"""Provides the diagnosis of SASL, mail submission, and user database lookup
configurations"""
# SPDX-License-Identifier: AGPL-3.0-or-later

import logging

from django.utils.translation import gettext_lazy as _

import plinth.modules.email_server.aliases as aliases
import plinth.modules.email_server.postconf as postconf
from plinth import actions

from . import models

default_config = {
    'smtpd_sasl_auth_enable':
        'yes',
    'smtpd_sasl_type':
        'dovecot',
    'smtpd_sasl_path':
        'private/auth',
    'mailbox_transport':
        'lmtp:unix:private/dovecot-lmtp',
    'virtual_transport':
        'lmtp:unix:private/dovecot-lmtp',
    'smtpd_relay_restrictions':
        ','.join([
            'permit_sasl_authenticated',
            'defer_unauth_destination',
        ])
}

submission_flags = postconf.ServiceFlags(service='submission', type='inet',
                                         private='n', unpriv='-', chroot='y',
                                         wakeup='-', maxproc='-',
                                         command_args='smtpd')

default_submission_options = {
    'syslog_name': 'postfix/submission',
    'smtpd_tls_security_level': 'encrypt',
    'smtpd_client_restrictions': 'permit_sasl_authenticated,reject',
    'smtpd_relay_restrictions': 'permit_sasl_authenticated,reject'
}

smtps_flags = postconf.ServiceFlags(service='smtps', type='inet', private='n',
                                    unpriv='-', chroot='y', wakeup='-',
                                    maxproc='-', command_args='smtpd')

default_smtps_options = {
    'syslog_name': 'postfix/smtps',
    'smtpd_tls_wrappermode': 'yes',
    'smtpd_sasl_auth_enable': 'yes',
    'smtpd_relay_restrictions': 'permit_sasl_authenticated,reject'
}

MAILSRV_DIR = '/var/lib/plinth/mailsrv'
SQLITE_ALIASES = 'sqlite:/etc/postfix/freedombox-aliases.cf'

logger = logging.getLogger(__name__)


def get():
    """Compare current values with the default. Generate an audit report

    Recommended endpoint name:
    GET /audit/ldap
    """
    translation_table = [
        (check_sasl, _('Postfix-Dovecot SASL integration')),
        (check_alias_maps, _('Postfix alias maps')),
    ]
    results = []
    with postconf.mutex.lock_all():
        for check, title in translation_table:
            results.append(check(title))
    return results


def repair():
    """Tries to repair SASL, mail submission, and user lookup settings

    Recommended endpoint name:
    POST /audit/ldap/repair
    """
    aliases.first_setup()
    actions.superuser_run('email_server', ['ldap', 'set_up'])


def action_set_up():
    action_set_sasl()
    action_set_submission()
    action_set_ulookup()


def check_sasl(title=''):
    diagnosis = models.MainCfDiagnosis(title)
    diagnosis.compare(default_config, postconf.get_many_unsafe)
    return diagnosis


def fix_sasl(diagnosis):
    diagnosis.apply_changes(postconf.set_many_unsafe)


def action_set_sasl():
    """Handles email_server -i ldap set_sasl"""
    with postconf.mutex.lock_all():
        fix_sasl(check_sasl())


def action_set_submission():
    """Handles email_server -i ldap set_submission"""
    postconf.set_master_cf_options(service_flags=submission_flags,
                                   options=default_submission_options)
    postconf.set_master_cf_options(service_flags=smtps_flags,
                                   options=default_smtps_options)


def check_alias_maps(title=''):
    """Check the ability to mail to usernames and user aliases"""
    diagnosis = models.MainCfDiagnosis(title)

    alias_maps = postconf.get_unsafe('alias_maps').replace(',', ' ').split(' ')
    if SQLITE_ALIASES not in alias_maps:
        diagnosis.flag_once('alias_maps', user=alias_maps)
        diagnosis.critical('Required maps not in list')

    return diagnosis


def fix_alias_maps(diagnosis):

    def fix_value(alias_maps):
        if SQLITE_ALIASES not in alias_maps:
            alias_maps.append(SQLITE_ALIASES)

        return ' '.join(alias_maps)

    diagnosis.repair('alias_maps', fix_value)
    diagnosis.apply_changes(postconf.set_many_unsafe)


def action_set_ulookup():
    """Handles email_server -i ldap set_ulookup"""
    with postconf.mutex.lock_all():
        fix_alias_maps(check_alias_maps())


def list_find(lst, element, start=None, end=None):
    if start is None:
        start = 0
    if end is None:
        end = len(lst)
    if start < 0 or end < 0:
        return -1
    try:
        return lst.index(element, start, end)
    except ValueError:
        return -1