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

#include "ClassIconFinder.h"
#include "UObject/ObjectMacros.h"
#include "UObject/Class.h"
#include "AssetData.h"
#include "Engine/Blueprint.h"
#include "Engine/Brush.h"

const FSlateBrush* FClassIconFinder::FindIconForActors(const TArray<TWeakObjectPtr<AActor>>& InActors, UClass*& CommonBaseClass)
{
    // Get the common base class of the selected actors
    FSlateIcon CommonIcon;

    for (int32 ActorIdx = 0; ActorIdx < InActors.Num(); ++ActorIdx)
    {
        TWeakObjectPtr<const AActor> Actor = InActors[ActorIdx];
        UClass* ObjClass                   = Actor->GetClass();
        check(ObjClass);

        if (!CommonBaseClass)
        {
            CommonBaseClass = ObjClass;
        }
        while (!ObjClass->IsChildOf(CommonBaseClass))
        {
            CommonBaseClass = CommonBaseClass->GetSuperClass();
        }

        FSlateIcon ActorIcon = FindSlateIconForActor(Actor);

        if (!CommonIcon.IsSet())
        {
            CommonIcon = ActorIcon;
        }

        if (CommonIcon != ActorIcon)
        {
            CommonIcon = FSlateIconFinder::FindIconForClass(CommonBaseClass);
        }
    }

    return CommonIcon.GetOptionalIcon();
}

FSlateIcon FClassIconFinder::FindSlateIconForActor(const TWeakObjectPtr<const AActor>& InActor)
{
    // Actor specific overrides to normal per-class icons
    const AActor* Actor = InActor.Get();

    if (Actor)
    {
        FName IconName = Actor->GetCustomIconName();
        if (IconName != NAME_None)
        {
            return FSlateIconFinder::FindIcon(IconName);
        }

        // Actor didn't specify an icon - fallback on the class icon
        return FSlateIconFinder::FindIconForClass(Actor->GetClass());
    }
    else
    {
        // If the actor reference is NULL it must have been deleted
        return FSlateIconFinder::FindIcon("ClassIcon.Deleted");
    }
}

const FSlateBrush* FClassIconFinder::FindIconForActor(const TWeakObjectPtr<const AActor>& InActor)
{
    return FindSlateIconForActor(InActor).GetOptionalIcon();
}

const UClass* FClassIconFinder::GetIconClassForBlueprint(const UBlueprint* InBlueprint)
{
    if (!InBlueprint)
    {
        return nullptr;
    }

    // If we're loaded and have a generated class, just use that
    if (const UClass* GeneratedClass = InBlueprint->GeneratedClass)
    {
        return GeneratedClass;
    }

    // We don't have a generated class, so instead try and use the parent class from our meta-data
    return GetIconClassForAssetData(FAssetData(InBlueprint));
}

const UClass* FClassIconFinder::GetIconClassForAssetData(const FAssetData& InAssetData, bool* bOutIsClassType)
{
    if (bOutIsClassType)
    {
        *bOutIsClassType = false;
    }

    UClass* AssetClass = FindObjectSafe<UClass>(ANY_PACKAGE, *InAssetData.AssetClass.ToString());
    if (!AssetClass)
    {
        return nullptr;
    }

    if (AssetClass == UClass::StaticClass())
    {
        if (bOutIsClassType)
        {
            *bOutIsClassType = true;
        }

        return FindObject<UClass>(ANY_PACKAGE, *InAssetData.AssetName.ToString());
    }

    static const FName IgnoreClassThumbnail(TEXT("IgnoreClassThumbnail"));
    if ((AssetClass->IsChildOf<UBlueprint>() || AssetClass->IsChildOf<UBlueprintGeneratedClass>()) &&
        !AssetClass->HasMetaDataHierarchical(IgnoreClassThumbnail))
    {
        if (bOutIsClassType)
        {
            *bOutIsClassType = true;
        }

        // We need to use the asset data to get the parent class as the blueprint may not be loaded
        FString ParentClassName;
        if (!InAssetData.GetTagValue(FBlueprintTags::NativeParentClassPath, ParentClassName))
        {
            InAssetData.GetTagValue(FBlueprintTags::ParentClassPath, ParentClassName);
        }
        if (!ParentClassName.IsEmpty())
        {
            UObject* Outer = nullptr;
            ResolveName(Outer, ParentClassName, false, false);
            return FindObject<UClass>(ANY_PACKAGE, *ParentClassName);
        }
    }

    // Default to using the class for the asset type
    return AssetClass;
}