using System.Drawing;
using System.Linq;
using System.Windows.Controls;
using System.Windows.Threading;
using Microsoft.Web.WebView2.Wpf;
using Xunit;
using ytLive.Models;
using ytLive.Services;

namespace ytLive.Tests;

[Collection("RealApp")]
public sealed class WebView2ManagerTests
{
    private readonly RealAppHost _app;

    public WebView2ManagerTests(RealAppHost app)
    {
        _app = app;
    }

    [Fact]
    public void WebView2_Control_Size_Is_Canvas_Resolution_Regardless_Of_Source()
    {
        _app.Run(() =>
        {
            var panel = new Canvas();
            var source = new Source
            {
                Type = SourceType.WebSource,
                Width = 640,
                Height = 480,
            };

            using var manager = new WebView2Manager(panel, Dispatcher.CurrentDispatcher);
            manager.Register(source);

            var webView = panel.Children.OfType<WebView2>().First();
            Assert.Equal(1920.0, webView.Width);
            Assert.Equal(1080.0, webView.Height);
        });
    }

    [Fact]
    public void WebView2_Control_Size_Does_Not_Track_Box_After_Register()
    {
        _app.Run(() =>
        {
            var panel = new Canvas();
            var source = new Source
            {
                Type = SourceType.WebSource,
                Width = 640,
                Height = 480,
            };

            using var manager = new WebView2Manager(panel, Dispatcher.CurrentDispatcher);
            manager.Register(source);

            var webView = panel.Children.OfType<WebView2>().First();

            source.Width = 1024;
            source.Height = 768;

            Assert.Equal(1920.0, webView.Width);
            Assert.Equal(1080.0, webView.Height);
        });
    }

    [Fact]
    public void WebView2_Control_Size_Ignores_Zero_Sized_Source()
    {
        _app.Run(() =>
        {
            var panel = new Canvas();
            var source = new Source
            {
                Type = SourceType.WebSource,
                Width = 0,
                Height = 0,
            };

            using var manager = new WebView2Manager(panel, Dispatcher.CurrentDispatcher);
            manager.Register(source);

            var webView = panel.Children.OfType<WebView2>().First();
            Assert.Equal(1920.0, webView.Width);
            Assert.Equal(1080.0, webView.Height);
        });
    }

    [Fact]
    public void WebView2_DefaultBackgroundColor_Is_Transparent()
    {
        _app.Run(() =>
        {
            var panel = new Canvas();
            var source = new Source
            {
                Type = SourceType.WebSource,
                Width = 640,
                Height = 480,
            };

            using var manager = new WebView2Manager(panel, Dispatcher.CurrentDispatcher);
            manager.Register(source);

            var webView = panel.Children.OfType<WebView2>().First();

            Assert.Equal(System.Drawing.Color.Transparent, webView.DefaultBackgroundColor);
        });
    }

    [Fact]
    public void FindContentBounds_Returns_Bounding_Box_Of_NonTransparent_Pixels()
    {
        const int w = 10, h = 6;
        var pixels = new byte[w * h * 4];
        for (int yy = 2; yy <= 4; yy++)
            for (int xx = 3; xx <= 6; xx++)
            {
                var i = (yy * w + xx) * 4;
                pixels[i] = 255;     // B
                pixels[i + 1] = 0;   // G
                pixels[i + 2] = 0;   // R
                pixels[i + 3] = 255; // A
            }

        var (x, y, bw, bh) = WebView2Manager.FindContentBounds(pixels, w, h, w * 4);

        Assert.Equal((3, 2, 4, 3), (x, y, bw, bh));
    }

    [Fact]
    public void FindContentBounds_No_Alpha_Means_No_Crop()
    {
        const int w = 10, h = 6;
        var pixels = new byte[w * h * 4];

        var (x, y, bw, bh) = WebView2Manager.FindContentBounds(pixels, w, h, w * 4);

        Assert.Equal((0, 0, w, h), (x, y, bw, bh));
    }

    [Fact]
    public void FindContentBounds_Full_Opacity_Means_No_Crop()
    {
        const int w = 10, h = 6;
        var pixels = new byte[w * h * 4];
        for (var i = 3; i < pixels.Length; i += 4)
            pixels[i] = 255;

        var (x, y, bw, bh) = WebView2Manager.FindContentBounds(pixels, w, h, w * 4);

        Assert.Equal((0, 0, w, h), (x, y, bw, bh));
    }

    [Fact]
    public async Task CaptureScheduler_Drops_Ticks_While_Capture_InFlight_And_Resumes()
    {
        // The ~30Hz recording cadence would stack concurrent CapturePreviewAsync calls
        // (full-HD PNG encode is ~10-30ms) without the latest-wins drop: ticks that
        // arrive while a capture is in flight must be skipped, never queued, and a
        // capture can always start once the previous one has finished.
        var calls = 0;
        var signal = new TaskCompletionSource(TaskCreationOptions.RunContinuationsAsynchronously);
        var scheduler = new CaptureScheduler(Dispatcher.CurrentDispatcher, 200, async () =>
        {
            calls++;
            await signal.Task;
        });

        scheduler.Tick();
        scheduler.Tick();
        scheduler.Tick();
        Assert.Equal(1, calls); // overlapping ticks dropped, never queued

        signal.SetResult();
        await scheduler.Pending; // durable: Pending completes only after the drop resets

        scheduler.Tick();
        Assert.Equal(2, calls); // once idle, the next tick captures again
        await scheduler.Pending;
    }
}