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

namespace ytLive.Tests;

/// <summary>
/// TASK 47 Good Dog (take three, 2026-09-26): the alert box's frame must be
/// DRAWN by the preview pane. The 14:26 and 14:28 live runs on build 90 proved
/// everything up to the last hop: <c>Alert preview: frame=680x200 a255</c> and
/// <c>Output resolver: frame 680x200 playing=True</c> every second for the whole
/// clip — a real, opaque, correctly-sized frame (the shipped llama asset decodes
/// bright, 1280x720 h264) handed to the canvas — and the box stayed blank.
/// Root cause: the preview's per-element <c>Image</c> only becomes Visible for
/// IsImageSource / IsChatBox / IsWebSource / IsWebcam, so an AlertBox's Image
/// stayed Collapsed and the bound frame was never rendered.
/// </summary>
[Collection("RealApp")]
public sealed class AlertBoxPreviewVisibilityTests
{
    private readonly RealAppHost _app;

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

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

    private void Run()
    {
        var tempDb = Path.Combine(Path.GetTempPath(), $"ytLlive-test-{Guid.NewGuid():N}.db");
        MainViewModel.LayoutPathOverride = tempDb;
        var window = new MainWindow();
        var vm = (MainViewModel)window.DataContext;
        try
        {
            window.Show();
            window.UpdateLayout();

            var box = new Source
            {
                Type = SourceType.AlertBox,
                Name = "Stream Alerts",
                X = 100,
                Y = 100,
                Width = 320,
                Height = 180,
            };
            vm.StagedScene!.Elements.Add(box);
            vm.SelectedElement = box;

            // Exactly what the layer writes onto the source every tick while a clip
            // plays: a real, opaque, box-sized frame.
            box.VideoImageSource = SolidFrame(320, 180);
            window.UpdateLayout();

            var pane = (UserControl)window.FindName("PreviewPane")!;
            var image = FindImageShowing(pane, box.VideoImageSource);
            Assert.True(image != null,
                "the preview pane never bound the alert box's frame to an Image");
            Assert.Equal(Visibility.Visible, image!.Visibility);
            Assert.True(image.IsVisible,
                "the alert box's Image is Collapsed, so the frame is never rendered");
        }
        finally
        {
            window.Close();
            MainViewModel.LayoutPathOverride = null;
            SqliteConnection.ClearAllPools();
            try { File.Delete(tempDb); } catch { /* best-effort cleanup */ }
        }
    }

    private static WriteableBitmap SolidFrame(int w, int h)
    {
        var bitmap = new WriteableBitmap(w, h, 96, 96, PixelFormats.Bgra32, null);
        var pixels = new byte[w * h * 4];
        for (var i = 0; i < pixels.Length; i += 4)
        {
            pixels[i] = 40;      // B
            pixels[i + 1] = 90;  // G
            pixels[i + 2] = 200; // R
            pixels[i + 3] = 255; // opaque
        }
        bitmap.WritePixels(new Int32Rect(0, 0, w, h), pixels, w * 4, 0);
        return bitmap;
    }

    private static Image? FindImageShowing(DependencyObject parent, ImageSource? source)
        => Walk(parent, e => e is Image i && ReferenceEquals(i.Source, source)) as Image;

    private static DependencyObject? Walk(DependencyObject parent, Func<DependencyObject, bool> predicate)
    {
        for (var i = 0; i < VisualTreeHelper.GetChildrenCount(parent); i++)
        {
            var child = VisualTreeHelper.GetChild(parent, i);
            if (predicate(child)) return child;
            var found = Walk(child, predicate);
            if (found != null) return found;
        }
        return null;
    }
}