using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using MailKit;
using MailKit.Net.Imap;
using MailKit.Search;
using Wino.Core.Domain.Entities.Mail;
using Wino.Core.Domain.Interfaces;
using Wino.Core.Integration;

namespace Wino.Core.Synchronizers.ImapSync
{
    /// <summary>
    /// Uid based IMAP Synchronization strategy.
    /// </summary>
    internal class UidBasedSynchronizer : ImapSynchronizationStrategyBase
    {
        public UidBasedSynchronizer(IFolderService folderService, Domain.Interfaces.IMailService mailService) : base(folderService, mailService)
        {
        }

        public override async Task<List<string>> HandleSynchronizationAsync(IImapClient client, MailItemFolder folder, IImapSynchronizer synchronizer, CancellationToken cancellationToken = default)
        {
            if (client is not WinoImapClient winoClient)
                throw new ArgumentException("Client must be of type WinoImapClient.", nameof(client));

            Folder = folder;

            var downloadedMessageIds = new List<string>();
            IMailFolder remoteFolder = null;

            try
            {
                remoteFolder = await winoClient.GetFolderAsync(folder.RemoteFolderId, cancellationToken).ConfigureAwait(false);

                await remoteFolder.OpenAsync(FolderAccess.ReadOnly, cancellationToken).ConfigureAwait(false);

                // Fetch UIDs from the remote folder
                var remoteUids = await remoteFolder.SearchAsync(SearchQuery.All, cancellationToken).ConfigureAwait(false);

                remoteUids = remoteUids.OrderByDescending(a => a.Id).Take((int)synchronizer.InitialMessageDownloadCountPerFolder).ToList();

                await HandleChangedUIdsAsync(synchronizer, remoteFolder, remoteUids, cancellationToken).ConfigureAwait(false);
                await ManageUUIdBasedDeletedMessagesAsync(folder, remoteFolder, cancellationToken).ConfigureAwait(false);
            }
            catch (FolderNotFoundException)
            {
                await FolderService.DeleteFolderAsync(folder.MailAccountId, folder.RemoteFolderId).ConfigureAwait(false);

                return default;
            }
            catch (Exception)
            {

                throw;
            }
            finally
            {
                if (!cancellationToken.IsCancellationRequested)
                {
                    if (remoteFolder != null)
                    {
                        if (remoteFolder.IsOpen)
                        {
                            await remoteFolder.CloseAsync(cancellationToken: cancellationToken).ConfigureAwait(false);
                        }
                    }
                }
            }

            return downloadedMessageIds;
        }

        internal override Task<IList<UniqueId>> GetChangedUidsAsync(IImapClient client, IMailFolder remoteFolder, IImapSynchronizer synchronizer, CancellationToken cancellationToken = default)
        {
            throw new NotImplementedException();
        }
    }
}