class PrefService;

// This singleton is used to receive updates about media events from the content
// layer. Based on chrome/browser/media/media_capture_devices_dispatcher.[h|cc].
class CefMediaCaptureDevicesDispatcher : public content::MediaObserver {
 public:
  static CefMediaCaptureDevicesDispatcher* GetInstance();

  // Registers the preferences related to Media Stream default devices.
  static void RegisterPrefs(PrefRegistrySimple* registry);

  // Helper to get the default devices which can be used by the media request,
  // if the return list is empty, it means there is no available device on the
  // OS. Called on the UI thread.
  void GetDefaultDevices(PrefService* prefs,
                         bool audio,
                         bool video,
                         content::MediaStreamDevices* devices);

  // Helper for picking the device that was requested for an OpenDevice request.
  // If the device requested is not available it will revert to using the first
  // available one instead or will return an empty list if no devices of the
  // requested kind are present. Called on the UI thread.
  void GetRequestedDevice(const std::string& requested_device_id,
                          bool audio,
                          bool video,
                          content::MediaStreamDevices* devices);

  // Overridden from content::MediaObserver:
  virtual void OnAudioCaptureDevicesChanged() OVERRIDE;
  virtual void OnVideoCaptureDevicesChanged() OVERRIDE;
  virtual void OnMediaRequestStateChanged(
      int render_process_id,
      int render_frame_id,
      int page_request_id,
      const GURL& security_origin,
      content::MediaStreamType stream_type,
      content::MediaRequestState state) OVERRIDE;
  virtual void OnCreatingAudioStream(int render_process_id,
                                     int render_view_id) OVERRIDE;
  virtual void OnAudioStreamPlaying(
      int render_process_id,
      int render_frame_id,
      int stream_id,
      const ReadPowerAndClipCallback& power_read_callback) OVERRIDE;
  virtual void OnAudioStreamStopped(
      int render_process_id,
      int render_frame_id,
      int stream_id) OVERRIDE;

 private:
  friend struct DefaultSingletonTraits<CefMediaCaptureDevicesDispatcher>;

  CefMediaCaptureDevicesDispatcher();
  virtual ~CefMediaCaptureDevicesDispatcher();

  const content::MediaStreamDevices& GetAudioCaptureDevices();
  const content::MediaStreamDevices& GetVideoCaptureDevices();
};

#endif  // CEF_LIBCEF_BROWSER_MEDIA_CAPTURE_DEVICES_DISPATCHER_H_