#!/usr/bin/env python3
import argparse
import boxsdk
import kadmin
import logging
import logging.handlers
import mcommunity
import os
import re
import string
import yaml

from .core import arg_prompt
from secrets import choice
from subprocess import check_output as cmd
from subprocess import CalledProcessError
from subprocess import STDOUT


class SharedAccount():

    def __init__(self, args, config):
        self.__dict__.update(args)
        self.config = config
        self.box_exists = False
        self.google_exists = False
        self.logger = logging.getLogger(__name__)
        self.groupname = re.sub(r'[\_\.]', ' ', self.account.strip()).lower()
        self.username = re.sub(r'[\_\s]', '.', self.account.strip()).lower()

    def check_box(self):
        try:
            auth = boxsdk.JWTAuth.from_settings_file(
                self.config['box']['auth_file']
            )
            boxClient = boxsdk.Client(auth)
            boxUsers = boxClient.users(filter_term=self.username)
            for _ in boxUsers:
                login = _['login'].split('@')[0]
                if self.username.lower() == login.lower():
                    self.box_exists = True
                    break
            return False
        except IOError as e:
            self.logger.error(e, extra={'entity': self.account})
        except boxsdk.exception.BoxAPIException as e:
            self.logger.error(e, extra={'entity': self.account})

    def check_google(self):
        try:
            output = cmd([
                self.config['google']['gam_command'],
                'whatis',
                self.username,
                'userview'
                ], stderr=STDOUT
            )
            if 'is a user' in output.decode('UTF-8'):
                self.google_exists = True
            return False
        except CalledProcessError:
            return False

    def check_mcommunity(self):
        try:
            client = mcommunity.MCommClient(
                self.config['mcommunity']['client_id'],
                self.config['mcommunity']['secret']
            )
            self.mcomm_group = client.group(self.groupname)
            assert self.mcomm_group.dn
        except mcommunity.core.MCommError as e:
            self.logger.error(e, extra={'entity': self.account})
            exit(2)
        except AssertionError:
            self.logger.error(
                'Unable to find matching group in MCommunity',
                extra={'entity': self.account}
            )
            exit(2)

    def set_kerberos_password(self):
        try:
            admin = '{}@{}'.format(
                self.config['kerberos']['admin'],
                self.config['kerberos']['realm'].upper()
            )
            kadm = kadmin.init_with_keytab(
                admin,
                self.config['kerberos']['keytab']
            )
            principal = '{}@{}'.format(
                self.username,
                self.config['kerberos']['realm'].upper()
            )
            princ = kadm.getprinc(principal)
            if not princ:
                self.logger.warning(
                    'Kerberos principal does not exist. Creating.',
                    extra={'entity': self.username}
                )
                kadm.addprinc(principal, self.password)
            else:
                princ.change_password(self.password)
        except IOError as e:
            self.logger.error(e, extra={'entity': self.account})
            exit(2)
        except kadmin.KAdminError as e:
            self.logger.error(e, extra={'entity': self.account})
            exit(2)

    def set_google_password(self):
        try:
            cmd([
                self.config['google']['gam_command'],
                'update',
                'user',
                self.username,
                'password',
                self.password
            ], stderr=STDOUT
            )
        except CalledProcessError as e:
            self.logger.error(e.output, extra={'entity': self.account})

    def upload_and_share_password(self):
        try:
            passFilePath = '{}/{}-passwd.txt'.format(
                self.config['general']['data_dir'],
                self.account
            )

            with open(passFilePath, 'w') as passwordFile:
                passwordFile.write(self.password)

            upload_output = cmd([
                self.config['google']['gam_command'],
                'user',
                self.config['google']['admin_account'],
                'add',
                'drivefile',
                'localfile',
                passFilePath,
                'parentname',
                'Shared Account Passwords'
            ], stderr=STDOUT)
            self.file_id = re.search(
                r'.*\((.*)\)',
                upload_output.decode('UTF-8')
            ).groups()[0]
        except CalledProcessError as e:
            self.logger.error(e.output, extra={'entity': self.account})

        for owner in self.mcomm_group.owners:
            try:
                whatis = cmd([
                    self.config['google']['gam_command'],
                    'whatis',
                    owner
                ], stderr=STDOUT)
            except CalledProcessError:
                self.logger.warning(
                    '{} does not seem to exist in Google.'.format(owner),
                    extra={'entity': self.account}
                )
                continue

