#!/usr/bin/env python3
# pylint: disable=W1309 W1203 W1510 C0116 W1401 C0103 R1715 R0914
"""Automation for cert renewal.

assumptions:
    * firewall has access configured for specified key
    * firewall sshd config contains: `AcceptEnv ssl_service state`
    * firewall has `ssl-update.sh` copied to /usr/local/bin and chmod +x
"""

import logging
import os
import pathlib
import pwd
import subprocess
import sys
import time
import pexpect

firewall = '10.0.0.1'
firewall_user = 'luke'
firewall_key = '/root/.ssh/id_autofirewall'
server_user = 'luke'
domain = 'drheck.dev'

supported_services = [
  'git',
  'photoprism',
  'plex',
  'read',
  'www',
]

restart_delay = {
  'plex': 10
}

pfx_key_path = {
    'plex': pathlib.Path('/data/plex/certs/certificate.pfx'),
    'jellyfin': pathlib.Path('/data/jellyfin/ssl/jellyfin.pfx'),
}

# Cert owning user if different than the name of the service
users = {
    'git': 'gitea',
    'read': 'http',
    'chat': 'synapse',
    'sync': 'syncv3',
    'www': 'http',
    'spacebar': '_spacebar',
}

# systemd service names that don't match the service name
# service : systemd_service
systemd_services = {
    'git': 'gitea',
    'plex': 'plexmediaserver',
    'read': 'kavita',
    'nextcloud': 'php-fpm',
    'chat': 'synapse',
    'sync': 'sliding-sync',
    'www': 'nginx',
}


remote = {
    'rng': {
    'user': 'luke',
    'auth': 'id_m',
    },
}

def firewall_mod(state, service, decrypt_pp):
  os.environ['state'] = state
  os.environ['ssl_service'] = service
  cmd = ['/usr/bin/ssh', '-i', firewall_key, '-o',
         'SendEnv=state', '-o', 'SendEnv=ssl_service', '-l', firewall_user,
         firewall, '/usr/local/bin/ssl-update.sh']
  log.info(f'env for fw: state: {os.environ["state"]}')
  log.info(f'env for fw: ssl_service: {service}')
  log.info(f'cmd to connect to firewall: "{" ".join(cmd)}"')
  p = pexpect.spawnu(' '.join(cmd))
  p.logfile = sys.stderr
  log.info(f'key string: {firewall_key}')
  res = p.expect([f'''Enter passphrase for key ['"]{firewall_key}['"]:''',
                  pexpect.TIMEOUT, pexpect.EOF])
  if res > 0:
    sys.exit('Couldnt send decryption key to ssh.')
  p.sendline(decrypt_pp)
  res = p.expect(['success', pexpect.TIMEOUT, pexpect.EOF])
  if res > 0:
    sys.exit(f'Failed. error: {p.before}')
  state_print = state.split('_')[1].lower()
  log.info(f'Turned {state_print} HTTP for {service}')


def recurse_rmdir(directory):
  directory = pathlib.Path(directory)
  for item in directory.iterdir():
    if item.is_dir():
      recurse_rmdir(item)
    else:
      item.unlink()
  directory.rmdir()


def jellyfin():
  log.info('custom function for jellyfin actions')
  pfx_gen('jellyfin')


def plex():
  log.info('custom function for plex actions')
  pfx_gen('plex')


def restart(service):
  if service in restart_delay:
    wait = restart_delay[service]
  else:
    wait = 5
  try:
    systemd_service = systemd_services[service]
  except KeyError:
    systemd_service = service

  log.info(f'going to restart service: {service}')
  cmd = ['/usr/bin/systemctl', 'restart', systemd_service]
  log.info(f'cmd to restart service: "{" ".join(cmd)}"')
  p = subprocess.run(cmd, capture_output=True)
  log.info(f'sleeping {wait} seconds')
  time.sleep(wait)

  cmd = ['/usr/bin/systemctl', 'is-active', '--quiet', systemd_service]
  log.info(f'cmd to check service status: "{" ".join(cmd)}"')
  p = subprocess.run(cmd)
  if p.returncode != 0:
    log.error(f'{service} failed to restart:')
    cmd = ['/usr/bin/systemctl', 'status', systemd_service]
    log.info(f'cmd to show status of service: "{" ".join(cmd)}"')
    p = subprocess.run(cmd, capture_output=True)
    stderr = p.stderr.decode('UTF-8')
    sys.stderr.write(stderr)
    sys.exit(1)
  log.info(f'{service} has restarted OK')


def pfx_gen(service):
  log.info(f'generate pfx file for {service}')
  cmd = ['/usr/bin/su', '-l', server_user,
         '/usr/bin/pass', 'show', f'ssl/{service}']
  log.info(f'cmd to get password to encrypt private key: "{" ".join(cmd)}"')
  p = subprocess.run(cmd, capture_output=True)
  export_pw = p.stdout.decode('UTF-8').strip()
  if not export_pw:
    sys.exit(f'Couldnt get ssl export password for {service}')
  try:
    pkp = pfx_key_path[service]
  except KeyError:
    sys.exit(f'{service} has no defined private key path.')

