import pyfits
import numpy as N
#from .. mappings import ins_spec_kw
from hstwcs.mappings import ins_spec_kw, prim_hdr_kw
    
class InstrWCS(object):
    """
    A base class for instrument specific keyword definition.
    It prvides a default implementation (modeled by ACS) for
    all set_kw methods.
    """
    def __init__(self, hdr0, hdr):
        self.exthdr = hdr   
        self.primhdr = hdr0
        
    def set_ins_spec_kw(self):
        """
        This method MUST call all set_kw methods.
        There should be a set_kw method for all kw listed in 
        mappings.ins_spec_kw
        """
        self.set_filter1()
        self.set_filter2()
        self.set_vafactor()
        self.set_naxis1()
        self.set_naxis2()
        self.set_ltv1()
        self.set_ltv2()
        self.set_binned()
        self.set_chip()
        self.set_parity()
        
    def set_filter1(self):
        self.filter1 = self.primhdr.get('FILTER1', None)
        
    def set_filter2(self):
        self.filter2 = self.primhdr.get('FILTER2', None) 
               
    def set_vafactor(self):
        self.vafactor = self.exthdr.get('vafactor', 1) 
    
    def set_naxis1(self):
        self.naxis1 = self.exthdr.get('naxis1', None)
        
    def set_naxis2(self):
        self.naxis2 = self.exthdr.get('naxis2', None)
        
    def set_ltv1(self):
        self.ltv1 = self.exthdr.get('ltv1', 0.0)
        
    def set_ltv2(self):
        self.ltv2 = self.exthdr.get('ltv2', 0.0)
        
    def set_binned(self):
        self.binned = self.exthdr.get('BINAXIS1', 1)

    def set_chip(self):
        self.chip = self.exthdr.get('CCDCHIP', 1)
    
    def set_parity(self):
        self.parity = [[1.0,0.0],[0.0,-1.0]]
        
class ACSWCS(InstrWCS):
    """
    get instrument specific kw    
    """
    
    def __init__(self, hdr0, hdr):
        self.primhdr = hdr0
        self.exthdr = hdr
        InstrWCS.__init__(self,hdr0, hdr)
        self.set_ins_spec_kw()
    
    def set_parity(self):
        parity = {'WFC':[[1.0,0.0],[0.0,-1.0]],
                'HRC':[[-1.0,0.0],[0.0,1.0]],
                'SBC':[[-1.0,0.0],[0.0,1.0]]}
        detector = self.primhdr.get('detector', None)  
        self.parity = parity[detector]
    
        
class WFPC2WCS(InstrWCS):   


    def __init__(self, hdr0, hdr):
        self.primhdr = hdr0
        self.exthdr = hdr
        InstrWCS.__init__(self,hdr0, hdr)
        self.set_ins_spec_kw()
    
    def set_filter1(self):
        self.filter1 = self.primhdr.get('FILTNAM1', None)
        if self.filter1 == " " or self.filter1 == None:
            self.filter1 = 'CLEAR1'

    def set_filter2(self):
        self.filter2 = self.primhdr.get('FILTNAM2', None)
        if self.filter2 == " " or self.filter2 == None:
            self.filter2 = 'CLEAR1'
            
    
    def set_binned(self):
        mode = self.primhdr.get('MODE', 1)
        if mode == 'FULL':
            self.binned = 1
        elif mode == 'AREA':
            self.binned = 2

    def set_chip(self):
        self.chip = self.exthdr.get('DETECTOR', 1)
    
    def set_parity(self):
        self.parity = [[-1.0,0.],[0.,1.0]]