#include "RadialMenu.h"


void URadialMenu::Configure(int32 NItems, float ItemHeight, float InnerRadius, float MinSpoke, float Spread)
{
    CNItems = NItems;
    CItemHeight = ItemHeight;
    CInnerRadius = InnerRadius;
    CMinSpoke = MinSpoke;
    CSpread = Spread;

    CNumRight = (NItems / 2);
    CNumLeft = NItems - CNumRight;
    Items.SetNum(NItems);

    LeftItems = View(Items.GetData(), CNumLeft);
    RightItems = View(Items.GetData() + CNumLeft, CNumRight);

    CalculateSide(LeftItems);
    CalculateSide(RightItems);
    FlipHorizontal(LeftItems);
}

FVector2D URadialMenu::PieSliceToVector(double Slice, double Slices)
{
    double HalfRevolutions = (Slice + 0.5) / Slices;
    double Radians = (HalfRevolutions * UE_PI);
    return FVector2D(FMath::Sin(Radians), -FMath::Cos(Radians));
}

void URadialMenu::FlipHorizontal(View V)
{
    for (FRadialMenuItem& Item : V)
    {
        Item.Point1.X = -Item.Point1.X;
        Item.Point2.X = -Item.Point2.X;
        Item.Point3.X = -Item.Point3.X;
        Item.RightSide = !Item.RightSide;
    }
}

void URadialMenu::CalculateSide(View V)
{
    // Point1 is simple. RightSide is always initialized to
    // true, it may get reversed in FlipHorizontal.
    for (int32 I = 0; I < V.Num(); I++)
    {
        V[I].RightSide = true;
        V[I].Point1 = PieSliceToVector(I, V.Num()) * CInnerRadius;
    }

    // Calculate point2 for all spokes.
    double NextLineMin = CItemHeight * 0.5;
    int32 Mid = (V.Num() / 2);
    if (V.Num() & 1)
    {
        V[Mid].Point2 = FVector2D(CInnerRadius + CMinSpoke, 0.0);
        NextLineMin = CItemHeight;
        Mid += 1;
    }
    for (int32 I = Mid; I < V.Num(); I++)
    {
        FVector2D UnitVec = PieSliceToVector(I, V.Num());
        double Y = (UnitVec.Y * (CInnerRadius + CMinSpoke));
        if (Y < NextLineMin) Y = NextLineMin;
        NextLineMin = Y + CItemHeight;
        FVector2D Point2 = UnitVec * (Y / UnitVec.Y);
        V[I].Point2 = Point2;
        V[V.Num() - I].Point2 = Point2 * FVector2D(1.0,-1.0);
    }

    // The rule we use for calculating point2 may result in
    // a very short horizontal spoke.  If so, fix it.
    if ((V.Num() & 1) && (V.Num() >= 3))
    {
        Mid = V.Num() / 2;
        if (V[Mid].Point2.X < V[Mid + 1].Point2.X)
            V[Mid].Point2.X = V[Mid + 1].Point2.X;
    }

    // Calculate Point3.
    for (int32 I = 0; I < V.Num(); I++)
    {
        V[I].Point3 = V[I].Point2 + FVector2D(CSpread, 0.0);
    }
}