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

#include "LevelSequenceBindingReference.h"
#include "LevelSequenceLegacyObjectReference.h"
#include "UObject/Package.h"
#include "UObject/ObjectMacros.h"
#include "MovieSceneFwd.h"
#include "Misc/PackageName.h"
#include "Engine/World.h"
#include "Animation/AnimInstance.h"
#include "Components/SkeletalMeshComponent.h"
#include "Engine/LevelStreamingDynamic.h"

namespace UE
{
namespace MovieScene
{

#if WITH_EDITORONLY_DATA

	int32 GTryLoadUnresolvedReferences = 1;
	FAutoConsoleVariableRef GTryLoadUnresolvedReferencesCVar(
		TEXT("Sequencer.TryLoadUnresolvedReferences"),
		GTryLoadUnresolvedReferences,
		TEXT("(Default: 1) When enabled, Sequencer will attempt to load the package for unresolved bindings in editor worlds. This feature will be removed in future since it can cause Actors from unrelated packages to be loaded into memory.\n"),
		ECVF_Default
	);

#endif // WITH_EDITORONLY_DATA

} // namespace MovieScene
} // namespace UE

FLevelSequenceBindingReference::FLevelSequenceBindingReference(UObject* InObject, UObject* InContext)
{
	check(InContext && InObject);

	if (!InContext->IsA<UWorld>() && InObject->IsIn(InContext))
	{
		ObjectPath = InObject->GetPathName(InContext);
	}
	else
	{
		FString FullPath = InObject->GetPathName();

#if WITH_EDITORONLY_DATA
		UPackage* ObjectPackage = InObject->GetOutermost();

		if (ensure(ObjectPackage))
		{
			// If this is being set from PIE we need to remove the pie prefix and point to the editor object
			if (ObjectPackage->PIEInstanceID != INDEX_NONE)
			{
				FString PIEPrefix = FString::Printf(PLAYWORLD_PACKAGE_PREFIX TEXT("_%d_"), ObjectPackage->PIEInstanceID);
				FullPath.ReplaceInline(*PIEPrefix, TEXT(""));
			}
		}
#endif
		
		ExternalObjectPath = FSoftObjectPath(FullPath);
	}
}

UObject* FLevelSequenceBindingReference::Resolve(UObject* InContext, FName StreamedLevelAssetPath) const
{
	if (InContext && InContext->IsA<AActor>())
	{
		if (ExternalObjectPath.IsNull())
		{
			return FindObject<UObject>(InContext, *ObjectPath, false);
		}
	}
	else if (InContext && InContext->IsA<ULevel>() && StreamedLevelAssetPath != NAME_None && ExternalObjectPath.GetAssetPathName() == StreamedLevelAssetPath)
	{
		// ExternalObjectPath.GetSubPathString() specifies the path from the package (so includes PersistentLevel.) so we must do a FindObject from its outer
		return FindObject<UObject>(InContext->GetOuter(), *ExternalObjectPath.GetSubPathString());
	}
	else
	{
		FSoftObjectPath TempPath = ExternalObjectPath;

		// Soft Object Paths don't follow asset redirectors when attempting to call ResolveObject or TryLoad.
		// We want to follow the asset redirector so that maps that have been renamed (from Untitled to their first asset name)
		// properly resolve. This fixes Possessable bindings losing their references the first time you save a map.
		TempPath.PreSavePath();

	#if WITH_EDITORONLY_DATA
		int32 ContextPlayInEditorID = InContext ? InContext->GetOutermost()->PIEInstanceID : INDEX_NONE;

		if (ContextPlayInEditorID != INDEX_NONE)
		{
			// We have an override PIE id, so set the global before entering
			TGuardValue<int32> PIEGuard(GPlayInEditorID, ContextPlayInEditorID);
			TempPath.FixupForPIE();
		}
		else
		{
			TempPath.FixupForPIE();
		}
	#endif

		UObject* Object = TempPath.ResolveObject();

