// Copyright 2018 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "chrome/browser/picture_in_picture/picture_in_picture_window_manager.h"

#include "base/memory/raw_ptr.h"
#include "base/numerics/safe_conversions.h"
#include "chrome/browser/picture_in_picture/picture_in_picture_bounds_cache.h"
#include "chrome/browser/picture_in_picture/picture_in_picture_occlusion_tracker.h"
#include "chrome/browser/ui/browser_navigator_params.h"
#include "chrome/common/url_constants.h"
#include "content/public/browser/document_picture_in_picture_window_controller.h"
#include "content/public/browser/navigation_handle.h"
#include "content/public/browser/picture_in_picture_window_controller.h"
#include "content/public/browser/video_picture_in_picture_window_controller.h"
#include "content/public/browser/web_contents.h"
#include "content/public/browser/web_contents_delegate.h"
#include "content/public/browser/web_contents_observer.h"
#include "content/public/common/url_constants.h"
#include "extensions/buildflags/buildflags.h"
#include "ui/display/display.h"
#include "ui/gfx/geometry/resize_utils.h"
#include "ui/gfx/geometry/size.h"
#if !BUILDFLAG(IS_ANDROID)
#include "base/metrics/histogram_functions.h"
#include "base/numerics/checked_math.h"
#include "base/task/sequenced_task_runner.h"
// TODO(crbug.com/421608904): include auto_picture_in_picture_tab_helper for
// Android.
#include "chrome/browser/picture_in_picture/auto_picture_in_picture_tab_helper.h"
#include "chrome/browser/picture_in_picture/picture_in_picture_window.h"
#include "media/base/media_switches.h"
#include "net/base/url_util.h"
#include "third_party/blink/public/common/features.h"
#include "ui/views/view.h"
#endif  // !BUILDFLAG(IS_ANDROID)

#if BUILDFLAG(ENABLE_EXTENSIONS)
#include "extensions/common/constants.h"
#endif  // BUILDFLAG(ENABLE_EXTENSIONS)

#if BUILDFLAG(IS_OZONE)
#include "ui/ozone/public/ozone_platform.h"
#endif

namespace {
// The initial aspect ratio for Document Picture-in-Picture windows. This does
// not apply to video Picture-in-Picture windows.
constexpr double kInitialAspectRatio = 1.0;

// The minimum window size for Document Picture-in-Picture windows. This does
// not apply to video Picture-in-Picture windows.
constexpr gfx::Size kMinWindowSize(240, 52);

// The maximum window size for Document Picture-in-Picture windows. This does
// not apply to video Picture-in-Picture windows.
constexpr double kMaxWindowSizeRatio = 0.8;

#if !BUILDFLAG(IS_ANDROID)
// The largest fraction of the screen that Document Picture-in-Picture windows
// can take up by request of the website. The user can still manually resize to
// `kMaxWindowSizeRatio`.
constexpr double kMaxSiteRequestedWindowSizeRatio = 0.25;

// Returns true if a document picture-in-picture window should be focused upon
// opening it.
bool ShouldFocusPictureInPictureWindow(const NavigateParams& params) {
  // All document picture-in-picture openings must have a source_contents.
  CHECK(params.source_contents);

  const auto* auto_picture_in_picture_tab_helper =
      AutoPictureInPictureTabHelper::FromWebContents(params.source_contents);
  if (!auto_picture_in_picture_tab_helper) {
    return true;
  }

  // The picture-in-picture window should be focused unless it's opened by the
  // AutoPictureInPictureTabHelper.
  return !auto_picture_in_picture_tab_helper->IsInAutoPictureInPicture();
}

// Returns the maximum area in pixels that the site can request a
// picture-in-picture window to be.
base::CheckedNumeric<int> GetMaximumSiteRequestedWindowArea(
    const display::Display& display) {
  return display.size().GetCheckedArea() * kMaxSiteRequestedWindowSizeRatio;
}
#endif  // !BUILDFLAG(IS_ANDROID)

}  // namespace

// This web contents observer is used only for video PiP.
class PictureInPictureWindowManager::VideoWebContentsObserver final
    : public content::WebContentsObserver {
 public:
  VideoWebContentsObserver(PictureInPictureWindowManager* owner,
                           content::WebContents* web_contents)
      : content::WebContentsObserver(web_contents), owner_(owner) {}

