// Copyright 2016 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef COMPONENTS_VIZ_SERVICE_SURFACES_SURFACE_OBSERVER_H_
#define COMPONENTS_VIZ_SERVICE_SURFACES_SURFACE_OBSERVER_H_

#include <vector>

#include "base/observer_list_types.h"
#include "components/viz/service/viz_service_export.h"
#include "ui/latency/latency_info.h"

namespace viz {

class Surface;
class SurfaceId;
class SurfaceInfo;
struct BeginFrameAck;
struct BeginFrameArgs;

class VIZ_SERVICE_EXPORT SurfaceObserver : public base::CheckedObserver {
 public:
  ~SurfaceObserver() override = default;

  // Called when a CompositorFrame with a new SurfaceId activates for the first
  // time.
  virtual void OnFirstSurfaceActivation(const SurfaceInfo& surface_info) {}

  // Called when there is new frame in uncommitted queue of the surface.
  virtual void OnSurfaceHasNewUncommittedFrame(const SurfaceId& surface_id) {}

  // Called when a CompositorFrame within a surface corresponding to
  // |surface_id| activates.
  virtual void OnSurfaceActivated(const SurfaceId& surface_id) {}

  // Called when a surface is marked for destruction (i.e. becomes a candidate
  // for garbage collection).
  virtual void OnSurfaceMarkedForDestruction(const SurfaceId& surface_id) {}

  // Called when a surface is destroyed.
  virtual void OnSurfaceDestroyed(const SurfaceId& surface_id) {}

  // Called when a Surface is modified, e.g. when a CompositorFrame is
  // activated, its producer confirms that no CompositorFrame will be submitted
  // in response to a BeginFrame, or a CopyOutputRequest is issued.
  //
  // |ack.sequence_number| is only valid if called in response to a BeginFrame.
  // Should return true if this causes a Display to be damaged.
  enum class HandleInteraction {
    // Surface is damaged due to user interaction (e.g., a frame activation with
    // scrolling).
    kYes,
    // Surface is no longer interactive (e.g. `DidNotProduceFrame` or frame
    // activation with no scrolling).
    kNo,
    // No change to the interaction state (e.g. `CopyOutputRequest` submission).
    kNoChange,
  };
  virtual bool OnSurfaceDamaged(
      const SurfaceId& surface_id,
      const BeginFrameAck& ack,
      HandleInteraction handle_interaction,
      const std::vector<ui::LatencyInfo>& latency_info);

  // Called when a Surface's CompositorFrame producer has received a BeginFrame
  // and, thus, is expected to produce damage soon.
  virtual void OnSurfaceDamageExpected(const SurfaceId& surface_id,
                                       const BeginFrameArgs& args) {}

  // Called whenever |surface| will be drawn in the next display frame.
  virtual void OnSurfaceWillBeDrawn(Surface* surface) {}

  // Called whenever the surface reference from the surface that has |parent_id|
  // to the surface that has |child_id| is added.
  // A matching `OnRemovedSurfaceReference` can be added if there are use cases.
  virtual void OnAddedSurfaceReference(const SurfaceId& parent_id,
                                       const SurfaceId& child_id) {}
};

}  // namespace viz

#endif  // COMPONENTS_VIZ_SERVICE_SURFACES_SURFACE_OBSERVER_H_