#!/usr/bin/env python3
# (c) 2023 th\@bogus.net
import qrcode # pip install
from PIL import Image
import pyotp # pip install
import argparse

parser = argparse.ArgumentParser(description='Generate Google Auth TOTP QR code .png', prog='gauth-qrcode.py')
parser.add_argument('--secret', type=str, dest='secret', action='store', help="TOTP secret string (optional)")
parser.add_argument('--uri', type=str, dest='uri', action='store', help="Identifying string e.g. user@myapp")
parser.add_argument('--out', type=str, dest="outfile", action='store', help="Output filename (default: gauth_qr_code.png)")
parser.add_argument('--print-key', dest="pk", action='store_true', help="Print the generated secret (default: no)")
opts = parser.parse_args()

if opts.secret:
    secret = opts.secret
else:
    secret = pyotp.random_base32()
    if opts.pk:
        print(secret)

if opts.uri:
    uri = opts.uri
else:
    print("Error: need --uri <somestring> to identify this TOTP key")
    exit(1)
    
if opts.outfile:
    outfile = opts.outfile
else:
    outfile = "gauth_qr_code.png"

# Create the TOTP object
totp = pyotp.TOTP(secret)

# Create the QR code object
qr = qrcode.QRCode(
    version=1,
    box_size=10,
    border=5
)

# Make the QR code
qr.add_data(totp.provisioning_uri(uri))
qr.make(fit=True)

# Create an image from the QR code
img = qr.make_image(fill_color="black", back_color="white")

# Save the QR code as an image file
img.save(outfile)