using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.EntityFrameworkCore;
using RdtClient.Data.Models.Data;

namespace RdtClient.Data.Data
{
    public class TorrentData
    {
        private static IList<Torrent> _torrentCache;
        private static readonly SemaphoreSlim TorrentCacheLock = new(1, 1);

        private readonly DataContext _dataContext;

        public TorrentData(DataContext dataContext)
        {
            _dataContext = dataContext;
        }

        public async Task<IList<Torrent>> Get()
        {
            await TorrentCacheLock.WaitAsync();

            try
            {
                _torrentCache ??= await _dataContext.Torrents
                                                    .AsNoTracking()
                                                    .Include(m => m.Downloads)
                                                    .ToListAsync();

                return _torrentCache.OrderBy(m => m.Priority ?? 9999).ThenBy(m => m.Added).ToList();
            }
            finally
            {
                TorrentCacheLock.Release();
            }
        }

        public async Task<Torrent> GetById(Guid torrentId)
        {
            var dbTorrent = await _dataContext.Torrents
                                              .AsNoTracking()
                                              .Include(m => m.Downloads)
                                              .FirstOrDefaultAsync(m => m.TorrentId == torrentId);

            if (dbTorrent == null)
            {
                return null;
            }

            foreach (var file in dbTorrent.Downloads)
            {
                file.Torrent = null;
            }

            return dbTorrent;
        }

        public async Task<Torrent> GetByHash(String hash)
        {
            var dbTorrent = await _dataContext.Torrents
                                              .AsNoTracking()
                                              .Include(m => m.Downloads)
                                              .FirstOrDefaultAsync(m => m.Hash.ToLower() == hash.ToLower());

            if (dbTorrent == null)
            {
                return null;
            }

            foreach (var file in dbTorrent.Downloads)
            {
                file.Torrent = null;
            }

            return dbTorrent;
        }

        public async Task<Torrent> Add(String realDebridId,
                                       String hash,
                                       String fileOrMagnetContents,
                                       Boolean isFile,
                                       Torrent torrent)
        {
            var newTorrent = new Torrent
            {
                TorrentId = Guid.NewGuid(),
                Added = DateTimeOffset.UtcNow,
                RdId = realDebridId,
                Hash = hash.ToLower(),
                Category = torrent.Category,
                DownloadAction = torrent.DownloadAction,
                FinishedAction = torrent.FinishedAction,
                DownloadMinSize = torrent.DownloadMinSize,
                DownloadManualFiles = torrent.DownloadManualFiles,
                FileOrMagnet = fileOrMagnetContents,
                IsFile = isFile,
                Priority = torrent.Priority,
                TorrentRetryAttempts = torrent.TorrentRetryAttempts,
                DownloadRetryAttempts = torrent.DownloadRetryAttempts
            };

            await _dataContext.Torrents.AddAsync(newTorrent);

            await _dataContext.SaveChangesAsync();

            await VoidCache();

            return newTorrent;
        }

        public async Task UpdateRdData(Torrent torrent)
        {
            var dbTorrent = await _dataContext.Torrents.FirstOrDefaultAsync(m => m.TorrentId == torrent.TorrentId);

            if (dbTorrent == null)
            {
                return;
            }

            dbTorrent.RdName = torrent.RdName;
            dbTorrent.RdSize = torrent.RdSize;
            dbTorrent.RdHost = torrent.RdHost;
            dbTorrent.RdSplit = torrent.RdSplit;
            dbTorrent.RdProgress = torrent.RdProgress;
            dbTorrent.RdStatus = torrent.RdStatus;
            dbTorrent.RdStatusRaw = torrent.RdStatusRaw;
            dbTorrent.RdAdded = torrent.RdAdded;
            dbTorrent.RdEnded = torrent.RdEnded;
            dbTorrent.RdSpeed = torrent.RdSpeed;
            dbTorrent.RdSeeders = torrent.RdSeeders;

            if (torrent.Files != null)
            {
                dbTorrent.RdFiles = torrent.RdFiles;
            }

            await _dataContext.SaveChangesAsync();

            await VoidCache();
        }

        public async Task Update(Torrent torrent)
        {
            var dbTorrent = await _dataContext.Torrents.FirstOrDefaultAsync(m => m.TorrentId == torrent.TorrentId);