  ~VideoWebContentsObserver() final = default;

  void PrimaryPageChanged(content::Page& page) final {
    // Closes the active Picture-in-Picture window if user navigates away.
    owner_->CloseWindowInternal();
  }

  void WebContentsDestroyed() final { owner_->CloseWindowInternal(); }

 private:
  // Owns |this|.
  raw_ptr<PictureInPictureWindowManager> owner_ = nullptr;
};

#if !BUILDFLAG(IS_ANDROID)
// This web contents observer is used only for document PiP.
class PictureInPictureWindowManager::DocumentWebContentsObserver final
    : public content::WebContentsObserver {
 public:
  DocumentWebContentsObserver(PictureInPictureWindowManager* owner,
                              content::WebContents* web_contents)
      : content::WebContentsObserver(web_contents), owner_(owner) {}

  ~DocumentWebContentsObserver() final = default;

  void WebContentsDestroyed() final { owner_->DocumentWebContentsDestroyed(); }

 private:
  // Owns |this|.
  raw_ptr<PictureInPictureWindowManager> owner_ = nullptr;
};
#endif  // !BUILDFLAG(IS_ANDROID)

PictureInPictureWindowManager* PictureInPictureWindowManager::GetInstance() {
  return base::Singleton<PictureInPictureWindowManager>::get();
}

void PictureInPictureWindowManager::EnterPictureInPictureWithController(
    content::PictureInPictureWindowController* pip_window_controller) {
  // If there was already a controller, close the existing window before
  // creating the next one.
  if (pip_window_controller_)
    CloseWindowInternal();

  pip_window_controller_ = pip_window_controller;

  pip_window_controller_->Show();

#if !BUILDFLAG(IS_ANDROID)
  if (number_of_existing_scoped_disallow_picture_in_pictures_ > 0) {
    // Don't exit picture-in-picture synchronously since exiting in the middle
    // of opening leaves us in a bad state.
    ExitPictureInPictureSoon();
    RecordPictureInPictureDisallowed(
        PictureInPictureDisallowedType::kNewWindowClosed);
  }

  MaybeRecordPictureInPictureChanged(true);
#endif  // !BUILDFLAG(IS_ANDROID)
}

#if !BUILDFLAG(IS_ANDROID)
void PictureInPictureWindowManager::EnterDocumentPictureInPicture(
    content::WebContents* parent_web_contents,
    content::WebContents* child_web_contents) {
  // If there was already a controller, close the existing window before
  // creating the next one. This needs to happen before creating the new
  // controller so that its precondition (no child_web_contents_) remains
  // valid.
  if (pip_window_controller_)
    CloseWindowInternal();

  // Start observing the parent web contents.
  document_web_contents_observer_ =
      std::make_unique<DocumentWebContentsObserver>(this, parent_web_contents);

  auto* controller = content::PictureInPictureWindowController::
      GetOrCreateDocumentPictureInPictureController(parent_web_contents);

  controller->SetChildWebContents(child_web_contents);

  // Show the new window. As a side effect, this also first closes any
  // pre-existing PictureInPictureWindowController's window (if any).
  EnterPictureInPictureWithController(controller);

  NotifyObserversOnEnterPictureInPicture();
}
#endif  // !BUILDFLAG(IS_ANDROID)

content::PictureInPictureResult
PictureInPictureWindowManager::EnterVideoPictureInPicture(
    content::WebContents* web_contents) {
  // Create or update |pip_window_controller_| for the current WebContents, if
  // it is a WebContents based video PIP.
  if (!pip_window_controller_ ||
      pip_window_controller_->GetWebContents() != web_contents ||
      !pip_window_controller_->GetWebContents()->HasPictureInPictureVideo()) {
    // If there was already a video PiP controller, close the existing window
    // before creating the next one.
    if (pip_window_controller_)
      CloseWindowInternal();

    CreateWindowInternal(web_contents);
  }

#if !BUILDFLAG(IS_ANDROID)
  MaybeRecordPictureInPictureChanged(true);
#endif  // !BUILDFLAG(IS_ANDROID)

  return content::PictureInPictureResult::kSuccess;
}

bool PictureInPictureWindowManager::ExitPictureInPictureViaWindowUi(
    UiBehavior behavior) {
  if (!pip_window_controller_) {
    return false;
  }

