// Copyright 2018 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.

#include "third_party/blink/renderer/core/html/media/video_wake_lock.h"

#include "third_party/blink/public/common/browser_interface_broker_proxy.h"
#include "third_party/blink/public/mojom/wake_lock/wake_lock.mojom-blink.h"
#include "third_party/blink/renderer/core/dom/document.h"
#include "third_party/blink/renderer/core/dom/events/event.h"
#include "third_party/blink/renderer/core/frame/local_frame.h"
#include "third_party/blink/renderer/core/frame/picture_in_picture_controller.h"
#include "third_party/blink/renderer/core/html/media/html_video_element.h"
#include "third_party/blink/renderer/core/html/media/remote_playback_controller.h"
#include "third_party/blink/renderer/core/intersection_observer/intersection_observer_entry.h"
#include "third_party/blink/renderer/core/page/page.h"

namespace blink {

VideoWakeLock::VideoWakeLock(HTMLVideoElement& video)
    : PageVisibilityObserver(video.GetDocument().GetPage()),
      ExecutionContextLifecycleStateObserver(video.GetExecutionContext()),
      video_element_(video) {
  VideoElement().addEventListener(event_type_names::kPlaying, this, true);
  VideoElement().addEventListener(event_type_names::kPause, this, true);
  VideoElement().addEventListener(event_type_names::kEmptied, this, true);
  VideoElement().addEventListener(event_type_names::kEnterpictureinpicture,
                                  this, true);
  VideoElement().addEventListener(event_type_names::kLeavepictureinpicture,
                                  this, true);
  VideoElement().addEventListener(event_type_names::kVolumechange, this, true);

  if (RuntimeEnabledFeatures::VideoWakeLockOptimisationHiddenMutedEnabled())
    StartIntersectionObserver();
  else
    is_visible_ = true;

  RemotePlaybackController* remote_playback_controller =
      RemotePlaybackController::From(VideoElement());
  if (remote_playback_controller)
    remote_playback_controller->AddObserver(this);

  UpdateStateIfNeeded();
}

void VideoWakeLock::ElementDidMoveToNewDocument() {
  SetExecutionContext(VideoElement().GetExecutionContext());

  if (RuntimeEnabledFeatures::VideoWakeLockOptimisationHiddenMutedEnabled()) {
    intersection_observer_->disconnect();
    StartIntersectionObserver();
  }
}

void VideoWakeLock::PageVisibilityChanged() {
  Update();
}

void VideoWakeLock::OnVisibilityChanged(
    const HeapVector<Member<IntersectionObserverEntry>>& entries) {
  DCHECK(RuntimeEnabledFeatures::VideoWakeLockOptimisationHiddenMutedEnabled());

  is_visible_ = (entries.back()->intersectionRatio() > 0);
  Update();
}

void VideoWakeLock::Trace(Visitor* visitor) const {
  NativeEventListener::Trace(visitor);
  PageVisibilityObserver::Trace(visitor);
  ExecutionContextLifecycleStateObserver::Trace(visitor);
  visitor->Trace(video_element_);
  visitor->Trace(intersection_observer_);
}

void VideoWakeLock::Invoke(ExecutionContext*, Event* event) {
  if (event->type() == event_type_names::kPlaying) {
    playing_ = true;
  } else if (event->type() == event_type_names::kPause ||
             event->type() == event_type_names::kEmptied) {
    // In 4.8.12.5 steps 6.6.1, the media element is paused when a new load
    // happens without actually firing a pause event. Because of this, we need
    // to listen to the emptied event.
    playing_ = false;
  } else {
    DCHECK(event->type() == event_type_names::kEnterpictureinpicture ||
           event->type() == event_type_names::kLeavepictureinpicture ||
           event->type() == event_type_names::kVolumechange);
  }

  Update();
}

void VideoWakeLock::OnRemotePlaybackStateChanged(
    mojom::blink::PresentationConnectionState state) {
  remote_playback_state_ = state;
  Update();
}

void VideoWakeLock::ContextLifecycleStateChanged(mojom::FrameLifecycleState) {
  Update();
}

void VideoWakeLock::ContextDestroyed() {
  Update();
}

void VideoWakeLock::Update() {
  bool should_be_active = ShouldBeActive();
  if (should_be_active == active_)
    return;

  active_ = should_be_active;
  UpdateWakeLockService();
}

bool VideoWakeLock::ShouldBeActive() const {
  bool page_visible = GetPage() && GetPage()->IsPageVisible();
  bool in_picture_in_picture =
      PictureInPictureController::IsElementInPictureInPicture(&VideoElement());
  bool context_is_running =
      VideoElement().GetExecutionContext() &&
      !VideoElement().GetExecutionContext()->IsContextPaused();

  // The visibility requirements are met if one of the following is true:
  //  - it's in Picture-in-Picture;
  //  - it's audibly playing on a visible page;
  //  - it's visible to the user.
  bool visibility_requirements_met =
      (in_picture_in_picture ||
       (page_visible &&
        (is_visible_ || VideoElement().EffectiveMediaVolume())));

  // The video wake lock should be active iif:
  //  - it's playing;
  //  - the visibility requirements are met (see above);
  //  - it's *not* playing in Remote Playback;
  //  - the document is not paused nor destroyed.
  return playing_ && visibility_requirements_met &&
         remote_playback_state_ !=
             mojom::blink::PresentationConnectionState::CONNECTED &&
         context_is_running;
}

void VideoWakeLock::EnsureWakeLockService() {
  if (wake_lock_service_)
    return;

  LocalFrame* frame = VideoElement().GetDocument().GetFrame();
  if (!frame)
    return;

  scoped_refptr<base::SingleThreadTaskRunner> task_runner =
      frame->GetTaskRunner(TaskType::kMediaElementEvent);

  mojo::Remote<blink::mojom::blink::WakeLockService> service;
  frame->GetBrowserInterfaceBroker().GetInterface(
      service.BindNewPipeAndPassReceiver(task_runner));
  service->GetWakeLock(device::mojom::WakeLockType::kPreventDisplaySleep,
                       device::mojom::blink::WakeLockReason::kVideoPlayback,
                       "Video Wake Lock",
                       wake_lock_service_.BindNewPipeAndPassReceiver());
  wake_lock_service_.set_disconnect_handler(
      WTF::Bind(&VideoWakeLock::OnConnectionError, WrapWeakPersistent(this)));
}

void VideoWakeLock::OnConnectionError() {
  wake_lock_service_.reset();
}

void VideoWakeLock::UpdateWakeLockService() {
  EnsureWakeLockService();

  if (!wake_lock_service_)
    return;

  if (active_)
    wake_lock_service_->RequestWakeLock();
  else
    wake_lock_service_->CancelWakeLock();
}

void VideoWakeLock::StartIntersectionObserver() {
  intersection_observer_ = IntersectionObserver::Create(
      {}, {IntersectionObserver::kMinimumThreshold},
      &VideoElement().GetDocument(),
      WTF::BindRepeating(&VideoWakeLock::OnVisibilityChanged,
                         WrapWeakPersistent(this)),
      LocalFrameUkmAggregator::kMediaIntersectionObserver);
  intersection_observer_->observe(&VideoElement());
}

}  // namespace blink