using System.Reflection;
using ErsatzTV.Application.Libraries;
using ErsatzTV.Controllers.Api;
using ErsatzTV.Controllers.Api.Requests;
using ErsatzTV.Core;
using ErsatzTV.Core.Api.MediaSources;
using ErsatzTV.Core.Domain;
using ErsatzTV.Core.Interfaces.Locking;
using ErsatzTV.Core.Interfaces.Repositories;
using LanguageExt;
using MediatR;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.Routing;
using NSubstitute;
using NUnit.Framework;
using Shouldly;
using Testably.Abstractions.Testing;
using Unit = LanguageExt.Unit;
using static LanguageExt.Prelude;

namespace ErsatzTV.Tests.Controllers;

[TestFixture]
public class LocalLibrariesControllerTests
{
    private LocalLibrariesController _controller = null!;
    private IEntityLocker _entityLocker = null!;
    private MockFileSystem _fileSystem = null!;
    private ILibraryRepository _libraryRepository = null!;
    private IMediator _mediator = null!;

    [SetUp]
    public void SetUp()
    {
        _mediator = Substitute.For<IMediator>();
        _entityLocker = Substitute.For<IEntityLocker>();
        _fileSystem = new MockFileSystem();
        _libraryRepository = Substitute.For<ILibraryRepository>();
        _controller = new LocalLibrariesController(_mediator, _entityLocker, _fileSystem, _libraryRepository);
    }

    [Test]
    public void Controller_Should_Expose_Idiomatic_Rest_Routes()
    {
        ShouldHaveActionRoute(nameof(LocalLibrariesController.GetAll), "GET", "/api/libraries/local");
        ShouldHaveActionRoute(nameof(LocalLibrariesController.GetById), "GET", "/api/libraries/local/{id:int}");
        ShouldHaveActionRoute(nameof(LocalLibrariesController.Create), "POST", "/api/libraries/local");
        ShouldHaveActionRoute(nameof(LocalLibrariesController.Update), "PUT", "/api/libraries/local/{id:int}");
        ShouldHaveActionRoute(nameof(LocalLibrariesController.Delete), "DELETE", "/api/libraries/local/{id:int}");
        ShouldHaveActionRoute(
            nameof(LocalLibrariesController.MovePath),
            "POST",
            "/api/libraries/local/paths/{pathId:int}/move");
        ShouldHaveActionRoute(
            nameof(LocalLibrariesController.CheckPathExists),
            "POST",
            "/api/libraries/local/path-exists");
    }

    [Test]
    public async Task GetAll_Should_Project_Libraries_And_Lock_State()
    {
        _mediator.Send(Arg.Any<GetAllLocalLibraries>(), Arg.Any<CancellationToken>())
            .Returns(new List<LocalLibraryViewModel>
            {
                new(1, "Movies", LibraryMediaKind.Movies, 0),
                new(2, "TV Shows", LibraryMediaKind.Shows, 0)
            });
        _entityLocker.IsLibraryLocked(1).Returns(true);
        _entityLocker.IsLibraryLocked(2).Returns(false);

        List<LocalLibraryResponseModel> result = await _controller.GetAll(CancellationToken.None);

        result.Count.ShouldBe(2);
        result[0].ShouldBe(new LocalLibraryResponseModel(1, "Movies", LibraryMediaKind.Movies, true));
        result[1].ShouldBe(new LocalLibraryResponseModel(2, "TV Shows", LibraryMediaKind.Shows, false));
    }

    [Test]
    public async Task GetById_Should_Return_404_When_Missing()
    {
        _mediator.Send(Arg.Any<GetLocalLibraryById>(), Arg.Any<CancellationToken>())
            .Returns(Option<LocalLibraryViewModel>.None);

        IActionResult result = await _controller.GetById(99, CancellationToken.None);

        var notFound = result.ShouldBeOfType<NotFoundObjectResult>();
        notFound.Value.ShouldBeOfType<ProblemDetails>().Status.ShouldBe(StatusCodes.Status404NotFound);
    }

    [Test]
    public async Task GetById_Should_Return_Detail_With_Paths_And_Counts()
    {
        _mediator.Send(Arg.Any<GetLocalLibraryById>(), Arg.Any<CancellationToken>())
            .Returns(Some(new LocalLibraryViewModel(3, "Movies", LibraryMediaKind.Movies, 0)));
        _mediator.Send(Arg.Any<GetLocalLibraryPaths>(), Arg.Any<CancellationToken>())
            .Returns(new List<LocalLibraryPathViewModel> { new(10, 3, "/media/movies") });
        _mediator.Send(Arg.Any<CountMediaItemsByLibrary>(), Arg.Any<CancellationToken>()).Returns(5);
        _mediator.Send(Arg.Any<CountMediaItemsByLibraryPath>(), Arg.Any<CancellationToken>()).Returns(5);
        _entityLocker.IsLibraryLocked(3).Returns(false);

