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

#include "MetasoundBPMToSecondsNode.h"

#include "Internationalization/Text.h"
#include "MetasoundExecutableOperator.h"
#include "MetasoundNodeRegistrationMacro.h"
#include "MetasoundPrimitives.h"
#include "MetasoundStandardNodesNames.h"
#include "MetasoundTime.h"

#define LOCTEXT_NAMESPACE "MetasoundStandardNodes_BPMToSeconds"

namespace Metasound
{
	namespace BPMToSecondsVertexNames
	{
		const FVertexName& GetInputBPMTempoName()
		{
			static FVertexName Name = TEXT("BPM");
			return Name;
		}

		const FVertexName& GetInputBeatMultiplierName()
		{
			static FVertexName Name = TEXT("Beat Multiplier");
			return Name;
		}

		const FVertexName& GetInputDivisionsOfWholeNoteName()
		{
			static FVertexName Name = TEXT("Divisions of Whole Note");
			return Name;
		}

		const FVertexName& GetOutputTimeSecondsName()
		{
			static FVertexName Name = TEXT("Seconds");
			return Name;
		}
	}

	class FBPMToSecondsOperator : public TExecutableOperator<FBPMToSecondsOperator>
	{
	public:

		static const FNodeClassMetadata& GetNodeInfo();
		static const FVertexInterface& GetVertexInterface();
		static TUniquePtr<IOperator> CreateOperator(const FCreateOperatorParams& InParams, FBuildErrorArray& OutErrors);

		FBPMToSecondsOperator(const FOperatorSettings& InSettings, const FFloatReadRef& InBPM, const FFloatReadRef& InBeatMultiplier, const FFloatReadRef& InDivOfWholeNote);

		virtual FDataReferenceCollection GetInputs() const override;
		virtual FDataReferenceCollection GetOutputs() const override;
		void Execute();

	private:
		void UpdateTime();

		FFloatReadRef BPM;
		FFloatReadRef BeatMultiplier;
		FFloatReadRef DivOfWholeNote;

		// The output seconds
		FTimeWriteRef TimeSeconds;

		// Cached midi note value. Used to catch if the value changes to recompute freq output.
		float PrevBPM = -1.0f;
		float PrevBeatMultiplier = -1.0f;
		float PrevDivOfWholeNote = -1.0f;
	};

	FBPMToSecondsOperator::FBPMToSecondsOperator(const FOperatorSettings& InSettings, const FFloatReadRef& InBPM, const FFloatReadRef& InBeatMultiplier, const FFloatReadRef& InDivOfWholeNote)
		: BPM(InBPM)
		, BeatMultiplier(InBeatMultiplier)
		, DivOfWholeNote(InDivOfWholeNote)
		, TimeSeconds(TDataWriteReferenceFactory<FTime>::CreateAny(InSettings))
	{
		UpdateTime();
	}

	FDataReferenceCollection FBPMToSecondsOperator::GetInputs() const
	{
		using namespace BPMToSecondsVertexNames;

		FDataReferenceCollection InputDataReferences;
		InputDataReferences.AddDataReadReference(GetInputBPMTempoName(), BPM);
		InputDataReferences.AddDataReadReference(GetInputBeatMultiplierName(), BeatMultiplier);
		InputDataReferences.AddDataReadReference(GetInputDivisionsOfWholeNoteName(), DivOfWholeNote);

		return InputDataReferences;
	}

	FDataReferenceCollection FBPMToSecondsOperator::GetOutputs() const
	{
		using namespace BPMToSecondsVertexNames;

		FDataReferenceCollection OutputDataReferences;
		OutputDataReferences.AddDataReadReference(GetOutputTimeSecondsName(), TimeSeconds);
		return OutputDataReferences;
	}

	void FBPMToSecondsOperator::UpdateTime()
	{
		float CurrBPM = FMath::Max(*BPM, 1.0f);
		float CurrBeatMultiplier = FMath::Max(*BeatMultiplier, KINDA_SMALL_NUMBER);
		float CurrDivOfWholeNote = FMath::Max(*DivOfWholeNote, 1.0f);

		if (!FMath::IsNearlyEqual(PrevBPM, CurrBPM) || 
			!FMath::IsNearlyEqual(PrevBeatMultiplier, CurrBeatMultiplier) || 
			!FMath::IsNearlyEqual(PrevDivOfWholeNote, CurrDivOfWholeNote))
		{
			PrevBPM = CurrBPM;
			PrevBeatMultiplier = CurrBeatMultiplier;
			PrevDivOfWholeNote = CurrDivOfWholeNote;

			check(CurrBPM > 0.0f);
			check(CurrDivOfWholeNote > 0.0f);
			const float QuarterNoteTime = 60.0f / CurrBPM;
			float NewTimeSeconds = 4.0f * (float)CurrBeatMultiplier * QuarterNoteTime / CurrDivOfWholeNote;
			*TimeSeconds = FTime(NewTimeSeconds);
		}

