public void FeedItemTo(FeedItemId fromFeedItemId, IFeedConsumer feedConsumer)
{
var feedId = fromFeedItemId.ToLong();
var id = (feedId - 1L) * _feed.MessagesPerFeedItem + 1;
_entryReader
.ReadNext(id.ToString(), _feed.MessagesPerFeedItem)
.AndThen(entries => {
var textEntries = entries.ToList();
feedConsumer.ConsumeFeedItem(ToFeedItem(fromFeedItemId, textEntries.Cast <TextEntry>().ToList()));
return(textEntries);
});
}
/// <summary>
/// Get a new <see cref="FeedItem"/> from converted <paramref name="entries"/>.
/// </summary>
/// <param name="feedItemId">The <see cref="FeedItemTo"/> of the current item</param>
/// <param name="entries">The list of <see cref="TextEntry"/> to convert</param>
/// <returns><see cref="FeedItem"/></returns>
private FeedItem ToFeedItem(FeedItemId feedItemId, List <TextEntry> entries)
{
var messages = new List <FeedMessage>(entries.Count);
foreach (var entry in entries)
{
var body = FeedMessageBody.With(entry.EntryData);
var message = FeedMessage.With(entry.Id, body, entry.TypeName, entry.TypeVersion);
messages.Add(message);
}
if (_feed.MessagesPerFeedItem == entries.Count)
{
return(FeedItem.ArchivedFeedItemWith(feedItemId, feedItemId.Next(), feedItemId.Previous(), messages));
}
return(FeedItem.CurrentFeedWith(feedItemId, feedItemId.Previous(), messages));
}
/// <summary>
/// Construct my state with identities, messages, and archive indicator.
/// </summary>
/// <param name="id">The <see cref="FeedItemId"/> identity</param>
/// <param name="nextId">The <see cref="FeedItemId"/> identity of the next FeedItem, if known</param>
/// <param name="previousId">The identity of the previous feed, if any</param>
/// <param name="messages">The <see cref="List{T}"/> of messages</param>
/// <param name="archived">The boolean indicator that this feed is considered archived or not</param>
/// <exception cref="ArgumentNullException">If any of the arguments is null</exception>
private FeedItem(FeedItemId id, FeedItemId nextId, FeedItemId previousId, List <FeedMessage> messages, bool archived)
{
if (id == null)
{
throw new ArgumentNullException(nameof(id));
}
if (nextId == null)
{
throw new ArgumentNullException(nameof(nextId));
}
if (previousId == null)
{
throw new ArgumentNullException(nameof(previousId));
}
Id = id;
NextId = nextId;
PreviousId = previousId;
Messages = messages;
Archived = archived;
}
/// <summary>
/// Construct my state with identities, messages, and <code>false</code> archive indicator
/// </summary>
/// <param name="id">The <see cref="FeedItemId"/> identity</param>
/// <param name="previousFeedId">The identity of the previous feed, if any</param>
/// <param name="messages">The <see cref="List{T}"/> of messages</param>
private FeedItem(FeedItemId id, FeedItemId previousFeedId, List <FeedMessage> messages) : this(id, FeedItemId.Unknown, previousFeedId, messages, false)
{
}
/// <summary>
/// Gets the new <see cref="FeedItem"/> that is considered current/head, with
/// <paramref name="id"/>, a <paramref name="previousId"/>, and <paramref name="messages"/>.
/// </summary>
/// <param name="id">The <see cref="FeedItemId"/> identity</param>
/// <param name="previousId">The identity of the previous feed, if any</param>
/// <param name="messages">The <see cref="List{T}"/> of messages</param>
/// <returns><see cref="FeedItem"/></returns>
public static FeedItem CurrentFeedWith(FeedItemId id, FeedItemId previousId, IEnumerable <FeedMessage> messages) =>
new FeedItem(id, previousId, messages.ToList());
/// <summary>
/// Gets the new <see cref="FeedItem"/> that is considered current/head, with
/// <paramref name="id"/>, a <paramref name="previousId"/>, and <paramref name="messages"/>.
/// </summary>
/// <param name="id">The <see cref="FeedItemId"/> identity</param>
/// <param name="nextId">The <see cref="FeedItemId"/> identity of the next FeedItem, if known</param>
/// <param name="previousId">The identity of the previous feed, if any</param>
/// <param name="messages">The <see cref="List{T}"/> of messages</param>
/// <returns><see cref="FeedItem"/></returns>
public static FeedItem ArchivedFeedItemWith(FeedItemId id, FeedItemId nextId, FeedItemId previousId, IEnumerable <FeedMessage> messages) =>
new FeedItem(id, nextId, previousId, messages.ToList(), true);