        IActionResult result = await _controller.GetById(3, CancellationToken.None);

        var ok = result.ShouldBeOfType<OkObjectResult>();
        var detail = ok.Value.ShouldBeOfType<LocalLibraryDetailResponseModel>();
        detail.Id.ShouldBe(3);
        detail.MediaItemCount.ShouldBe(5);
        detail.Paths.Count.ShouldBe(1);
        detail.Paths[0].ShouldBe(new LocalLibraryPathResponseModel(10, "/media/movies", 5));
    }

    [Test]
    public async Task Create_Should_Return_201_With_Location_And_Body()
    {
        _mediator.Send(Arg.Any<CreateLocalLibrary>(), Arg.Any<CancellationToken>())
            .Returns(Right<BaseError, LocalLibraryViewModel>(
                new LocalLibraryViewModel(5, "Movies", LibraryMediaKind.Movies, 0)));

        IActionResult result = await _controller.Create(
            new CreateLocalLibraryRequest("Movies", LibraryMediaKind.Movies, ["/media/movies"]),
            CancellationToken.None);

        var created = result.ShouldBeOfType<CreatedResult>();
        created.Location.ShouldBe("/api/libraries/local/5");
        created.Value.ShouldBeOfType<LocalLibraryResponseModel>().Name.ShouldBe("Movies");
        await _mediator.Received(1).Send(
            Arg.Is<CreateLocalLibrary>(c => c.Name == "Movies" && c.MediaKind == LibraryMediaKind.Movies),
            Arg.Any<CancellationToken>());
    }

    [Test]
    public async Task Create_Should_Return_422_On_Validation_Error()
    {
        _mediator.Send(Arg.Any<CreateLocalLibrary>(), Arg.Any<CancellationToken>())
            .Returns(Left<BaseError, LocalLibraryViewModel>(BaseError.New("bad")));

        IActionResult result = await _controller.Create(
            new CreateLocalLibraryRequest(string.Empty, LibraryMediaKind.Movies, []),
            CancellationToken.None);

        result.ShouldBeOfType<UnprocessableEntityObjectResult>();
    }

    [Test]
    public async Task Update_Should_Return_404_When_Missing()
    {
        _mediator.Send(Arg.Any<GetLocalLibraryById>(), Arg.Any<CancellationToken>())
            .Returns(Option<LocalLibraryViewModel>.None);

        IActionResult result = await _controller.Update(
            99,
            new UpdateLocalLibraryRequest("New Name", []),
            CancellationToken.None);

        var notFound = result.ShouldBeOfType<NotFoundObjectResult>();
        notFound.Value.ShouldBeOfType<ProblemDetails>().Status.ShouldBe(StatusCodes.Status404NotFound);
        await _mediator.DidNotReceive().Send(Arg.Any<UpdateLocalLibrary>(), Arg.Any<CancellationToken>());
    }

    [Test]
    public async Task Update_Should_Return_409_When_Locked()
    {
        _mediator.Send(Arg.Any<GetLocalLibraryById>(), Arg.Any<CancellationToken>())
            .Returns(Some(new LocalLibraryViewModel(3, "Movies", LibraryMediaKind.Movies, 0)));
        _entityLocker.IsLibraryLocked(3).Returns(true);

        IActionResult result = await _controller.Update(
            3,
            new UpdateLocalLibraryRequest("New Name", []),
            CancellationToken.None);

        var conflict = result.ShouldBeOfType<ConflictObjectResult>();
        conflict.Value.ShouldBeOfType<ProblemDetails>().Status.ShouldBe(StatusCodes.Status409Conflict);
        await _mediator.DidNotReceive().Send(Arg.Any<UpdateLocalLibrary>(), Arg.Any<CancellationToken>());
    }

    [Test]
    public async Task Update_Should_Return_422_On_Validation_Error()
    {
        _mediator.Send(Arg.Any<GetLocalLibraryById>(), Arg.Any<CancellationToken>())
            .Returns(Some(new LocalLibraryViewModel(3, "Movies", LibraryMediaKind.Movies, 0)));
        _entityLocker.IsLibraryLocked(3).Returns(false);
        _mediator.Send(Arg.Any<UpdateLocalLibrary>(), Arg.Any<CancellationToken>())
            .Returns(Left<BaseError, LocalLibraryViewModel>(BaseError.New("bad")));

