Sentinel-3 angles calculation

How can one calculate OLCI observation geometry (solar and viewing zenith and azimuth angles) for a point?

The issue is that ESA has a long term archive and not all products are available, whereas google earth engine has some products, but without angle bands.

I have an idea how to do it from orbit files .kml, sensing time in product name and xfdumanifest.xml but do not want to reinvent the wheel.