#if WITH_EDITORONLY_DATA
		if (Object == nullptr && UE::MovieScene::GTryLoadUnresolvedReferences != 0)
		{
			UWorld* WorldContext = InContext ? InContext->GetWorld() : nullptr;
			if (!WorldContext || !WorldContext->IsPlayInEditor())
			{
				Object = TempPath.TryLoad();
			}
		}
#endif
		return Object;
	}

	return nullptr;
}

bool FLevelSequenceBindingReference::operator==(const FLevelSequenceBindingReference& Other) const
{
	return ExternalObjectPath == Other.ExternalObjectPath && ObjectPath == Other.ObjectPath;
}

void FLevelSequenceBindingReference::PostSerialize(const FArchive& Ar)
{
	if (Ar.IsLoading() && !PackageName_DEPRECATED.IsEmpty())
	{
		// This was saved as two strings, combine into one soft object path so it handles PIE and redirectors properly
		FString FullPath = PackageName_DEPRECATED + TEXT(".") + ObjectPath;

		ExternalObjectPath.SetPath(FullPath);
		ObjectPath.Reset();
		PackageName_DEPRECATED.Reset();
	}
}

UObject* ResolveByPath(UObject* InContext, const FString& InObjectPath)
{
	if (!InObjectPath.IsEmpty())
	{
		if (UObject* FoundObject = FindObject<UObject>(InContext, *InObjectPath, false))
		{
			return FoundObject;
		}

#if WITH_EDITOR
		UWorld* WorldContext = InContext->GetWorld();
		if (WorldContext && WorldContext->IsPlayInEditor())
		{
			FString PackageRoot, PackagePath, PackageName;
			if (FPackageName::SplitLongPackageName(InObjectPath, PackageRoot, PackagePath, PackageName))
			{
				int32 ObjectDelimiterIdx = INDEX_NONE;
				PackageName.FindChar('.', ObjectDelimiterIdx);
				const FString SubLevelObjPath = PackageName.Mid(ObjectDelimiterIdx + 1);

				for (ULevel* Level : WorldContext->GetLevels())
				{
					UPackage* Pkg = Level->GetOutermost();
					if (UObject* FoundObject = FindObject<UObject>(Pkg, *SubLevelObjPath, false))
 					{
 						return FoundObject;
					}
				}
			}
		}
#endif

		if (UObject* FoundObject = FindObject<UObject>(ANY_PACKAGE, *InObjectPath, false))
		{
			return FoundObject;
		}
	}

	return nullptr;
}

UObject* FLevelSequenceLegacyObjectReference::Resolve(UObject* InContext) const
{
	if (ObjectId.IsValid() && InContext != nullptr)
	{
		int32 PIEInstanceID = InContext->GetOutermost()->PIEInstanceID;
		FUniqueObjectGuid FixedUpId = PIEInstanceID == -1 ? ObjectId : ObjectId.FixupForPIE(PIEInstanceID);

		if (PIEInstanceID != -1 && FixedUpId == ObjectId)
		{
			UObject* FoundObject = ResolveByPath(InContext, ObjectPath);
			if (FoundObject)
			{
				return FoundObject;
			}

			UE_LOG(LogMovieScene, Warning, TEXT("Attempted to resolve object (%s) with a PIE instance that has not been fixed up yet. This is probably due to a streamed level not being available yet."), *ObjectPath);
			return nullptr;
		}
		FLazyObjectPtr LazyPtr;
		LazyPtr = FixedUpId;

		if (UObject* FoundObject = LazyPtr.Get())
		{
			return FoundObject;
		}
	}

	return ResolveByPath(InContext, ObjectPath);
}

bool FLevelSequenceObjectReferenceMap::Serialize(FArchive& Ar)
{
	int32 Num = Map.Num();
	Ar << Num;

	if (Ar.IsLoading())
	{
		while(Num-- > 0)
		{
			FGuid Key;
			Ar << Key;

			FLevelSequenceLegacyObjectReference Value;
			Ar << Value;

			Map.Add(Key, Value);
		}
	}
	else if (Ar.IsSaving() || Ar.IsCountingMemory() || Ar.IsObjectReferenceCollector())
	{
		for (auto& Pair : Map)
		{
			Ar << Pair.Key;
			Ar << Pair.Value;
		}
	}
	return true;
}

bool FLevelSequenceBindingReferences::HasBinding(const FGuid& ObjectId) const
{
	return BindingIdToReferences.Contains(ObjectId) || AnimSequenceInstances.Contains(ObjectId);
}

void FLevelSequenceBindingReferences::AddBinding(const FGuid& ObjectId, UObject* InObject, UObject* InContext)
{
	if (InObject->IsA<UAnimInstance>())
	{
		AnimSequenceInstances.Add(ObjectId);
	}
	else
	{
		BindingIdToReferences.FindOrAdd(ObjectId).References.Emplace(InObject, InContext);
	}
}

