using System;
using System.Collections.Generic;
using System.Linq;
using ErsatzTV.Core.Domain;

namespace ErsatzTV.Core.Scheduling
{
    internal class ChronologicalMediaComparer : IComparer<MediaItem>
    {
        public int Compare(MediaItem x, MediaItem y)
        {
            if (x == null || y == null)
            {
                return 0;
            }

            DateTime date1 = x switch
            {
                Episode e => e.EpisodeMetadata.HeadOrNone().Match(
                    em => em.ReleaseDate ?? DateTime.MaxValue,
                    () => DateTime.MaxValue),
                Movie m => m.MovieMetadata.HeadOrNone().Match(
                    mm => mm.ReleaseDate ?? DateTime.MaxValue,
                    () => DateTime.MaxValue),
                MusicVideo mv => mv.MusicVideoMetadata.HeadOrNone().Match(
                    mvm => mvm.ReleaseDate ?? DateTime.MaxValue,
                    () => DateTime.MaxValue),
                _ => DateTime.MaxValue
            };

            DateTime date2 = y switch
            {
                Episode e => e.EpisodeMetadata.HeadOrNone().Match(
                    em => em.ReleaseDate ?? DateTime.MaxValue,
                    () => DateTime.MaxValue),
                Movie m => m.MovieMetadata.HeadOrNone().Match(
                    mm => mm.ReleaseDate ?? DateTime.MaxValue,
                    () => DateTime.MaxValue),
                MusicVideo mv => mv.MusicVideoMetadata.HeadOrNone().Match(
                    mvm => mvm.ReleaseDate ?? DateTime.MaxValue,
                    () => DateTime.MaxValue),
                _ => DateTime.MaxValue
            };

            if (date1 != date2)
            {
                return date1.CompareTo(date2);
            }

            int season1 = x switch
            {
                Episode e => e.Season?.SeasonNumber ?? int.MaxValue,
                _ => int.MaxValue
            };

            int season2 = y switch
            {
                Episode e => e.Season?.SeasonNumber ?? int.MaxValue,
                _ => int.MaxValue
            };

            if (season1 != season2)
            {
                return season1.CompareTo(season2);
            }

            int episode1 = x switch
            {
                Episode e => e.EpisodeMetadata.HeadOrNone().Match(
                    em => em.EpisodeNumber,
                    () => int.MaxValue),
                _ => int.MaxValue
            };

            int episode2 = y switch
            {
                Episode e => e.EpisodeMetadata.HeadOrNone().Match(
                    em => em.EpisodeNumber,
                    () => int.MaxValue),
                _ => int.MaxValue
            };

            if (episode1 != episode2)
            {
                return episode1.CompareTo(episode2);
            }

            return x.Id.CompareTo(y.Id);
        }
    }
}