using Avalonia.Controls;
using Avalonia.Headless.XUnit;
using Avalonia.Threading;
using Avalonia.VisualTree;
using AvParser.Core.Parsing;
using AvParser.Core.Parsing.Samples;
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 ParseViewTests
{
    private static (ParseView View, ParseViewModel ViewModel, Window Window) ShowPage(params ITextParser[] extra)
    {
        var catalog = new ParserCatalog([new DelimitedTextParser(), new KeyValueTextParser(), .. extra]);
        var lastParser = extra.Length > 0 ? extra[0].Id : null;

        var viewModel = new ParseViewModel(
            catalog,
            new FakeSettingsService(new AppSettings { LastParserId = lastParser }),
            new ProxyPool([], new FakeProxyProbe(), new ProxyOptions()),
            new EmptyServiceProvider(),
            NullLogger<ParseViewModel>.Instance,
            ImmediateSequencer.Instance
        );

        var view = new ParseView { 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(ParseView view) => view.FindControl<Border>("ProxyGateBanner").ShouldNotBeNull();

    [AvaloniaFact]
    public void No_banner_is_shown_for_a_parser_that_needs_no_network()
    {
        var (view, viewModel, _) = ShowPage();

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

    [AvaloniaFact]
    public void A_blocked_network_parser_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(new NetworkParser());
        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(new NetworkParser());
        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_parser()
    {
        var (view, viewModel, _) = ShowPage(new NetworkParser());
        viewModel.InputText = "anything";
        Dispatcher.UIThread.RunJobs();

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

        run.IsEffectivelyEnabled.ShouldBeFalse();
    }

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

    private sealed class NetworkParser : ITextParser
    {
        public string Id => "network";

        public string DisplayName => "Network parser";

        public string Description => "Fetches something";

        public bool RequiresNetwork => true;

        public bool CanParse(string input) => true;

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