	}

	void FBPMToSecondsOperator::Execute()
	{
		UpdateTime();
	}

	const FVertexInterface& FBPMToSecondsOperator::GetVertexInterface()
	{
		using namespace BPMToSecondsVertexNames;

		static const FVertexInterface Interface(
			FInputVertexInterface(
				TInputDataVertexModel<float>(GetInputBPMTempoName(), LOCTEXT("BPMToSecsBPMTT", "Input BPM (Beats Per Minute)."), 90.0f),
				TInputDataVertexModel<float>(GetInputBeatMultiplierName(), LOCTEXT("BPMToSecsBeatMultiplierTT", "The multipilier of the BPM."), 1.0f),
				TInputDataVertexModel<float>(GetInputDivisionsOfWholeNoteName(), LOCTEXT("BPMToSecsDivOfWholeNoteTT", "Divisions of a whole note."), 4.0f)
			),
			FOutputVertexInterface(
				TOutputDataVertexModel<FTime>(GetOutputTimeSecondsName(), LOCTEXT("BPMToSecsOutputTimeTT", "The output time in seconds give the BPM inputs."))
			)
		);

		return Interface;
	}

	const FNodeClassMetadata& FBPMToSecondsOperator::GetNodeInfo()
	{
		auto InitNodeInfo = []() -> FNodeClassMetadata
		{
			FNodeClassMetadata Info;
			Info.ClassName = { StandardNodes::Namespace, TEXT("BPMToSeconds"), TEXT("") };
			Info.MajorVersion = 1;
			Info.MinorVersion = 0;
			Info.DisplayName = LOCTEXT("BPMToSecondsDisplayName", "BPM To Seconds");
			Info.Description = LOCTEXT("BPMToSecondsDesc", "Calculates a beat time in seconds from the given BPM, beat multiplier and divisions of a whole note.");
			Info.Author = PluginAuthor;
			Info.PromptIfMissing = PluginNodeMissingPrompt;
			Info.DefaultInterface = GetVertexInterface();

			return Info;
		};

		static const FNodeClassMetadata Info = InitNodeInfo();

		return Info;
	}

	TUniquePtr<IOperator> FBPMToSecondsOperator::CreateOperator(const FCreateOperatorParams& InParams, FBuildErrorArray& OutErrors)
	{
		using namespace BPMToSecondsVertexNames;

		const FDataReferenceCollection& InputCollection = InParams.InputDataReferences;
		const FInputVertexInterface& InputInterface = GetVertexInterface().GetInputInterface();

		FFloatReadRef InBPM = InputCollection.GetDataReadReferenceOrConstructWithVertexDefault<float>(InputInterface, GetInputBPMTempoName(), InParams.OperatorSettings);
		FFloatReadRef InBeatMultiplier = InputCollection.GetDataReadReferenceOrConstructWithVertexDefault<float>(InputInterface, GetInputBeatMultiplierName(), InParams.OperatorSettings);
		FFloatReadRef InDivOfWholeNote = InputCollection.GetDataReadReferenceOrConstructWithVertexDefault<float>(InputInterface, GetInputDivisionsOfWholeNoteName(), InParams.OperatorSettings);

		return MakeUnique<FBPMToSecondsOperator>(InParams.OperatorSettings, InBPM, InBeatMultiplier, InDivOfWholeNote);
	}

	FBPMToSecondsNode::FBPMToSecondsNode(const FNodeInitData& InitData)
		: FNodeFacade(InitData.InstanceName, InitData.InstanceID, TFacadeOperatorClass<FBPMToSecondsOperator>())
	{
	}

	METASOUND_REGISTER_NODE(FBPMToSecondsNode)
}

#undef LOCTEXT_NAMESPACE