#include "UniStrokeRecognizer.h"

FUniStrokeRecognizer::FUniStrokeRecognizer()
{
	this->Templates = TArray<FUniStrokeTemplate>();
}

FUniStrokeRecognizer::~FUniStrokeRecognizer()
{
	// DO NOTHING
}

// TODO: Review this function
FUniStrokeResult
FUniStrokeRecognizer::Recognize(const TArray<FVector2D>& VectorPoints,
                                const bool& UseProtractor)
{
	TArray<FUniStrokePoint> Points = FUniStrokePoint::From(VectorPoints);

	// Edge case: Not enough points
	if (Points.Num() < 2 || FUniStrokePoint::PathLength(Points) < 100.0f)
	{
		return FUniStrokeResult("Too few points made", 0.0);
	}

	const FUniStrokeTemplate Candidate = FUniStrokeTemplate("", Points);
	int TemplateIndex = -1;

	// b <- +infty
	float b = TNumericLimits<float>::Max();

	// foreach template T in templates do
	for (int i = 0; i < Templates.Num(); i++)
	{
		// d <- DistanceAtBestAngle(points, T, -theta, theta, threshold)
		const float d = UseProtractor
			                ? FUniStrokePoint::OptimalCosineDistance(
				                Templates[i].Vector,
				                Candidate.Vector
			                )
			                : FUniStrokePoint::DistanceAtBestAngle(
				                Candidate.Points,
				                Templates[i].Points,
				                -AngleRange,
				                AngleRange,
				                AnglePrecision
			                );

		// if d < b then
		if (d < b)
		{
			// b <- d
			b = d;
			// T' <- T
			TemplateIndex = i;
		}
	}

	// score <- 1 – b / 0.5 sqrt(size^2 + size^2)
	const float Score = UseProtractor ? 1.0 - b : 1.0 - b / HalfDiagonal;

	// return <T', score>
	return TemplateIndex == -1
		       ? FUniStrokeResult("No match", 0.0)
		       : FUniStrokeResult(Templates[TemplateIndex].Name, Score);
}

void
FUniStrokeRecognizer::AddTemplate(const FString& Name,
                                  const TArray<FVector2D>& VectorPoints)
{
	const TArray<FUniStrokePoint> Points = FUniStrokePoint::From(VectorPoints);
	this->Templates.Add(FUniStrokeTemplate(Name, Points));
}

void FUniStrokeRecognizer::Reset()
{
	Templates.SetNum(NumTemplates);
}