  cmd = ['/usr/bin/openssl', 'pkcs12', '-export', '-out', str(pkp),
         '-inkey', f'/etc/letsencrypt/live/{service}.{domain}/privkey.pem',
         '-in', f'/etc/letsencrypt/live/{service}.{domain}/cert.pem',
         '-certfile', f'/etc/letsencrypt/live/{service}.{domain}/chain.pem']
  user = service
  if service in users:
    user = users[service]
  uid = pwd.getpwnam(user).pw_uid
  gid = pwd.getpwnam(user).pw_gid

  # chown after custom service in case pfx or other key is generated

  log.info(f'changing owner of {pkp} - uid: {uid} gid: {gid}')
  os.chown(pkp, uid, gid)

  log.info(f'chmod {pkp} to 0o600')
  pkp.chmod(0o600)

  log.info(f'cmd to encrypt private key: "{" ".join(cmd)}"')
  p = pexpect.spawnu(' '.join(cmd))
  p.logfile = sys.stderr
  res = p.expect(['Enter Export Password:', pexpect.EOF, pexpect.TIMEOUT])
  if res > 0:
    sys.exit('Failed to run openssl to generate '
             f'pkcs12 keys for {service}: {p.before}')
  p.sendline(export_pw)
  log.info('send password to encrypt private key')
  res = p.expect(['Verifying - Enter Export Password:',
                  pexpect.EOF, pexpect.TIMEOUT])
  if res > 0:
    sys.exit('Failed to run openssl to generate '
             f'pkcs12 keys for {service}: {p.before}')
  p.sendline(export_pw)
  log.info(f'send password to encrypt private key...again')
  res = p.expect([pexpect.EOF, pexpect.TIMEOUT])
  if res > 0:
    sys.exit(f'Failed to run openssl to generate '
              'pkcs12 keys for {service}: {p.before}')
  log.info(f'this did not explicitly fail')


def get_ssh_pw():
  log.info('Get SSH decryption pw')
  cmd = ['/usr/bin/su', '-l', server_user,
         '/usr/bin/pass', 'show', 'ssh/autofirewall']
  log.info(f'cmd: "{" ".join(cmd)}"')
  p = subprocess.run(cmd, capture_output=True)
  decrypt_pp = p.stdout.decode('UTF-8').strip()
  if not decrypt_pp:
    sys.exit('Could not get decryption passpharase')
  log.info('Got SSH decryption pw')
  return decrypt_pp


def reset_challenge_path():
  challenge_path = pathlib.Path(
      '/usr/share/nginx/html/.well-known/acme-challenge/')
  if challenge_path.is_dir():
    recurse_rmdir(challenge_path)
  log.info('Challenge path deleted')
  challenge_path.mkdir()
  log.info('Challenge path created')
  challenge_path.chmod(0o755)
  log.info('Challenge path chmodded')
  return challenge_path

def run_cert_bot(fqdn, service, challenge_path, decrypt_pp):
  cmd = ['/usr/bin/certbot', 'certonly', '--manual', '-d', fqdn]
  log.info(f'certbot cmd: "{" ".join(cmd)}"')
  cb = pexpect.spawnu(' '.join(cmd))
  cb.logfile = sys.stderr
  do_update = True
  matches = [
      'Create a file containing just this data:\r\n\r\n([^\r]+)\r', # 0
      ('You have an existing certificate that has exactly the '     # 1
       "same domains or certificate name you requested and isn't "
       'close to expiry'),
      '(U)pdate key type/(K)eep existing key type:',                # 2
      'no action taken',                                            # 3
      'No such authorization',                                      # 4
      pexpect.TIMEOUT,
      pexpect.EOF]
  while True:
    res = cb.expect(matches, timeout=20)
    print(f'\nresult: {matches[res]}, {res}')
    if res > 4:
      sys.exit('Timed out')
    if res == 3 or res == 4:
      do_update = False
      break
    if res == 2:
      cb.sendline('U')
      continue
    if res == 1:
      log.info('Current cert is not yet expired')
      res = cb.expect_exact(['cancel):', pexpect.TIMEOUT, pexpect.EOF])
      if res > 0:
        sys.exit('Timed out in setup with existing cert')
      cb.sendline('1')
      continue
      # res = cb.expect(
      #     ['Create a file containing just this data:\r\n\r\n([^\r]+)\r',
      #      pexpect.TIMEOUT, pexpect.EOF], timeout=20)
      # if res > 1:
      #   sys.exit('Timed out')
    if res == 0:
      break

