#!/usr/bin/env python3
#
# Copyright (C) 2018 VyOS maintainers and contributors
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 2 or later as
# published by the Free Software Foundation.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT 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, see <http://www.gnu.org/licenses/>.
#
#

import sys
import os
import re
import subprocess

from vyos import ConfigError
from vyos.config import Config

proxy_def=r'/etc/profile.d/vyos-system-proxy.sh'

def get_config():
  c = Config()
  if not c.exists('system proxy'):
    return None

  c.set_level('system proxy')

  cnf = {
    'url'     : None,
    'port'    : None,
    'usr'     : None,
    'passwd'  : None
  }

  if c.exists('url'):
    cnf['url'] = c.return_value('url')
  if c.exists('port'):
    cnf['port'] = c.return_value('port')
  if c.exists('username'):
    cnf['usr'] = c.return_value('username')
  if c.exists('password'):
    cnf['passwd'] = c.return_value('password')

  return cnf

def verify(c):
  if not c:
    return None 
  if not c['url'] or not c['port']:
    raise ConfigError("proxy url and port requires a value")
  elif c['usr'] and not c['passwd']:
    raise ConfigError("proxy password requires a value")
  elif not c['usr'] and c['passwd']:
    raise ConfigError("proxy username requires a value")

def generate(c):
  if not c:
    return None
  if not c['usr']:
    return str("export http_proxy={url}:{port}\nexport https_proxy=$http_proxy\nexport ftp_proxy=$http_proxy"\
              .format(url=c['url'], port=c['port']))
  else:
    return str("export http_proxy=http://{usr}:{passwd}@{url}:{port}\nexport https_proxy=$http_proxy\nexport ftp_proxy=$http_proxy"\
              .format(url=re.sub('http://','',c['url']), port=c['port'], usr=c['usr'], passwd=c['passwd']))

def apply(ln):
  if not ln and os.path.exists(proxy_def):
    subprocess.call(['unset http_proxy https_proxy ftp_proxy'], shell=True)
    os.remove(proxy_def)
  else:
    open(proxy_def,'w').write("# generated by system-proxy.py\n{}\n".format(ln))
    subprocess.call(['. /etc/profile.d/vyos-system-proxy.sh'], shell=True)

if __name__ == '__main__':
    try:
        c = get_config()
        verify(c)
        ln = generate(c)
        apply(ln)
    except ConfigError as e:
        print(e)
        sys.exit(1)