using System.Collections.Immutable;
using System.Linq;
using UnitTestSharp;

namespace Vellum.Generator.UnitTests
{
    public class EquatableArrayTests : TestFixture
    {
        public static EquatableArray<string> Of(params string[] items)
        {
            return new EquatableArray<string>(items.ToImmutableArray());
        }

        public class ItemsTests : TestFixture
        {
            public void ArrayItWasGiven_IsReturned()
            {
                CheckEqual(new[] { "a", "b" }, Of("a", "b").Items.ToArray());
            }

            public void DefaultArray_IsEmpty()
            {
                CheckEqual(0, new EquatableArray<string>().Items.Length);
            }
        }

        public class EqualsTests : TestFixture
        {
            public void SameItems_AreEqual()
            {
                CheckTrue(Of("a", "b").Equals(Of("a", "b")));
                CheckTrue(Of("a", "b").Equals((object)Of("a", "b")));
            }

            public void DefaultAndEmpty_AreEqual()
            {
                CheckTrue(new EquatableArray<string>().Equals(Of()));
            }

            public void DifferentItem_IsNotEqual()
            {
                CheckFalse(Of("a", "b").Equals(Of("a", "c")));
            }

            public void DifferentOrder_IsNotEqual()
            {
                CheckFalse(Of("a", "b").Equals(Of("b", "a")));
            }

            public void DifferentLength_IsNotEqual()
            {
                CheckFalse(Of("a", "b").Equals(Of("a")));
            }

            public void OtherType_IsNotEqual()
            {
                CheckFalse(Of("a").Equals("a"));
                CheckFalse(Of("a").Equals(null));
            }
        }

        public class GetHashCodeTests : TestFixture
        {
            public void SameItems_HaveEqualHashCodes()
            {
                CheckEqual(Of("a", "b").GetHashCode(), Of("a", "b").GetHashCode());
            }

            public void DefaultAndEmpty_HaveEqualHashCodes()
            {
                CheckEqual(Of().GetHashCode(), new EquatableArray<string>().GetHashCode());
            }

            public void NullItem_IsCounted()
            {
                CheckEqual(Of(null, "a").GetHashCode(), Of(null, "a").GetHashCode());
            }
        }
    }
}