jellyfin/MediaBrowser.Server.Implementations/LiveTv/TunerHosts/BaseTunerHost.cs

using MediaBrowser.Common.Configuration;
using MediaBrowser.Controller.LiveTv;
using MediaBrowser.Model.LiveTv;
using MediaBrowser.Model.Logging;
using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;

namespace MediaBrowser.Server.Implementations.LiveTv.TunerHosts
{
    public abstract class BaseTunerHost
    {
        protected readonly IConfigurationManager Config;
        protected readonly ILogger Logger;

        private readonly ConcurrentDictionary<string, ChannelCache> _channelCache =
            new ConcurrentDictionary<string, ChannelCache>(StringComparer.OrdinalIgnoreCase);

        public BaseTunerHost(IConfigurationManager config, ILogger logger)
        {
            Config = config;
            Logger = logger;
        }

        protected abstract Task<IEnumerable<ChannelInfo>> GetChannelsInternal(TunerHostInfo tuner, CancellationToken cancellationToken);
        public abstract string Type { get; }

        public async Task<IEnumerable<ChannelInfo>> GetChannels(TunerHostInfo tuner, bool enableCache, CancellationToken cancellationToken)
        {
            ChannelCache cache = null;

            if (enableCache && _channelCache.TryGetValue(tuner.Id, out cache))
            {
                if ((DateTime.UtcNow - cache.Date) < TimeSpan.FromMinutes(60))
                {
                    return cache.Channels.ToList();
                }
            }

            var result = await GetChannelsInternal(tuner, cancellationToken).ConfigureAwait(false);

            cache = cache ?? new ChannelCache();

            cache.Date = DateTime.UtcNow;
            cache.Channels = result.ToList();

            _channelCache.AddOrUpdate(tuner.Id, cache, (k, v) => cache);

            return cache.Channels.ToList();
        }

        private List<TunerHostInfo> GetTunerHosts()
        {
            return GetConfiguration().TunerHosts
                .Where(i => i.IsEnabled && string.Equals(i.Type, Type, StringComparison.OrdinalIgnoreCase))
                .ToList();
        }

        public async Task<IEnumerable<ChannelInfo>> GetChannels(CancellationToken cancellationToken)
        {
            var list = new List<ChannelInfo>();

            var hosts = GetTunerHosts();

            foreach (var host in hosts)
            {
                try
                {
                    var channels = await GetChannels(host, true, cancellationToken).ConfigureAwait(false);
                    var newChannels = channels.Where(i => !list.Any(l => string.Equals(i.Id, l.Id, StringComparison.OrdinalIgnoreCase))).ToList();

                    list.AddRange(newChannels);
                }
                catch (Exception ex)
                {
                    Logger.ErrorException("Error getting channel list", ex);
                }
            }

            return list;
        }

        protected LiveTvOptions GetConfiguration()
        {
            return Config.GetConfiguration<LiveTvOptions>("livetv");
        }
        
        private class ChannelCache
        {
            public DateTime Date;
            public List<ChannelInfo> Channels;
        }
    }
}