// Copyright 2018 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CHROME_BROWSER_VR_UI_INTERFACE_H_
#define CHROME_BROWSER_VR_UI_INTERFACE_H_

#include <memory>
#include <queue>
#include <utility>
#include <vector>

#include "base/memory/weak_ptr.h"
#include "base/time/time.h"
#include "chrome/browser/vr/fov_rectangle.h"
#include "chrome/browser/vr/gl_texture_location.h"

namespace gfx {
class Point3F;
class PointF;
class Transform;
}

namespace vr {

class BrowserUiInterface;
class InputEvent;
class PlatformUiInputDelegate;
class SchedulerUiInterface;
class UiBrowserInterface;
struct ControllerModel;
struct RenderInfo;
struct ReticleModel;
struct UiInitialState;
enum class UserFriendlyElementName;

using InputEventList = std::vector<std::unique_ptr<InputEvent>>;

// This interface represents the methods that should be called by its owner, and
// also serves to make all such methods virtual for the sake of separating a UI
// feature module.
class UiInterface {
 public:
  virtual ~UiInterface() = default;

  virtual base::WeakPtr<BrowserUiInterface> GetBrowserUiWeakPtr() = 0;
  virtual SchedulerUiInterface* GetSchedulerUiPtr() = 0;

  virtual void OnGlInitialized() = 0;

  virtual void SetAlertDialogEnabled(bool enabled,
                                     PlatformUiInputDelegate* delegate,
                                     float width,
                                     float height) = 0;
  virtual void SetContentOverlayAlertDialogEnabled(
      bool enabled,
      PlatformUiInputDelegate* delegate,
      float width_percentage,
      float height_percentage) = 0;
  virtual void OnPause() = 0;
  virtual void OnControllersUpdated(
      const std::vector<ControllerModel>& controller_models,
      const ReticleModel& reticle_model) = 0;
  virtual void OnProjMatrixChanged(const gfx::Transform& proj_matrix) = 0;
  virtual gfx::Point3F GetTargetPointForTesting(
      UserFriendlyElementName element_name,
      const gfx::PointF& position) = 0;
  virtual bool GetElementVisibilityForTesting(
      UserFriendlyElementName element_name) = 0;
  virtual bool IsContentVisibleAndOpaque() = 0;
  virtual bool OnBeginFrame(base::TimeTicks current_time,
                            const gfx::Transform& head_pose) = 0;
  virtual bool SceneHasDirtyTextures() const = 0;
  virtual void UpdateSceneTextures() = 0;
  virtual void Draw(const RenderInfo& render_info) = 0;
  virtual void DrawWebXr(int texture_data_handle,
                         const float (&uv_transform)[16]) = 0;
  virtual void DrawWebVrOverlayForeground(const RenderInfo&) = 0;
  virtual bool HasWebXrOverlayElementsToDraw() = 0;
  virtual void HandleInput(base::TimeTicks current_time,
                           const RenderInfo& render_info,
                           ReticleModel* reticle_model,
                           InputEventList* input_event_list) = 0;
  virtual void HandleMenuButtonEvents(InputEventList* input_event_list) = 0;

  // This function calculates the minimal FOV (in degrees) which covers all
  // visible overflow elements as if it was viewing from fov_recommended. For
  // example, if fov_recommended is {20.f, 20.f, 20.f, 20.f}. And all elements
  // appear on screen within a FOV of {-11.f, 19.f, 9.f, 9.f} if we use
  // fov_recommended. Ideally, the calculated minimal FOV should be the same. In
  // practice, the elements might get clipped near the edge sometimes due to
  // float precision. To fix this, we add a small margin (1 degree) to all
  // directions. So the |out_fov| set by this function should be {-10.f, 20.f,
  // 10.f, 10.f} in the example case.
  // Using a smaller FOV could improve the performance a lot while we are
  // showing UIs on top of WebVR content.
  virtual FovRectangles GetMinimalFovForWebXrOverlayElements(
      const gfx::Transform& left_view,
      const FovRectangle& fov_recommended_left,
      const gfx::Transform& right_view,
      const FovRectangle& fov_recommended_right,
      float z_near) = 0;
};

// After obtaining a void pointer to CreateUi() via dlsym, the resulting pointer
// should be cast to this type.  Hence, the arguments in this type must exactly
// match the actual CreateUi method.
typedef UiInterface* CreateUiFunction(UiBrowserInterface* browser,
                                      const UiInitialState& ui_initial_state);

}  // namespace vr

#endif  // CHROME_BROWSER_VR_UI_INTERFACE_H_