/// <summary>
/// When folder removed and created again, its messages UIs counter clears, and starts from 0.
/// Due to imap protocol realization, search method with "UId N:*" query allways returns last message index in folder.
/// Theafore, when last message index UId is less then <see cref="CurrentMessageUidInFolder"/> value,
/// we assume that folder was recreated.
/// </summary>
/// <param name="messageIndexCollection"><see cref="MessageIndexCollection"/> instance.</param>
/// <returns><c>True</c> if folder was recreated in mailbox, <c>false</c> otherwise.</returns>
private bool IsFolderWasRecreated(MessageIndexCollection messageIndexCollection)
{
List <long> messageIndexList = messageIndexCollection.Cast <long>().ToList();
messageIndexList.Sort();
return(messageIndexList.Count > 0 && messageIndexList.First() < long.Parse(CurrentMessageUidInFolder));
}
/// <summary>
/// Loads not synchronized messages indexes form selected folder.
/// Selected folder must be specified in <paramref name="client"/>, using <see cref="ImapClient.SelectFolderForSyncronization"/> method.
/// Due to imap protocol realization, search method with "UId N:*" query allways returns last message index in folder.
/// Message index with <see cref="CurrentMessageUidInFolder"/> UId will be skipped.
/// If current folder was removed and created again in mailbox, synchronization strategy will use new folder query string.
/// </summary>
/// <param name="client"><see cref="Imap"/> instance.</param>
/// <returns><see cref="MessageIndexCollection"/> instance.</returns>
private MessageIndexCollection GetNotSyncedMessageIndexes(Imap client)
{
MessageIndexCollection messageIndexCollection = GetUnsyncMsgIndexCollection(client);
if (IsFolderWasRecreated(messageIndexCollection))
{
CurrentMessageUidInFolder = "0";
messageIndexCollection = GetUnsyncMsgIndexCollection(client);
}
List <long> messageIndexList = messageIndexCollection.Cast <long>().ToList();
messageIndexList.Sort();
if (messageIndexList.Count > 0 && messageIndexList.First().ToString() == CurrentMessageUidInFolder)
{
messageIndexCollection.RemoveAt(0);
}
return(messageIndexCollection);
}
/// <summary>
/// Gets list mailbox indexes from <paramref name="msgIndexes"/>.
/// </summary>
/// <param name="msgIndexes"><see cref="MessageIndexCollection"/> instance.</param>
/// <returns>List mailbox indexes.</returns>
protected virtual List <long> GetMsgIndexesList(MessageIndexCollection msgIndexes)
{
return(msgIndexes.Cast <long>().ToList());
}