        IActionResult result = await _controller.Update(
            3,
            new UpdateLocalLibraryRequest("New Name", []),
            CancellationToken.None);

        result.ShouldBeOfType<UnprocessableEntityObjectResult>();
    }

    [Test]
    public async Task Update_Should_Reload_And_Return_Detail_On_Success()
    {
        _mediator.Send(Arg.Any<GetLocalLibraryById>(), Arg.Any<CancellationToken>())
            .Returns(
                Some(new LocalLibraryViewModel(3, "Movies", LibraryMediaKind.Movies, 0)),
                Some(new LocalLibraryViewModel(3, "New Name", LibraryMediaKind.Movies, 0)));
        _entityLocker.IsLibraryLocked(3).Returns(false);
        _mediator.Send(Arg.Any<UpdateLocalLibrary>(), Arg.Any<CancellationToken>())
            .Returns(Right<BaseError, LocalLibraryViewModel>(
                new LocalLibraryViewModel(3, "New Name", LibraryMediaKind.Movies, 0)));
        _mediator.Send(Arg.Any<GetLocalLibraryPaths>(), Arg.Any<CancellationToken>())
            .Returns(new List<LocalLibraryPathViewModel>());
        _mediator.Send(Arg.Any<CountMediaItemsByLibrary>(), Arg.Any<CancellationToken>()).Returns(0);

        IActionResult result = await _controller.Update(
            3,
            new UpdateLocalLibraryRequest("New Name", []),
            CancellationToken.None);

        var ok = result.ShouldBeOfType<OkObjectResult>();
        ok.Value.ShouldBeOfType<LocalLibraryDetailResponseModel>().Name.ShouldBe("New Name");
        await _mediator.Received(1).Send(
            Arg.Is<UpdateLocalLibrary>(c => c.Id == 3 && c.Name == "New Name"),
            Arg.Any<CancellationToken>());
    }

    [Test]
    public async Task Delete_Should_Return_404_When_Missing()
    {
        _mediator.Send(Arg.Any<GetLocalLibraryById>(), Arg.Any<CancellationToken>())
            .Returns(Option<LocalLibraryViewModel>.None);

        IActionResult result = await _controller.Delete(99, CancellationToken.None);

        var notFound = result.ShouldBeOfType<NotFoundObjectResult>();
        notFound.Value.ShouldBeOfType<ProblemDetails>().Status.ShouldBe(StatusCodes.Status404NotFound);
        await _mediator.DidNotReceive().Send(Arg.Any<DeleteLocalLibrary>(), Arg.Any<CancellationToken>());
    }

    [Test]
    public async Task Delete_Should_Return_409_When_Locked()
    {
        _mediator.Send(Arg.Any<GetLocalLibraryById>(), Arg.Any<CancellationToken>())
            .Returns(Some(new LocalLibraryViewModel(3, "Movies", LibraryMediaKind.Movies, 0)));
        _entityLocker.IsLibraryLocked(3).Returns(true);

        IActionResult result = await _controller.Delete(3, CancellationToken.None);

        var conflict = result.ShouldBeOfType<ConflictObjectResult>();
        conflict.Value.ShouldBeOfType<ProblemDetails>().Status.ShouldBe(StatusCodes.Status409Conflict);
        await _mediator.DidNotReceive().Send(Arg.Any<DeleteLocalLibrary>(), Arg.Any<CancellationToken>());
    }

    [Test]
    public async Task Delete_Should_Return_204_On_Success()
    {
        _mediator.Send(Arg.Any<GetLocalLibraryById>(), Arg.Any<CancellationToken>())
            .Returns(Some(new LocalLibraryViewModel(3, "Movies", LibraryMediaKind.Movies, 0)));
        _entityLocker.IsLibraryLocked(3).Returns(false);
        _mediator.Send(Arg.Any<DeleteLocalLibrary>(), Arg.Any<CancellationToken>())
            .Returns(Right<BaseError, Unit>(Unit.Default));

        IActionResult result = await _controller.Delete(3, CancellationToken.None);

        result.ShouldBeOfType<NoContentResult>();
        await _mediator.Received(1).Send(
            Arg.Is<DeleteLocalLibrary>(c => c.LocalLibraryId == 3),
            Arg.Any<CancellationToken>());
    }

