#include "AnimQueue.h"

FlxAnimationStep::FlxAnimationStep(uint64 hash, std::string_view body) {
	Hash = hash;
	Body.SetNum(body.size());
	memcpy(Body.GetData(), body.data(), body.size());
}

static bool ClearProperties(const FString& prefix, UObject* obj) {
	UClass* uclass = obj->GetClass();
	if (prefix.IsEmpty()) {
		return false;
	}
	FName prefixlo(prefix);
	FName prefixhi(prefix + TEXT("\xFFFF"));
	for (TFieldIterator<FProperty> It(uclass); It; ++It)
	{
		FProperty* fprop = *It;
		bool match1 = (fprop->GetFName().Compare(prefixlo) > 0);
		bool match2 = (fprop->GetFName().Compare(prefixhi) < 0);
		if (match1 && match2) {
			uint8* pptr = fprop->ContainerPtrToValuePtr<uint8>(obj);
			fprop->ClearValue(pptr);
		}
	}
	return true;
}

static bool SetProperty(const FString& name, UObject* obj, const FlxAnimationField& field) {
	UClass* uclass = obj->GetClass();
	FName nname(name);
	switch (field.Type) {
		case ElxAnimValueType::STRING: {
			FStrProperty* fprop = FindFProperty<FStrProperty>(uclass, nname);
			if (fprop == nullptr) return false;
			FString* pptr = fprop->ContainerPtrToValuePtr<FString>(obj);
			*pptr = FString(field.S.size(), (const UTF8CHAR*)field.S.data());
			return true;
		}
		case ElxAnimValueType::NUMBER: {
			FDoubleProperty* fprop = FindFProperty<FDoubleProperty>(uclass, nname);
			if (fprop == nullptr) return false;
			double* pptr = fprop->ContainerPtrToValuePtr<double>(obj);
			*pptr = field.X;
			return true;
		}
		case ElxAnimValueType::BOOLEAN: {
			FBoolProperty* fprop = FindFProperty<FBoolProperty>(uclass, nname);
			if (fprop == nullptr) return false;
			uint8* pptr = fprop->ContainerPtrToValuePtr<uint8>(obj);
			fprop->SetPropertyValue(pptr, (field.X == 1.0));
			return true;
		}
		case ElxAnimValueType::XYZ: {
			FStructProperty* fprop = FindFProperty<FStructProperty>(uclass, nname);
			if (fprop == nullptr) return false;
			if (fprop->Struct != TBaseStructure<FVector>::Get()) return false;
			FVector* pptr = fprop->ContainerPtrToValuePtr<FVector>(obj);
			*pptr = FVector(field.X, field.Y, field.Z);
			return true;
		}
	}
	return false;
}

bool FlxAnimationStep::Unpack(const FString& prefix, UObject* into, bool preclear) const {
	UClass* uclass = into->GetClass();
	std::string_view body((const char*)(Body.GetData()), Body.Num());
	FlxAnimationStepDecoder decoder(body);
	bool ok = true;
	if (preclear) {
		ok &= ClearProperties(prefix, into);
	}
	while (!decoder.AtEOF()) {
		FlxAnimationField field = decoder.ReadField();
		FString sname(field.Name.size(), (const UTF8CHAR*)field.Name.data());
		ok &= SetProperty(prefix + sname, into, field);
	}
	return ok;
}

FString UlxAnimationStepLibrary::AnimationStepDebugString(const FlxAnimationStep& step) {
	std::string_view body((const char*)(step.Body.GetData()), step.Body.Num());
	return FlxAnimationStepDecoder::DebugString(step.Hash, body);
}

void UlxAnimationStepLibrary::UnpackAnimationStep(const FlxAnimationStep& step,
			const FString& prefix, UObject* into) {
	step.Unpack(prefix, into, true);
};

static FlxAnimationField FindAnimationField(const FlxAnimationStep& step, const FString& name) {
	std::string_view body((const char*)(step.Body.GetData()), step.Body.Num());
	FTCHARToUTF8 utf8name(name);
	std::string_view uname(utf8name.Get(), utf8name.Length());
	FlxAnimationStepDecoder decoder(body);
	FlxAnimationField result;
	while (!decoder.AtEOF()) {
		result = decoder.ReadField();
		if (result.Name == uname) {
			return result;
		}
	}
	result.Type = ElxAnimValueType::INVALID;
	return result;
}

