using System.IO.Abstractions;
using CliWrap;
using ErsatzTV.Application.Streaming;
using ErsatzTV.Core;
using ErsatzTV.Core.Domain;
using ErsatzTV.Core.Interfaces.Emby;
using ErsatzTV.Core.Interfaces.FFmpeg;
using ErsatzTV.Core.Interfaces.Jellyfin;
using ErsatzTV.Core.Interfaces.Plex;
using ErsatzTV.Core.Interfaces.Repositories;
using ErsatzTV.Core.Interfaces.Streaming;
using ErsatzTV.FFmpeg;
using ErsatzTV.Infrastructure.Data;
using ErsatzTV.Tests.Support;
using LanguageExt;
using Microsoft.Extensions.Logging.Abstractions;
using NSubstitute;
using NSubstitute.Core;
using NSubstitute.Extensions;
using NUnit.Framework;
using Shouldly;
using DomainChannel = ErsatzTV.Core.Domain.Channel;

namespace ErsatzTV.Tests.Application.Streaming;

/// <summary>
///     ersatztv#473: a media-server item that is missing from disk used to fall back to the
///     remote-stream URL unconditionally. It must now be probed first, and an unavailable
///     remote stream must render an error card instead of a real playout process.
/// </summary>
[TestFixture]
public class GetPlayoutItemProcessByChannelNumberHandlerTests
{
    private const string ChannelNumber = "1";
    private const string JellyfinItemId = "abc123";
    private const string EmbyItemId = "def456";

    private readonly List<string> _tempFiles = [];
    private InMemoryTvContext _db = null!;
    private IFFmpegProcessService _ffmpegProcessService = null!;
    private IRemoteStreamProber _remoteStreamProber = null!;

    [SetUp]
    public async Task SetUp()
    {
        _db = await InMemoryTvContext.CreateAsync();
        _remoteStreamProber = Substitute.For<IRemoteStreamProber>();

        _ffmpegProcessService = Substitute.For<IFFmpegProcessService>();

        // both ForError and ForPlayoutItem must hand back a real value; the handler dereferences them
        _ffmpegProcessService.ReturnsForAll(Task.FromResult(Cli.Wrap("ffmpeg")));
        _ffmpegProcessService.ReturnsForAll(
            Task.FromResult(
                new PlayoutItemResult(
                    Cli.Wrap("ffmpeg"),
                    Option<GraphicsEngineContext>.None,
                    Option<int>.None)));
    }

    [TearDown]
    public async Task TearDown()
    {
        await _db.DisposeAsync();
        foreach (string tempFile in _tempFiles)
        {
            if (File.Exists(tempFile))
            {
                File.Delete(tempFile);
            }
        }
    }

    [Test]
    public async Task Should_Render_Error_Card_When_Remote_Stream_Is_Unavailable()
    {
        DateTimeOffset now = await SeedAll();
        _remoteStreamProber.IsAvailable(Arg.Any<string>(), Arg.Any<CancellationToken>()).Returns(false);

        Either<BaseError, PlayoutItemProcessModel> result =
            await CreateHandler().Handle(Request(now), CancellationToken.None);

        result.IsRight.ShouldBeTrue();

        await _remoteStreamProber.Received(1)
            .IsAvailable($"http://localhost:{Settings.StreamingPort}/media/jellyfin/{JellyfinItemId}", Arg.Any<CancellationToken>());

        List<ICall> errorCalls = CallsTo(nameof(IFFmpegProcessService.ForError));
        errorCalls.Count.ShouldBe(1);
        CallsTo(nameof(IFFmpegProcessService.ForPlayoutItem)).Count.ShouldBe(0);

        // the `case PlayoutItemNotAvailableFromMediaServer:` arm exists to surface the real error
        // text; without it the error falls to `default:` and the card says "Channel is Offline".
        // Assert the message, or the case label is untested dead weight.
        object?[] arguments = errorCalls[0].GetArguments();
        string errorMessage = arguments.OfType<string>().Single(a => a.Contains("not available"));
        errorMessage.ShouldContain($"/media/jellyfin/{JellyfinItemId}");
    }

