Camera & microphone

using Rask.Core;
using Rask.Site;
using Rask.Wasm.Browser;

namespace Rask.Site.Features;

/// <summary>
///     <see cref="IMediaDevices" /> — capture the camera/microphone (or screen) and show it in a
///     <c>&lt;video&gt;</c>. The live stream lives JS-side; dispose the handle to stop every track and
///     release the hardware (the camera indicator turns off).
/// </summary>
public sealed partial class MediaDevicesDemo(IMediaDevices media) : Component, IAsyncDisposable
{
    private readonly ElementRef _video = ElementRef.New();
    private IMediaStreamHandle? _stream;
    private string _status = "(idle)";

    protected override Component? Render() =>
        Div.Class($"{Tw.Card} shadow-sm border-0")[
            Div.Class(Tw.CardBody)[
                Video
                    .Ref(_video)
                    .Width(320)
                    .Height(240)
                    .Muted(true)
                    .PlaysInline(true)
                    .Class("rounded border mb-2 bg-slate-900 block"),
                Div.Class("flex gap-2 flex-wrap mb-2")[
                    Button.Class(Tw.BtnPrimary).Id("media-start").OnClickAsync(StartCamera)[
                        UiIcon.Name(UiIconName.VideoCamera).Class("me-1"), "Start camera"],
                    Button.Class(Tw.BtnOutlinePrimary).Id("media-screen").OnClickAsync(ShareScreen)[
                        UiIcon.Name(UiIconName.Desktop).Class("me-1"), "Share screen"],
                    Button
                        .Class(Tw.BtnOutlineDanger)
                        .Id("media-stop")
                        .Disabled(_stream is null)
                        .OnClickAsync(Stop)["Stop"]
                ],
                Div.Class("text-sm text-ui-muted")["Status: ", Code.Id("media-status")[_status]]
            ]
        ];

    private Task StartCamera() => Capture(() => media.GetUserMediaAsync(new MediaConstraints(Video: true)), "Camera live");

    private Task ShareScreen() => Capture(() => media.GetDisplayMediaAsync(), "Screen sharing");

    private async Task Capture(Func<ValueTask<IMediaStreamHandle>> request, string okStatus)
    {
        try
        {
            if (!await media.IsSupportedAsync())
            {
                _status = "Media capture not supported in this browser";
                return;
            }

            await StopInternal();
            _stream = await request();
            await _stream.AttachToAsync(_video);
            _status = okStatus;
        }
        catch (Exception ex)
        {
            _status = "Failed: " + ex.Message;
        }
    }

    private async Task Stop()
    {
        await StopInternal();
        _status = "Stopped — hardware released";
    }

    private async Task StopInternal()
    {
        if (_stream is not null)
        {
            await _stream.DisposeAsync();
            _stream = null;
        }
    }

    public async ValueTask DisposeAsync() => await StopInternal();
}