#if !BUILDFLAG(IS_ANDROID)
  // The user manually closed the pip window, so let the tab helper know in case
  // the auto-pip permission dialog was visible.
  if (auto* tab_helper = AutoPictureInPictureTabHelper::FromWebContents(
          pip_window_controller_->GetWebContents())) {
    tab_helper->OnUserClosedWindow();
  }
#endif  // !BUILDFLAG(IS_ANDROID)

  switch (behavior) {
    case UiBehavior::kCloseWindowOnly:
      pip_window_controller_->Close(/*should_pause_video=*/false);
      break;
    case UiBehavior::kCloseWindowAndPauseVideo:
      pip_window_controller_->Close(/*should_pause_video=*/true);
      break;
    case UiBehavior::kCloseWindowAndFocusOpener:
      pip_window_controller_->CloseAndFocusInitiator();
      break;
  }

#if !BUILDFLAG(IS_ANDROID)
  MaybeRecordPictureInPictureChanged(false);
#endif  // !BUILDFLAG(IS_ANDROID)

  return true;
}

bool PictureInPictureWindowManager::ExitPictureInPicture() {
  if (pip_window_controller_) {
    CloseWindowInternal();
    return true;
  }

#if !BUILDFLAG(IS_ANDROID)
  MaybeRecordPictureInPictureChanged(false);
#endif  // !BUILDFLAG(IS_ANDROID)

  return false;
}

// static
void PictureInPictureWindowManager::ExitPictureInPictureSoon() {
  // Unretained is safe because we're a singleton.
  base::SequencedTaskRunner::GetCurrentDefault()->PostTask(
      FROM_HERE,
      base::BindOnce(base::IgnoreResult(
                         &PictureInPictureWindowManager::ExitPictureInPicture),
                     base::Unretained(GetInstance())));
}

void PictureInPictureWindowManager::FocusInitiator() {
  if (pip_window_controller_)
    pip_window_controller_->FocusInitiator();
}

content::WebContents* PictureInPictureWindowManager::GetWebContents() const {
  if (!pip_window_controller_)
    return nullptr;

  return pip_window_controller_->GetWebContents();
}

content::WebContents* PictureInPictureWindowManager::GetChildWebContents()
    const {
  if (!pip_window_controller_)
    return nullptr;

  return pip_window_controller_->GetChildWebContents();
}

// static
bool PictureInPictureWindowManager::IsChildWebContents(
    content::WebContents* wc) {
  auto* instance =
      base::Singleton<PictureInPictureWindowManager>::GetIfExists();
  if (!instance) {
    // No manager => no pip window.
    return false;
  }

  return instance->GetChildWebContents() == wc;
}

// static
gfx::Size PictureInPictureWindowManager::AdjustRequestedSizeIfNecessary(
    const gfx::Size& requested_size,
    const display::Display& display) {
#if BUILDFLAG(IS_ANDROID)
  return requested_size;
#else   // BUILDFLAG(IS_ANDROID)
  base::CheckedNumeric<int> requested_area = requested_size.GetCheckedArea();
  base::CheckedNumeric<int> max_requested_area =
      GetMaximumSiteRequestedWindowArea(display);

  // If the website has requested an area too large to calculate, then their
  // request isn't particularly useful and we will fall back to the minimum
  // size.
  if (!requested_area.IsValid()) {
    return GetMinimumInnerWindowSize();
  }

  // If the screen size is too large to calculate, then fall back to allowing
  // the requested size. Note that this should only occur with a ridiculous
  // monitor size that would only happen in a test environment.
  if (!max_requested_area.IsValid()) {
    return requested_size;
  }

  // If the website's requested size is not too large, then there's nothing that
  // needs to change.
  if (requested_area.ValueOrDie() <= max_requested_area.ValueOrDie()) {
    return requested_size;
  }

  // Otherwise, if the website's requested size is too large, then shrink it to
  // the maximum allowed size while maintaining the given aspect ratio.
  gfx::Size minimum_size(GetMinimumInnerWindowSize());
  gfx::Size maximum_size(GetMaximumWindowSize(display));
  maximum_size.SetToMax(minimum_size);

  double original_width = static_cast<double>(requested_size.width());
  double original_height = static_cast<double>(requested_size.height());

