using MediaBrowser.Common.Extensions;
using MediaBrowser.Common.IO;
using MediaBrowser.Controller.Channels;
using MediaBrowser.Controller.Configuration;
using MediaBrowser.Controller.Dto;
using MediaBrowser.Controller.Entities;
using MediaBrowser.Controller.Library;
using MediaBrowser.Controller.Providers;
using MediaBrowser.Model.Channels;
using MediaBrowser.Model.Dto;
using MediaBrowser.Model.Entities;
using MediaBrowser.Model.Logging;
using MediaBrowser.Model.Querying;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;

namespace MediaBrowser.Server.Implementations.Channels
{
    public class ChannelManager : IChannelManager
    {
        private IChannel[] _channels;
        private IChannelFactory[] _factories;
        private List<Channel> _channelEntities = new List<Channel>();

        private readonly IUserManager _userManager;
        private readonly IUserDataManager _userDataManager;
        private readonly IDtoService _dtoService;
        private readonly ILibraryManager _libraryManager;
        private readonly ILogger _logger;
        private readonly IServerConfigurationManager _config;
        private readonly IFileSystem _fileSystem;

        public ChannelManager(IUserManager userManager, IDtoService dtoService, ILibraryManager libraryManager, ILogger logger, IServerConfigurationManager config, IFileSystem fileSystem, IUserDataManager userDataManager)
        {
            _userManager = userManager;
            _dtoService = dtoService;
            _libraryManager = libraryManager;
            _logger = logger;
            _config = config;
            _fileSystem = fileSystem;
            _userDataManager = userDataManager;
        }

        public void AddParts(IEnumerable<IChannel> channels, IEnumerable<IChannelFactory> factories)
        {
            _channels = channels.ToArray();
            _factories = factories.ToArray();
        }

        private IEnumerable<IChannel> GetAllChannels()
        {
            return _factories
                .SelectMany(i =>
                {
                    try
                    {
                        return i.GetChannels().ToList();
                    }
                    catch (Exception ex)
                    {
                        _logger.ErrorException("Error getting channel list", ex);
                        return new List<IChannel>();
                    }
                })
                .Concat(_channels)
                .OrderBy(i => i.Name);
        }

        public Task<QueryResult<BaseItemDto>> GetChannels(ChannelQuery query, CancellationToken cancellationToken)
        {
            var user = string.IsNullOrWhiteSpace(query.UserId)
                ? null
                : _userManager.GetUserById(new Guid(query.UserId));

            var channels = _channelEntities.OrderBy(i => i.SortName).ToList();

            if (user != null)
            {
                channels = channels.Where(i => GetChannelProvider(i).IsEnabledFor(user) && i.IsVisible(user))
                    .ToList();
            }

            // Get everything
            var fields = Enum.GetNames(typeof(ItemFields))
                    .Select(i => (ItemFields)Enum.Parse(typeof(ItemFields), i, true))
                    .ToList();

            var returnItems = channels.Select(i => _dtoService.GetBaseItemDto(i, fields, user))
                .ToArray();

            var result = new QueryResult<BaseItemDto>
            {
                Items = returnItems,
                TotalRecordCount = returnItems.Length
            };

            return Task.FromResult(result);
        }

        public async Task RefreshChannels(IProgress<double> progress, CancellationToken cancellationToken)
        {
            var allChannelsList = GetAllChannels().ToList();

            var list = new List<Channel>();

            var numComplete = 0;

            foreach (var channelInfo in allChannelsList)
            {
                cancellationToken.ThrowIfCancellationRequested();

                try
                {
                    var item = await GetChannel(channelInfo, cancellationToken).ConfigureAwait(false);

                    list.Add(item);

                    _libraryManager.RegisterItem(item);
                }
                catch (OperationCanceledException)
                {
                    throw;
                }
                catch (Exception ex)
                {
                    _logger.ErrorException("Error getting channel information for {0}", ex, channelInfo.Name);
                }

                numComplete++;
                double percent = numComplete;
                percent /= allChannelsList.Count;

                progress.Report(100 * percent);
            }

            _channelEntities = list.ToList();
            progress.Report(100);
        }

        private async Task<Channel> GetChannel(IChannel channelInfo, CancellationToken cancellationToken)
        {
            var path = Path.Combine(_config.ApplicationPaths.ItemsByNamePath, "channels", _fileSystem.GetValidFilename(channelInfo.Name));

            var fileInfo = new DirectoryInfo(path);

            var isNew = false;

            if (!fileInfo.Exists)
            {
                _logger.Debug("Creating directory {0}", path);

