using System.Net;
using Avalonia;
using Avalonia.Controls;
using Avalonia.Controls.Templates;
using Avalonia.Headless.XUnit;
using Avalonia.Logging;
using Avalonia.Threading;
using Avalonia.VisualTree;
using Markdown.Avalonia;
using ColorTextBlock.Avalonia;
using PostIt.Models;
using PostIt.Services;
using PostIt.ViewModels;
using PostIt.Views;
using PostIt.Views.Blogs;
using Yavsc.Api.Client;
using Yavsc.Blogspot;
using SkiaSharp;

namespace PostIt.Tests;

public class BlogReaderTests
{
    private static BlogPostDto Post(string article = "Texte du billet.") => new()
    {
        Id = 42,
        Title = "Un billet à lire",
        Article = article,
        AuthorId = "user-id-not-login",
        Author = new BlogPostAuthorDto { UserName = "paul" },
        DateModified = DateTime.UtcNow
    };

    private static BlogsViewModel CreateViewModel(BlogResourceService? resources = null)
        => new(new BlogApiClient(new RecordingYavscApiClient(new CallRecorder()), "https://blogs.example.test/api/v1/"),
            new Settings { Authentication = new AuthenticationSettings { Authority = "https://org.example.test" } },
            resources: resources);

    [Fact]
    public void Selecting_a_post_defaults_to_reading_and_uses_the_author_login()
    {
        var vm = CreateViewModel();
        vm.SelectedPost = Post();
        Assert.False(vm.IsEditing);
        Assert.Equal("paul", vm.ReaderAuthor);
        Assert.Equal("https://org.example.test/files/paul/", vm.ReaderBaseUrl);
        Assert.Equal("Texte du billet.", vm.ReaderArticle);
    }

    [Fact]
    public void Reading_does_not_publish_or_discard_unsaved_editor_changes()
    {
        var vm = CreateViewModel();
        vm.SelectedPost = Post();
        vm.EditPostCommand.Execute(null);
        vm.DraftArticle = "Modifications non enregistrées";
        vm.ReadPostCommand.Execute(null);
        Assert.False(vm.IsEditing);
        Assert.Equal("Texte du billet.", vm.ReaderArticle);
        Assert.Equal("Modifications non enregistrées", vm.DraftArticle);
        Assert.True(vm.IsDraftModified);
        vm.EditPostCommand.Execute(null);
        Assert.True(vm.IsEditing);
        Assert.Equal("Modifications non enregistrées", vm.DraftArticle);
    }

    [Fact]
    public void New_post_is_an_explicit_action_and_protects_unsaved_changes()
    {
        var vm = CreateViewModel();
        vm.SelectedPost = Post();
        vm.NewPostCommand.Execute(null);
        Assert.True(vm.IsEditing);
        Assert.Null(vm.SelectedPost);
        Assert.Empty(vm.DraftTitle);
        Assert.Empty(vm.DraftArticle!);
        vm.DraftTitle = "Nouveau brouillon";
        vm.NewPostCommand.Execute(null);
        Assert.Equal("Nouveau brouillon", vm.DraftTitle);
        Assert.Equal(StatusSeverity.Warning, vm.ActionStatus.Severity);
    }

    [AvaloniaFact]
    public async Task Reader_hides_editor_and_wires_hyperlinks_to_the_application()
    {
        var vm = CreateViewModel();
        await vm.InitializeAsync();
        vm.SelectedPost = Post("[Vidéo](clip.mp4)");
        var page = new BlogsPage { DataContext = vm };
        var nav = new NavigationPage();
        await nav.PushAsync(page);
        var window = new Window { Width = 800, Height = 700, Content = nav };
        try
        {
            window.Show();
            Dispatcher.UIThread.RunJobs();
            window.UpdateLayout();
            Assert.True(page.FindControl<Grid>("PostReader")!.IsVisible);
            Assert.False(page.FindControl<Grid>("PostEditor")!.IsVisible);
            Assert.False(page.SaveButton.IsVisible);
            var reader = page.FindControl<MarkdownScrollViewer>("ArticleReader")!;
            Assert.Equal(vm.ReaderArticle, reader.Markdown);
            Assert.Equal(vm.ReaderBaseUrl, reader.AssetPathRoot);
            Assert.Same(vm.OpenResourceCommand, Assert.IsAssignableFrom<IMarkdownEngine2>(reader.Engine).HyperlinkCommand);
            vm.EditPostCommand.Execute(null);
            Assert.False(page.FindControl<Grid>("PostReader")!.IsVisible);
            Assert.True(page.FindControl<Grid>("PostEditor")!.IsVisible);
            Assert.True(page.SaveButton.IsVisible);
        }
        finally
        {
            window.Close();
        }
    }

