using System;
using System.Security.Cryptography;
using Google.Protobuf;

namespace FrostFS.SDK.Cryptography;

public static class FrostFsExtensions
{
    public static byte[] Sha256(this IMessage data)
    {
        using var sha256 = SHA256.Create();
        using HashStream stream = new(sha256);
        data.WriteTo(stream);
        return stream.Hash();
    }

    public static Guid ToUuid(this ByteString id)
    {
        if (id == null)
            throw new ArgumentNullException(nameof(id));

        return new Guid(
           (id[0] << 24) + (id[1] << 16) + (id[2] << 8) + id[3],
           (short)((id[4] << 8) + id[5]),
           (short)((id[6] << 8) + id[7]),
           id[8],
           id[9],
           id[10],
           id[11],
           id[12],
           id[13],
           id[14],
           id[15]);
    }

    /// <summary>
    /// Serializes Guid to binary representation in direct order bytes format
    /// </summary>
    /// <param name="id"></param>
    /// <returns></returns>
    public unsafe static void ToBytes(this Guid id, Span<byte> span)
    {
        var pGuid = (byte*)&id;

        span[0] = pGuid[3];
        span[1] = pGuid[2];
        span[2] = pGuid[1];
        span[3] = pGuid[0];
        span[4] = pGuid[5];
        span[5] = pGuid[4];
        span[6] = pGuid[7];
        span[7] = pGuid[6];
        span[8] = pGuid[8];
        span[9] = pGuid[9];
        span[10] = pGuid[10];
        span[11] = pGuid[11];
        span[12] = pGuid[12];
        span[13] = pGuid[13];
        span[14] = pGuid[14];
        span[15] = pGuid[15];
    }
}