  // Ideally, we could resize to perfectly maintain the aspect ratio while
  // hitting the max requested area.
  double ideal_scale_for_area =
      std::sqrt(static_cast<double>(max_requested_area.ValueOrDie()) /
                static_cast<double>(requested_area.ValueOrDie()));

  // However, we need to ensure that we remain large enough for the minimum size
  // in both dimensions.
  double scale_needed_for_min_width =
      static_cast<double>(minimum_size.width()) / original_width;
  double scale_needed_for_min_height =
      static_cast<double>(minimum_size.height()) / original_height;
  double minimum_scale =
      std::max(scale_needed_for_min_width, scale_needed_for_min_height);

  // And also that we remain small enough to be within the maximum size in both
  // dimensions.
  double scale_needed_for_max_width =
      static_cast<double>(maximum_size.width()) / original_width;
  double scale_needed_for_max_height =
      static_cast<double>(maximum_size.height()) / original_height;
  double maximum_scale =
      std::min(scale_needed_for_max_width, scale_needed_for_max_height);

  gfx::Size output_size;

  // If the smallest scale needed to reach the minimum size is larger than the
  // largest scale that fits within the maximum bounds, then we can't perfectly
  // maintain aspect ratio.
  if (minimum_scale > maximum_scale) {
    if (original_width > original_height) {
      // If this is because the requested width is too large, then fall back to
      // the minimum height with as much width as is allowed.
      output_size.set_width(
          static_cast<double>(max_requested_area.ValueOrDie()) /
          minimum_size.height());
      output_size.set_height(minimum_size.height());
    } else {
      // If this is because the requested height is too large, then fall back to
      // the minimum width with as much height as is allowed.
      output_size.set_width(minimum_size.width());
      output_size.set_height(
          static_cast<double>(max_requested_area.ValueOrDie()) /
          minimum_size.width());
    }
  } else {
    // Otherwise, either scale by the ideal factor or make it smaller than that
    // to fit within the maximum size.
    double effective_scale = std::min(ideal_scale_for_area, maximum_scale);
    output_size.set_width(original_width * effective_scale);
    output_size.set_height(original_height * effective_scale);
  }

  // Ensure the standard size restrictions are still met.
  output_size.SetToMax(minimum_size);
  output_size.SetToMin(maximum_size);

  return output_size;
#endif  // BUILDFLAG(IS_ANDROID)
}

std::optional<gfx::Rect>
PictureInPictureWindowManager::GetPictureInPictureWindowBounds() const {
  return pip_window_controller_ ? pip_window_controller_->GetWindowBounds()
                                : std::nullopt;
}

gfx::Rect PictureInPictureWindowManager::CalculateOuterWindowBounds(
    const blink::mojom::PictureInPictureWindowOptions& pip_options,
    const display::Display& display,
    const gfx::Size& minimum_outer_window_size,
    const gfx::Size& excluded_margin) {
  // TODO(crbug.com/40841415): This copies a bunch of logic from
  // VideoOverlayWindowViews. That class and this one should be refactored so
  // VideoOverlayWindowViews uses PictureInPictureWindowManager to calculate
  // window sizing.
  gfx::Rect work_area = display.work_area();
  gfx::Rect window_bounds;

  // If the outer bounds for this request are cached, then ignore everything
  // else and use those, unless the site requested that we don't.
  //
  // Typically, we have a window controller at this point, but often during
  // tests we don't.  Don't worry about the cache if it's missing.
  if (pip_window_controller_) {
    auto* const web_contents = pip_window_controller_->GetWebContents();
    std::optional<gfx::Size> requested_content_bounds;
    if (pip_options.width > 0 && pip_options.height > 0) {
      requested_content_bounds.emplace(pip_options.width, pip_options.height);
    }
    auto cached_window_bounds =
        PictureInPictureBoundsCache::GetBoundsForNewWindow(
            web_contents, display, requested_content_bounds);
    // Ignore the result if we're asked to do so.  Note that we still have to
    // ask the cache, so that it's set up to accept position updates later for
    // this request.
    if (cached_window_bounds && !pip_options.prefer_initial_window_placement) {
      // Cache hit!  Just return it as the window bounds.
      return *cached_window_bounds;
    }
  }

  if (pip_options.width > 0 && pip_options.height > 0) {
    // Use width and height if we have them both, and ensure that the size isn't
    // too large.
    gfx::Size requested_window_size(
        base::saturated_cast<int>(pip_options.width),
        base::saturated_cast<int>(pip_options.height));
    gfx::Size window_size =
        AdjustRequestedSizeIfNecessary(requested_window_size, display);