    [AvaloniaFact]
    public async Task Reader_initialization_and_empty_selection_do_not_report_binding_errors()
    {
        var vm = CreateViewModel();
        await vm.InitializeAsync();
        var post = Post();
        vm.Posts.Add(post);
        vm.FilteredPosts.Add(post);
        var previousSink = Logger.Sink;
        var sink = new RecordingLogSink();
        Logger.Sink = sink;
        Window? window = null;
        try
        {
            var page = new BlogsPage();
            var reader = page.FindControl<MarkdownScrollViewer>("ArticleReader")!;
            var engine = Assert.IsAssignableFrom<IMarkdownEngine2>(reader.Engine);
            Assert.Null(engine.HyperlinkCommand);
            page.DataContext = vm;
            var nav = new NavigationPage();
            await nav.PushAsync(page);
            window = new Window { Width = 800, Height = 700, Content = nav };
            window.Show();
            Dispatcher.UIThread.RunJobs();
            Assert.Empty(vm.ReaderTitle);
            Assert.Null(vm.ReaderDateModified);
            Assert.Same(vm.OpenResourceCommand, engine.HyperlinkCommand);
            Assert.IsType<BlogImageResolver>(reader.Plugins.PathResolver);

            vm.SelectedPost = post;
            Dispatcher.UIThread.RunJobs();
            Assert.Equal(post.Title, vm.ReaderTitle);
            Assert.Equal(post.DateModified, vm.ReaderDateModified);

            vm.SelectedPost = null;
            page.DataContext = null;
            Dispatcher.UIThread.RunJobs();
            Assert.Empty(vm.ReaderTitle);
            Assert.Null(vm.ReaderDateModified);
            Assert.Null(engine.HyperlinkCommand);
            Assert.DoesNotContain(sink.Entries, entry => entry.Area == LogArea.Binding);
        }
        finally
        {
            window?.Close();
            Logger.Sink = previousSink;
        }
    }

    [AvaloniaFact]
    public async Task Image_http_failure_is_logged_with_its_url_and_is_not_swallowed()
    {
        const string url = "https://org.example.test/files/paul/absent.jpg";
        using var client = new HttpClient(new BlogResourceServiceTests.StubHandler(
            _ => new HttpResponseMessage(HttpStatusCode.NotFound)));
        var resolver = new BlogImageResolver(client);
        var previousSink = Logger.Sink;
        var sink = new RecordingLogSink();
        Logger.Sink = sink;
        try
        {
            await Assert.ThrowsAsync<HttpRequestException>(() => resolver.ResolveImageResource(url));
            var error = Assert.Single(sink.Entries, entry => entry.Area == "BlogImages");
            Assert.Contains(url, error.Values);
        }
        finally
        {
            Logger.Sink = previousSink;
        }
    }

    private sealed class RecordingLogSink : ILogSink
    {
        public List<(string Area, object?[] Values)> Entries { get; } = [];
        public bool IsEnabled(LogEventLevel level, string area) => level >= LogEventLevel.Warning;
        public void Log(LogEventLevel level, string area, object? source, string messageTemplate)
            => Entries.Add((area, []));
        public void Log(LogEventLevel level, string area, object? source, string messageTemplate, params object?[] values)
            => Entries.Add((area, values));
    }

    [AvaloniaFact]
    public async Task Long_reading_content_scrolls_and_clears_when_selection_is_removed()
    {
        var vm = CreateViewModel();
        await vm.InitializeAsync();
        vm.SelectedPost = Post(string.Join("\n\n", Enumerable.Range(0, 100).Select(i => $"Paragraphe {i}.")));
        var page = new BlogsPage { DataContext = vm };
        var nav = new NavigationPage();
        await nav.PushAsync(page);
        var window = new Window { Width = 800, Height = 700, Content = nav };
        try
        {
            window.Show();
            Dispatcher.UIThread.RunJobs();
            window.UpdateLayout();
            var reader = page.FindControl<MarkdownScrollViewer>("ArticleReader")!;
            var scroll = reader.GetVisualDescendants().OfType<ScrollViewer>().Single();
            Assert.InRange(scroll.Viewport.Height, 1, window.ClientSize.Height);
            Assert.True(scroll.Extent.Height > scroll.Viewport.Height);
            scroll.ScrollToEnd();
            Assert.True(scroll.Offset.Y > 0);
            vm.SelectedPost = null;
            Dispatcher.UIThread.RunJobs();
            Assert.Empty(reader.Markdown!);
        }
        finally
        {
            window.Close();
        }
    }

