using GSS2.FrameDecoders;

using LibCameraSharp;

public static class FrameDecoderHelper
{
    private static readonly IReadOnlyList<IFrameDecoder> _decoders;

    static FrameDecoderHelper()
    {
        _decoders = LoadDecoders();
    }

    private static IReadOnlyList<IFrameDecoder> LoadDecoders()
    {
        var decoderInterface = typeof(IFrameDecoder);
        var assembly = decoderInterface.Assembly;

        var decoders = assembly
            .GetTypes()
            .Where(t =>
                !t.IsAbstract &&
                !t.IsInterface &&
                decoderInterface.IsAssignableFrom(t))
            .Select(CreateDecoderInstance)
            .Where(d => d is not null)
            .Cast<IFrameDecoder>()
            .ToList();

        return decoders;
    }
    private static IFrameDecoder? CreateDecoderInstance(Type type)
    {
        if (type.GetConstructor(Type.EmptyTypes) is null)
            return null;

        try
        {
            return (IFrameDecoder?)Activator.CreateInstance(type);
        }
        catch
        {
            return null;
        }
    }

    public static IFrameDecoder? FindDecoder(
        uint fourcc,
        ulong modifier,
        ColorSpace.PrimariesEnum primariesEnum,
        ColorSpace.TransferFunctionEnum transferFunctionEnum,
        ColorSpace.YcbcrEncodingEnum ycbcrEncodingEnum,
        ColorSpace.RangeEnum rangeEnum)
    {
        return _decoders.FirstOrDefault(d =>
            d.Fourcc == fourcc &&
            d.Modifier == modifier &&
            d.PrimariesEnum == primariesEnum &&
            d.TransferFunctionEnum == transferFunctionEnum &&
            d.YcbcrEncodingEnum == ycbcrEncodingEnum &&
            d.RangeEnum == rangeEnum);
    }
}