#if !BUILDFLAG(IS_ANDROID)
    if (is_calculating_initial_document_pip_size_) {
      base::UmaHistogramBoolean(
          "Media.DocumentPictureInPicture.RequestedLargeInitialSize",
          requested_window_size != window_size);
    }
#endif  // !BUILDFLAG(IS_ANDROID)

    // The pip options are the desired inner size, so we add any non-client size
    // we need to convert to outer size by adding back the margin around the
    // inner area.
    window_size += excluded_margin;

    window_size.SetToMin(GetMaximumWindowSize(display));
    window_size.SetToMax(minimum_outer_window_size);
    window_bounds = gfx::Rect(window_size);
  } else {
    // Otherwise, fall back to the aspect ratio.
    gfx::Size window_size(work_area.width() / 5, work_area.height() / 5);
    window_size.SetToMin(GetMaximumWindowSize(display));
    window_size.SetToMax(minimum_outer_window_size);
    window_bounds = gfx::Rect(window_size);
    gfx::SizeRectToAspectRatioWithExcludedMargin(
        gfx::ResizeEdge::kTopLeft, kInitialAspectRatio,
        GetMinimumInnerWindowSize(), GetMaximumWindowSize(display),
        excluded_margin, window_bounds);
  }

#if BUILDFLAG(IS_OZONE)
  // Some platforms like ozone/wayland don't allow clients to control windows
  // in global screen coordinates. So it is not possible to position windows in
  // that case.
  if (!ui::OzonePlatform::GetInstance()
           ->GetPlatformProperties()
           .supports_global_screen_coordinates) {
    return window_bounds;
  }
#endif
  // Position the window.
  int window_diff_width = work_area.right() - window_bounds.width();
  int window_diff_height = work_area.bottom() - window_bounds.height();

  // Keep a margin distance of 2% the average of the two window size
  // differences, keeping the margins consistent.
  int buffer = (window_diff_width + window_diff_height) / 2 * 0.02;

  gfx::Point default_origin =
      gfx::Point(window_diff_width - buffer, window_diff_height - buffer);
  window_bounds.set_origin(default_origin);

  return window_bounds;
}

gfx::Rect
PictureInPictureWindowManager::CalculateInitialPictureInPictureWindowBounds(
    const blink::mojom::PictureInPictureWindowOptions& pip_options,
    const display::Display& display) {
#if !BUILDFLAG(IS_ANDROID)
  RecordDocumentPictureInPictureRequestedSizeMetrics(pip_options, display);
  base::AutoReset<bool> auto_reset(&is_calculating_initial_document_pip_size_,
                                   true);
#endif  // !BUILDFLAG(IS_ANDROID)

  // Use an empty `excluded_margin`, which more or less guarantees that these
  // bounds are incorrect if `pip_options` includes a requested inner size that
  // we'd like to honor.  It's okay, because we'll recompute it later once we
  // know the excluded margin.
  return CalculateOuterWindowBounds(pip_options, display,
                                    GetMinimumInnerWindowSize(), gfx::Size());
}

void PictureInPictureWindowManager::UpdateCachedBounds(
    const gfx::Rect& most_recent_bounds) {
  // Typically, we have a window controller at this point, but often during
  // tests we don't.  Don't worry about the cache if it's missing.
  if (!pip_window_controller_) {
    return;
  }
  auto* const web_contents = pip_window_controller_->GetWebContents();
  PictureInPictureBoundsCache::UpdateCachedBounds(web_contents,
                                                  most_recent_bounds);
}

void PictureInPictureWindowManager::ClearCachedBounds() {
  if (!pip_window_controller_) {
    return;
  }
  auto* const web_contents = pip_window_controller_->GetWebContents();
  PictureInPictureBoundsCache::ClearCachedBounds(web_contents);
}

// static
gfx::Size PictureInPictureWindowManager::GetMinimumInnerWindowSize() {
  return kMinWindowSize;
}

// static
gfx::Size PictureInPictureWindowManager::GetMaximumWindowSize(
    const display::Display& display) {
  return gfx::ScaleToRoundedSize(display.size(), kMaxWindowSizeRatio);
}

