// Copyright 2014 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 "cc/blink/scrollbar_impl.h"

#include "base/logging.h"
#include "third_party/WebKit/public/platform/WebScrollbar.h"
#include "third_party/WebKit/public/platform/WebScrollbarThemeGeometry.h"

using blink::WebScrollbar;

namespace cc_blink {

ScrollbarImpl::ScrollbarImpl(
    std::unique_ptr<WebScrollbar> scrollbar,
    blink::WebScrollbarThemePainter painter,
    std::unique_ptr<blink::WebScrollbarThemeGeometry> geometry)
    : scrollbar_(std::move(scrollbar)),
      painter_(painter),
      geometry_(std::move(geometry)) {}

ScrollbarImpl::~ScrollbarImpl() {
}

cc::ScrollbarOrientation ScrollbarImpl::Orientation() const {
  if (scrollbar_->orientation() == WebScrollbar::Horizontal)
    return cc::HORIZONTAL;
  return cc::VERTICAL;
}

bool ScrollbarImpl::IsLeftSideVerticalScrollbar() const {
  return scrollbar_->isLeftSideVerticalScrollbar();
}

bool ScrollbarImpl::HasThumb() const {
  return geometry_->hasThumb(scrollbar_.get());
}

bool ScrollbarImpl::IsOverlay() const {
  return scrollbar_->isOverlay();
}

gfx::Point ScrollbarImpl::Location() const {
  return scrollbar_->location();
}

int ScrollbarImpl::ThumbThickness() const {
  gfx::Rect thumb_rect = geometry_->thumbRect(scrollbar_.get());
  if (scrollbar_->orientation() == WebScrollbar::Horizontal)
    return thumb_rect.height();
  return thumb_rect.width();
}

int ScrollbarImpl::ThumbLength() const {
  gfx::Rect thumb_rect = geometry_->thumbRect(scrollbar_.get());
  if (scrollbar_->orientation() == WebScrollbar::Horizontal)
    return thumb_rect.width();
  return thumb_rect.height();
}

gfx::Rect ScrollbarImpl::TrackRect() const {
  return geometry_->trackRect(scrollbar_.get());
}

float ScrollbarImpl::ThumbOpacity() const {
  return painter_.thumbOpacity();
}

bool ScrollbarImpl::NeedsPaintPart(cc::ScrollbarPart part) const {
  if (part == cc::THUMB)
    return painter_.thumbNeedsRepaint();
  return painter_.trackNeedsRepaint();
}

void ScrollbarImpl::PaintPart(SkCanvas* canvas,
                              cc::ScrollbarPart part,
                              const gfx::Rect& content_rect) {
  if (part == cc::THUMB) {
    painter_.paintThumb(canvas, content_rect);
    return;
  }

  // The following is a simplification of ScrollbarThemeComposite::paint.
  painter_.paintScrollbarBackground(canvas, content_rect);

  if (geometry_->hasButtons(scrollbar_.get())) {
    gfx::Rect back_button_start_paint_rect =
        geometry_->backButtonStartRect(scrollbar_.get());
    painter_.paintBackButtonStart(canvas, back_button_start_paint_rect);

    gfx::Rect back_button_end_paint_rect =
        geometry_->backButtonEndRect(scrollbar_.get());
    painter_.paintBackButtonEnd(canvas, back_button_end_paint_rect);

    gfx::Rect forward_button_start_paint_rect =
        geometry_->forwardButtonStartRect(scrollbar_.get());
    painter_.paintForwardButtonStart(canvas, forward_button_start_paint_rect);

    gfx::Rect forward_button_end_paint_rect =
        geometry_->forwardButtonEndRect(scrollbar_.get());
    painter_.paintForwardButtonEnd(canvas, forward_button_end_paint_rect);
  }

  gfx::Rect track_paint_rect = geometry_->trackRect(scrollbar_.get());
  painter_.paintTrackBackground(canvas, track_paint_rect);

  bool thumb_present = geometry_->hasThumb(scrollbar_.get());
  if (thumb_present) {
    painter_.paintForwardTrackPart(canvas, track_paint_rect);
    painter_.paintBackTrackPart(canvas, track_paint_rect);
  }

  painter_.paintTickmarks(canvas, track_paint_rect);
}

}  // namespace cc_blink
