using System.Text;
using AVEVA.Historian.Client.Protocol;

namespace AVEVA.Historian.Client.Tests;

public sealed class BinaryPrimitiveTests
{
    [Fact]
    public void ToFileTimeUtc_TreatsUnspecifiedAsUtc()
    {
        DateTime value = new(2020, 4, 5, 10, 7, 42, DateTimeKind.Unspecified);

        long actual = HistorianBinaryPrimitives.ToFileTimeUtc(value);

        Assert.Equal(DateTime.SpecifyKind(value, DateTimeKind.Utc).ToFileTimeUtc(), actual);
    }

    [Fact]
    public void WriteUtf16NullTerminated_WritesUnicodeWithTerminator()
    {
        using MemoryStream stream = new();

        HistorianBinaryPrimitives.WriteUtf16NullTerminated(stream, "UTC");

        Assert.Equal(Encoding.Unicode.GetBytes("UTC\0"), stream.ToArray());
    }

    [Fact]
    public void WriteFileTimeUtc_WritesLittleEndianUInt64()
    {
        DateTime value = new(2020, 4, 5, 10, 7, 42, DateTimeKind.Utc);
        using MemoryStream stream = new();

        HistorianBinaryPrimitives.WriteFileTimeUtc(stream, value);

        Assert.Equal(BitConverter.GetBytes(value.ToFileTimeUtc()), stream.ToArray());
    }
}