            if b'is a user' in whatis:
                entity_type = 'user'
            elif b'is a group' in whatis:
                entity_type = 'group'

            try:
                cmd([
                    self.config['google']['gam_command'],
                    'user',
                    self.config['google']['admin_account'],
                    'add',
                    'drivefileacl',
                    self.file_id,
                    entity_type,
                    owner,
                    'role',
                    'reader'
                ], stderr=STDOUT)
            except CalledProcessError:
                self.logger.warning(
                    'Unable to share password with {}'.format(owner),
                    extra={'entity': self.account}
                )
                continue

        os.remove(passFilePath)

    def print_canned_text(self):
        print('''
Hello,

The password for your shared account has been changed. The new password for
this account is stored in your Google Drive space, and can be found at the
following link:

https://docs.google.com/a/{}/file/d/{}.

Please note that this file will expire automatically in ten (10) days, and
has been shared with any additional owners of the MCommunity group associated
with this account. Coordinate with other account owners before making changes
to this password.

For information on setting this password to a value of your choosing, please
see our documentation found at the following link:

https://documentation.its.umich.edu/?q=node/339#password

If you are still unable to log into your shared account, or if you have any
additional questions or concerns, simply reply to this message and your request
will be automatically re-opened.

'''.format(self.config['google']['domain'], self.file_id))


def main():

    helptext = '''example:
    collab-reset-shared -a umcollab -p pass12word
    collab-reset-shared --a umcollab --password pass12word
    '''

    parser = argparse.ArgumentParser(
        description='Resets the password in Google and'
                    'kerberos for a shared account.',
        epilog=helptext,
        formatter_class=argparse.RawDescriptionHelpFormatter
    )
    parser.add_argument(
        '--account',
        '-a',
        help='The target account name.',
    )
    parser.add_argument(
        '--password',
        '-p',
        help='The new password to use.',
    )
    parser.add_argument(
        '--config',
        '-c',
        help='The CAK config to use.',
        default='/etc/collab-admin-kit.yml'
    )
    args = parser.parse_args()

    # Argument prompt fallback
    if not args.account:
        args.account = arg_prompt(
            'Target shared account to reset password for'
        )
        args.password = arg_prompt(
            '(optional) Password to set',
            default=''
        )

    # Argument sanity check
    _required = ['account']
    for r in _required:
        try:
            if isinstance(r, str):
                assert getattr(args, r)
            if isinstance(r, tuple):
                assert getattr(args, r[0]) or getattr(args, r[1])
        except AssertionError:
            print('Missing required argument {}'.format(r))

    # Open the CAK Config
    with open(args.config) as stream:
        config = yaml.load(stream, Loader=yaml.BaseLoader)

    # Get the root logger and set the debug level
    logger = logging.getLogger(__name__)
    logger.setLevel(logging.DEBUG)

    # Create a syslog handler, set format, and associate.
    sh = logging.handlers.SysLogHandler(
        address='/dev/log',
        facility=config['general']['log_facility']
    )
    formatter = logging.Formatter(config['general']['log_format'])
    sh.setFormatter(formatter)
    logger.addHandler(sh)

    # Create a console handler, set format, and associate.
    ch = logging.StreamHandler()
    formatter = logging.Formatter(
        config['general']['console_format'],
        config['general']['date_format']
    )
    ch.setFormatter(formatter)
    logger.addHandler(ch)

    if not args.password:
        pool = string.ascii_letters + string.digits + '!@#$%&*'
        args.password = ''.join(choice(pool) for i in range(12))

    sa = SharedAccount(vars(args), config)
    sa.check_mcommunity()
    sa.check_box()
    sa.check_google()

    # Exit out if a shared account doesn't exist.
    if not sa.google_exists and not sa.box_exists:
        logger.error(
            'Entity does not exist as a shared account',
            extra={'entity': args.account}
        )
        exit(2)

    # Set the password in kerberos
    sa.set_kerberos_password()

    # Set in Google if available:
    if sa.google_exists:
        sa.set_google_password()

    # Upload password doc and share to group owners
    sa.upload_and_share_password()

    # Print canned text to send to the user.
    sa.print_canned_text()


if __name__ == '__main__':
    main()