// Copyright 2019 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "ui/views/layout/layout_manager_base.h"

#include <utility>

#include "base/auto_reset.h"
#include "base/check_op.h"
#include "base/containers/contains.h"
#include "base/dcheck_is_on.h"
#include "base/memory/raw_ptr.h"
#include "base/trace_event/trace_event.h"
#include "ui/views/view.h"
#include "ui/views/view_class_properties.h"

#if DCHECK_IS_ON()
#include <algorithm>
#endif

namespace views {

namespace {

// Adjusts |child_available_size| by adding the difference between the host
// view's size and the size available to it.
SizeBounds AdjustAvailableSizeForParentAvailableSize(
    const View* host,
    const SizeBounds& child_available_size) {
  SizeBounds available_size = child_available_size;
  if (host && host->parent() && available_size != SizeBounds()) {
    SizeBounds host_additional_size = host->parent()->GetAvailableSize(host);
    host_additional_size.Enlarge(-host->width(), -host->height());
    if (host_additional_size.width().is_bounded()) {
      available_size.width() += host_additional_size.width();
    }
    if (host_additional_size.height().is_bounded()) {
      available_size.height() += host_additional_size.height();
    }
  }
  return available_size;
}

bool IncludeInLayout(const View* view) {
  return !view->GetProperty(kViewIgnoredByLayoutKey);
}

}  // anonymous namespace

LayoutManagerBase::~LayoutManagerBase() = default;

gfx::Size LayoutManagerBase::GetPreferredSize(const View* host) const {
  DCHECK_EQ(host_view_, host);
  if (!cached_preferred_size_) {
    cached_preferred_size_ = CalculateProposedLayout(SizeBounds()).host_size;
  }
  return *cached_preferred_size_;
}

gfx::Size LayoutManagerBase::GetPreferredSize(
    const View* host,
    const SizeBounds& available_size) const {
  DCHECK_EQ(host_view_, host);
  if (available_size.width().is_bounded()) {
    return CalculateProposedLayout(available_size).host_size;
  }

  return GetPreferredSize(host);
}

gfx::Size LayoutManagerBase::GetMinimumSize(const View* host) const {
  DCHECK_EQ(host_view_, host);
  if (!cached_minimum_size_) {
    cached_minimum_size_ = CalculateProposedLayout(SizeBounds(0, 0)).host_size;
  }
  return *cached_minimum_size_;
}

int LayoutManagerBase::GetPreferredHeightForWidth(const View* host,
                                                  int width) const {
  if (!cached_height_for_width_ || cached_height_for_width_->width() != width) {
    const int height = CalculateProposedLayout(SizeBounds(width, SizeBound()))
                           .host_size.height();
    cached_height_for_width_ = gfx::Size(width, height);
  }

  return cached_height_for_width_->height();
}

SizeBounds LayoutManagerBase::GetAvailableSize(const View* host,
                                               const View* view) const {
  DCHECK_EQ(host_view_, host);
  if (!cached_layout_size_) {
    GetProposedLayout(host->size());
  }
  if (cached_layout_size_) {
    for (const auto& child_layout : cached_layout_.child_layouts) {
      if (child_layout.child_view == view) {
        return AdjustAvailableSizeForParentAvailableSize(
            host, child_layout.available_size);
      }
    }
  }
  return SizeBounds();
}

void LayoutManagerBase::Layout(View* host) {
  DCHECK_EQ(host_view_, host);
  TRACE_EVENT1("ui", "LayoutManagerBase::Layout", "class",
               host->GetClassName());
  // A handful of views will cause invalidations while they are being
  // positioned, which can result in loops or loss of layout data during layout
  // application. Therefore we protect the layout manager from spurious
  // invalidations during the layout process.
  base::AutoReset<bool> setter(&suppress_invalidate_, true);
  LayoutImpl();
}

void LayoutManagerBase::OnViewPropertyChanged(View* observed_view,
                                              const void* key,
                                              int64_t old_value) {
  if (key != kViewIgnoredByLayoutKey) {
    return;
  }

  CHECK_EQ(GetRootLayoutManager(), this);

  const bool include = IncludeInLayout(observed_view);
  if (include != child_infos_[observed_view].included_in_layout) {
    base::AutoReset<bool> setter(&suppress_invalidate_, true);
    PropagateChildViewIncludedInLayout(observed_view, include);
    InvalidateHost(false);
  }
}

std::vector<raw_ptr<View, VectorExperimental>>
LayoutManagerBase::GetChildViewsInPaintOrder(const View* host) const {
  DCHECK_EQ(host_view_, host);
  return LayoutManager::GetChildViewsInPaintOrder(host);
}

