// 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 "chrome/browser/ui/views/tabs/tab_group_highlight.h"

#include "chrome/browser/ui/layout_constants.h"
#include "chrome/browser/ui/tabs/tab_style.h"
#include "chrome/browser/ui/views/tabs/tab_group_views.h"
#include "third_party/skia/include/core/SkPath.h"
#include "third_party/skia/include/core/SkPathBuilder.h"
#include "ui/base/metadata/metadata_impl_macros.h"
#include "ui/gfx/canvas.h"
#include "ui/views/background.h"
#include "ui/views/view.h"
#include "ui/views/widget/widget.h"

TabGroupHighlight::TabGroupHighlight(TabGroupViews* tab_group_views,
                                     const tab_groups::TabGroupId& group,
                                     const TabGroupStyle& style)
    : tab_group_views_(tab_group_views), group_(group), style_(style) {
  // Don't accept any mouse events, otherwise this will prevent tabs and group
  // headers from getting clicked.
  SetCanProcessEventsWithinSubtree(false);
}

void TabGroupHighlight::UpdateBounds(views::View* leading_view,
                                     views::View* trailing_view) {
  // If there are no views to highlight, do nothing. Our visibility is
  // controlled by our parent TabDragContext.
  if (!leading_view) {
    return;
  }
  gfx::Rect bounds = leading_view->bounds();
  bounds.UnionEvenIfEmpty(trailing_view->bounds());
  SetBoundsRect(bounds);
}

void TabGroupHighlight::OnPaint(gfx::Canvas* canvas) {
  SkPath path = GetPath();
  cc::PaintFlags flags;
  flags.setAntiAlias(true);
  flags.setStyle(cc::PaintFlags::kFill_Style);
  flags.setColor(TabStyle::Get()->GetTabBackgroundColor(
      TabStyle::TabSelectionState::kSelected, /*hovered=*/false,
      GetWidget()->ShouldPaintAsActive(), GetColorProvider()));
  canvas->DrawPath(path, flags);
}

SkPath TabGroupHighlight::GetPath() const {
  // This path imitates the shape of a tab (see GM2TabStyle::GetPath()). It
  // doesn't reuse the exact same GetPath() function because it doesn't need
  // much of the complexity there. Group highlights only appear on group drag,
  // which is a well-scoped interaction. A dragging group doesn't nestle in with
  // the tabs around it, so there are no special cases needed when determining
  // its shape.
  const int corner_radius = TabStyle::Get()->GetBottomCornerRadius();
  const int top = GetLayoutConstant(LayoutConstant::kTabStripPadding);

  return SkPathBuilder()
      .moveTo(0, bounds().height())
      .arcTo(SkVector(corner_radius, corner_radius), 0,
             SkPathBuilder::kSmall_ArcSize, SkPathDirection::kCCW,
             SkPoint(corner_radius, bounds().height() - corner_radius))
      .lineTo(corner_radius, top + corner_radius)
      .arcTo(SkVector(corner_radius, corner_radius), 0,
             SkPathBuilder::kSmall_ArcSize, SkPathDirection::kCW,
             SkPoint(2 * corner_radius, top))
      .lineTo(bounds().width() - 2 * corner_radius, top)
      .arcTo(SkVector(corner_radius, corner_radius), 0,
             SkPathBuilder::kSmall_ArcSize, SkPathDirection::kCW,
             SkPoint(bounds().width() - corner_radius, top + corner_radius))
      .lineTo(bounds().width() - corner_radius,
              bounds().height() - corner_radius)
      .arcTo(SkVector(corner_radius, corner_radius), 0,
             SkPathBuilder::kSmall_ArcSize, SkPathDirection::kCCW,
             SkPoint(bounds().width(), bounds().height()))
      .close()
      .detach();
}

BEGIN_METADATA(TabGroupHighlight)
END_METADATA