using System;
using UnitTestSharp;

namespace Amphora.UnitTests
{
    public class FailureKindOfPayloadTests : TestFixture
    {
        public class FailTests : TestFixture
        {
            public void MakesAFailureOfThisKind()
            {
                Status failure = BlockedCellKind.Instance.Fail(FailureTestKinds.Wall);

                CheckEqual(BlockedCellKind.Instance, failure.Kind);
            }

            public void StoresWhatPackProduced()
            {
                Status failure = BlockedCellKind.Instance.Fail(FailureTestKinds.Wall);

                CheckEqual("a wall", failure.Ref);
                CheckEqual((-3L << 32) | 7L, failure.Bits);
            }

            public void AllocatesNothing()
            {
                CheckEqual(0L, Allocations.During(
                    () => Allocations.StatusSink = BlockedCellKind.Instance.Fail(FailureTestKinds.Wall)));
            }
        }

        public class ReadTests : TestFixture
        {
            public void ReturnsThePayloadItWasFailedWith()
            {
                Status failure = BlockedCellKind.Instance.Fail(FailureTestKinds.Wall);

                BlockedCell payload = BlockedCellKind.Instance.Read(failure);

                CheckEqual(-3, payload.X);
                CheckEqual(7, payload.Y);
                CheckEqual("a wall", payload.Blocker);
            }

            public void OtherKind_Throws()
            {
                Status other = FailureTestKinds.Unreachable.Fail();

                CheckThrow(typeof(ArgumentException));
                BlockedCellKind.Instance.Read(other);
            }

            public void NoFailure_Throws()
            {
                CheckThrow(typeof(ArgumentException));
                BlockedCellKind.Instance.Read(default);
            }

            public void AllocatesNothing()
            {
                Allocations.StatusSink = BlockedCellKind.Instance.Fail(FailureTestKinds.Wall);

                CheckEqual(0L, Allocations.During(
                    () => Allocations.PayloadSink = BlockedCellKind.Instance.Read(Allocations.StatusSink)));
            }
        }

        public class DescribeTests : TestFixture
        {
            public void DescribesThePayloadWithTheContext()
            {
                Status failure = BlockedCellKind.Instance.Fail(FailureTestKinds.Wall);

                CheckEqual("The pawn can't reach (-3, 7) past a wall.",
                    BlockedCellKind.Instance.Describe(failure, context: "The pawn"));
            }

            public void OtherKind_Throws()
            {
                Status other = FailureTestKinds.Unreachable.Fail();

                CheckThrow(typeof(ArgumentException));
                BlockedCellKind.Instance.Describe(other, context: null);
            }
        }
    }
}