/// <summary>
/// Creates a new <see cref="NntpArticle"/> object.
/// </summary>
/// <param name="number">The number of the <see cref="NntpArticle"/>.</param>
/// <param name="messageId">The <see cref="NntpMessageId"/> of the <see cref="NntpArticle"/>.</param>
/// <param name="groups">The NNTP newsgroups this <see cref="NntpArticle"/> is posted in.</param>
/// <param name="headers">The headers of the <see cref="NntpArticle"/>.</param>
/// <param name="body">The body of the <see cref="NntpArticle"/>.</param>
public NntpArticle(
long number,
NntpMessageId messageId,
NntpGroups groups,
IDictionary <string, ICollection <string> > headers,
IEnumerable <string> body)
{
Number = number;
MessageId = messageId ?? NntpMessageId.Empty;
Groups = groups ?? NntpGroups.Empty;
Headers = (headers ?? MultiValueDictionary <string, string> .Empty).ToImmutableDictionaryWithHashSets();
switch (body)
{
case null:
// create empty immutable list
Body = new List <string>(0).ToImmutableList();
break;
case ICollection <string> collection:
// make immutable
Body = collection.ToImmutableList();
break;
default:
// not a collection but a stream of lines, keep enumerator
// this is immutable already
Body = body;
break;
}
}