    [Test]
    public async Task Should_Stream_Remotely_When_Remote_Stream_Is_Available()
    {
        DateTimeOffset now = await SeedAll();
        _remoteStreamProber.IsAvailable(Arg.Any<string>(), Arg.Any<CancellationToken>()).Returns(true);

        Either<BaseError, PlayoutItemProcessModel> result =
            await CreateHandler().Handle(Request(now), CancellationToken.None);

        result.IsRight.ShouldBeTrue();

        CallsTo(nameof(IFFmpegProcessService.ForError)).Count.ShouldBe(0);

        List<ICall> playoutCalls = CallsTo(nameof(IFFmpegProcessService.ForPlayoutItem));
        playoutCalls.Count.ShouldBe(1);

        // videoPath is the 7th parameter of ForPlayoutItem
        object?[] arguments = playoutCalls[0].GetArguments();
        arguments[6].ShouldBe($"http://localhost:{Settings.StreamingPort}/media/jellyfin/{JellyfinItemId}");
    }

    // the fix changed all three remote-stream branches; Jellyfin above covers one, this pins that a
    // second provider is probed too rather than the fix being Jellyfin-only (ersatztv#473 review)
    [Test]
    public async Task Should_Render_Error_Card_When_Emby_Remote_Stream_Is_Unavailable()
    {
        DateTimeOffset now = await SeedAll(emby: true);
        _remoteStreamProber.IsAvailable(Arg.Any<string>(), Arg.Any<CancellationToken>()).Returns(false);

        Either<BaseError, PlayoutItemProcessModel> result =
            await CreateHandler().Handle(Request(now), CancellationToken.None);

        result.IsRight.ShouldBeTrue();

        await _remoteStreamProber.Received(1)
            .IsAvailable(
                $"http://localhost:{Settings.StreamingPort}/media/emby/{EmbyItemId}",
                Arg.Any<CancellationToken>());

        CallsTo(nameof(IFFmpegProcessService.ForError)).Count.ShouldBe(1);
        CallsTo(nameof(IFFmpegProcessService.ForPlayoutItem)).Count.ShouldBe(0);
    }

    private List<ICall> CallsTo(string methodName) =>
        _ffmpegProcessService.ReceivedCalls()
            .Where(c => c.GetMethodInfo().Name == methodName)
            .ToList();

    private static GetPlayoutItemProcessByChannelNumber Request(DateTimeOffset now) =>
        new(
            ChannelNumber,
            StreamingMode.TransportStream,
            now,
            StartAtZero: false,
            HlsRealtime: true,
            ChannelStart: now,
            PtsOffset: TimeSpan.Zero,
            TargetFramerate: Option<FrameRate>.None,
            IsTroubleshooting: false,
            FFmpegProfileId: Option<int>.None);

    private GetPlayoutItemProcessByChannelNumberHandler CreateHandler()
    {
        var fileSystem = Substitute.For<IFileSystem>();
        fileSystem.File.Exists(Arg.Any<string>()).Returns(false);

        return new GetPlayoutItemProcessByChannelNumberHandler(
            _db.Factory,
            _ffmpegProcessService,
            fileSystem,
            Substitute.For<IExternalJsonPlayoutItemProvider>(),
            Substitute.For<IPlexPathReplacementService>(),
            Substitute.For<IJellyfinPathReplacementService>(),
            Substitute.For<IEmbyPathReplacementService>(),
            Substitute.For<IMediaCollectionRepository>(),
            Substitute.For<ITelevisionRepository>(),
            Substitute.For<IArtistRepository>(),
            Substitute.For<ISongVideoGenerator>(),
            Substitute.For<IMusicVideoCreditsGenerator>(),
            Substitute.For<IWatermarkSelector>(),
            Substitute.For<IGraphicsElementSelector>(),
            Substitute.For<IDecoSelector>(),
            _remoteStreamProber,
            NullLogger<GetPlayoutItemProcessByChannelNumberHandler>.Instance);
    }