    [Theory]
    [InlineData("https://yavsc.pschneider.fr/files/paul/blogs/14/IMG-20260923-WA0001.jpg")]
    [InlineData("/files/paul/blogs/14/IMG-20260923-WA0001.jpg")]
    [InlineData("blogs/14/IMG-20260923-WA0001.jpg")]
    public async Task Embedded_jpeg_stream_is_seekable_at_the_start_for_markdown_decoding(string url)
    {
        using var source = new SKBitmap(32, 24);
        source.Erase(SKColors.CornflowerBlue);
        using var encoded = source.Encode(SKEncodedImageFormat.Jpeg, 90);
        var jpeg = encoded.ToArray();
        using var client = new HttpClient(new BlogResourceServiceTests.StubHandler(request =>
        {
            Assert.Equal("https://yavsc.pschneider.fr/files/paul/blogs/14/IMG-20260923-WA0001.jpg",
                request.RequestUri!.AbsoluteUri);
            return new HttpResponseMessage(HttpStatusCode.OK)
            {
                Content = new StreamContent(new NonSeekableStream(jpeg))
            };
        }));
        var resolver = new BlogImageResolver(client)
        {
            AssetPathRoot = "https://yavsc.pschneider.fr/files/paul/"
        };
        await using var stream = await resolver.ResolveImageResource(url);
        Assert.NotNull(stream);
        Assert.True(stream.CanSeek);
        Assert.Equal(0, stream.Position);
        using var decoded = SKBitmap.Decode(stream);
        Assert.NotNull(decoded);
        Assert.Equal(32, decoded.Width);
        Assert.Equal(24, decoded.Height);
    }

    private sealed class NonSeekableStream(byte[] bytes) : Stream
    {
        private readonly MemoryStream _inner = new(bytes, writable: false);
        public override bool CanRead => _inner.CanRead;
        public override bool CanSeek => false;
        public override bool CanWrite => false;
        public override long Length => throw new NotSupportedException();
        public override long Position
        {
            get => throw new NotSupportedException();
            set => throw new NotSupportedException();
        }
        public override int Read(byte[] buffer, int offset, int count) => _inner.Read(buffer, offset, count);
        public override ValueTask<int> ReadAsync(Memory<byte> buffer, CancellationToken cancellationToken = default)
            => _inner.ReadAsync(buffer, cancellationToken);
        public override void Flush() => throw new NotSupportedException();
        public override long Seek(long offset, SeekOrigin origin) => throw new NotSupportedException();
        public override void SetLength(long value) => throw new NotSupportedException();
        public override void Write(byte[] buffer, int offset, int count) => throw new NotSupportedException();
        protected override void Dispose(bool disposing)
        {
            if (disposing)
                _inner.Dispose();
            base.Dispose(disposing);
        }
    }

    [AvaloniaFact]
    public async Task Clicking_a_user_video_pushes_a_dedicated_video_viewmodel()
    {
        using var client = new HttpClient(new BlogResourceServiceTests.StubHandler(request =>
        {
            Assert.Equal("https://org.example.test/files/paul/clip.mp4", request.RequestUri!.AbsoluteUri);
            var response = new HttpResponseMessage(HttpStatusCode.OK);
            response.Content.Headers.ContentType = new("video/mp4");
            return response;
        }));
        var vm = CreateViewModel(new BlogResourceService(client));
        vm.SelectedPost = Post();
        var app = (App)Application.Current!;
        var root = new MainView();
        app.AttachMainWindow(root);
        var template = new FuncDataTemplate<VideoPageViewModel>((_, _) => new ContentPage());
        app.DataTemplates.Insert(0, template);
        try
        {
            var page = new BlogsPage { DataContext = vm };
            var reader = page.FindControl<MarkdownScrollViewer>("ArticleReader")!;
            Dispatcher.UIThread.RunJobs();
            var engine = Assert.IsAssignableFrom<IMarkdownEngine2>(reader.Engine);
            var link = Assert.IsType<CHyperlink>(Assert.Single(engine.ParseGamutInline("[Vidéo](clip.mp4)")));
            Assert.NotNull(link.Command);
            link.Command(link.CommandParameter!);
            Assert.NotNull(vm.OpenResourceCommand.ExecutionTask);
            await vm.OpenResourceCommand.ExecutionTask;
            var target = Assert.IsType<VideoPageViewModel>(root.NavRoot.NavigationStack.Last().DataContext);
            Assert.Equal("https://org.example.test/files/paul/clip.mp4", target.Source.AbsoluteUri);
            Assert.Equal("video/mp4", target.MimeType);
        }
        finally
        {
            app.DataTemplates.Remove(template);
        }
    }

    [AvaloniaFact]
    public void Video_viewmodel_resolves_to_a_page_with_a_vlc_control()
    {
        var vm = new VideoPageViewModel(new Uri("https://org.example.test/files/paul/clip.mp4"), "video/mp4");
        var page = Assert.IsType<VideoPage>(new ViewLocator().Build(vm));
        Assert.NotNull(page.FindControl<LibVLCSharp.Avalonia.VideoView>("Video"));
    }

    [Fact]
    public async Task Broken_resource_reports_an_error_and_releases_busy_state()
    {
        using var client = new HttpClient(new BlogResourceServiceTests.StubHandler(_ => new(HttpStatusCode.NotFound)));
        var vm = CreateViewModel(new BlogResourceService(client));
        vm.SelectedPost = Post();
        await vm.OpenResourceCommand.ExecuteAsync("absent.mp4");
        Assert.False(vm.IsBusy);
        Assert.Equal(StatusSeverity.Error, vm.ActionStatus.Severity);
    }
}