// Copyright 2013 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/layers/solid_color_scrollbar_layer_impl.h"
#include "cc/quads/solid_color_draw_quad.h"
#include "cc/trees/layer_tree_impl.h"
#include "cc/trees/layer_tree_settings.h"
#include "cc/trees/occlusion_tracker.h"

namespace cc {

scoped_ptr<SolidColorScrollbarLayerImpl> SolidColorScrollbarLayerImpl::Create(
    LayerTreeImpl* tree_impl,
    int id,
    ScrollbarOrientation orientation,
    int thumb_thickness,
    int track_start,
    bool is_left_side_vertical_scrollbar,
    bool is_overlay) {
  return make_scoped_ptr(
      new SolidColorScrollbarLayerImpl(tree_impl,
                                       id,
                                       orientation,
                                       thumb_thickness,
                                       track_start,
                                       is_left_side_vertical_scrollbar,
                                       is_overlay));
}

SolidColorScrollbarLayerImpl::~SolidColorScrollbarLayerImpl() {}

scoped_ptr<LayerImpl> SolidColorScrollbarLayerImpl::CreateLayerImpl(
    LayerTreeImpl* tree_impl) {
  return SolidColorScrollbarLayerImpl::Create(tree_impl,
                                              id(),
                                              orientation(),
                                              thumb_thickness_,
                                              track_start_,
                                              is_left_side_vertical_scrollbar(),
                                              is_overlay_scrollbar())
      .PassAs<LayerImpl>();
}

SolidColorScrollbarLayerImpl::SolidColorScrollbarLayerImpl(
    LayerTreeImpl* tree_impl,
    int id,
    ScrollbarOrientation orientation,
    int thumb_thickness,
    int track_start,
    bool is_left_side_vertical_scrollbar,
    bool is_overlay)
    : ScrollbarLayerImplBase(tree_impl,
                             id,
                             orientation,
                             is_left_side_vertical_scrollbar,
                             is_overlay),
      thumb_thickness_(thumb_thickness),
      track_start_(track_start),
      color_(tree_impl->settings().solid_color_scrollbar_color) {
  SetOpacity(0.f);
}

void SolidColorScrollbarLayerImpl::PushPropertiesTo(LayerImpl* layer) {
  ScrollbarLayerImplBase::PushPropertiesTo(layer);
}

int SolidColorScrollbarLayerImpl::ThumbThickness() const {
  if (thumb_thickness_ != -1)
    return thumb_thickness_;

  if (orientation() == HORIZONTAL)
    return bounds().height();
  else
    return bounds().width();
}

int SolidColorScrollbarLayerImpl::ThumbLength() const {
  return std::max(
      static_cast<int>(visible_to_total_length_ratio() * TrackLength()),
      ThumbThickness());
}

float SolidColorScrollbarLayerImpl::TrackLength() const {
  if (orientation() == HORIZONTAL)
    return bounds().width() - TrackStart() * 2;
  else
    return bounds().height() + vertical_adjust() - TrackStart() * 2;
}

int SolidColorScrollbarLayerImpl::TrackStart() const { return track_start_; }

bool SolidColorScrollbarLayerImpl::IsThumbResizable() const {
  return true;
}

void SolidColorScrollbarLayerImpl::AppendQuads(
    RenderPass* render_pass,
    const OcclusionTracker<LayerImpl>& occlusion_tracker,
    AppendQuadsData* append_quads_data) {
  SharedQuadState* shared_quad_state =
      render_pass->CreateAndAppendSharedQuadState();
  PopulateSharedQuadState(shared_quad_state);

  AppendDebugBorderQuad(
      render_pass, content_bounds(), shared_quad_state, append_quads_data);

  gfx::Rect thumb_quad_rect(ComputeThumbQuadRect());
  gfx::Rect visible_quad_rect =
      occlusion_tracker.GetCurrentOcclusionForLayer(
                            draw_properties().target_space_transform)
          .GetUnoccludedContentRect(thumb_quad_rect);
  if (visible_quad_rect.IsEmpty())
    return;

  SolidColorDrawQuad* quad =
      render_pass->CreateAndAppendDrawQuad<SolidColorDrawQuad>();
  quad->SetNew(
      shared_quad_state, thumb_quad_rect, visible_quad_rect, color_, false);
}

}  // namespace cc