/* -*- 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/. */
#include "MediaSourceDecoder.h"

#include "base/process_util.h"
#include "mozilla/Logging.h"
#include "ExternalEngineStateMachine.h"
#include "MediaDecoder.h"
#include "MediaDecoderStateMachine.h"
#include "MediaShutdownManager.h"
#include "MediaSource.h"
#include "MediaSourceDemuxer.h"
#include "MediaSourceUtils.h"
#include "SourceBuffer.h"
#include "SourceBufferList.h"
#include "VideoUtils.h"
#include <algorithm>

extern mozilla::LogModule* GetMediaSourceLog();

#define MSE_DEBUG(arg, ...)                                              \
  DDMOZ_LOG(GetMediaSourceLog(), mozilla::LogLevel::Debug, "::%s: " arg, \
            __func__, ##__VA_ARGS__)
#define MSE_DEBUGV(arg, ...)                                               \
  DDMOZ_LOG(GetMediaSourceLog(), mozilla::LogLevel::Verbose, "::%s: " arg, \
            __func__, ##__VA_ARGS__)

using namespace mozilla::media;

namespace mozilla {

MediaSourceDecoder::MediaSourceDecoder(MediaDecoderInit& aInit)
    : MediaDecoder(aInit), mMediaSource(nullptr), mEnded(false) {
  mExplicitDuration.emplace(UnspecifiedNaN<double>());
}

MediaDecoderStateMachineBase* MediaSourceDecoder::CreateStateMachine(
    bool aDisableExternalEngine) {
  MOZ_ASSERT(NS_IsMainThread());
  // if `mDemuxer` already exists, that means we're in the process of recreating
  // the state machine. The track buffers are tied to the demuxer so we would
  // need to reuse it.
  if (!mDemuxer) {
    mDemuxer = new MediaSourceDemuxer(AbstractMainThread());
  }
  MediaFormatReaderInit init;
  init.mVideoFrameContainer = GetVideoFrameContainer();
  init.mKnowsCompositor = GetCompositor();
  init.mCrashHelper = GetOwner()->CreateGMPCrashHelper();
  init.mFrameStats = mFrameStats;
  init.mMediaDecoderOwnerID = mOwner;
  static Atomic<uint32_t> sTrackingIdCounter(0);
  init.mTrackingId.emplace(TrackingId::Source::MSEDecoder, sTrackingIdCounter++,
                           TrackingId::TrackAcrossProcesses::Yes);
  mReader = new MediaFormatReader(init, mDemuxer);
#ifdef MOZ_WMF_MEDIA_ENGINE
  // TODO : Only for testing development for now. In the future this should be
  // used for encrypted content only.
  if (StaticPrefs::media_wmf_media_engine_enabled() &&
      !aDisableExternalEngine) {
    return new ExternalEngineStateMachine(this, mReader);
  }
#endif
  return new MediaDecoderStateMachine(this, mReader);
}

nsresult MediaSourceDecoder::Load(nsIPrincipal* aPrincipal) {
  MOZ_ASSERT(NS_IsMainThread());
  MOZ_ASSERT(!GetStateMachine());

  mPrincipal = aPrincipal;

  nsresult rv = MediaShutdownManager::Instance().Register(this);
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }
  return CreateAndInitStateMachine(!mEnded);
}

template <typename IntervalType>
IntervalType MediaSourceDecoder::GetSeekableImpl() {
  MOZ_ASSERT(NS_IsMainThread());
  if (!mMediaSource) {
    NS_WARNING("MediaSource element isn't attached");
    return IntervalType();
  }

  TimeIntervals seekable;
  double duration = mMediaSource->Duration();
  if (std::isnan(duration)) {
    // Return empty range.
  } else if (duration > 0 && std::isinf(duration)) {
    media::TimeIntervals buffered = GetBuffered();

    // 1. If live seekable range is not empty:
    if (mMediaSource->HasLiveSeekableRange()) {
      // 1. Let union ranges be the union of live seekable range and the
      // HTMLMediaElement.buffered attribute.
      TimeRanges unionRanges =
          media::TimeRanges(buffered) + mMediaSource->LiveSeekableRange();
      // 2. Return a single range with a start time equal to the earliest start
      // time in union ranges and an end time equal to the highest end time in
      // union ranges and abort these steps.
      if constexpr (std::is_same<IntervalType, TimeRanges>::value) {
        TimeRanges seekableRange = media::TimeRanges(
            TimeRange(unionRanges.GetStart(), unionRanges.GetEnd()));
        return seekableRange;
      } else {
        MOZ_RELEASE_ASSERT(false);
      }
    }

