// Copyright (c) Meta Platforms, Inc. and affiliates.

#pragma once

#include "CoreMinimal.h"
#include "Components/ActorComponent.h"
#include "Components/PoseableMeshComponent.h"

#include "OculusXRMovementTypes.h"

#include "OculusXREyeTrackingComponent.generated.h"

struct FOculusXREyeTrackingData
{
public:
	FOculusXREyeTrackingData()
		: EyeIsMapped(false)
		, MappedBoneName(NAME_None)
	{
	}

	bool EyeIsMapped;
	FName MappedBoneName;
	FQuat InitialRotation;
};

UCLASS(Blueprintable, meta = (BlueprintSpawnableComponent, DisplayName = "OculusXR Eye Tracking Component"), ClassGroup = OculusXRHMD)
class OCULUSXRMOVEMENT_API UOculusXREyeTrackingComponent : public UActorComponent
{
	GENERATED_BODY()
public:
	UOculusXREyeTrackingComponent();

	virtual void BeginPlay() override;
	virtual void EndPlay(const EEndPlayReason::Type EndPlayReason) override;
	virtual void TickComponent(float DeltaTime, enum ELevelTick TickType, FActorComponentTickFunction* ThisTickFunction) override;

	/**
	* Reset the rotation values of the eyes to their initial rotation
	*/
	UFUNCTION(BlueprintCallable, Category = "Oculus|Movement")
	void ClearRotationValues();

	/**
	 * The name of the poseable mesh component that this component targets for eyes glazes movement.
	 * This must be the name of a component on this actor.
	 */
	UPROPERTY(EditAnywhere, BlueprintReadOnly, Category = "OculusXR|Movement")
	FName TargetMeshComponentName;

	/**
	 * The map of eye to mesh bone that this component supports.
	 * Names are validated on (@see BeginPlay) so only valid bone names will be targeted.
	 */
	UPROPERTY(EditAnywhere, BlueprintReadOnly, Category = "OculusXR|Movement")
	TMap<EOculusXREye, FName> EyeToBone;

	/**
	 * Update the target mesh position when eye state changes
	 */
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "OculusXR|Movement")
	bool bUpdatePosition;

	/**
	 * Update the target mesh rotation when eye state changes
	 */
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "OculusXR|Movement")
	bool bUpdateRotation;

	/**
	 * Do not accept an eye gaze state if confidence is lower than this value. Confidence is in range [0,1].
	 */
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "OculusXR|Movement")
	float ConfidenceThreshold;

	/**
	 * Bypass eye gaze state validity.
	 * 
	 * @Note: It doesn't check the confidence (@see ConfidenceThreshold). The eye gaze state can be marked as invalid. This flag bypass that state flag.
	 */
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "OculusXR|Movement")
	bool bAcceptInvalid;

private:
	bool InitializeEyes();

	// One meter in unreal world units.
	float WorldToMeters;

	// Per eye, eye tracking data
	TStaticArray<FOculusXREyeTrackingData, static_cast<uint32>(EOculusXREye::COUNT)> PerEyeData;

	// The mesh component targeted for eyes
	UPROPERTY()
	UPoseableMeshComponent* TargetPoseableMeshComponent;

	// Stop the tracker just once.
	static int TrackingInstanceCount;
};