using Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.CSharp;
using Microsoft.CodeAnalysis.Text;
using UnitTestSharp;

namespace Ariadne.Generator.UnitTests
{
    public class SourcePlaceTests : TestFixture
    {
        public static SourcePlace Variant(string filePath = "File.cs", int start = 1, int line = 1)
        {
            return new SourcePlace(filePath, new TextSpan(start, 4),
                new LinePositionSpan(new LinePosition(line, 0), new LinePosition(line, 4)));
        }

        public class CtorTests : TestFixture
        {
            public void KeepsEveryArgument()
            {
                SourcePlace place = Variant(start: 3, line: 2);

                CheckEqual("File.cs", place.FilePath);
                CheckEqual(new TextSpan(3, 4), place.Span);
                CheckEqual(new LinePositionSpan(new LinePosition(2, 0), new LinePosition(2, 4)), place.LineSpan);
            }
        }

        public class OfTests : TestFixture
        {
            public void LocationInSource_IsItsFileAndSpans()
            {
                CSharpCompilation compilation = GeneratorRun.Compile(("Source.cs", "public class Foo { }"));
                Location location = compilation.GetTypeByMetadataName("Foo").Locations[0];
                SourcePlace place = SourcePlace.Of(location);

                CheckEqual("Source.cs", place.FilePath);
                CheckEqual(location.SourceSpan, place.Span);
                CheckEqual(location.GetLineSpan().Span, place.LineSpan);
            }

            public void LocationNotInSource_HasNoFile()
            {
                CSharpCompilation compilation = GeneratorRun.Compile(("Source.cs", ""));
                Location location = compilation.GetSpecialType(SpecialType.System_Object).Locations[0];

                CheckNull(SourcePlace.Of(location).FilePath);
            }

            public void NoLocation_HasNoFile()
            {
                CheckNull(SourcePlace.Of(null).FilePath);
                CheckNull(SourcePlace.Of(Location.None).FilePath);
            }
        }

        public class LocationInTests : TestFixture
        {
            public void FileInTheCompilation_IsAtTheSpanOfItsOwnSyntaxTree()
            {
                CSharpCompilation compilation = GeneratorRun.Compile(("Source.cs", "public class Foo { }"));
                SourcePlace place = SourcePlace.Of(compilation.GetTypeByMetadataName("Foo").Locations[0]);
                Location location = place.LocationIn(compilation);

                CheckEqual(LocationKind.SourceFile, location.Kind);
                CheckTrue(location.SourceTree == compilation.SyntaxTrees[1]);
                CheckEqual(place.Span, location.SourceSpan);
            }

            public void FileOutsideTheCompilation_IsAtItsPath()
            {
                CSharpCompilation compilation = GeneratorRun.Compile(("Source.cs", "public class Foo { }"));
                Location location = Variant(filePath: "Elsewhere.cs", start: 2, line: 3).LocationIn(compilation);

                CheckEqual(LocationKind.ExternalFile, location.Kind);
                CheckEqual("Elsewhere.cs", location.GetLineSpan().Path);
                CheckEqual(new TextSpan(2, 4), location.SourceSpan);
            }

            public void NoFile_IsNowhere()
            {
                CSharpCompilation compilation = GeneratorRun.Compile(("Source.cs", ""));

                CheckEqual(Location.None, SourcePlace.Of(null).LocationIn(compilation));
            }
        }

        public class EqualsTests : TestFixture
        {
            public void SameValues_AreEqual()
            {
                CheckTrue(Variant().Equals(Variant()));
                CheckTrue(Variant().Equals((object)Variant()));
            }

            public void Null_IsNotEqual()
            {
                CheckFalse(Variant().Equals((SourcePlace)null));
                CheckFalse(Variant().Equals((object)null));
            }

            public void OtherType_IsNotEqual()
            {
                CheckFalse(Variant().Equals("File.cs"));
            }

            public void DifferentFilePath_IsNotEqual()
            {
                CheckFalse(Variant().Equals(Variant(filePath: "Other.cs")));
            }

            public void DifferentSpan_IsNotEqual()
            {
                CheckFalse(Variant().Equals(Variant(start: 2)));
            }

            public void DifferentLineSpan_IsNotEqual()
            {
                CheckFalse(Variant().Equals(Variant(line: 2)));
            }
        }

        public class GetHashCodeTests : TestFixture
        {
            public void EqualPlaces_HaveEqualHashCodes()
            {
                CheckEqual(Variant().GetHashCode(), Variant().GetHashCode());
            }
        }
    }
}