;+
; NAME:
;	O_ADDKEY
;
; PURPOSE:
;	add keywords to OSIRIS raw files
;
; EXPLANATION:
;	Usually for SSCALE as many DRP modules don't work without it
;
; CALLING SEQUENCE:
;       o_addkey, add=string
;
; INPUTS:
;       add - string to be added to the filename to avoid overwriting
;
; OUTPUTS:
;	fits file - can overwrite existing file
;
; OPTIONAL OUPUTS:
;	
;
; OPTIONAL INPUT KEYWORDS:
;       filedir, filename, add, key, value, comment
;
; EXAMPLE:
;	o_addkey, add='key'
;
; ERROR HANDLING:
;	none.  Be careful about messing with your fits headers!
;
; RESTRICTIONS:
;	one file at a time
;
; NOTES:
;       none
;
; PROCEDURES USED:
;	Functions:	o_make_filename
;                       fxaddpar
;
; MODIFICATION HISTORY:
;	2007 Jul 30 jlyke ORIGINAL
;-
PRO O_ADDKEY, filedir=filedir, file=file, add=add, $
                 key=key, value=value, comment=comment


if ( not keyword_set(filedir) ) then begin
    filedir = './'
endif
if ( not keyword_set(file) ) then begin
    file = dialog_pickfile( title='File to add keyword', $
                                     filter='*.fits', $
                                     get_path=new_path, $
                                     /MUST_EXIST )
    ; separate the directory from the filename
    filedir = new_path
    temp = strsplit(file, '/', /extract)
    filename = temp[n_elements(temp)-1]
endif
if ( keyword_set(add) ) then begin
    outfile = o_make_filename(filename, add)
endif else begin
    outfile=filename
endelse
if ( not keyword_set(key) ) then begin
    key = 'SSCALE'
endif
if ( not keyword_set(value) ) then begin
    value = '0.035 '
endif
if ( not keyword_set(comment) ) then begin
     comment = ' Spec scale'
endif

    data = readfits(filedir+filename, data_hdr)
    noise = readfits(filedir+filename, exten_no = 1)
    qual = readfits(filedir+filename, exten_no = 2)

    zeroth = n_elements(data[*,0,0])
    first  = n_elements(data[0,*,0])
    second = n_elements(data[0,0,*])

; update the header info
    fxaddpar, data_hdr, key, value, comment

; write out the file
    writefits, filedir+outfile, data, data_hdr
    writefits, filedir+outfile, noise, /append
    writefits, filedir+outfile, qual, /append




END