#!/bin/env python
# coding: utf-8

VERSION='1.2'

# Version 1.2 : partie droite débute à 1086 et non 1087

import pyfits
from optparse import OptionParser

import numpy
from scipy import *

parser = OptionParser()
parser.add_option("-n","--nobias",action="store_true",
                  dest="nobias", default=False,
                  help="no suppression of the bias (based on overscans)")

(options, args) = parser.parse_args ()

if (len(args) !=2) :
    print "Usage : pre.py [-n --nobias] input.fits output.fits"
    exit(1)

# Ouverture de l'image fits en argument
hdulist = pyfits.open(args[0])
scidata = hdulist[0].data

# suppression prescan/overscan/bord de plage

gauche = scidata[:2048,50:1074]
droite = scidata[:2048,1086:2110]

# Suppression du fond selon moyenne des overscans

if options.nobias :
    print "No bias substraction"
else:
    bias_gauche = mean(scidata[:2048,:50])-10
    bias_droite = mean(scidata[:2048,2110:])-10
    print "Warning ! bias removed (%f / %f) " % (bias_gauche, bias_droite)
    gauche -= bias_gauche
    droite -= bias_droite

scidata = numpy.hstack((gauche,droite))
dim = scidata.shape

# Pixel min = 0
scidata = numpy.where(scidata<0,0,scidata)

prihdr = hdulist[0].header
prihdr.add_history('pre.py V'+VERSION)
prihdr.add_history('Suppression os/ps')

# Ajout du WCS
prihdr.update('CRPIX1',1024,'crpix1')
prihdr.update('CRPIX2',1024,'crpix2')
prihdr.update('CRVAL1',0,'crval1')
prihdr.update('CRVAL2',0,'crval2')
prihdr.update('CD1_1',0,'crdelt1')
prihdr.update('CD1_2',1.0593,'crdelt2')
prihdr.update('CD2_1',-1.0593,'crota1')
prihdr.update('CD2_2',0.0,'crota2')
prihdr.update('CTYPE1',' ','ctype1')
prihdr.update('CTYPE2',' ','ctype2')


hdulist[0].data = scidata
hdulist.writeto(args[1],clobber=True)


hdulist.close()