using System;
using UnitTestSharp;

namespace Annulus.UnitTests
{
    public class PointyHexDirectionExtensionsTests : TestFixture
    {
        public class OppositeTests : TestFixture
        {
            public void EastIsWest()
            {
                CheckEqual(PointyHexDirection.West, PointyHexDirection.East.Opposite());
            }

            public void SouthEastIsNorthWest()
            {
                CheckEqual(PointyHexDirection.NorthWest, PointyHexDirection.SouthEast.Opposite());
            }

            public void SouthWestIsNorthEast()
            {
                CheckEqual(PointyHexDirection.NorthEast, PointyHexDirection.SouthWest.Opposite());
            }

            public void IsItsOwnInverse()
            {
                for (var direction = PointyHexDirection.East; direction <= PointyHexDirection.NorthEast; ++direction)
                {
                    CheckEqual(direction, direction.Opposite().Opposite());
                }
            }

            public void NotAHexDirection_Throws()
            {
                CheckThrow(typeof(ArgumentOutOfRangeException));
                ((PointyHexDirection)6).Opposite();
            }
        }

        public class RotatedClockwiseTests : TestFixture
        {
            public void OneSixthTurnFromEastIsSouthEast()
            {
                CheckEqual(PointyHexDirection.SouthEast, PointyHexDirection.East.RotatedClockwise(1));
            }

            public void WrapsPastNorthEastBackToEast()
            {
                CheckEqual(PointyHexDirection.East, PointyHexDirection.NorthEast.RotatedClockwise(1));
            }

            public void NegativeTurnsGoCounterclockwise()
            {
                CheckEqual(PointyHexDirection.NorthEast, PointyHexDirection.East.RotatedClockwise(-1));
            }

            public void NotAHexDirection_Throws()
            {
                CheckThrow(typeof(ArgumentOutOfRangeException));
                ((PointyHexDirection)(-1)).RotatedClockwise(1);
            }
        }
    }
}