using System;
using System.IO;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;
using Microsoft.Data.Sqlite;
using Xunit;
using ytLive.Controls;
using ytLive.Models;
using ytLive.Services;
using ytLive.Services.Compositor;
using ytLive.ViewModels;

namespace ytLive.Tests;

[Collection("RealApp")]
public sealed class TextLayerOutputTests
{
    private readonly RealAppHost _app;

    public TextLayerOutputTests(RealAppHost app) => _app = app;

    [Fact]
    public void Text_Layers_Share_The_Preview_Raster_With_Full_And_Baked_Output_And_Refresh_On_Edit()
    {
        _app.Run(Run);
    }

    private static void Run()
    {
        var dbPath = Path.Combine(Path.GetTempPath(), $"ytLlive-text-output-{Guid.NewGuid():N}.db");
        MainViewModel.LayoutPathOverride = dbPath;
        MainWindow? window = null;
        try
        {
            window = new MainWindow();
            var vm = (MainViewModel)window.DataContext;
            vm.EditingActive = true;
            var scene = new Scene { Name = "Text output test" };
            vm.Scenes.Add(scene);
            vm.StagedScene = scene;

            var art = new Source
            {
                Name = "Test background",
                Type = SourceType.Image,
                Width = 320,
                Height = 180,
            };
            var lowerText = new Source
            {
                Name = "Lower text",
                Type = SourceType.TextOverlay,
                TextContent = "Lower layer",
                X = 12,
                Y = 12,
                Width = 140,
                Height = 52,
                TextFontSize = 32,
            };
            var dynamic = new Source
            {
                Name = "Dynamic split",
                Type = SourceType.WebSource,
                Width = 20,
                Height = 20,
            };
            var upperText = new Source
            {
                Name = "Upper text",
                Type = SourceType.TextOverlay,
                TextContent = "Upper layer",
                X = 150,
                Y = 90,
                Width = 150,
                Height = 52,
                TextFontSize = 30,
                TextBold = true,
            };
            scene.Elements.Add(art);
            scene.Elements.Add(lowerText);
            scene.Elements.Add(dynamic);
            scene.Elements.Add(upperText);
            vm.SelectedElement = lowerText;

            window.Show();
            window.UpdateLayout();

            var preview = (PreviewPane)window.FindName("PreviewPane")!;
            AssertPreviewUsesTextFrame(preview, lowerText);
            AssertPreviewUsesTextFrame(preview, upperText);

            var background = Solid(320, 180, 24, 38, 52);
            VideoFrame? Resolve(SceneElement element) => ReferenceEquals(element, art)
                ? background
                : vm.ResolveOutputFrame(element);
            var options = new CompositorOptions
            {
                SourceRectX = 0,
                SourceRectY = 0,
                SourceRectWidth = 320,
                SourceRectHeight = 180,
                OutputWidth = 320,
                OutputHeight = 180,
            };
            var compositor = new SceneCompositor();
            var fullBefore = compositor.Render(scene, Resolve, null, options);
            AssertHasTextPixels(fullBefore, background);

            var graph = vm.SceneGraphForTests;
            var split = graph.GetSplitPoint(scene);
            Assert.Equal(2, split);
            var bakedBefore = graph.GetBakedBase(scene, Resolve, () => options);
            Assert.NotNull(bakedBefore);
            var mixedBefore = SceneCompositor.CompositeLayers(bakedBefore!, scene, split, Resolve, options);
            AssertHasTextPixels(mixedBefore, background);

            var lowerFrameBefore = Assert.IsType<VideoFrame>(vm.ResolveOutputFrame(lowerText));
            var leftPanel = (LeftPanel)window.FindName("LeftPanel")!;
            var editor = (TextBox)leftPanel.FindName("TextLayerEditor")!;
            editor.Text = "Edited lower layer";
            editor.GetBindingExpression(TextBox.TextProperty)?.UpdateSource();
            var colorEditor = (TextBox)leftPanel.FindName("TextLayerColorEditor")!;
            colorEditor.Text = "#FF0000";
            colorEditor.GetBindingExpression(TextBox.TextProperty)?.UpdateSource();
            window.UpdateLayout();

