/// <summary>
/// Generates a Message-Id.
/// </summary>
/// <remarks>
/// Generates a new Message-Id using the supplied domain.
/// </remarks>
/// <returns>The message identifier.</returns>
/// <param name="domain">A domain to use.</param>
/// <exception cref="System.ArgumentNullException">
/// <paramref name="domain"/> is <c>null</c>.
/// </exception>
/// <exception cref="System.ArgumentException">
/// <paramref name="domain"/> is invalid.
/// </exception>
public static string GenerateMessageId(string domain)
{
if (domain == null)
{
throw new ArgumentNullException(nameof(domain));
}
if (domain.Length == 0)
{
throw new ArgumentException("The domain is invalid.", nameof(domain));
}
ulong value = (ulong)DateTime.Now.Ticks;
var id = new StringBuilder();
var block = new byte[8];
GetRandomBytes(block);
do
{
id.Append(base36[(int)(value % 36)]);
value /= 36;
} while (value != 0);
id.Append('.');
value = 0;
for (int i = 0; i < 8; i++)
{
value = (value << 8) | (ulong)block[i];
}
do
{
id.Append(base36[(int)(value % 36)]);
value /= 36;
} while (value != 0);
id.Append('@').Append(ParseUtils.IdnEncode(domain));
return(id.ToString());
}