                Directory.CreateDirectory(path);
                fileInfo = new DirectoryInfo(path);

                if (!fileInfo.Exists)
                {
                    throw new IOException("Path not created: " + path);
                }

                isNew = true;
            }

            var id = GetInternalChannelId(channelInfo.Name);

            var item = _libraryManager.GetItemById(id) as Channel;

            if (item == null)
            {
                item = new Channel
                {
                    Name = channelInfo.Name,
                    Id = id,
                    DateCreated = _fileSystem.GetCreationTimeUtc(fileInfo),
                    DateModified = _fileSystem.GetLastWriteTimeUtc(fileInfo),
                    Path = path
                };

                isNew = true;
            }

            var info = channelInfo.GetChannelInfo();

            item.HomePageUrl = info.HomePageUrl;
            item.OriginalChannelName = channelInfo.Name;

            if (string.IsNullOrEmpty(item.Name))
            {
                item.Name = channelInfo.Name;
            }

            await item.RefreshMetadata(new MetadataRefreshOptions
            {
                ForceSave = isNew

            }, cancellationToken);

            return item;
        }

        private Guid GetInternalChannelId(string name)
        {
            if (string.IsNullOrWhiteSpace(name))
            {
                throw new ArgumentNullException("name");
            }

            return ("Channel " + name).GetMBId(typeof(Channel));
        }

        public async Task<QueryResult<BaseItemDto>> GetChannelItems(ChannelItemQuery query, CancellationToken cancellationToken)
        {
            var user = string.IsNullOrWhiteSpace(query.UserId)
                ? null
                : _userManager.GetUserById(new Guid(query.UserId));

            var id = new Guid(query.ChannelId);
            var channel = _channelEntities.First(i => i.Id == id);
            var channelProvider = GetChannelProvider(channel);

            var items = await GetChannelItems(channelProvider, user, query.CategoryId, cancellationToken)
                        .ConfigureAwait(false);

            return await GetReturnItems(items, user, query, cancellationToken).ConfigureAwait(false);
        }

        private async Task<IEnumerable<ChannelItemInfo>> GetChannelItems(IChannel channel, User user, string categoryId, CancellationToken cancellationToken)
        {
            // TODO: Put some caching in here

            var query = new InternalChannelItemQuery
            {
                User = user,
                CategoryId = categoryId
            };

            var result = await channel.GetChannelItems(query, cancellationToken).ConfigureAwait(false);

            return result.Items;
        }

        private async Task<QueryResult<BaseItemDto>> GetReturnItems(IEnumerable<ChannelItemInfo> items, User user, ChannelItemQuery query, CancellationToken cancellationToken)
        {
            // Get everything
            var fields = Enum.GetNames(typeof(ItemFields))
                    .Select(i => (ItemFields)Enum.Parse(typeof(ItemFields), i, true))
                    .ToList();

            var tasks = items.Select(i => GetChannelItemEntity(i, cancellationToken));

            IEnumerable<BaseItem> entities = await Task.WhenAll(tasks).ConfigureAwait(false);

            entities = ApplyFilters(entities, query.Filters, user);

            entities = _libraryManager.Sort(entities, user, query.SortBy, query.SortOrder ?? SortOrder.Ascending);

            var all = entities.ToList();
            var totalCount = all.Count;

            if (query.StartIndex.HasValue)
            {
                all = all.Skip(query.StartIndex.Value).ToList();
            }
            if (query.Limit.HasValue)
            {
                all = all.Take(query.Limit.Value).ToList();
            }

            await RefreshIfNeeded(all, cancellationToken).ConfigureAwait(false);

            var returnItemArray = all.Select(i => _dtoService.GetBaseItemDto(i, fields, user))
                .ToArray();

            return new QueryResult<BaseItemDto>
            {
                Items = returnItemArray,
                TotalRecordCount = totalCount
            };
        }

        private string GetIdToHash(string externalId)
        {
            // Increment this as needed to force new downloads
            return externalId + "3";
        }

        private async Task<BaseItem> GetChannelItemEntity(ChannelItemInfo info, CancellationToken cancellationToken)
        {
            BaseItem item;
            Guid id;
            var isNew = false;

            if (info.Type == ChannelItemType.Category)
            {
                id = GetIdToHash(info.Id).GetMBId(typeof(ChannelCategoryItem));

                item = _libraryManager.GetItemById(id) as ChannelCategoryItem;

                if (item == null)
                {
                    isNew = true;
                    item = new ChannelCategoryItem();
                }
            }
            else if (info.MediaType == ChannelMediaType.Audio)
            {
                id = GetIdToHash(info.Id).GetMBId(typeof(ChannelCategoryItem));

                item = _libraryManager.GetItemById(id) as ChannelAudioItem;

                if (item == null)
                {
                    isNew = true;
                    item = new ChannelAudioItem();
                }
            }
            else
            {
                id = GetIdToHash(info.Id).GetMBId(typeof(ChannelVideoItem));

                item = _libraryManager.GetItemById(id) as ChannelVideoItem;

