using System.Buffers.Binary;
using System.Text;

namespace AVEVA.Historian.Client.Protocol;

internal static class HistorianBinaryPrimitives
{
    public static long ToFileTimeUtc(DateTime value)
    {
        return value.Kind == DateTimeKind.Unspecified
            ? DateTime.SpecifyKind(value, DateTimeKind.Utc).ToFileTimeUtc()
            : value.ToUniversalTime().ToFileTimeUtc();
    }

    public static void WriteUInt16LittleEndian(Stream stream, ushort value)
    {
        Span<byte> buffer = stackalloc byte[sizeof(ushort)];
        BinaryPrimitives.WriteUInt16LittleEndian(buffer, value);
        stream.Write(buffer);
    }

    public static void WriteUInt32LittleEndian(Stream stream, uint value)
    {
        Span<byte> buffer = stackalloc byte[sizeof(uint)];
        BinaryPrimitives.WriteUInt32LittleEndian(buffer, value);
        stream.Write(buffer);
    }

    public static void WriteUInt64LittleEndian(Stream stream, ulong value)
    {
        Span<byte> buffer = stackalloc byte[sizeof(ulong)];
        BinaryPrimitives.WriteUInt64LittleEndian(buffer, value);
        stream.Write(buffer);
    }

    public static void WriteFileTimeUtc(Stream stream, DateTime value)
    {
        WriteUInt64LittleEndian(stream, unchecked((ulong)ToFileTimeUtc(value)));
    }

    public static void WriteUtf16NullTerminated(Stream stream, string value)
    {
        ArgumentNullException.ThrowIfNull(value);

        byte[] bytes = Encoding.Unicode.GetBytes(value);
        stream.Write(bytes);
        stream.WriteByte(0);
        stream.WriteByte(0);
    }
}