    if (!buffered.IsEmpty()) {
      seekable += media::TimeInterval(TimeUnit::Zero(), buffered.GetEnd());
    }
  } else {
    if constexpr (std::is_same<IntervalType, TimeRanges>::value) {
      // Common case: seekable in entire range of the media.
      return TimeRanges(TimeRange(0, duration));
    } else if constexpr (std::is_same<IntervalType, TimeIntervals>::value) {
      seekable += media::TimeInterval(TimeUnit::Zero(),
                                      mDuration.match(DurationToTimeUnit()));
    } else {
      MOZ_RELEASE_ASSERT(false);
    }
  }
  MSE_DEBUG("ranges=%s", DumpTimeRanges(seekable).get());
  return IntervalType(seekable);
}

media::TimeIntervals MediaSourceDecoder::GetSeekable() {
  return GetSeekableImpl<media::TimeIntervals>();
}

media::TimeRanges MediaSourceDecoder::GetSeekableTimeRanges() {
  return GetSeekableImpl<media::TimeRanges>();
}

media::TimeIntervals MediaSourceDecoder::GetBuffered() {
  MOZ_ASSERT(NS_IsMainThread());

  if (!mMediaSource) {
    NS_WARNING("MediaSource element isn't attached");
    return media::TimeIntervals::Invalid();
  }
  dom::SourceBufferList* sourceBuffers = mMediaSource->ActiveSourceBuffers();
  if (!sourceBuffers) {
    // Media source object is shutting down.
    return TimeIntervals();
  }
  TimeUnit highestEndTime;
  nsTArray<media::TimeIntervals> activeRanges;
  media::TimeIntervals buffered;

  for (uint32_t i = 0; i < sourceBuffers->Length(); i++) {
    bool found;
    dom::SourceBuffer* sb = sourceBuffers->IndexedGetter(i, found);
    MOZ_ASSERT(found);

    activeRanges.AppendElement(sb->GetTimeIntervals());
    highestEndTime =
        std::max(highestEndTime, activeRanges.LastElement().GetEnd());
  }

  buffered += media::TimeInterval(TimeUnit::Zero(), highestEndTime);

  for (auto& range : activeRanges) {
    if (mEnded && !range.IsEmpty()) {
      // Set the end time on the last range to highestEndTime by adding a
      // new range spanning the current end time to highestEndTime, which
      // Normalize() will then merge with the old last range.
      range += media::TimeInterval(range.GetEnd(), highestEndTime);
    }
    buffered.Intersection(range);
  }

  MSE_DEBUG("ranges=%s", DumpTimeRanges(buffered).get());
  return buffered;
}

void MediaSourceDecoder::Shutdown() {
  MOZ_ASSERT(NS_IsMainThread());
  MSE_DEBUG("Shutdown");
  // Detach first so that TrackBuffers are unused on the main thread when
  // shut down on the decode task queue.
  if (mMediaSource) {
    mMediaSource->Detach();
  }
  mDemuxer = nullptr;

  MediaDecoder::Shutdown();
}

void MediaSourceDecoder::AttachMediaSource(dom::MediaSource* aMediaSource) {
  MOZ_ASSERT(!mMediaSource && !GetStateMachine() && NS_IsMainThread());
  mMediaSource = aMediaSource;
  DDLINKCHILD("mediasource", aMediaSource);
}

void MediaSourceDecoder::DetachMediaSource() {
  MOZ_ASSERT(mMediaSource && NS_IsMainThread());
  DDUNLINKCHILD(mMediaSource);
  mMediaSource = nullptr;
}

void MediaSourceDecoder::Ended(bool aEnded) {
  MOZ_ASSERT(NS_IsMainThread());
  if (aEnded) {
    // We want the MediaSourceReader to refresh its buffered range as it may
    // have been modified (end lined up).
    NotifyDataArrived();
  }
  mEnded = aEnded;
  GetStateMachine()->DispatchIsLiveStream(!mEnded);
}

void MediaSourceDecoder::AddSizeOfResources(ResourceSizes* aSizes) {
  MOZ_ASSERT(NS_IsMainThread());
  if (GetDemuxer()) {
    GetDemuxer()->AddSizeOfResources(aSizes);
  }
}

void MediaSourceDecoder::SetInitialDuration(const TimeUnit& aDuration) {
  MOZ_ASSERT(NS_IsMainThread());
  // Only use the decoded duration if one wasn't already
  // set.
  if (!mMediaSource || !std::isnan(ExplicitDuration())) {
    return;
  }
  SetMediaSourceDuration(aDuration);
}

void MediaSourceDecoder::SetMediaSourceDuration(const TimeUnit& aDuration) {
  MOZ_ASSERT(NS_IsMainThread());
  MOZ_ASSERT(!IsShutdown());
  if (aDuration.IsPositiveOrZero()) {
    SetExplicitDuration(ToMicrosecondResolution(aDuration.ToSeconds()));
  } else {
    SetExplicitDuration(PositiveInfinity<double>());
  }
}

void MediaSourceDecoder::SetMediaSourceDuration(double aDuration) {
  MOZ_ASSERT(NS_IsMainThread());
  MOZ_ASSERT(!IsShutdown());
  if (aDuration >= 0) {
    SetExplicitDuration(aDuration);
  } else {
    SetExplicitDuration(PositiveInfinity<double>());
  }
}

