using System.Runtime.Versioning;
using System.Threading;
using System.Threading.Tasks;
using Blacklight.Core;
using Blacklight.Core.Cameras;
using Blacklight.Testbed;
using Blacklight.WebGL2;

// [JSImport]/[JSExport] require the assembly to be marked browser-targeted, or they won't compile.
[assembly: SupportedOSPlatform("browser")]

namespace Blacklight.WebGL2.Testbed
{
    internal static class Program
    {
        private static WindowHandle windowHandle = null!;
        private static World world = null!;

        private static void OnFrame(double timestampMs)
        {
            windowHandle.FrameReset();
            world.DrawScene();
            windowHandle.SubmitDrawCalls();
        }

        private static async Task Main()
        {
            await GL.EnsureLoadedAsync();

            windowHandle = WebGL2Backend.CreateWindowHandle();
            // Matches the desktop testbed's background so the two are visually comparable.
            windowHandle.BackgroundColor = new Color(0, 0.5, 1.0);

            var camera = new MicroscopeCamera(windowHandle);
            world = new World();
            world.Bind(windowHandle, camera);

            var controller = new MicroscopeController { Handle = windowHandle };
            var input = new WebGL2Input(WebGL2Backend.DefaultCanvasElementId, controller);

            GL.StartRenderLoop(OnFrame);

            // Don't let Main return.  The browser drives frames, but the runtime must stay resident.
            await Task.Delay(Timeout.Infinite);
        }
    }
}