    [Test]
    public async Task MovePath_Should_Return_404_When_Path_Unknown()
    {
        _libraryRepository.GetLibraryIdForPath(999).Returns(Option<int>.None);

        IActionResult result = await _controller.MovePath(
            999,
            new MoveLocalLibraryPathRequest(2),
            CancellationToken.None);

        var notFound = result.ShouldBeOfType<NotFoundObjectResult>();
        notFound.Value.ShouldBeOfType<ProblemDetails>().Status.ShouldBe(StatusCodes.Status404NotFound);
        await _mediator.DidNotReceive().Send(Arg.Any<MoveLocalLibraryPath>(), Arg.Any<CancellationToken>());
    }

    [Test]
    public async Task MovePath_Should_Return_409_When_Source_Library_Locked()
    {
        _libraryRepository.GetLibraryIdForPath(10).Returns(Some(1));
        _entityLocker.IsLibraryLocked(1).Returns(true);

        IActionResult result = await _controller.MovePath(
            10,
            new MoveLocalLibraryPathRequest(2),
            CancellationToken.None);

        var conflict = result.ShouldBeOfType<ConflictObjectResult>();
        conflict.Value.ShouldBeOfType<ProblemDetails>().Status.ShouldBe(StatusCodes.Status409Conflict);
        await _mediator.DidNotReceive().Send(Arg.Any<MoveLocalLibraryPath>(), Arg.Any<CancellationToken>());
    }

    [Test]
    public async Task MovePath_Should_Return_204_On_Success()
    {
        _libraryRepository.GetLibraryIdForPath(10).Returns(Some(1));
        _entityLocker.IsLibraryLocked(1).Returns(false);
        _mediator.Send(Arg.Any<MoveLocalLibraryPath>(), Arg.Any<CancellationToken>())
            .Returns(Right<BaseError, Unit>(Unit.Default));

        IActionResult result = await _controller.MovePath(
            10,
            new MoveLocalLibraryPathRequest(2),
            CancellationToken.None);

        result.ShouldBeOfType<NoContentResult>();
        await _mediator.Received(1).Send(
            Arg.Is<MoveLocalLibraryPath>(c => c.LibraryPathId == 10 && c.TargetLibraryId == 2),
            Arg.Any<CancellationToken>());
    }

    [Test]
    public async Task MovePath_Should_Return_422_When_Handler_Rejects_Move_After_PreCheck_Passes()
    {
        // documents the residual check-then-act race (design #202 §C5): the pre-check passed, but
        // the handler's own validation (e.g. same-kind/different-library) still fails 422, not 404.
        _libraryRepository.GetLibraryIdForPath(10).Returns(Some(1));
        _entityLocker.IsLibraryLocked(1).Returns(false);
        _mediator.Send(Arg.Any<MoveLocalLibraryPath>(), Arg.Any<CancellationToken>())
            .Returns(Left<BaseError, Unit>(BaseError.New("Target library must be different from the source path's current library")));

        IActionResult result = await _controller.MovePath(
            10,
            new MoveLocalLibraryPathRequest(1),
            CancellationToken.None);

        result.ShouldBeOfType<UnprocessableEntityObjectResult>();
    }

    [Test]
    public void CheckPathExists_Should_Return_True_When_Directory_Exists()
    {
        _fileSystem.Directory.CreateDirectory("/media/movies");

        IActionResult result = _controller.CheckPathExists(new LocalPathCheckRequest("/media/movies"));

        var ok = result.ShouldBeOfType<OkObjectResult>();
        ok.Value.ShouldBeOfType<LocalPathCheckResponseModel>().Exists.ShouldBeTrue();
    }

    [Test]
    public void CheckPathExists_Should_Return_False_When_Directory_Missing()
    {
        IActionResult result = _controller.CheckPathExists(new LocalPathCheckRequest("/media/does-not-exist"));

        var ok = result.ShouldBeOfType<OkObjectResult>();
        ok.Value.ShouldBeOfType<LocalPathCheckResponseModel>().Exists.ShouldBeFalse();
    }

    private static void ShouldHaveActionRoute(string actionName, string httpMethod, string route)
    {
        MethodInfo action = typeof(LocalLibrariesController).GetMethod(actionName)
            ?? throw new AssertionException($"Missing action {actionName}");

        HttpMethodAttribute attribute = action.GetCustomAttributes<HttpMethodAttribute>(inherit: true).Single();
        attribute.HttpMethods.ShouldContain(httpMethod);
        attribute.Template.ShouldBe(route);
    }
}