using System.Runtime.CompilerServices;
using Avalonia.Controls;
using Avalonia.Headless.XUnit;
using Avalonia.Threading;
using Avalonia.VisualTree;
using AvParser.Core.Collecting;
using AvParser.Core.Parsing;
using AvParser.Core.Proxies;
using AvParser.Core.Settings;
using AvParser.UI.ViewModels;
using AvParser.UI.Views;
using Microsoft.Extensions.Logging.Abstractions;
using ReactiveUI.Primitives.Concurrency;

namespace AvParser.UI.HeadlessTests;

public class CollectViewTests
{
    private sealed class StubSource(string id, string name, bool network) : IMediaSource
    {
        public string Id => id;

        public string DisplayName => name;

        public string Description => "A source";

        public bool RequiresNetwork => network;

        public bool CanParse(MediaQuery input) => true;

        public async IAsyncEnumerable<ParseOutcome<MediaCandidate>> ParseAsync(
            MediaQuery input,
            IProgress<ParseProgress>? progress,
            [EnumeratorCancellation] CancellationToken cancellationToken
        )
        {
            await Task.Yield();
            yield break;
        }
    }

    private sealed class IdleRunner : ICollectRunner
    {
        public async IAsyncEnumerable<ParseOutcome<CollectedItem>> RunAsync(
            IMediaSource source,
            MediaQuery query,
            CollectOptions options,
            IProgress<ParseProgress>? progress,
            [EnumeratorCancellation] CancellationToken cancellationToken
        )
        {
            await Task.Yield();
            yield break;
        }
    }

    private sealed class EmptyServiceProvider : IServiceProvider
    {
        public object? GetService(Type serviceType) => null;
    }

    private static (CollectView View, CollectViewModel ViewModel, Window Window) ShowPage(bool networkSource)
    {
        IMediaSource[] sources = networkSource
            ? [new StubSource("url-list", "URL list", false), new StubSource("own-service", "Own service", true)]
            : [new StubSource("url-list", "URL list", false)];

        var viewModel = new CollectViewModel(
            new MediaSourceCatalog(sources, networkSource ? "own-service" : "url-list"),
            new FakeSettingsService(new AppSettings { LastSourceId = networkSource ? "own-service" : "url-list" }),
            new ProxyPool([], new FakeProxyProbe(), new ProxyOptions()),
            new IdleRunner(),
            new FakeMediaStore(),
            new FakeThumbnailCache(),
            new EmptyServiceProvider(),
            NullLogger<CollectViewModel>.Instance,
            ImmediateSequencer.Instance
        );

        var view = new CollectView { DataContext = viewModel };
        var window = new Window
        {
            Width = 1400,
            Height = 900,
            Content = view,
        };

        window.Show();
        Dispatcher.UIThread.RunJobs();

        return (view, viewModel, window);
    }

    private static Border Banner(CollectView view) => view.FindControl<Border>("ProxyGateBanner").ShouldNotBeNull();

    [AvaloniaFact]
    public void The_page_renders()
    {
        var (view, _, _) = ShowPage(networkSource: false);

        view.GetVisualDescendants().OfType<ListBox>().ShouldNotBeEmpty();
    }

    [AvaloniaFact]
    public void No_banner_is_shown_for_a_source_that_needs_no_network()
    {
        var (view, viewModel, _) = ShowPage(networkSource: false);

        viewModel.IsBlockedWithoutProxy.ShouldBeFalse();
        Banner(view).IsVisible.ShouldBeFalse();
    }

    [AvaloniaFact]
    public void A_blocked_network_source_puts_the_banner_on_screen()
    {
        // Rendered rather than asserted on the view model: an IsVisible binding that never fires
        // leaves the page silently unhelpful, which is exactly the failure this guards.
        var (view, viewModel, _) = ShowPage(networkSource: true);
        Dispatcher.UIThread.RunJobs();

        viewModel.IsBlockedWithoutProxy.ShouldBeTrue();
        Banner(view).IsEffectivelyVisible.ShouldBeTrue();
    }

    [AvaloniaFact]
    public void The_banner_offers_a_way_to_the_proxies_page()
    {
        var (view, viewModel, _) = ShowPage(networkSource: true);
        Dispatcher.UIThread.RunJobs();

        var button = Banner(view).GetVisualDescendants().OfType<Button>().ShouldHaveSingleItem();

        button.Command.ShouldBeSameAs(viewModel.GoToProxiesCommand);
    }

    [AvaloniaFact]
    public void A_blocked_page_will_not_run_the_collector()
    {
        var (view, viewModel, _) = ShowPage(networkSource: true);
        viewModel.EndpointText = "https://own.test/api/list";
        Dispatcher.UIThread.RunJobs();

        var run = view.GetVisualDescendants()
            .OfType<Button>()
            .First(candidate => ReferenceEquals(candidate.Command, viewModel.CollectCommand));

        run.IsEffectivelyEnabled.ShouldBeFalse();
    }

    [AvaloniaFact]
    public void An_endpoint_source_shows_an_address_box_rather_than_a_paste_box()
    {
        var (view, _, _) = ShowPage(networkSource: true);
        Dispatcher.UIThread.RunJobs();

        var boxes = view.GetVisualDescendants().OfType<TextBox>().Where(box => box.IsEffectivelyVisible).ToList();

        boxes.ShouldHaveSingleItem();
        boxes[0].PlaceholderText.ShouldNotBeNull().ShouldContain("api/list");
    }

    [AvaloniaFact]
    public void A_pasted_list_source_shows_the_paste_box()
    {
        var (view, _, _) = ShowPage(networkSource: false);
        Dispatcher.UIThread.RunJobs();

        var boxes = view.GetVisualDescendants().OfType<TextBox>().Where(box => box.IsEffectivelyVisible).ToList();

        boxes.ShouldHaveSingleItem();
        boxes[0].AcceptsReturn.ShouldBeTrue();
    }
}