ProposedLayout LayoutManagerBase::GetProposedLayout(
    const gfx::Size& host_size) const {
  if (cached_layout_size_ != host_size) {
#if (DCHECK_IS_ON())
    // This calculation must not be re-entrant.
    DCHECK(!calculating_layout_);
    base::AutoReset<bool> calculating_layout(&calculating_layout_, true);
#endif
    cached_layout_size_ = host_size;
    cached_layout_ = CalculateProposedLayout(SizeBounds(host_size));
  }
  return cached_layout_;
}

ProposedLayout LayoutManagerBase::GetProposedLayout(
    const SizeBounds& size_bounds,
    PassKeyType) const {
  return CalculateProposedLayout(size_bounds);
}

LayoutManagerBase::LayoutManagerBase() = default;

SizeBounds LayoutManagerBase::GetAvailableHostSize() const {
  DCHECK(host_view());
  const auto* const parent = host_view()->parent();
  return parent ? parent->GetAvailableSize(host_view()) : SizeBounds();
}

bool LayoutManagerBase::IsChildIncludedInLayout(const View* child,
                                                bool include_hidden) const {
  const auto it = child_infos_.find(child);

  // During callbacks when a child is removed we can get in a state where a view
  // in the child list of the host view is not in |child_infos_|. In that case,
  // the view is being removed and is not part of the layout.
  if (it == child_infos_.end()) {
    return false;
  }

  return it->second.included_in_layout &&
         (include_hidden || it->second.can_be_visible);
}

bool LayoutManagerBase::CanBeVisible(const View* child) const {
  const auto it = child_infos_.find(child);

  // During callbacks when a child is removed we can get in a state where a view
  // in the child list of the host view is not in |child_infos_|. In that case,
  // the view is being removed and is not part of the layout.
  if (it == child_infos_.end()) {
    return false;
  }

  return it->second.can_be_visible;
}

void LayoutManagerBase::LayoutImpl() {
  ApplyLayout(GetProposedLayout(host_view_->size()));
}

void LayoutManagerBase::ApplyLayout(const ProposedLayout& layout) {
  const SizeBounds new_available_size = GetAvailableHostSize();

  for (auto& child_layout : layout.child_layouts) {
    DCHECK_EQ(host_view_, child_layout.child_view->parent());

    // Since we have a non-const reference to the parent here, we can safely use
    // a non-const reference to the child.
    View* const child_view = child_layout.child_view;
    // Should not be attempting to modify a child view that has been removed.
    DCHECK(host_view()->GetIndexOf(child_view).has_value());
    if (child_view->GetVisible() != child_layout.visible) {
      SetViewVisibility(child_view, child_layout.visible);
    }

    // If the child view is not visible and we haven't bothered to specify
    // bounds, don't bother setting them (which would cause another cascade of
    // events that wouldn't do anything useful).
    if (new_available_size != cached_available_size_ || child_layout.visible ||
        !child_layout.bounds.IsEmpty()) {
      const bool size_changed =
          child_view->bounds().size() != child_layout.bounds.size();
      if (child_view->bounds() != child_layout.bounds) {
        child_view->SetBoundsRect(child_layout.bounds);
      }
      // Child layouts which are not invalid will not be laid out by the default
      // View::Layout() implementation, but if there is an available size
      // constraint it's important that the child view be laid out. So we'll do
      // it here.
      // TODO(dfried): figure out a better way to handle this.
      if (!size_changed && child_layout.available_size != SizeBounds()) {
        child_view->DeprecatedLayoutImmediately();
      }
    }
  }

  cached_available_size_ = new_available_size;
}

void LayoutManagerBase::InvalidateHost(bool mark_layouts_changed) {
  if (mark_layouts_changed) {
    DCHECK(!suppress_invalidate_);
    if (host_view()) {
      // This has the side-effect of also invalidating all of the layouts
      // associated with the host view, from the view's layout through its
      // owned layouts (and their owned layouts).
      host_view()->InvalidateLayout();
    } else {
      // Even without a host view, ensure that the layout tree is invalidated.
      GetRootLayoutManager()->InvalidateLayout();
    }
  } else if (host_view()) {
    // Suppress invalidation at the root layout, so host view layout does not
    // propagate down the layout manager tree.
    LayoutManagerBase* const root_layout = GetRootLayoutManager();
    base::AutoReset<bool> setter(&root_layout->suppress_invalidate_, true);
    host_view()->InvalidateLayout();
  }
}

bool LayoutManagerBase::OnChildViewIncludedInLayoutSet(View* child_view,
                                                       bool ignored) {
  OnLayoutChanged();
  return false;
}

bool LayoutManagerBase::OnViewAdded(View* host, View* view) {
  OnLayoutChanged();
  return false;
}

