using Amphora;
using UnitTestSharp;

namespace Glass.UnitTests
{
    public class FileSystemExtensionsTests : TestFixture
    {
        public class ReadAllBytesTests : TestFixture
        {
            public void ReturnsWhatTheFileHolds()
            {
                var files = new InMemoryFileSystem();
                InMemoryFileSystemTests.WriteAll(files.OpenWrite("/a.bin").Value, 4, 5, 6);

                CheckEqual(new byte[] { 4, 5, 6 }, files.ReadAllBytes("/a.bin").Value);
            }

            public void AnEmptyFile_ReturnsNoBytes()
            {
                var files = new InMemoryFileSystem();
                files.AddFile("/empty.bin", size: 0);

                CheckEqual(0, files.ReadAllBytes("/empty.bin").Value.Length);
            }

            public void AFileThatIsntThere_FailsAsNotFound()
            {
                var files = new InMemoryFileSystem();

                StatusOr<byte[]> read = files.ReadAllBytes("/missing.bin");

                CheckTrue(ReferenceEquals(FileSystemFailures.NotFound, read.Kind));
            }
        }

        public class WriteAllBytesTests : TestFixture
        {
            public void MakesAFileHoldingTheBytes()
            {
                var files = new InMemoryFileSystem();

                Status written = files.WriteAllBytes("/a.bin", new byte[] { 1, 2, 3 });

                CheckTrue(written.IsOk);
                CheckEqual(new byte[] { 1, 2, 3 }, files.ReadAllBytes("/a.bin").Value);
            }

            public void ReplacesWhatWasThere()
            {
                var files = new InMemoryFileSystem();
                files.WriteAllBytes("/a.bin", new byte[] { 1, 2, 3 });

                files.WriteAllBytes("/a.bin", new byte[] { 9 });

                CheckEqual(new byte[] { 9 }, files.ReadAllBytes("/a.bin").Value);
            }

            public void IntoADirectoryThatIsntThere_FailsAsNotFound()
            {
                var files = new InMemoryFileSystem();

                Status written = files.WriteAllBytes("/nowhere/a.bin", new byte[] { 1 });

                CheckTrue(ReferenceEquals(FileSystemFailures.NotFound, written.Kind));
            }

            public void ToAStoreThatIsFull_FailsAsAnIoError()
            {
                var store = new KeyValueFileSystemTests.FullStore { Full = true };
                var files = new KeyValueFileSystem(store);

                Status written = files.WriteAllBytes("/a.bin", new byte[] { 1 });

                CheckTrue(ReferenceEquals(FileSystemFailures.IoError, written.Kind));
            }
        }

        public class EnsureDirectoryTests : TestFixture
        {
            public void AMissingDirectory_IsMade()
            {
                var files = new InMemoryFileSystem();

                files.EnsureDirectory("/saves");

                CheckTrue(files.List("/saves").TryGetValue(out _));
            }

            public void AnExistingDirectory_KeepsItsContents()
            {
                var files = new InMemoryFileSystem();
                files.CreateDirectory("/saves");
                files.CreateDirectory("/saves/kept");

                files.EnsureDirectory("/saves");

                CheckEqual(1, files.List("/saves").Value.Count);
            }

            public void AMissingDirectoryWithNoParent_IsLeftMissing()
            {
                var files = new InMemoryFileSystem();

                files.EnsureDirectory("/no/such/saves");

                CheckFalse(files.List("/no/such/saves").TryGetValue(out _));
            }
        }
    }
}