void FLevelSequenceBindingReferences::RemoveBinding(const FGuid& ObjectId)
{
	BindingIdToReferences.Remove(ObjectId);
	AnimSequenceInstances.Remove(ObjectId);
}

void FLevelSequenceBindingReferences::RemoveObjects(const FGuid& ObjectId, const TArray<UObject*>& InObjects, UObject* InContext)
{
	FLevelSequenceBindingReferenceArray* ReferenceArray = BindingIdToReferences.Find(ObjectId);
	if (!ReferenceArray)
	{
		return;
	}

	for (int32 ReferenceIndex = 0; ReferenceIndex < ReferenceArray->References.Num(); )
	{
		UObject* ResolvedObject = ReferenceArray->References[ReferenceIndex].Resolve(InContext, NAME_None);

		if (InObjects.Contains(ResolvedObject))
		{
			ReferenceArray->References.RemoveAt(ReferenceIndex);
		}
		else
		{
			++ReferenceIndex;
		}
	}
}

void FLevelSequenceBindingReferences::RemoveInvalidObjects(const FGuid& ObjectId, UObject* InContext)
{
	FLevelSequenceBindingReferenceArray* ReferenceArray = BindingIdToReferences.Find(ObjectId);
	if (!ReferenceArray)
	{
		return;
	}

	for (int32 ReferenceIndex = 0; ReferenceIndex < ReferenceArray->References.Num(); )
	{
		UObject* ResolvedObject = ReferenceArray->References[ReferenceIndex].Resolve(InContext, NAME_None);

		if (!ResolvedObject || ResolvedObject->IsPendingKill())
		{
			ReferenceArray->References.RemoveAt(ReferenceIndex);
		}
		else
		{
			++ReferenceIndex;
		}
	}
}

void FLevelSequenceBindingReferences::ResolveBinding(const FGuid& ObjectId, UObject* InContext, FName StreamedLevelAssetPath, TArray<UObject*, TInlineAllocator<1>>& OutObjects) const
{
	if (const FLevelSequenceBindingReferenceArray* ReferenceArray = BindingIdToReferences.Find(ObjectId))
	{
		for (const FLevelSequenceBindingReference& Reference : ReferenceArray->References)
		{
			UObject* ResolvedObject = Reference.Resolve(InContext, StreamedLevelAssetPath);
			if (ResolvedObject && ResolvedObject->GetWorld())
			{
				OutObjects.Add(ResolvedObject);
			}
		}
	}
	else if (USkeletalMeshComponent* SkeletalMeshComponent = Cast<USkeletalMeshComponent>(InContext))
	{
		// If the object ID exists in the AnimSequenceInstances set, then this binding relates to an anim instance on a skeletal mesh component
		if (SkeletalMeshComponent && AnimSequenceInstances.Contains(ObjectId) && SkeletalMeshComponent->GetAnimInstance())
		{
			OutObjects.Add(SkeletalMeshComponent->GetAnimInstance());
		}
	}
}

FGuid FLevelSequenceBindingReferences::FindBindingFromObject(UObject* InObject, UObject* InContext) const
{
	FLevelSequenceBindingReference Predicate(InObject, InContext);

	for (const TPair<FGuid, FLevelSequenceBindingReferenceArray>& Pair : BindingIdToReferences)
	{
		if (Pair.Value.References.Contains(Predicate))
		{
			return Pair.Key;
		}
	}

	return FGuid();
}

void FLevelSequenceBindingReferences::RemoveInvalidBindings(const TSet<FGuid>& ValidBindingIDs)
{
	for (auto It = BindingIdToReferences.CreateIterator(); It; ++It)
	{
		if (!ValidBindingIDs.Contains(It->Key))
		{
			It.RemoveCurrent();
		}
	}
}


UObject* FLevelSequenceObjectReferenceMap::ResolveBinding(const FGuid& ObjectId, UObject* InContext) const
{
	const FLevelSequenceLegacyObjectReference* Reference = Map.Find(ObjectId);
	UObject* ResolvedObject = Reference ? Reference->Resolve(InContext) : nullptr;
	if (ResolvedObject != nullptr)
	{
		// if the resolved object does not have a valid world (e.g. world is being torn down), dont resolve
		return ResolvedObject->GetWorld() != nullptr ? ResolvedObject : nullptr;
	}
	return nullptr;
}