    /// <summary>
    ///     Seeds ffmpeg/ffprobe config, an ffmpeg profile, a channel, a playout and a playout item
    ///     covering "now" whose media item is a jellyfin episode missing from disk — or, when
    ///     <paramref name="emby" /> is set, an emby episode.
    /// </summary>
    /// <returns>The "now" the request should use.</returns>
    private async Task<DateTimeOffset> SeedAll(bool emby = false)
    {
        string ffmpeg = Path.GetTempFileName();
        string ffprobe = Path.GetTempFileName();
        _tempFiles.Add(ffmpeg);
        _tempFiles.Add(ffprobe);

        var now = new DateTimeOffset(2026, 1, 1, 12, 0, 0, TimeSpan.Zero);

        await using TvContext context = _db.CreateContext();

        context.ConfigElements.Add(new ConfigElement { Key = ConfigElementKey.FFmpegPath.Key, Value = ffmpeg });
        context.ConfigElements.Add(new ConfigElement { Key = ConfigElementKey.FFprobePath.Key, Value = ffprobe });

        var profile = new FFmpegProfile
        {
            Name = "Test",
            Resolution = new Resolution { Name = "1080p", Width = 1920, Height = 1080 }
        };
        context.FFmpegProfiles.Add(profile);
        await context.SaveChangesAsync();

        var channel = new DomainChannel(Guid.NewGuid())
        {
            Number = ChannelNumber,
            Name = "Test",
            Group = "ErsatzTV",
            Categories = string.Empty,
            FFmpegProfileId = profile.Id,
            StreamSelector = string.Empty,
            PreferredAudioLanguageCode = string.Empty,
            PreferredAudioTitle = string.Empty,
            PreferredSubtitleLanguageCode = string.Empty,
            MusicVideoCreditsTemplate = string.Empty,
            StreamingMode = StreamingMode.TransportStream,
            PlayoutSource = ChannelPlayoutSource.Generated,
            PlayoutMode = ChannelPlayoutMode.Continuous
        };
        context.Channels.Add(channel);

        List<EpisodeMetadata> metadata =
            [new EpisodeMetadata { Title = "Missing", SortTitle = "Missing", Subtitles = [] }];
        List<MediaVersion> versions =
        [
            new MediaVersion
            {
                Name = "Main",
                Duration = TimeSpan.FromMinutes(30),
                MediaFiles = [new MediaFile { Path = "/gone/episode.mkv", PathHash = "gone" }],
                Streams = []
            }
        ];

        Episode episode = emby
            ? new EmbyEpisode { ItemId = EmbyItemId, EpisodeMetadata = metadata, MediaVersions = versions }
            : new JellyfinEpisode { ItemId = JellyfinItemId, EpisodeMetadata = metadata, MediaVersions = versions };

        context.AddRange(episode);
        await context.SaveChangesAsync();

        var playout = new Playout
        {
            ChannelId = channel.Id,
            ScheduleKind = PlayoutScheduleKind.Classic
        };
        context.Playouts.Add(playout);
        await context.SaveChangesAsync();

        context.PlayoutItems.Add(
            new PlayoutItem
            {
                PlayoutId = playout.Id,
                MediaItemId = episode.Id,
                Start = now.AddMinutes(-5).UtcDateTime,
                Finish = now.AddMinutes(25).UtcDateTime,
                InPoint = TimeSpan.FromMinutes(5),
                OutPoint = TimeSpan.FromMinutes(30),
                Watermarks = [],
                PlayoutItemWatermarks = [],
                GraphicsElements = [],
                PlayoutItemGraphicsElements = []
            });
        await context.SaveChangesAsync();

        return now;
    }
}