// static
void PictureInPictureWindowManager::SetWindowParams(NavigateParams& params) {
#if !BUILDFLAG(IS_ANDROID)
  // Always show document picture-in-picture in a new window. When this is
  // not opened via the AutoPictureInPictureTabHelper, focus the window.
  params.window_action = ShouldFocusPictureInPictureWindow(params)
                             ? NavigateParams::SHOW_WINDOW
                             : NavigateParams::SHOW_WINDOW_INACTIVE;
#endif  // !BUILDFLAG(IS_ANDROID)
}

// static
bool PictureInPictureWindowManager::IsSupportedForDocumentPictureInPicture(
    const GURL& url) {
#if !BUILDFLAG(IS_ANDROID)
  // Only allow document PiP to be opened if the URL is of a type that we know
  // how to display in the title bar.  Otherwise, the title bar might be
  // misleading in certain scenarios.  See https://crbug.com/1460025 .
#if BUILDFLAG(ENABLE_EXTENSIONS)
  if (url.SchemeIs(extensions::kExtensionScheme)) {
    return true;
  }
#endif  // BUILDFLAG(ENABLE_EXTENSIONS)

  return url.SchemeIs(url::kHttpsScheme) || url.SchemeIsFile() ||
         net::IsLocalhost(url) || url.SchemeIs(content::kChromeUIScheme) ||
         url.SchemeIs(chrome::kIsolatedAppScheme);
#else
  return false;
#endif  // !BUILDFLAG(IS_ANDROID)
}

void PictureInPictureWindowManager::CreateWindowInternal(
    content::WebContents* web_contents) {
  video_web_contents_observer_ =
      std::make_unique<VideoWebContentsObserver>(this, web_contents);
  auto* video_pip_window_controller =
      content::PictureInPictureWindowController::
          GetOrCreateVideoPictureInPictureController(web_contents);

  video_pip_window_controller->SetOnWindowCreatedNotifyObserversCallback(
      base::BindOnce(&PictureInPictureWindowManager::
                         NotifyObserversOnEnterPictureInPicture,
                     base::Unretained(this)));
  pip_window_controller_ = video_pip_window_controller;

#if !BUILDFLAG(IS_ANDROID)
  if (number_of_existing_scoped_disallow_picture_in_pictures_ > 0) {
    // Don't exit picture-in-picture synchronously since exiting in the middle
    // of opening leaves us in a bad state.
    ExitPictureInPictureSoon();
    RecordPictureInPictureDisallowed(
        PictureInPictureDisallowedType::kNewWindowClosed);
  }
#endif  // !BUILDFLAG(IS_ANDROID)
}

void PictureInPictureWindowManager::CloseWindowInternal() {
  CHECK(pip_window_controller_);

  video_web_contents_observer_.reset();
  pip_window_controller_->Close(false /* should_pause_video */);
  pip_window_controller_ = nullptr;

#if !BUILDFLAG(IS_ANDROID)
  MaybeRecordPictureInPictureChanged(false);
#endif  // !BUILDFLAG(IS_ANDROID)
}

bool PictureInPictureWindowManager::IsPictureInPictureDisabled() const {
#if !BUILDFLAG(IS_ANDROID)
  return number_of_existing_scoped_disallow_picture_in_pictures_ > 0;
#else
  return false;
#endif  // !BUILDFLAG(IS_ANDROID)
}

#if !BUILDFLAG(IS_ANDROID)
void PictureInPictureWindowManager::DocumentWebContentsDestroyed() {
  // Document PiP window controller also observes the parent and child web
  // contents, so we only need to forget the controller here when user closes
  // the parent web contents with the PiP window open.
  document_web_contents_observer_.reset();
  if (pip_window_controller_)
    pip_window_controller_ = nullptr;
}

std::unique_ptr<AutoPipSettingOverlayView>
PictureInPictureWindowManager::GetOverlayView(
    views::View* anchor_view,
    views::BubbleBorder::Arrow arrow) {
  // This should probably CHECK, but tests often can't set the controller.
  if (!pip_window_controller_) {
    return nullptr;
  }

  // This is redundant with the check for `auto_pip_tab_helper`, below.
  // However, for safety, early-out here when the flag is off.
  if (!base::FeatureList::IsEnabled(
          blink::features::kMediaSessionEnterPictureInPicture)) {
    return nullptr;
  }

