#!/usr/bin/env python
# -*- coding: utf-8 -*-
# Copyright (C) Marco Trevisan
#
# Authors:
#  Marco Trevisan <marco@trevisan.xyz>
#
# Revision for new URL:
#  Andrea Costantino <costan@amg.it>
#
# Revision for new XPath Query (add a filter by service type identifier)
#  Antonio Musarra <antonio.musarra@gmail.com>
#
# This program is free software; you can redistribute it and/or modify it under
# the terms of the GNU General Public License as published by the Free Software
# Foundation; version 3.
#
# This program is distributed in the hope that it will be useful, but WITHOUTa
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
# details.
#
# You should have received a copy of the GNU General Public License along with
# this program; if not, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
#
# Get Italian government Certification Authority certificates from used by
# by various National Service SmartCards (Carta Nazionale dei Servizi- CNS)
#
# Original URI:
#  - http://www.agid.gov.it/agenda-digitale/infrastrutture-architetture/firme-elettroniche/certificati
#
# Current XML file:
#  - https://eidas.agid.gov.it/TL/TSL-IT.xml

import argparse
import re
import sys
import xml.etree.ElementTree as ET
import textwrap
import os

DEFAULT_XML_URI = "https://eidas.agid.gov.it/TL/TSL-IT.xml"
EXTENSION = ".pem"

def get_certs_xml():
  if sys.version_info[0] == 2:
    import urllib2
    request = urllib2
  else:
    import urllib.request
    request = urllib.request

  return request.urlopen(DEFAULT_XML_URI)

def write_certificate(f, x509_cert):
  f.write('-----BEGIN CERTIFICATE-----\n')
  for line in textwrap.wrap(x509_cert, 65):
    f.write(line+'\n')
  f.write('-----END CERTIFICATE-----\n')

def get_service_info(service):
  name = service.find("*/"+ns+"Name").text
  x509_cert = service.find("*//"+ns+"X509Certificate").text
  return {'name': name, 'x509_cert': x509_cert}

parser = argparse.ArgumentParser()
action = parser.add_mutually_exclusive_group(required=True)
action.add_argument("--output-folder", help="Where to save the certs files")
action.add_argument("--output-file", help="File saving certificates")
parser.add_argument("--cert-file", help="Input Xml file, instead of %s" % DEFAULT_XML_URI)
parser.add_argument("--service-type-identifier", help="Save certs by Service Type Identifier, instead of all")
args = parser.parse_args()

if args.output_folder:
  if os.path.exists(args.output_folder):
    if not os.path.isdir(args.output_folder):
      print("Impossible to save certificates in `%s': file exists and is not a folder." % args.output_folder)
      sys.exit(1)
  else:
    os.makedirs(args.output_folder)
elif args.output_file:
  if os.path.exists(args.output_file):
    if not os.path.isfile(args.output_file):
      print("Impossible to write on `%s', it's not a file." % args.output_file)
      sys.exit(1)

    print("File `%s' will be overwritten..." % args.output_file)


if args.cert_file:
  tree = ET.parse(args.cert_file)
  root = tree.getroot()
else:
  root = ET.fromstring(get_certs_xml().read())

try:
  [ns] = re.findall("({[^}]*}).*", root.tag)
except:
  ns = ""

print("Namespace: `%s`", ns)

if args.service_type_identifier:
    services = root.findall(ns+"TrustServiceProviderList//"+ns+"TSPService/"+ns+"ServiceInformation["+ns+"ServiceTypeIdentifier='"+args.service_type_identifier+"']")
else:
    services = root.findall(ns+"TrustServiceProviderList//"+ns+"TSPService/"+ns+"ServiceInformation")

if args.output_folder:
  for service in services:
    try:
      info = get_service_info(service)
      name = re.sub('[A-z]{1,2}=', '_', re.sub('[/\,\' "]', '_', info['name'])).replace('__', '_').strip('_- ')
      filename = args.output_folder+os.path.sep+name

      idx = 1
      tmpname = filename
      while os.path.exists(tmpname+EXTENSION):
        tmpname = filename+str(idx)
        idx += 1
      filename = tmpname+EXTENSION

      f = open(filename, 'w')
      write_certificate(f, info['x509_cert'])
      f.close()
      print("Added certificate: %s" % filename)

    except Exception as e:
      print("Impossible to add file: %s" % e)
      pass

else:
  f = open(args.output_file, 'w')

  for service in services:
    try:
      info = get_service_info(service)
      write_certificate(f, info['x509_cert'])

      print("Added certificate %s" % info['name'])

    except Exception as e:
      print("Impossible to add certificate to file: %s" % e)
      pass

  f.close()