#!/opt/local/bin/ipython
#2019.02.05 Frayer
#Python 3.7.2
#IPython 7.2.0
#
#Swapping the RA and DEC positions for Argus beam 2 and 3 due to
#cable mis-match for Argus data taken before 2018.10.22 19:30 UT
#
#This program assumes input is raw SDFITS files 
#where scan and integration numbers are in the exact same order
#between beams.   If this is not the case or not sure, then should
#loop through unqiue scan numbers and integration numbers and
#replace individual records which would be much slower.
#Beam 2 and Beam 3 data are in different VEGAS banks so need to read
#in the C and D bank VEGAS files 
#
#SDFITS files for the GBT are large tables stored in extension=1 where
#each row represents a specific interation number, scan number,
#spectral window, beam number, frequency-state, subreflector-state,
#and other states/parameters that are used by other instruments (83
#columns)
#
#
#Usage: %swap23RawSDFITS.py raw.vegas.C.fits  raw.vegas.D.fits
#Warning: Replaces data in original input files  
#
#
from astropy.io import fits 
import sys
import numpy as np

#sys.argv[0] is name of script
FileC = sys.argv[1]
FileD = sys.argv[2]


#fileC 
tabC=fits.getdata(FileC,ext=1)
hC=fits.getheader(FileC,ext=1)
raC = tabC["CRVAL2"]
decC = tabC["CRVAL3"]
feedC = tabC["FEED"]
nraC=np.copy(raC)
ndecC=np.copy(decC)

#fileD
tabD=fits.getdata(FileD,ext=1)
hD=fits.getheader(FileD,ext=1)
raD = tabD["CRVAL2"]
decD = tabD["CRVAL3"]
feedD = tabD["FEED"]
nraD=np.copy(raD)
ndecD=np.copy(decD)

#Beam-3 is in C Bank and Beam-2 is in D Bank
id2=np.where(feedD==2)
id3=np.where(feedC==3)
idx2=id2[0]
idx3=id3[0]

#swap idexes
nraD[idx2]=raC[idx3]
nraC[idx3]=raD[idx2]
ndecD[idx2]=decC[idx3]
ndecC[idx3]=decD[idx2]

#replace values
tabD["CRVAL2"]=nraD
tabD["CRVAL3"]=ndecD
tabC["CRVAL2"]=nraC
tabC["CRVAL3"]=ndecC

#update input files
fits.update(FileC,tabC,hC,ext=1)
fits.update(FileD,tabD,hD,ext=1)