import numpy as np
import sys

#Script to return the count rates in the UV filters
#by Atreyee Sinha
#please report bugs to atreyees@iucaa.in; atreyee.sinha@gmail.com
#This script will give the count rates in the UV channels, indicating unsafe channels

#run as uvit_checkuv.py magnuv magfuv
#please keep the order in mind
#put -999 if fuv magnitude not known


"""
The count rates for NUV & FUV filters using the 7x7 pixel2 window seem to underestimate the flux for the bright GALEX objects, because of the larger FWHM for the saturated stars. Therefore, to make a safer decision, the cataloged magnitude (for point sources, FWHM < 1500), after saturation correction as per the prescriptions in the Proposers Guide document, are used to generate the count rates for the UVIT filters.

IMP: Input the magnitude brightest object in the field
"""

def counts_fuv(mag_fuv):
    m=mag_fuv
    if (mag_fuv < 15.0):
        C0 = 5.371
        C1 = 20.000
        C2 = -210
        m = C0 + np.sqrt(C1*mag_fuv + C2)

    m0 = 18.22
    c0 = [1.0,0.85,0.63,0.22]
    filt = ["FUV-CaF2","FUV-BaF2","FUV-Sapphire","FUV-Silica"]

    print "FUV counts for magnitude ", m
    for i in range(len(c0)):
        t=" SAFE"
        k = m0 + 2.5*np.log10(c0[i])
        cps = np.power(10.0, (k-m)/2.5)
        if cps>1500:
            t="  UNSAFE"
        print filt[i],cps,t

    print "\n\n"

def counts_nuv(mag_nuv):
    m=mag_nuv
    if (mag_nuv < 15.0):
        C0 = 2.634
        C1 = 26.316
        C2 = -245.329
        m = C0 + np.sqrt(C1*mag_nuv + C2)

    m0 = 20.0
    c0 = [1.0,0.22,0.27,0.074,0.055]
    filt = ["NUV-Silica","NUV-B4","NUV-B13","NUV-B15","NUV-N2"]

    print "NUV counts for magnitude ", m
    for i in range(len(c0)):
        t=" SAFE"
        k = m0 + 2.5*np.log10(c0[i])
        cps = np.power(10.0, (k-m)/2.5)
        if cps>1500:
            t="  UNSAFE"
        print filt[i],cps,t

    print "\n\n"

def main():
    mag_fuv=float(sys.argv[-1])
    mag_nuv=float(sys.argv[-2])

    print "\n\n"
    if (mag_fuv==-999):
        mag_fuv=mag_nuv-1.65

    counts_fuv(mag_fuv)
    counts_nuv(mag_nuv)

if __name__=="__main__":
    main()