FVector UlxAnimationStepLibrary::AnimationStepGetVector(const FlxAnimationStep& step, const FString& name) {
	FlxAnimationField field = FindAnimationField(step, name);
	if (field.Type != ElxAnimValueType::XYZ) return FVector(0, 0, 0);
	return FVector(field.X, field.Y, field.Z);
}

double UlxAnimationStepLibrary::AnimationStepGetFloat(const FlxAnimationStep& step, const FString& name) {
	FlxAnimationField field = FindAnimationField(step, name);
	if (field.Type != ElxAnimValueType::NUMBER) return 0.0;
	return field.X;
}

#pragma optimize("", off)
FString UlxAnimationStepLibrary::AnimationStepGetString(const FlxAnimationStep& step, const FString& name) {
	FlxAnimationField field = FindAnimationField(step, name);
	if (field.Type != ElxAnimValueType::STRING) return TEXT("");
	return FString(field.S.size(), (const UTF8CHAR*)(field.S.data()));
}

bool UlxAnimationStepLibrary::AnimationStepGetBool(const FlxAnimationStep& step, const FString& name) {
	FlxAnimationField field = FindAnimationField(step, name);
	if (field.Type != ElxAnimValueType::BOOLEAN) return false;
	return field.X == 1.0;
}

FlxAnimationStepView FlxAnimQueueDecoder::ReadStep() {
	FlxAnimationStepView result;
	result.Hash = Decoder.read_uint64();
	result.Body = Decoder.read_string_view();
	return result;
}

FlxAnimationField FlxAnimationStepDecoder::ReadField() {
	FlxAnimationField result;
	result.Name = Decoder.read_string_view();
	result.Persistent = Decoder.read_bool();
	result.Type = (ElxAnimValueType)Decoder.read_uint8();
	switch (result.Type) {
		case ElxAnimValueType::STRING: {
			result.S = Decoder.read_string_view();
			break;
		}
		case ElxAnimValueType::NUMBER: {
			result.X = Decoder.read_double();
			break;
		}
		case ElxAnimValueType::BOOLEAN: {
			result.X = Decoder.read_bool() ? 1.0 : 0.0;
			break;
		}
		case ElxAnimValueType::XYZ: {
			result.X = Decoder.read_double();
			result.Y = Decoder.read_double();
			result.Z = Decoder.read_double();
			break;
		}
		default: {
			Decoder.set_at_eof();
			result.Type = ElxAnimValueType::BOOLEAN;
			result.X = 0;
			break;
		}
	}
	return result;
}

FString FlxAnimationStepDecoder::DebugString(uint64 hash, std::string_view body) {
	FString result;
	FlxAnimationStepDecoder decoder(body);
	result.Appendf(TEXT("Hash=%016llx"), hash);
	while (!decoder.AtEOF()) {
		FlxAnimationField field = decoder.ReadField();
		result.Append(TEXT(" "));
		result.Append(FString(field.Name.size(), (const UTF8CHAR*)field.Name.data()));
		result.Append(field.Persistent ? TEXT("=") : TEXT(":"));
		switch (field.Type) {
		case ElxAnimValueType::STRING:
			result.Append(FString(field.S.size(), (const UTF8CHAR*)field.S.data()));
			break;
		case ElxAnimValueType::NUMBER:
			result.Appendf(TEXT("%lf"), field.X);
			break;
		case ElxAnimValueType::BOOLEAN:
			result.Append((field.X) == 1.0 ? TEXT("true") : TEXT("false"));
			break;
		case ElxAnimValueType::XYZ:
			result.Appendf(TEXT("%lf,%lf,%lf"), field.X, field.Y, field.Z);
			break;
		}
	}
	return result;
}

FString FlxAnimQueueDecoder::DebugString(std::string_view queue) {
	FString result;
	FlxAnimQueueDecoder decoder(queue);
	while (!decoder.AtEOF()) {
		FlxAnimationStepView step = decoder.ReadStep();
		FString stepdebug = FlxAnimationStepDecoder::DebugString(step.Hash, step.Body);
		result.Appendf(TEXT("%s\n"), *stepdebug);
	}
	return result;
}