  // It would be nice to create this in `EnterPictureInPicture*`, but detecting
  // auto-pip while pip is in the process of opening doesn't work.
  //
  // Remember that this can be called more than once per pip window instance,
  // such as on theme change in some cases or on Linux at any time at all, when
  // the window frame is destroyed and recreated.  Thus, one must be careful not
  // to get confused between the user closing the pip window and the pip window
  // closing itself.  Otherwise, these events would adjust the embargo counter
  // incorrectly.  As it is, we explicitly call back when the user closes the
  // pip window for that purpose.

  auto* const web_contents = pip_window_controller_->GetWebContents();
  CHECK(web_contents);

  auto* auto_pip_tab_helper =
      AutoPictureInPictureTabHelper::FromWebContents(web_contents);
  if (!auto_pip_tab_helper) {
    return nullptr;
  }

  // See if we should display the allow / block UI.  This might call back the
  // close cb, if the pip window should be blocked.
  auto overlay_view = auto_pip_tab_helper->CreateOverlayPermissionViewIfNeeded(
      base::BindOnce(&PictureInPictureWindowManager::ExitPictureInPictureSoon),
      anchor_view, arrow);

  if (!overlay_view) {
    // It's already allowed or blocked / embargoed.
    return nullptr;
  }

  // We need to ask the user.
  if (auto* pip_contents = GetChildWebContents()) {
    // For document pip, block input too while the permission dialog is shown.
    overlay_view->IgnoreInputEvents(pip_contents);
  }

  return overlay_view;
}

PictureInPictureOcclusionTracker*
PictureInPictureWindowManager::GetOcclusionTracker() {
  CreateOcclusionTrackerIfNecessary();
  return occlusion_tracker_.get();
}

void PictureInPictureWindowManager::CreateOcclusionTrackerIfNecessary() {
  if (occlusion_tracker_) {
    return;
  }

  if (base::FeatureList::IsEnabled(media::kPictureInPictureOcclusionTracking)) {
    occlusion_tracker_ = std::make_unique<PictureInPictureOcclusionTracker>();
  }
}

bool PictureInPictureWindowManager::ShouldFileDialogBlockPictureInPicture(
    content::WebContents* owner_web_contents) {
  if (!base::FeatureList::IsEnabled(media::kFileDialogsBlockPictureInPicture)) {
    return false;
  }

  // File dialogs opened inside document picture-in-picture windows should not
  // block picture-in-picture.
  if (pip_window_controller_ &&
      pip_window_controller_->GetChildWebContents() == owner_web_contents) {
    return false;
  }

  return true;
}

void PictureInPictureWindowManager::OnScopedDisallowPictureInPictureCreated(
    base::PassKey<ScopedDisallowPictureInPicture>) {
  number_of_existing_scoped_disallow_picture_in_pictures_++;
  if (pip_window_controller_) {
    ExitPictureInPicture();
    RecordPictureInPictureDisallowed(
        PictureInPictureDisallowedType::kExistingWindowClosed);
  }
}

void PictureInPictureWindowManager::OnScopedDisallowPictureInPictureDestroyed(
    base::PassKey<ScopedDisallowPictureInPicture>) {
  CHECK_NE(number_of_existing_scoped_disallow_picture_in_pictures_, 0u);
  number_of_existing_scoped_disallow_picture_in_pictures_--;
}

void PictureInPictureWindowManager::OnPictureInPictureWindowShown(
    PictureInPictureWindow* window) {
  picture_in_picture_window_ = window;
  if (IsPictureInPictureForceTucked()) {
    picture_in_picture_window_->SetForcedTucking(true);
    RecordPictureInPictureTucked(PictureInPictureTuckedType::kNewWindowTucked);
  }
}

void PictureInPictureWindowManager::OnPictureInPictureWindowHidden(
    PictureInPictureWindow* window) {
  if (picture_in_picture_window_ == window) {
    picture_in_picture_window_ = nullptr;
  }
}

bool PictureInPictureWindowManager::ShouldFileDialogTuckPictureInPicture(
    content::WebContents* owner_web_contents) {
  if (!base::FeatureList::IsEnabled(media::kFileDialogsTuckPictureInPicture)) {
    return false;
  }

