ersatztv/ErsatzTV.Infrastructure/Extensions/PlayoutItemQueryableExtensions.cs

using System;
using System.Linq;
using System.Threading.Tasks;
using ErsatzTV.Core.Domain;
using LanguageExt;
using Microsoft.EntityFrameworkCore;
using static LanguageExt.Prelude;

namespace ErsatzTV.Infrastructure.Extensions
{
    public static class PlayoutItemQueryableExtensions
    {
        public static Task<Option<PlayoutItem>> ForChannelAndTime(
            this IQueryable<PlayoutItem> dbSet,
            int channelId,
            DateTimeOffset time) =>
            dbSet.Filter(pi => pi.Playout.ChannelId == channelId)
                .Filter(pi => pi.Start <= time.UtcDateTime && pi.Finish > time.UtcDateTime)
                .OrderBy(pi => pi.Start)
                .FirstOrDefaultAsync()
                .Map(Optional);
    }
}