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

/* vim:set ts=2 sw=2 sts=2 et cindent: */

/* 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/. */

#if !defined(MediaMetadataManager_h__)

#define MediaMetadataManager_h__

#include "mozilla/AbstractThread.h"

#include "mozilla/LinkedList.h"

#include "nsAutoPtr.h"

#include "MediaEventSource.h"

#include "TimeUnits.h"

#include "VideoUtils.h"

namespace mozilla {

class TimedMetadata;

typedef MediaEventProducerExc<TimedMetadata> TimedMetadataEventProducer;

typedef MediaEventSourceExc<TimedMetadata> TimedMetadataEventSource;

// A struct that contains the metadata of a media, and the time at which those

// metadata should start to be reported.

class TimedMetadata : public LinkedListElement<TimedMetadata> {

public:

  TimedMetadata(const media::TimeUnit& aPublishTime,

                nsAutoPtr<MetadataTags>&& aTags,

                nsAutoPtr<MediaInfo>&& aInfo)

    : mPublishTime(aPublishTime)

    , mTags(std::move(aTags))

    , mInfo(std::move(aInfo)) {}

  // Define our move constructor because we don't want to move the members of

  // LinkedListElement to change the list.

  TimedMetadata(TimedMetadata&& aOther)

    : mPublishTime(aOther.mPublishTime)

    , mTags(std::move(aOther.mTags))

    , mInfo(std::move(aOther.mInfo)) {}

  // The time, in microseconds, at which those metadata should be available.

  media::TimeUnit mPublishTime;

  // The metadata. The ownership is transfered to the element when dispatching to

  // the main threads.

  nsAutoPtr<MetadataTags> mTags;

  // The media info, including the info of audio tracks and video tracks.

  // The ownership is transfered to MediaDecoder when dispatching to the

  // main thread.

  nsAutoPtr<MediaInfo> mInfo;

};

// This class encapsulate the logic to give the metadata from the reader to

// the content, at the right time.

class MediaMetadataManager {

public:

  ~MediaMetadataManager() {

    TimedMetadata* element;

    while((element = mMetadataQueue.popFirst()) != nullptr) {

      delete element;

    }

  }

  // Connect to an event source to receive TimedMetadata events.

  void Connect(TimedMetadataEventSource& aEvent, AbstractThread* aThread) {

    mListener = aEvent.Connect(

      aThread, this, &MediaMetadataManager::OnMetadataQueued);

  }

  // Stop receiving TimedMetadata events.

  void Disconnect() {

    mListener.Disconnect();

  }

  // Return an event source through which we will send TimedMetadata events

  // when playback position reaches the publish time.

  TimedMetadataEventSource& TimedMetadataEvent() {

    return mTimedMetadataEvent;

  }

  void DispatchMetadataIfNeeded(const media::TimeUnit& aCurrentTime) {

    TimedMetadata* metadata = mMetadataQueue.getFirst();

    while (metadata && aCurrentTime >= metadata->mPublishTime) {

      // Our listener will figure out what to do with TimedMetadata.

      mTimedMetadataEvent.Notify(std::move(*metadata));

      delete mMetadataQueue.popFirst();

      metadata = mMetadataQueue.getFirst();

    }

  }

protected:

  void OnMetadataQueued(TimedMetadata&& aMetadata) {

    mMetadataQueue.insertBack(new TimedMetadata(std::move(aMetadata)));

  }

  LinkedList<TimedMetadata> mMetadataQueue;

  MediaEventListener mListener;

  TimedMetadataEventProducer mTimedMetadataEvent;

};

} // namespace mozilla

#endif