Remix of @piano_miles 's project but using Lazanyi's Fresnel approximation for metals instead of schlick's (https://www.researchgate.net/publication/221546550_Fresnel_Term_Approximations_for_Metals). IOR is a complex number, the real part (n) refers to the actual IOR part while the imaginary part (k) refers to the extinction coefficient. For dielectrics k is really small so it's usually just approximated to be 0, but for metals k is large enough that we need to account for it. Interestingly, complex IOR is in the form of n - ik, unlike the form of n + ik like most complex numbers are written in.