                if (item == null)
                {
                    isNew = true;
                    item = new ChannelVideoItem();
                }
            }

            item.Id = id;
            item.RunTimeTicks = info.RunTimeTicks;

            var mediaSource = info.MediaSources.FirstOrDefault();

            item.Path = mediaSource == null ? null : mediaSource.Path;

            if (isNew)
            {
                item.Name = info.Name;
                item.Genres = info.Genres;
                item.Studios = info.Studios;
                item.CommunityRating = info.CommunityRating;
                item.OfficialRating = info.OfficialRating;
                item.Overview = info.Overview;
                item.People = info.People;
                item.PremiereDate = info.PremiereDate;
                item.ProductionYear = info.ProductionYear;
                item.ProviderIds = info.ProviderIds;

                if (info.DateCreated.HasValue)
                {
                    item.DateCreated = info.DateCreated.Value;
                }
            }

            var channelItem = (IChannelItem)item;

            channelItem.OriginalImageUrl = info.ImageUrl;
            channelItem.ExternalId = info.Id;
            channelItem.ChannelItemType = info.Type;

            var channelMediaItem = item as IChannelMediaItem;

            if (channelMediaItem != null)
            {
                channelMediaItem.IsInfiniteStream = info.IsInfiniteStream;
                channelMediaItem.ContentType = info.ContentType;
            }

            if (isNew)
            {
                await _libraryManager.CreateItem(item, cancellationToken).ConfigureAwait(false);
                _libraryManager.RegisterItem(item);
            }

            return item;
        }

        private async Task RefreshIfNeeded(IEnumerable<BaseItem> programs, CancellationToken cancellationToken)
        {
            foreach (var program in programs)
            {
                await RefreshIfNeeded(program, cancellationToken).ConfigureAwait(false);
            }
        }

        private async Task RefreshIfNeeded(BaseItem program, CancellationToken cancellationToken)
        {
            //if (_refreshedPrograms.ContainsKey(program.Id))
            {
                //return;
            }

            await program.RefreshMetadata(cancellationToken).ConfigureAwait(false);

            //_refreshedPrograms.TryAdd(program.Id, true);
        }

        internal IChannel GetChannelProvider(Channel channel)
        {
            return GetAllChannels().First(i => string.Equals(i.Name, channel.OriginalChannelName, StringComparison.OrdinalIgnoreCase));
        }

        private IEnumerable<BaseItem> ApplyFilters(IEnumerable<BaseItem> items, IEnumerable<ItemFilter> filters, User user)
        {
            foreach (var filter in filters.OrderByDescending(f => (int)f))
            {
                items = ApplyFilter(items, filter, user);
            }

            return items;
        }

        private IEnumerable<BaseItem> ApplyFilter(IEnumerable<BaseItem> items, ItemFilter filter, User user)
        {
            // Avoid implicitly captured closure
            var currentUser = user;

            switch (filter)
            {
                case ItemFilter.IsFavoriteOrLikes:
                    return items.Where(item =>
                    {
                        var userdata = _userDataManager.GetUserData(user.Id, item.GetUserDataKey());

                        if (userdata == null)
                        {
                            return false;
                        }

                        var likes = userdata.Likes ?? false;
                        var favorite = userdata.IsFavorite;

                        return likes || favorite;
                    });

                case ItemFilter.Likes:
                    return items.Where(item =>
                    {
                        var userdata = _userDataManager.GetUserData(user.Id, item.GetUserDataKey());

                        return userdata != null && userdata.Likes.HasValue && userdata.Likes.Value;
                    });

                case ItemFilter.Dislikes:
                    return items.Where(item =>
                    {
                        var userdata = _userDataManager.GetUserData(user.Id, item.GetUserDataKey());

                        return userdata != null && userdata.Likes.HasValue && !userdata.Likes.Value;
                    });

                case ItemFilter.IsFavorite:
                    return items.Where(item =>
                    {
                        var userdata = _userDataManager.GetUserData(user.Id, item.GetUserDataKey());

                        return userdata != null && userdata.IsFavorite;
                    });

                case ItemFilter.IsResumable:
                    return items.Where(item =>
                    {
                        var userdata = _userDataManager.GetUserData(user.Id, item.GetUserDataKey());

                        return userdata != null && userdata.PlaybackPositionTicks > 0;
                    });

                case ItemFilter.IsPlayed:
                    return items.Where(item => item.IsPlayed(currentUser));

                case ItemFilter.IsUnplayed:
                    return items.Where(item => item.IsUnplayed(currentUser));

                case ItemFilter.IsFolder:
                    return items.Where(item => item.IsFolder);

                case ItemFilter.IsNotFolder:
                    return items.Where(item => !item.IsFolder);
            }

            return items;
        }
    }
}