bool LayoutManagerBase::OnViewRemoved(View* host, View* view) {
  OnLayoutChanged();
  return false;
}

bool LayoutManagerBase::OnViewVisibilitySet(View* host,
                                            View* view,
                                            bool visible) {
  OnLayoutChanged();
  return false;
}

void LayoutManagerBase::OnInstalled(View* host) {}

void LayoutManagerBase::OnLayoutChanged() {
  cached_minimum_size_.reset();
  cached_preferred_size_.reset();
  cached_height_for_width_.reset();
  cached_layout_size_.reset();
}

void LayoutManagerBase::InvalidateLayout() {
  if (!suppress_invalidate_) {
    base::AutoReset<bool> setter(&suppress_invalidate_, true);
    PropagateInvalidateLayout();
  }
}

void LayoutManagerBase::Installed(View* host_view) {
  DCHECK(host_view);
  DCHECK(!host_view_);
  DCHECK(child_infos_.empty());
  DCHECK_EQ(GetRootLayoutManager(), this);

  for (View* child : host_view->children()) {
    view_observations_.AddObservation(child);
  }

  base::AutoReset<bool> setter(&suppress_invalidate_, true);
  PropagateInstalled(host_view);
}

void LayoutManagerBase::ViewAdded(View* host, View* view) {
  DCHECK_EQ(host_view_, host);
  DCHECK(!base::Contains(child_infos_, view));
  DCHECK_EQ(GetRootLayoutManager(), this);

  view_observations_.AddObservation(view);

  base::AutoReset<bool> setter(&suppress_invalidate_, true);
  const bool invalidate = PropagateViewAdded(host, view);
  if (invalidate || view->GetVisible()) {
    InvalidateHost(false);
  }
}

void LayoutManagerBase::ViewRemoved(View* host, View* view) {
  DCHECK_EQ(host_view_, host);
  DCHECK(base::Contains(child_infos_, view));
  DCHECK_EQ(GetRootLayoutManager(), this);

  auto it = child_infos_.find(view);
  CHECK(it != child_infos_.end());
  const bool removed_visible =
      it->second.can_be_visible && it->second.included_in_layout;

  view_observations_.RemoveObservation(view);

  base::AutoReset<bool> setter(&suppress_invalidate_, true);
  const bool invalidate = PropagateViewRemoved(host, view);
  if (invalidate || removed_visible) {
    InvalidateHost(false);
  }
}

void LayoutManagerBase::ViewVisibilitySet(View* host,
                                          View* view,
                                          bool old_visibility,
                                          bool new_visibility) {
  DCHECK_EQ(host_view_, host);
  auto it = child_infos_.find(view);
  CHECK(it != child_infos_.end());
  if (it->second.can_be_visible == new_visibility) {
    return;
  }

  base::AutoReset<bool> setter(&suppress_invalidate_, true);
  const bool invalidate =
      PropagateViewVisibilitySet(host, view, new_visibility);
  if (invalidate || it->second.included_in_layout) {
    InvalidateHost(false);
  }
}

void LayoutManagerBase::AddOwnedLayoutInternal(
    std::unique_ptr<LayoutManagerBase> owned_layout) {
  DCHECK(owned_layout);
  DCHECK(!owned_layout->parent_layout_);

  // View observations should only exist on the root.
#if DCHECK_IS_ON()
  // If `owned_layout` knows about views the root doesn't, something is going to
  // go wrong.
  const LayoutManagerBase* const root_layout = GetRootLayoutManager();
  std::ranges::for_each(
      owned_layout->view_observations_.sources(), [&](View* source) {
        DCHECK(root_layout->view_observations_.IsObservingSource(source));
      });
#endif
  owned_layout->view_observations_.RemoveAllObservations();

  // Inform `owned_layout` about `host_view_` and its children.
  if (host_view_) {
    base::AutoReset<bool> setter(&suppress_invalidate_, true);
    owned_layout->PropagateInstalled(host_view_);
    for (View* child_view : host_view_->children()) {
      const ChildInfo& child_info = child_infos_.find(child_view)->second;
      owned_layout->PropagateChildViewIncludedInLayout(
          child_view, child_info.included_in_layout);
      owned_layout->PropagateViewVisibilitySet(host_view_, child_view,
                                               child_info.can_be_visible);
    }
  }

  // Attach `owned_layout` to us.
  owned_layout->parent_layout_ = this;
  owned_layouts_.emplace_back(std::move(owned_layout));
}