RefPtr<GenericPromise> MediaSourceDecoder::RequestDebugInfo(
    dom::MediaSourceDecoderDebugInfo& aInfo) {
  // This should be safe to call off main thead, but there's no such usage at
  // time of writing. Can be carefully relaxed if needed.
  MOZ_ASSERT(NS_IsMainThread(), "Expects to be called on main thread.");
  nsTArray<RefPtr<GenericPromise>> promises;
  if (mReader) {
    promises.AppendElement(mReader->RequestDebugInfo(aInfo.mReader));
  }
  if (mDemuxer) {
    promises.AppendElement(mDemuxer->GetDebugInfo(aInfo.mDemuxer));
  }
  return GenericPromise::All(GetCurrentSerialEventTarget(), promises)
      ->Then(
          GetCurrentSerialEventTarget(), __func__,
          []() { return GenericPromise::CreateAndResolve(true, __func__); },
          [] {
            return GenericPromise::CreateAndReject(NS_ERROR_FAILURE, __func__);
          });
}

double MediaSourceDecoder::GetDuration() {
  MOZ_ASSERT(NS_IsMainThread());
  return ExplicitDuration();
}

MediaDecoderOwner::NextFrameStatus
MediaSourceDecoder::NextFrameBufferedStatus() {
  MOZ_ASSERT(NS_IsMainThread());

  if (!mMediaSource ||
      mMediaSource->ReadyState() == dom::MediaSourceReadyState::Closed) {
    return MediaDecoderOwner::NEXT_FRAME_UNAVAILABLE;
  }

  // Next frame hasn't been decoded yet.
  // Use the buffered range to consider if we have the next frame available.
  auto currentPosition = CurrentPosition();
  TimeIntervals buffered = GetBuffered();
  buffered.SetFuzz(MediaSourceDemuxer::EOS_FUZZ / 2);
  TimeInterval interval(
      currentPosition, currentPosition + DEFAULT_NEXT_FRAME_AVAILABLE_BUFFERED);
  return buffered.ContainsWithStrictEnd(ClampIntervalToEnd(interval))
             ? MediaDecoderOwner::NEXT_FRAME_AVAILABLE
             : MediaDecoderOwner::NEXT_FRAME_UNAVAILABLE;
}

bool MediaSourceDecoder::CanPlayThroughImpl() {
  MOZ_ASSERT(NS_IsMainThread());

  if (NextFrameBufferedStatus() == MediaDecoderOwner::NEXT_FRAME_UNAVAILABLE) {
    return false;
  }

  if (std::isnan(mMediaSource->Duration())) {
    // Don't have any data yet.
    return false;
  }
  TimeUnit duration = TimeUnit::FromSeconds(mMediaSource->Duration());
  auto currentPosition = CurrentPosition();
  if (duration <= currentPosition) {
    return true;
  }
  // If we have data up to the mediasource's duration or 3s ahead, we can
  // assume that we can play without interruption.
  dom::SourceBufferList* sourceBuffers = mMediaSource->ActiveSourceBuffers();
  TimeUnit bufferedEnd = sourceBuffers->GetHighestBufferedEndTime();
  TimeUnit timeAhead =
      std::min(duration, currentPosition + TimeUnit::FromSeconds(3));
  TimeInterval interval(currentPosition, timeAhead);
  return bufferedEnd >= timeAhead;
}

TimeInterval MediaSourceDecoder::ClampIntervalToEnd(
    const TimeInterval& aInterval) {
  MOZ_ASSERT(NS_IsMainThread());

  if (!mEnded) {
    return aInterval;
  }
  TimeUnit duration = mDuration.match(DurationToTimeUnit());
  if (duration < aInterval.mStart) {
    return aInterval;
  }
  return TimeInterval(aInterval.mStart, std::min(aInterval.mEnd, duration),
                      aInterval.mFuzz);
}

void MediaSourceDecoder::NotifyInitDataArrived() {
  MOZ_ASSERT(NS_IsMainThread());
  if (mDemuxer) {
    mDemuxer->NotifyInitDataArrived();
  }
}

void MediaSourceDecoder::NotifyDataArrived() {
  MOZ_ASSERT(NS_IsMainThread());
  MOZ_DIAGNOSTIC_ASSERT(!IsShutdown());
  NotifyReaderDataArrived();
  GetOwner()->DownloadProgressed();
}

already_AddRefed<nsIPrincipal> MediaSourceDecoder::GetCurrentPrincipal() {
  MOZ_ASSERT(NS_IsMainThread());
  return do_AddRef(mPrincipal);
}

bool MediaSourceDecoder::HadCrossOriginRedirects() {
  MOZ_ASSERT(NS_IsMainThread());
  return false;
}

#undef MSE_DEBUG
#undef MSE_DEBUGV

}  // namespace mozilla
