using System;
using System.Data;
using NHibernate;
using NHibernate.SqlTypes;
using NHibernate.UserTypes;

public class BinaryGuidType : IUserType
{
    private static readonly int[] ByteOrder = new[] { 10,11,12,13,14,15,8,9,6,7,4,5,0,1,2,3 };
    private static readonly SqlType[] Types = new[] { new SqlType(DbType.Binary) };

    public SqlType[] SqlTypes
    {
        get { return Types; }
    }

    public Type ReturnedType
    {
        get { return typeof(Guid); }
    }

    public new bool Equals(object x, object y)
    {
        return (x != null && x.Equals(y));
    }

    public int GetHashCode(object x)
    {
        return x.GetHashCode();
    }

    public object NullSafeGet(IDataReader rs, string[] names, object owner)
    {
        var bytes = (byte[]) NHibernateUtil.Binary.NullSafeGet(rs, names[0]);
        if (bytes == null || bytes.Length == 0) return null;

        var reorderedBytes = new byte[16];

        for (var i = 0 ; i < 16; i++)
        {
            reorderedBytes[ByteOrder[i]] = bytes[i];
        }

        return new Guid(reorderedBytes);
    }

    public void NullSafeSet(IDbCommand cmd, object value, int index)
    {
        if (null != value)
        {
            var bytes = ((Guid) value).ToByteArray();
            var reorderedBytes = new byte[16];

            for (var i = 0; i < 16; i++)
            {
                reorderedBytes[i] = bytes[ByteOrder[i]];
            }

            NHibernateUtil.Binary.NullSafeSet(cmd, reorderedBytes, index);
        }
        else
        {
            NHibernateUtil.Binary.NullSafeSet(cmd, null, index);
        }
    }

    public object DeepCopy(object value)
    {
        return value;
    }

    public bool IsMutable
    {
        get { return false; }
    }

    public object Replace(object original, object target, object owner)
    {
        return original;
    }

    public object Assemble(object cached, object owner)
    {
        return cached;
    }

    public object Disassemble(object value)
    {
        return value;
    }
}