LayoutManagerBase* LayoutManagerBase::GetRootLayoutManager() {
  LayoutManagerBase* result = this;
  while (result->parent_layout_) {
    result = result->parent_layout_;
  }
  return result;
}

bool LayoutManagerBase::PropagateChildViewIncludedInLayout(View* child_view,
                                                           bool include) {
  child_infos_[child_view].included_in_layout = include;

  bool result = false;
  for (auto& owned_layout : owned_layouts_) {
    result |=
        owned_layout->PropagateChildViewIncludedInLayout(child_view, include);
  }
  result |= OnChildViewIncludedInLayoutSet(child_view, include);
  return result;
}

bool LayoutManagerBase::PropagateViewAdded(View* host, View* view) {
  child_infos_.emplace(view,
                       ChildInfo{.can_be_visible = view->GetVisible(),
                                 .included_in_layout = IncludeInLayout(view)});

  bool result = false;

  for (auto& owned_layout : owned_layouts_) {
    result |= owned_layout->PropagateViewAdded(host, view);
  }

  result |= OnViewAdded(host, view);
  return result;
}

bool LayoutManagerBase::PropagateViewRemoved(View* host, View* view) {
  child_infos_.erase(view);

  bool result = false;

  for (auto& owned_layout : owned_layouts_) {
    result |= owned_layout->PropagateViewRemoved(host, view);
  }

  result |= OnViewRemoved(host, view);
  return result;
}

bool LayoutManagerBase::PropagateViewVisibilitySet(View* host,
                                                   View* view,
                                                   bool visible) {
  child_infos_[view].can_be_visible = visible;

  bool result = false;

  for (auto& owned_layout : owned_layouts_) {
    result |= owned_layout->PropagateViewVisibilitySet(host, view, visible);
  }

  result |= OnViewVisibilitySet(host, view, visible);
  return result;
}

void LayoutManagerBase::PropagateInstalled(View* host) {
  host_view_ = host;
  for (View* child : host->children()) {
    child_infos_.emplace(
        child, ChildInfo{.can_be_visible = child->GetVisible(),
                         .included_in_layout = IncludeInLayout(child)});
  }

  for (auto& owned_layout : owned_layouts_) {
    owned_layout->PropagateInstalled(host);
  }

  OnInstalled(host);
}

void LayoutManagerBase::PropagateInvalidateLayout() {
  for (auto& owned_layout : owned_layouts_) {
    owned_layout->PropagateInvalidateLayout();
  }

  OnLayoutChanged();
}

ManualLayoutUtil::ManualLayoutUtil(LayoutManagerBase* layout_manager)
    : layout_manager_(layout_manager) {}

ManualLayoutUtil::~ManualLayoutUtil() = default;

void ManualLayoutUtil::SetViewHidden(View* child_view, bool hidden) {
  // If the child view is visible but we are not allowing visibility, update its
  // visibility. This doesn't necessarily invalidate anything.
  if (child_view->GetVisible() && hidden) {
    layout_manager_->SetViewVisibility(child_view, false);
  }

  // If the view cannot be visible, it should be ignored by the layout, and
  // vice-versa. This may invalidate layout data.
  const auto it = layout_manager_->child_infos_.find(child_view);
  CHECK(it != layout_manager_->child_infos_.end());
  const bool can_be_visible = !hidden;
  if (can_be_visible != it->second.can_be_visible) {
    layout_manager_->PropagateViewVisibilitySet(layout_manager_->host_view(),
                                                child_view, can_be_visible);
  }
}

ManualLayoutUtil::TemporaryExclusion
ManualLayoutUtil::TemporarilyExcludeFromLayout(View* child_view) {
  const auto it = layout_manager_->child_infos_.find(child_view);
  CHECK(it != layout_manager_->child_infos_.end());
  CHECK_EQ(IncludeInLayout(child_view), it->second.included_in_layout)
      << "Cannot nest exclusions for the same child view.";

  // If this view is already excluded, this is a no-op.
  if (it->second.included_in_layout) {
    // Write a temporary exclusion into the layout.
    layout_manager_->PropagateChildViewIncludedInLayout(child_view, false);
  }
  return TemporaryExclusion(new TemporaryExclusionData(this, child_view));
}

void ManualLayoutUtil::TemporaryExclusionDeleter::operator()(
    TemporaryExclusionData* data) const {
  if (data) {
    data->first->EndTemporaryExclusion(data->second);
    delete data;
  }
}

void ManualLayoutUtil::EndTemporaryExclusion(View* child_view) {
  // If the child view would still be excluded, this is a no-op.
  const bool included = IncludeInLayout(child_view);
  if (!included) {
    return;
  }

  // Restore inclusion of the view.
  CHECK(base::Contains(layout_manager_->child_infos_, child_view));
  layout_manager_->PropagateChildViewIncludedInLayout(child_view, true);
}

}  // namespace views