            Assert.Equal("#FF0000", lowerText.TextColor);
            var updatedFrame = Assert.IsType<VideoFrame>(vm.ResolveOutputFrame(lowerText));
            var fullAfter = compositor.Render(scene, Resolve, null, options);
            Assert.NotSame(lowerFrameBefore, updatedFrame);
            Assert.False(fullBefore.BgraPixels.AsSpan().SequenceEqual(fullAfter.BgraPixels));
            AssertHasTextPixels(fullAfter, background);

            var bakedAfter = graph.GetBakedBase(scene, Resolve, () => options);
            Assert.NotNull(bakedAfter);
            Assert.NotSame(bakedBefore, bakedAfter);
            var mixedAfter = SceneCompositor.CompositeLayers(bakedAfter!, scene, split, Resolve, options);
            AssertHasTextPixels(mixedAfter, background);
            AssertPreviewUsesTextFrame(preview, lowerText);

            scene.Elements.Remove(dynamic);
            vm.SaveLayoutNow();
            window.Close();
            window = null;
            SqliteConnection.ClearAllPools();

            window = new MainWindow();
            var reloadedVm = (MainViewModel)window.DataContext;
            reloadedVm.EditingActive = true;
            var reloadedScene = reloadedVm.Scenes.Single(item => item.Name == scene.Name);
            reloadedVm.StagedScene = reloadedScene;
            var reloadedLowerText = reloadedScene.Elements.OfType<Source>()
                .Single(source => source.Name == lowerText.Name);
            var reloadedUpperText = reloadedScene.Elements.OfType<Source>()
                .Single(source => source.Name == upperText.Name);
            reloadedVm.SelectedElement = reloadedLowerText;

            window.Show();
            window.UpdateLayout();
            AssertPreviewUsesTextFrame((PreviewPane)window.FindName("PreviewPane")!, reloadedLowerText);
            var loadedFrameBefore = Assert.IsType<VideoFrame>(reloadedVm.ResolveOutputFrame(reloadedLowerText));
            var loadedUpperBitmap = reloadedUpperText.VideoImageSource;
            var loadedGraph = reloadedVm.SceneGraphForTests;
            var loadedResolve = new Func<SceneElement, VideoFrame?>(element =>
                string.Equals(element.Name, "Test background", StringComparison.Ordinal)
                    ? background
                    : reloadedVm.ResolveOutputFrame(element));
            var loadedBakeBefore = loadedGraph.GetBakedBase(reloadedScene, loadedResolve, () => options);
            Assert.NotNull(loadedBakeBefore);

            var reloadedPanel = (LeftPanel)window.FindName("LeftPanel")!;
            var reloadedEditor = (TextBox)reloadedPanel.FindName("TextLayerEditor")!;
            reloadedEditor.Text = "Edited after reload";
            reloadedEditor.GetBindingExpression(TextBox.TextProperty)?.UpdateSource();
            window.UpdateLayout();

            var loadedFrameAfter = Assert.IsType<VideoFrame>(reloadedVm.ResolveOutputFrame(reloadedLowerText));
            var loadedBakeAfter = loadedGraph.GetBakedBase(reloadedScene, loadedResolve, () => options);
            Assert.NotSame(loadedFrameBefore, loadedFrameAfter);
            Assert.NotSame(loadedBakeBefore, loadedBakeAfter);
            Assert.Same(loadedUpperBitmap, reloadedUpperText.VideoImageSource);
            Assert.Equal("Edited after reload", reloadedLowerText.TextContent);
            AssertPreviewUsesTextFrame((PreviewPane)window.FindName("PreviewPane")!, reloadedLowerText);
        }
        finally
        {
            window?.Close();
            MainViewModel.LayoutPathOverride = null;
            SqliteConnection.ClearAllPools();
            try { File.Delete(dbPath); } catch { /* best-effort cleanup */ }
        }
    }

    private static void AssertPreviewUsesTextFrame(PreviewPane preview, Source source)
    {
        var image = FindTextImage(preview, source);
        Assert.NotNull(image);
        Assert.Same(source.VideoImageSource, image!.Source);
        Assert.Same(source.VideoImageSource, source.DisplaySource);
        Assert.True(image.IsVisible);
    }

    private static Image? FindTextImage(DependencyObject parent, Source source)
    {
        if (parent is Image image && ReferenceEquals(image.DataContext, source))
            return image;
        for (var i = 0; i < VisualTreeHelper.GetChildrenCount(parent); i++)
        {
            var result = FindTextImage(VisualTreeHelper.GetChild(parent, i), source);
            if (result != null) return result;
        }
        return null;
    }

    private static void AssertHasTextPixels(VideoFrame frame, VideoFrame background)
    {
        var changed = false;
        for (var i = 0; i < frame.BgraPixels.Length; i += 4)
        {
            if (frame.BgraPixels[i] != background.BgraPixels[i]
                || frame.BgraPixels[i + 1] != background.BgraPixels[i + 1]
                || frame.BgraPixels[i + 2] != background.BgraPixels[i + 2])
            {
                changed = true;
                break;
            }
        }
        Assert.True(changed, "the text layer did not composite over the background pixels");
    }

    private static VideoFrame Solid(int width, int height, byte r, byte g, byte b)
    {
        var pixels = new byte[width * height * 4];
        for (var i = 0; i < pixels.Length; i += 4)
        {
            pixels[i] = b;
            pixels[i + 1] = g;
            pixels[i + 2] = r;
            pixels[i + 3] = 255;
        }
        return new VideoFrame(width, height, pixels);
    }
}