using System;
using UnitTestSharp;

namespace Annulus.UnitTests
{
    public class FlatHexDirectionExtensionsTests : TestFixture
    {
        public class OppositeTests : TestFixture
        {
            public void SouthEastIsNorthWest()
            {
                CheckEqual(FlatHexDirection.NorthWest, FlatHexDirection.SouthEast.Opposite());
            }

            public void SouthIsNorth()
            {
                CheckEqual(FlatHexDirection.North, FlatHexDirection.South.Opposite());
            }

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

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

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

        public class RotatedClockwiseTests : TestFixture
        {
            public void OneSixthTurnFromSouthEastIsSouth()
            {
                CheckEqual(FlatHexDirection.South, FlatHexDirection.SouthEast.RotatedClockwise(1));
            }

            public void WrapsPastNorthEastBackToSouthEast()
            {
                CheckEqual(FlatHexDirection.SouthEast, FlatHexDirection.NorthEast.RotatedClockwise(1));
            }

            public void NegativeTurnsGoCounterclockwise()
            {
                CheckEqual(FlatHexDirection.NorthEast, FlatHexDirection.SouthEast.RotatedClockwise(-1));
            }

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