  // File dialogs opened inside document picture-in-picture windows should not
  // tuck picture-in-picture.
  if (pip_window_controller_ &&
      pip_window_controller_->GetChildWebContents() == owner_web_contents) {
    return false;
  }

  return true;
}

void PictureInPictureWindowManager::OnScopedTuckPictureInPictureCreated(
    base::PassKey<ScopedTuckPictureInPicture>) {
  number_of_existing_scoped_tuck_picture_in_pictures_++;
  if (picture_in_picture_window_) {
    picture_in_picture_window_->SetForcedTucking(true);
    RecordPictureInPictureTucked(
        PictureInPictureTuckedType::kExistingWindowTucked);
  }
}

void PictureInPictureWindowManager::OnScopedTuckPictureInPictureDestroyed(
    base::PassKey<ScopedTuckPictureInPicture>) {
  CHECK_NE(number_of_existing_scoped_tuck_picture_in_pictures_, 0u);
  number_of_existing_scoped_tuck_picture_in_pictures_--;
  if (picture_in_picture_window_ && !IsPictureInPictureForceTucked()) {
    picture_in_picture_window_->SetForcedTucking(false);
  }
}

bool PictureInPictureWindowManager::IsPictureInPictureForceTucked() const {
  return number_of_existing_scoped_tuck_picture_in_pictures_ > 0;
}

void PictureInPictureWindowManager::
    RecordDocumentPictureInPictureRequestedSizeMetrics(
        const blink::mojom::PictureInPictureWindowOptions& pip_options,
        const display::Display& display) {
  // Directly record the requested width and height.
  base::UmaHistogramCounts1000(
      "Media.DocumentPictureInPicture.RequestedInitialWidth",
      pip_options.width);
  base::UmaHistogramCounts1000(
      "Media.DocumentPictureInPicture.RequestedInitialHeight",
      pip_options.height);

  // Calculate and record the ratio of requested picture-in-picture size to the
  // total screen size.
  gfx::Size requested_size(pip_options.width, pip_options.height);
  base::CheckedNumeric<int> requested_area = requested_size.GetCheckedArea();
  base::CheckedNumeric<int> screen_area =
      display.GetSizeInPixel().GetCheckedArea();
  if (requested_area.IsValid() && screen_area.IsValid()) {
    int recorded_percent;

    // We already know `screen_area` is valid, so `ValueOrDie()` should never
    // die.
    if (screen_area.ValueOrDie() == base::MakeStrictNum(0)) {
      // If we have an empty screen area (which should generally not happen in
      // practice), then record the requested size as 100 percent of the screen
      // size.
      recorded_percent = 100;
    } else {
      // Otherwise, calculate the actual percentage, and clamp to a value
      // between 1 and 100 percent.
      base::CheckedNumeric<int> percent_screen_coverage_requested =
          (requested_area * 100) / screen_area;
      recorded_percent = std::min(
          std::max(percent_screen_coverage_requested.ValueOrDefault(100),
                   base::MakeStrictNum(1)),
          base::MakeStrictNum(100));
    }
    base::UmaHistogramPercentage(
        "Media.DocumentPictureInPicture.RequestedSizeToScreenRatio",
        recorded_percent);
  }
}

void PictureInPictureWindowManager::RecordPictureInPictureDisallowed(
    PictureInPictureDisallowedType type) {
  base::UmaHistogramEnumeration("Media.PictureInPicture.Disallowed", type);
}

void PictureInPictureWindowManager::RecordPictureInPictureTucked(
    PictureInPictureTuckedType type) {
  base::UmaHistogramEnumeration("Media.PictureInPicture.Tucked", type);
}

void PictureInPictureWindowManager::MaybeRecordPictureInPictureChanged(
    bool is_picture_in_picture) {
  if (!uma_helper_) {
    uma_helper_ = std::make_unique<PictureInPictureWindowManagerUmaHelper>();
  }

  uma_helper_->MaybeRecordPictureInPictureChanged(is_picture_in_picture);

  if (!is_picture_in_picture) {
    uma_helper_.reset();
  }
}

#endif  // !BUILDFLAG(IS_ANDROID)

void PictureInPictureWindowManager::NotifyObserversOnEnterPictureInPicture() {
  for (Observer& observer : observers_) {
    observer.OnEnterPictureInPicture();
  }
}

PictureInPictureWindowManager::PictureInPictureWindowManager() = default;

PictureInPictureWindowManager::~PictureInPictureWindowManager() = default;