/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

/* vim: set ts=8 sts=2 et sw=2 tw=80: */

/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this file,

 * You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef mozilla_dom_TextTrackManager_h

#define mozilla_dom_TextTrackManager_h

#include "mozilla/dom/TextTrack.h"

#include "mozilla/dom/TextTrackList.h"

#include "mozilla/dom/TextTrackCueList.h"

#include "mozilla/StaticPtr.h"

#include "nsContentUtils.h"

class nsIWebVTTParserWrapper;

namespace mozilla {

namespace dom {

class HTMLMediaElement;

class CompareTextTracks {

private:

  HTMLMediaElement* mMediaElement;

  int32_t TrackChildPosition(TextTrack* aTrack) const;

public:

  explicit CompareTextTracks(HTMLMediaElement* aMediaElement);

  bool Equals(TextTrack* aOne, TextTrack* aTwo) const;

  bool LessThan(TextTrack* aOne, TextTrack* aTwo) const;

};

class TextTrack;

class TextTrackCue;

class TextTrackManager final : public nsIDOMEventListener

{

  ~TextTrackManager();

public:

  NS_DECL_CYCLE_COLLECTING_ISUPPORTS

  NS_DECL_CYCLE_COLLECTION_CLASS(TextTrackManager)

  NS_DECL_NSIDOMEVENTLISTENER

  explicit TextTrackManager(HTMLMediaElement* aMediaElement);

  TextTrackList* GetTextTracks() const;

  already_AddRefed<TextTrack> AddTextTrack(TextTrackKind aKind,

                                           const nsAString& aLabel,

                                           const nsAString& aLanguage,

                                           TextTrackMode aMode,

                                           TextTrackReadyState aReadyState,

                                           TextTrackSource aTextTrackSource);

  void AddTextTrack(TextTrack* aTextTrack);

  void RemoveTextTrack(TextTrack* aTextTrack, bool aPendingListOnly);

  void DidSeek();

  void NotifyCueAdded(TextTrackCue& aCue);

  void AddCues(TextTrack* aTextTrack);

  void NotifyCueRemoved(TextTrackCue& aCue);

  /**

   * Overview of WebVTT cuetext and anonymous content setup.

   *

   * WebVTT nodes are the parsed version of WebVTT cuetext. WebVTT cuetext is

   * the portion of a WebVTT cue that specifies what the caption will actually

   * show up as on screen.

   *

   * WebVTT cuetext can contain markup that loosely relates to HTML markup. It

   * can contain tags like <b>, <u>, <i>, <c>, <v>, <ruby>, <rt>, <lang>,

   * including timestamp tags.

   *

   * When the caption is ready to be displayed the WebVTT nodes are converted

   * over to anonymous DOM content. <i>, <u>, <b>, <ruby>, and <rt> all become

   * HTMLElements of their corresponding HTML markup tags. <c> and <v> are

   * converted to <span> tags. Timestamp tags are converted to XML processing

   * instructions. Additionally, all cuetext tags support specifying of classes.

   * This takes the form of <foo.class.subclass>. These classes are then parsed

   * and set as the anonymous content's class attribute.

   *

   * Rules on constructing DOM objects from WebVTT nodes can be found here

   * http://dev.w3.org/html5/webvtt/#webvtt-cue-text-dom-construction-rules.

   * Current rules are taken from revision on April 15, 2013.

   */

  void PopulatePendingList();

  void AddListeners();

  // The HTMLMediaElement that this TextTrackManager manages the TextTracks of.

  RefPtr<HTMLMediaElement> mMediaElement;

  void DispatchTimeMarchesOn();

  void TimeMarchesOn();

  void DispatchUpdateCueDisplay();

  void NotifyShutdown()

  {

    mShutdown = true;

  }

  void NotifyCueUpdated(TextTrackCue *aCue);

  void NotifyReset();

  bool IsLoaded();

private:

  /**

   * Converts the TextTrackCue's cuetext into a tree of DOM objects

   * and attaches it to a div on its owning TrackElement's

   * MediaElement's caption overlay.

   */

  void UpdateCueDisplay();

  // List of the TextTrackManager's owning HTMLMediaElement's TextTracks.

  RefPtr<TextTrackList> mTextTracks;

  // List of text track objects awaiting loading.

  RefPtr<TextTrackList> mPendingTextTracks;

  // List of newly introduced Text Track cues.

  // Contain all cues for a MediaElement. Not sorted.

  RefPtr<TextTrackCueList> mNewCues;

  // The active cues for the last TimeMarchesOn iteration.

  RefPtr<TextTrackCueList> mLastActiveCues;

  // True if the media player playback changed due to seeking prior to and

  // during running the "Time Marches On" algorithm.

  bool mHasSeeked;

  // Playback position at the time of last "Time Marches On" call

  double mLastTimeMarchesOnCalled;

  bool mTimeMarchesOnDispatched;

  bool mUpdateCueDisplayDispatched;

  static StaticRefPtr<nsIWebVTTParserWrapper> sParserWrapper;

  bool performedTrackSelection;

  // Runs the algorithm for performing automatic track selection.

  void HonorUserPreferencesForTrackSelection();

  // Performs track selection for a single TextTrackKind.

  void PerformTrackSelection(TextTrackKind aTextTrackKind);

  //Performs track selection for a set of TextTrackKinds, for example,

  // 'subtitles' and 'captions' should be selected together.

  void PerformTrackSelection(TextTrackKind aTextTrackKinds[], uint32_t size);

  void GetTextTracksOfKinds(TextTrackKind aTextTrackKinds[], uint32_t size,

                            nsTArray<TextTrack*>& aTextTracks);

  void GetTextTracksOfKind(TextTrackKind aTextTrackKind,

                           nsTArray<TextTrack*>& aTextTracks);

  bool TrackIsDefault(TextTrack* aTextTrack);

  void ReportTelemetryForTrack(TextTrack* aTextTrack) const;

  void ReportTelemetryForCue();

  bool IsShutdown() const;

  // If there is at least one cue has been added to the cue list once, we would

  // report the usage of cue to Telemetry.

  bool mCueTelemetryReported;

  class ShutdownObserverProxy final : public nsIObserver

  {

    NS_DECL_ISUPPORTS

  public:

    explicit ShutdownObserverProxy(TextTrackManager* aManager)

      : mManager(aManager)

    {

      nsContentUtils::RegisterShutdownObserver(this);

    }

    NS_IMETHODIMP Observe(nsISupports *aSubject, const char *aTopic, const char16_t *aData) override

    {

      MOZ_ASSERT(NS_IsMainThread());

      if (strcmp(aTopic, NS_XPCOM_SHUTDOWN_OBSERVER_ID) == 0) {

        nsContentUtils::UnregisterShutdownObserver(this);

        mManager->NotifyShutdown();

      }

      return NS_OK;

    }

  private:

    ~ShutdownObserverProxy() {};

    TextTrackManager* mManager;

  };

  RefPtr<ShutdownObserverProxy> mShutdownProxy;

  bool mShutdown;

};

} // namespace dom

} // namespace mozilla

#endif // mozilla_dom_TextTrackManager_h