FlxAnimTracker::FlxAnimTracker() {
	Clear();
}

void FlxAnimTracker::Clear() {
	AQ.Empty();
	FirstSeqno = 0;
	HashToSeqno.Empty();
	UnstartedSeqno = 0;
	PlaybackMode = ElxAnimationMode::INVALID;
	AbortedHashes.Empty();
}

void FlxAnimTracker::Update(std::string_view encqueue) {
	// Check for an exact match.  If the most recent entry
	// in encqueue has the same hash as the most recent
	// entry in AQ, then that's an exact match.   Or,
	// if both are empty, that's also an exact match.
	// In case of exact match, abort early, there's no
	// further work needed.
	//
	if (encqueue.empty()) {
		if (AQ.IsEmpty()) {
			return;
		}
	} else {
		if (!AQ.IsEmpty()) {
			FlxStringDecoder qdecoder(encqueue);
			uint64 hash = qdecoder.read_uint64();
			if (hash == AQ.Last().Hash) {
				return;
			}
		}
	}

	// Search for a Luprex animation record that matches
	// something that we already have.  Yields the sequence
	// number of the most recent matching record.
	//
	// At the same time, push all non-matching records
	// after the matching record onto a stack of new records.
	//
	FlxAnimQueueDecoder decoder(encqueue);
	TArray<FlxAnimationStepView> newsteps;
	int32 matchingseqno = -1;
	while (!decoder.AtEOF()) {
		FlxAnimationStepView step = decoder.ReadStep();
		int32* stepseq = HashToSeqno.Find(step.Hash);
		if (stepseq == nullptr) {
			newsteps.Emplace(step);
		} else {
			matchingseqno = *stepseq;
			break;
		}
	}

	// Remove all animations after the most recent matching
	// record.  If we remove a 'started' animation, add that
	// animation to the list of aborted animations.
	// 
	int32 nremove = (FirstSeqno + AQ.Num()) - (matchingseqno + 1);
	check((nremove >= 0) && (nremove <= AQ.Num()));
	for (int32 i = 0; i < nremove; i++) {
		uint64 lasthash = AQ.Last().Hash;
		int32 seqno = FirstSeqno + AQ.Num() - 1;
		HashToSeqno.Remove(lasthash);
		if (seqno < UnstartedSeqno) {
			AbortedHashes.Emplace(lasthash);
		}
		AQ.PopLast();
	}

	// If we aborted a 'started' animation, we have to fix
	// up the Unstarted animation pointer.
	// 
	// Note: this could leave the Unstarted pointer at
	// seqno less than FirstSeqno.  We will fix that state
	// of affairs up later.
	//
	if (UnstartedSeqno > (FirstSeqno + AQ.Num())) {
		UnstartedSeqno = matchingseqno;
		PlaybackMode = ElxAnimationMode::BlendToFinal;
	}

	// Transfer the new animations onto the queue.
	//
	while (!newsteps.IsEmpty()) {
		FlxAnimationStepView step = newsteps.Pop();
		int32 seqno = FirstSeqno + AQ.Num();
		AQ.EmplaceLast(step.Hash, step.Body);
		HashToSeqno.Emplace(step.Hash, seqno);
	}

	// If there are too many animations in AQ, discard
	// any very old ones.
	//
	if (AQ.Num() > 10) {
		int ndiscard = AQ.Num() - 10;
		for (int i = 0; i < ndiscard; i++) {
			uint64 hash = AQ.First().Hash;
			HashToSeqno.Remove(hash);
			AQ.PopFirst();
			FirstSeqno += 1;
		}
	}

	// If UnstartedSeqno is before the live range,
	// then the whole queue has to be replayed.  Don't
	// do that: just fast skip to the end.
	//
	if (UnstartedSeqno <= FirstSeqno) {
		if (AQ.Num() == 0) {
			UnstartedSeqno = FirstSeqno;
		} else {
			UnstartedSeqno = FirstSeqno + AQ.Num() - 1;
		}
		PlaybackMode = ElxAnimationMode::WarpToFinal;
	}
}

TArray<uint64> FlxAnimTracker::GetAborted() {
	TArray<uint64> result;
	result = std::move(AbortedHashes);
	AbortedHashes.Empty();
	return result;
}

ElxAnimationMode FlxAnimTracker::GetNextStep(FlxAnimationStep &step) {
	int offset = UnstartedSeqno - FirstSeqno;
	if (offset < AQ.Num()) {
		step = AQ[offset];
		return PlaybackMode;
	} else {
		step.Hash = 0;
		step.Body.Empty();
		return ElxAnimationMode::INVALID;
	}
}

void FlxAnimTracker::StartedStep(uint64 hash) {
	int offset = UnstartedSeqno - FirstSeqno;
	check(offset < AQ.Num());
	check(AQ[offset].Hash == hash);
	UnstartedSeqno += 1;
	PlaybackMode = ElxAnimationMode::StartAnimation;
}