// Copyright Epic Games, Inc. All Rights Reserved.

#include "ThumbnailRendering/ClassThumbnailRenderer.h"
#include "ShowFlags.h"
#include "SceneView.h"
#include "Misc/App.h"

UClassThumbnailRenderer::UClassThumbnailRenderer(const FObjectInitializer& ObjectInitializer)
    : Super(ObjectInitializer)
{
}

bool UClassThumbnailRenderer::CanVisualizeAsset(UObject* Object)
{
    UClass* Class = Cast<UClass>(Object);

    // Only visualize actor based classes
    if (Class && Class->IsChildOf(AActor::StaticClass()))
    {
        // Try to find any visible primitive components in the class' CDO
        AActor* CDO = Class->GetDefaultObject<AActor>();

        for (UActorComponent* Component: CDO->GetComponents())
        {
            if (FClassThumbnailScene::IsValidComponentForVisualization(Component))
            {
                return true;
            }
        }
    }

    return false;
}

void UClassThumbnailRenderer::Draw(UObject* Object, int32 X, int32 Y, uint32 Width, uint32 Height, FRenderTarget* RenderTarget, FCanvas* Canvas, bool bAdditionalViewFamily)
{
    UClass* Class = Cast<UClass>(Object);
    if (Class != nullptr)
    {
        TSharedRef<FClassThumbnailScene> ThumbnailScene = ThumbnailScenes.EnsureThumbnailScene(Class);

        ThumbnailScene->SetClass(Class);
        FSceneViewFamilyContext ViewFamily(FSceneViewFamily::ConstructionValues(RenderTarget, ThumbnailScene->GetScene(), FEngineShowFlags(ESFIM_Game))
                                               .SetWorldTimes(FApp::GetCurrentTime() - GStartTime, FApp::GetDeltaTime(), FApp::GetCurrentTime() - GStartTime)
                                               .SetAdditionalViewFamily(bAdditionalViewFamily));

        ViewFamily.EngineShowFlags.DisableAdvancedFeatures();
        ViewFamily.EngineShowFlags.MotionBlur = 0;

        ThumbnailScene->GetView(&ViewFamily, X, Y, Width, Height);
        RenderViewFamily(Canvas, &ViewFamily);
    }
}

void UClassThumbnailRenderer::BeginDestroy()
{
    ThumbnailScenes.Clear();

    Super::BeginDestroy();
}