// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CC_TREES_DEBUG_RECT_HISTORY_H_
#define CC_TREES_DEBUG_RECT_HISTORY_H_

#include <memory>
#include <vector>

#include "cc/cc_export.h"
#include "cc/debug/debug_colors.h"
#include "cc/input/main_thread_scrolling_reason.h"
#include "cc/input/touch_action.h"
#include "cc/layers/layer_collections.h"
#include "ui/gfx/geometry/rect.h"

namespace cc {

class LayerImpl;
class LayerTreeDebugState;
class LayerTreeImpl;
class HeadsUpDisplayLayerImpl;

// There are various types of debug rects:
//
// - Paint rects (update rects): regions of a layer that needed to be
// re-uploaded to the texture resource; in most cases implying that they had to
// be repainted, too.
//
// - Property-changed rects: enclosing bounds of layers that cause changes to
// the screen even if the layer did not change internally. (For example, if the
// layer's opacity or position changes.)
//
// - Surface damage rects: the aggregate damage on a target surface that is
// caused by all layers and surfaces that contribute to it. This includes (1)
// paint rects, (2) property- changed rects, and (3) newly exposed areas.
//
// - Screen space rects: this is the region the contents occupy in screen space.
//
// - Layout shift rects: regions of an animation frame that were shifted while
// the page is loading content.
enum class DebugRectType {
  kPaint,
  kPropertyChanged,
  kSurfaceDamage,
  kScreenSpace,
  kTouchEventHandler,
  kWheelEventHandler,
  kScrollEventHandler,
  kMainThreadScrollHitTest,
  kMainThreadScrollRepaint,
  kRasterInducingScroll,
  kAnimationBounds,
  kLayoutShift,
  kInteractionContentfulPaint,
  kNavigationContentfulPaint,
};

struct DebugRect {
  DebugRect(DebugRectType new_type,
            const gfx::Rect& new_rect,
            TouchAction new_touch_action = TouchAction::kNone,
            MainThreadRepaintReasons main_thread_scroll_repaint_reasons = {},
            int fade_step = 1)
      : type(new_type),
        rect(new_rect),
        touch_action(new_touch_action),
        main_thread_scroll_repaint_reasons(main_thread_scroll_repaint_reasons),
        fade_step(fade_step) {
    DCHECK(type == DebugRectType::kTouchEventHandler ||
           touch_action == TouchAction::kNone);
    DCHECK(type != DebugRectType::kMainThreadScrollRepaint ||
           main_thread_scroll_repaint_reasons.empty());
  }
  DebugRectType type;
  gfx::Rect rect;
  // Valid when `type` is `kTouchEventHandler`, otherwise default to
  // `TouchAction::kNone`.
  TouchAction touch_action;
  // Valid when `type` is `kMainThreadScrollRepaint`, otherwise empty.
  MainThreadRepaintReasons main_thread_scroll_repaint_reasons;
  int fade_step;
};

// This class maintains a history of rects of various types that can be used
// for debugging purposes. The overhead of collecting rects is performed only if
// the appropriate LayerTreeSettings are enabled.
class CC_EXPORT DebugRectHistory {
 public:
  static std::unique_ptr<DebugRectHistory> Create();

  DebugRectHistory(const DebugRectHistory&) = delete;
  ~DebugRectHistory();

  DebugRectHistory& operator=(const DebugRectHistory&) = delete;

  // Note: Saving debug rects must happen before layers' change tracking is
  // reset.
  void SaveDebugRectsForCurrentFrame(
      LayerTreeImpl* tree_impl,
      HeadsUpDisplayLayerImpl* hud_layer,
      const RenderSurfaceList& render_surface_list,
      const LayerTreeDebugState& debug_state);

  std::vector<DebugRect>& debug_rects() { return debug_rects_; }
  void clear_rects() { debug_rects_.clear(); }

 private:
  DebugRectHistory();

  void SaveWebVitalsDebugRects(HeadsUpDisplayLayerImpl* hud);
  void SavePaintRects(LayerTreeImpl* tree_impl);
  void SavePropertyChangedRects(LayerTreeImpl* tree_impl, LayerImpl* hud_layer);
  void SaveSurfaceDamageRects(LayerTreeImpl* tree_impl,
                              const RenderSurfaceList& render_surface_list);
  void SaveScreenSpaceRects(LayerTreeImpl* tree_impl,
                            const RenderSurfaceList& render_surface_list);
  void SaveTouchEventHandlerRects(LayerTreeImpl* tree_impl);
  void SaveWheelEventHandlerRects(LayerTreeImpl* tree_impl);
  void SaveScrollEventHandlerRects(LayerTreeImpl* tree_impl);
  void SaveMainThreadScrollHitTestRects(LayerTreeImpl* tree_impl);
  void SaveMainThreadScrollRepaintOrRasterInducingScrollRects(
      LayerTreeImpl* tree_impl,
      DebugRectType type);

  std::vector<DebugRect> debug_rects_;
};

}  // namespace cc

#endif  // CC_TREES_DEBUG_RECT_HISTORY_H_