// Copyright (c) 2012-2022 Wojciech Figat. All rights reserved.

#pragma once

#include "Engine/Core/Delegate.h"
#include "Engine/Core/Collections/Array.h"
#include "Engine/Core/Math/BoundingSphere.h"
#include "Engine/Level/Actor.h"

class SceneRenderTask;
struct PostProcessSettings;
struct RenderContext;
struct RenderView;

/// <summary>
/// Interface for actors that can override the default rendering settings (eg. PostFxVolume actor).
/// </summary>
class FLAXENGINE_API IPostFxSettingsProvider
{
public:
    /// <summary>
    /// Collects the settings for rendering of the specified task.
    /// </summary>
    /// <param name="renderContext">The rendering context.</param>
    virtual void Collect(RenderContext& renderContext) = 0;

    /// <summary>
    /// Blends the object settings to the given settings using given weight.
    /// </summary>
    /// <param name="other">The other settings to blend to.</param>
    /// <param name="weight">The blending weight (normalized to 0-1 range).</param>
    virtual void Blend(PostProcessSettings& other, float weight) = 0;
};

/// <summary>
/// Scene rendering helper subsystem that boosts the level rendering by providing efficient objects cache and culling implementation.
/// </summary>
class FLAXENGINE_API SceneRendering
{
#if USE_EDITOR
    typedef Function<void(RenderView&)> PhysicsDebugCallback;
    friend class ViewportIconsRendererService;
#endif
public:
    struct DrawActor
    {
        Actor* Actor;
        uint32 LayerMask;
        int8 NoCulling : 1;
        BoundingSphere Bounds;
    };

    Array<DrawActor> Actors;
    Array<IPostFxSettingsProvider*> PostFxProviders;

private:
#if USE_EDITOR
    Array<PhysicsDebugCallback> PhysicsDebug;
    Array<Actor*> ViewportIcons;
#endif

public:
    /// <summary>
    /// Draws the scene. Performs the optimized actors culling and draw calls submission for the current render pass (defined by the render view).
    /// </summary>
    /// <param name="renderContext">The rendering context.</param>
    void Draw(RenderContext& renderContext);

    /// <summary>
    /// Collects the post fx volumes for the given rendering view.
    /// </summary>
    /// <param name="renderContext">The rendering context.</param>
    void CollectPostFxVolumes(RenderContext& renderContext);

    /// <summary>
    /// Clears this instance data.
    /// </summary>
    void Clear();

public:
    int32 AddActor(Actor* a);
    void UpdateActor(Actor* a, int32 key);
    void RemoveActor(Actor* a, int32& key);

    FORCE_INLINE void AddPostFxProvider(IPostFxSettingsProvider* obj)
    {
        PostFxProviders.Add(obj);
    }

    FORCE_INLINE void RemovePostFxProvider(IPostFxSettingsProvider* obj)
    {
        PostFxProviders.Remove(obj);
    }

#if USE_EDITOR
    template<class T, void(T::*Method)(RenderView&)>
    FORCE_INLINE void AddPhysicsDebug(T* obj)
    {
        PhysicsDebugCallback f;
        f.Bind<T, Method>(obj);
        PhysicsDebug.Add(f);
    }

    template<class T, void(T::*Method)(RenderView&)>
    void RemovePhysicsDebug(T* obj)
    {
        PhysicsDebugCallback f;
        f.Bind<T, Method>(obj);
        PhysicsDebug.Remove(f);
    }

    FORCE_INLINE void AddViewportIcon(Actor* obj)
    {
        ViewportIcons.Add(obj);
    }

    FORCE_INLINE void RemoveViewportIcon(Actor* obj)
    {
        ViewportIcons.Remove(obj);
    }
#endif
};