#!/usr/bin/env python3
# scan.py (AHG, 2023), output directory in line 24
import os,sane
from subprocess import run
from string import ascii_letters
from time import strftime
from pypdf import PdfReader, PdfWriter
#
my_name = "Gitter"
san = sane.init()
if not sane.get_devices():
    print("\nScan Program",__file__)
    print("ERROR: no scanner found",\
"(use USB 3 or an active USB hub)\n")
    sane.exit() ; os._exit(1)
else:
	print("\nScan Program",__file__+\
", scanner:",sane.get_devices()[0][2])
#
dev = sane.open(sane.get_devices()[0][0])
wh = dev.get_parameters()[2]
print("width x height (pixels):",str(wh[0]),"x",\
str(wh[1])+",","output file format: PDF")
dir = os.getenv("HOME")+"/docum/scan/" # directory
if os.path.isdir(dir)==False:
    print("ERROR: missing directory", dir,"\n")
    sane.exit() ; os._exit(1)
#
print("\nName your file without extension .pdf,")
dat = input("output file (ENTER for default): ")
dat = dat.strip().replace(" ","_") # remove spaces
if dat: # string not empty -> check file name
    if dat[0] not in ascii_letters:
        print("ERROR: must start with letter\n")
        sane.exit() ; os._exit(1)
    dat=dir+dat+".pdf" # path to output file
    if os.path.exists(dat)==True:
        print("ERROR: cannot overwrite file\n")
        sane.exit() ; os._exit(1)
else: # string is empty -> use the default name
    dat = dir+"scan"+strftime("%y%m%d%H%M%S.pdf")
#
tit = input("Title of PDF (ENTER for default): ")
tit = tit.strip().replace(" ","_") # remove spaces
if not tit:  # string is empty -> use the default name
    tit = my_name+"_scan_"+strftime("%y%m%d")
#
# now we scan, save in PDF file and show result:
dev.start() ; img = dev.snap() ; img.save(dat)
dev.close() ; sane.exit()
rdr = PdfReader(dat) ; wrt =PdfWriter()
for p in rdr.pages: wrt.add_page(p)
wrt.add_metadata(rdr.metadata)
wrt.add_metadata({"/Title":tit})
with open(dat,"wb") as f: wrt.write(f)
try: run(["fbgs",dat]) # we need fbgs to show PDF
except: print("WARNING: cannot show output file\n")
print("\nEnd of scanning, output file:",dat,"\n")