using Windows.Media.MediaProperties;
using Xunit;
using ytLive.Services;

namespace ytLive.Tests;

/// <summary>
/// Take-2026-09-15 fix: a camera that another app has left in MJPG mode can't be
/// read as Bgra8 by a MediaFrameReader (StartAsync answers OutputFormatNotSupported) —
/// exactly what a browser grabbing the webcam causes. The reader-subtype ladder in
/// MediaCaptureFrameSource picks an output the source can actually produce; these
/// tests lock the ordering so the fix can't regress into the silent empty webcam box.
/// </summary>
public sealed class MediaCaptureFrameSourceTests
{
    [Fact]
    public void ReaderSubtypeCandidates_MjpgActive_NeverAsksBgra8()
    {
        var candidates = MediaCaptureFrameSource.ReaderSubtypeCandidates("MJPG");
        Assert.DoesNotContain(candidates, s => s == MediaEncodingSubtypes.Bgra8);
        Assert.Equal(MediaEncodingSubtypes.Nv12, candidates[0]);
        Assert.Null(candidates[^1]);
    }

    [Fact]
    public void ReaderSubtypeCandidates_MjpgActive_IsCaseInsensitive()
    {
        var candidates = MediaCaptureFrameSource.ReaderSubtypeCandidates("mjpg");
        Assert.Equal(MediaEncodingSubtypes.Nv12, candidates[0]);
        Assert.DoesNotContain(candidates, s => s == MediaEncodingSubtypes.Bgra8);
    }

    [Fact]
    public void ReaderSubtypeCandidates_UncompressedActive_KeepsBgra8FastPath()
    {
        var yuy2 = MediaCaptureFrameSource.ReaderSubtypeCandidates("YUY2");
        var nv12 = MediaCaptureFrameSource.ReaderSubtypeCandidates("NV12");
        Assert.Equal(MediaEncodingSubtypes.Bgra8, yuy2[0]);
        Assert.Equal(MediaEncodingSubtypes.Bgra8, nv12[0]);
    }

    [Fact]
    public void ReaderSubtypeCandidates_UnknownActive_DefaultsToBgra8()
    {
        Assert.Equal(MediaEncodingSubtypes.Bgra8,
            MediaCaptureFrameSource.ReaderSubtypeCandidates(null)[0]);
        Assert.Equal(MediaEncodingSubtypes.Bgra8,
            MediaCaptureFrameSource.ReaderSubtypeCandidates("")[0]);
    }
}