  if do_update:
    data = cb.match.group(1)
    log.info(f'secret data: {data}')
    log.info('the data string and location for the shared secret are known')
    long_match = ('And make it available on your web server at this URL:'
                  '\r\n\r\nhttp://%s/.well-known/acme-challenge/([^\r]+)\r')
    res = cb.expect([long_match % (fqdn,), pexpect.TIMEOUT, pexpect.EOF])
    if res > 0:
      sys.exit('Timed out')
    filename = cb.match.group(1)
    log.info(f'filename of secret: {filename}')
    res = cb.expect(['Press Enter to Continue', pexpect.EOF], timeout=0)

    data_file = challenge_path / pathlib.Path(filename)
    try:
      with open(data_file, 'w') as f:
        f.write(data)
    except:
      sys.exit(f'Failed to write {data_file}')
    log.info('created secret file with secret data')
    data_file.chmod(0o644)
    log.info('and chmodded')

    symlink_name = pathlib.Path(f'{service}-le')
    log.info(f'nginx symlink: {symlink_name}')
    nx_conf = pathlib.Path('/etc/nginx')
    avail_path = nx_conf / pathlib.Path('sites-available')
    enabled_path = nx_conf / pathlib.Path('sites-enabled')

    service_available_file = avail_path / symlink_name
    log.info(f'nginx service avail symlink: {service_available_file}')
    service_enabled_symlink = enabled_path / symlink_name
    log.info(f'nginx service enabled symlink: {service_enabled_symlink}')
    if not service_enabled_symlink.is_symlink():
      service_enabled_symlink.symlink_to(service_available_file)
      log.info('created symlink to enable service')

    log.info(f'open port 80 to {service}')
    firewall_mod('HTTP_UP', service, decrypt_pp)
    restart('nginx')

    cb.sendline()
    log.info(f'sent <enter> to certbot to continue process')
    res = cb.expect([pexpect.EOF])
    log.info(f'cerbot completed. final output: {cb.before}')

    output_text = str(cb.before)
    if 'failed' in output_text:
      sys.exit('Something went wrong')

    log.info(f'close port 80 to {service}')
    firewall_mod('HTTP_DOWN', service, decrypt_pp)

    service_enabled_symlink.unlink()
    if service_enabled_symlink.is_symlink():
      sys.exit(f'Could not unlink {service_enabled_symlink}')
      log.info('created symlink to enable service')
    log.info('removed symlink in nginx to disable HTTP')

    restart('nginx')

  key_path = pathlib.Path('/etc/letsencrypt')
  live = key_path / pathlib.Path(f'live/{service}.{domain}')
  archive = key_path / pathlib.Path(f'archive/{service}.{domain}')
  log.info(f'live keypath: {live}')
  log.info(f'archive keypath: {archive}')

  if service in globals():
    log.info(f'{service} has a service specific function to run')
    eval(f'{service}()')
  log.info(f'{service} specific work complete.')

  user = service
  if service in users:
    user = users[service]
  log.info(f'service {service} has user {user}')
  uid = pwd.getpwnam(user).pw_uid
  gid = pwd.getpwnam(user).pw_gid

  # chown after custom service in case pfx or other key is generated

  log.info(f'uid: {uid} gid: {gid}')
  os.chown(live, uid, gid)
  log.info(f'live keypath chmodded')
  os.chown(archive, uid, gid)

  log.info(f'archive keypath chmodded')
  for dirpath, _, filenames in os.walk(archive):
    os.chown(dirpath, uid, gid)
    for filename in filenames:
      os.chown(os.path.join(dirpath, filename), uid, gid)
  log.info(f'chmodded new keys from certbot')


def main(args):
  # logging.basicConfig(level=os.environ.get("LOGLEVEL", "WARNING"))
  logging.basicConfig(level=os.environ.get("LOGLEVEL", "INFO"))
  log.info(f'program start: {sys.argv}')
  if len(args) != 1:
    sys.exit(f'Give a service to renew: {", ".join(supported_services)} ')
  service = args[0]
  if service not in supported_services:
    sys.exit(f'Give a service to renew: {", ".join(supported_services)} ')

  uid = os.getuid()
  if uid != 0:
    sys.exit('Run as root')

  decrypt_pp = get_ssh_pw()
  challenge_path = reset_challenge_path()

  fqdn = f'{service}.{domain}'
  log.info(f'fqdn: {fqdn}')
  run_cert_bot(fqdn, service, challenge_path, decrypt_pp)
  restart(service)


log = logging.getLogger(__name__)
if __name__ == '__main__':
  main(sys.argv[1:])