            if (dbTorrent == null)
            {
                return;
            }

            dbTorrent.Priority = torrent.Priority;
            dbTorrent.DownloadRetryAttempts = torrent.DownloadRetryAttempts;
            dbTorrent.TorrentRetryAttempts = torrent.TorrentRetryAttempts;

            await _dataContext.SaveChangesAsync();

            await VoidCache();
        }

        public async Task UpdateCategory(Guid torrentId, String category)
        {
            var dbTorrent = await _dataContext.Torrents.FirstOrDefaultAsync(m => m.TorrentId == torrentId);

            if (dbTorrent == null)
            {
                return;
            }

            dbTorrent.Category = category;

            await _dataContext.SaveChangesAsync();

            await VoidCache();
        }

        public async Task UpdateComplete(Guid torrentId, String error, DateTimeOffset? datetime)
        {
            var dbTorrent = await _dataContext.Torrents.FirstOrDefaultAsync(m => m.TorrentId == torrentId);

            if (dbTorrent == null)
            {
                return;
            }

            if (String.IsNullOrWhiteSpace(error))
            {
                var downloads = await _dataContext.Downloads.AsNoTracking().Where(m => m.TorrentId == torrentId).ToListAsync();
                var downloadWithErrors = downloads.Where(m => !String.IsNullOrWhiteSpace(m.Error)).ToList();

                if (downloads.Any())
                {
                    error = $"{downloadWithErrors.Count}/{downloads.Count} downloads failed with errors";
                }
            }

            if (!String.IsNullOrWhiteSpace(error))
            {
                if (dbTorrent.RetryCount < dbTorrent.TorrentRetryAttempts)
                {
                    dbTorrent.RetryCount += 1;
                    dbTorrent.Retry = DateTime.UtcNow;
                }
            }

            dbTorrent.Completed = datetime;
            dbTorrent.Error = error;

            await _dataContext.SaveChangesAsync();

            await VoidCache();
        }

        public async Task UpdateFilesSelected(Guid torrentId, DateTimeOffset datetime)
        {
            var dbTorrent = await _dataContext.Torrents.FirstOrDefaultAsync(m => m.TorrentId == torrentId);

            if (dbTorrent == null)
            {
                return;
            }

            dbTorrent.FilesSelected = datetime;

            await _dataContext.SaveChangesAsync();

            await VoidCache();
        }

        public async Task UpdatePriority(Guid torrentId, Int32? priority)
        {
            var dbTorrent = await _dataContext.Torrents.FirstOrDefaultAsync(m => m.TorrentId == torrentId);

            if (dbTorrent == null)
            {
                return;
            }

            dbTorrent.Priority = priority;

            await _dataContext.SaveChangesAsync();

            await VoidCache();
        }

        public async Task UpdateRetry(Guid torrentId, DateTimeOffset? dateTime, Int32 retryCount)
        {
            var dbTorrent = await _dataContext.Torrents.FirstOrDefaultAsync(m => m.TorrentId == torrentId);

            if (dbTorrent == null)
            {
                return;
            }

            dbTorrent.RetryCount = retryCount;
            dbTorrent.Retry = dateTime;

            await _dataContext.SaveChangesAsync();

            await VoidCache();
        }

        public async Task UpdateError(Guid torrentId, String error)
        {
            var dbTorrent = await _dataContext.Torrents.FirstOrDefaultAsync(m => m.TorrentId == torrentId);

            if (dbTorrent == null)
            {
                return;
            }

            dbTorrent.Error = error;

            await _dataContext.SaveChangesAsync();

            await VoidCache();
        }

        public async Task Delete(Guid torrentId)
        {
            var dbTorrent = await _dataContext.Torrents.FirstOrDefaultAsync(m => m.TorrentId == torrentId);

            if (dbTorrent == null)
            {
                return;
            }

            _dataContext.Torrents.Remove(dbTorrent);

            await _dataContext.SaveChangesAsync();

            await VoidCache();
        }

        public static async Task VoidCache()
        {
            await TorrentCacheLock.WaitAsync();

            try
            {
                _torrentCache = null;
            }
            finally
            {
                TorrentCacheLock.Release();
            }
        }
    }
}