from flask import current_app
from ldap3_orm import AttrDef, EntryBase as _EntryBase, ObjectDef, EntryType
from ldap3_orm import Reader
from ldap3 import Entry
from ldap3.utils.conv import escape_filter_chars
from flask_login import UserMixin
from ldap3.core.exceptions import LDAPSessionTerminatedByServerError
from cryptography.hazmat.primitives import hashes
from cryptography.hazmat.primitives import serialization
from collections.abc import MutableSequence
from datetime import datetime
from dateutil import tz
import pyotp
import json

ldap_conn = None  # type: Connection
base_dn = ''


class SecurityUser(UserMixin):

    def __init__(self, username):
        self._username = username

    def get_id(self):
        return self._username


class LambdaStr:

    def __init__(self, lam):
        self.lam = lam

    def __str__(self):
        return self.lam()


class EntryBase(object):
    _type = None  # will get replaced by the local type
    _query_object = None  # will get replaced by the local type
    _base_dn = LambdaStr(lambda: base_dn)

    def __init__(self, ldap_object=None, **kwargs):
        if ldap_object is None:
            self._ldap_object = self.get_type()(**kwargs)
        else:
            self._ldap_object = ldap_object

    def __str__(self):
        return str(self._ldap_object)

    @classmethod
    def get_object_def(cls):
        return ObjectDef(cls.object_classes, ldap_conn)

    @classmethod
    def get_base(cls):
        return cls.base_dn.format(_base_dn=base_dn)

    @classmethod
    def get_type(cls):
        if cls._type is None:
            cls._type = EntryType(cls.dn.replace('{base_dn}',cls.get_base()), cls.object_classes, ldap_conn)
        return cls._type

    def commit(self):
        print(self._ldap_object.entry_attributes_as_dict)
        ret = ldap_conn.add(
                self.dn, self.object_classes, self._ldap_object.entry_attributes_as_dict)
        print(ret)
        pass

    @classmethod
    def query(cls):
        if cls._query_object is None:
            cls._query_object = cls._query(cls)
        return cls._query_object


    class _query(object):
        def __init__(self, clazz):
            self._class = clazz

        def _mapping(self, ldap_object):
            return ldap_object

        def _query(self, ldap_filter: str):
            reader = Reader(ldap_conn, self._class.get_object_def(), self._class.get_base(), ldap_filter)
            try:
                reader.search()
            except LDAPSessionTerminatedByServerError:
                ldap_conn.bind()
                reader.search()
            return [self._mapping(entry) for entry in reader]

        def all(self):
            return self._query(None)




class Service(object):

    def __init__(self, name):
        self._name = name
        self._client_cert = False
        self._pki_config = {
                    'cn': '{username}',
                    'email': '{username}@{domain}'
                }

    @staticmethod
    def from_config(name, config):
        """
        """
        service = Service(name)
        if 'client_cert' in config:
            service._client_cert = bool(config['client_cert'])
        if 'pki_config' in config:
            service._pki_config.update(config['pki_config'])

        return service

    @property
    def name(self):
        return self._name

    @property
    def client_cert(self):
        return self._client_cert

    @property
    def pki_config(self):
        if not self._client_cert:
            raise Exception('invalid call')
        return self._pki_config


class Certificate(object):

    def __init__(self, cn, ca_name: str, cert_data, revoked=False):
        self._cn = cn
        self._ca_name = ca_name
        self._cert_data = cert_data
        self._revoked = revoked
        self._cert_data.not_valid_after.replace(tzinfo=tz.tzutc())
        self._cert_data.not_valid_before.replace(tzinfo=tz.tzutc())

    @property
    def cn(self):
        return self._cn

    @property
    def ca_name(self):
        return self._ca_name

    @property
    def not_valid_before(self) -> datetime:
        return self._cert_data.not_valid_before.replace(tzinfo=tz.tzutc()).astimezone(tz.tzlocal()).replace(tzinfo=None)

    @property
    def not_valid_after(self) -> datetime:
        return self._cert_data.not_valid_after.replace(tzinfo=tz.tzutc()).astimezone(tz.tzlocal()).replace(tzinfo=None)

    @property
    def serial_number(self) -> int:
        return self._cert_data.serial_number

    @property
    def serial_number_hex(self) -> str:
        return f'{self._cert_data.serial_number:X}'

    def fingerprint(self, algorithm=hashes.SHA256()) -> bytes:
        return self._cert_data.fingerprint(algorithm)

    @property
    def is_valid(self) -> bool:
        return self.not_valid_after > datetime.now() and not self._revoked

    def pem(self) -> str:
        return self._cert_data.public_bytes(encoding=serialization.Encoding.PEM).decode()

    @property
    def raw(self):
        return self._cert_data

    def __str__(self):
        return f'Certificate(cn={self._cn}, ca_name={self._ca_name}, not_valid_before={self.not_valid_before}, not_valid_after={self.not_valid_after})'


class Totp(object):

    def __init__(self, name, secret, created_at=datetime.now()):
        self._secret = secret
        self._name = name
        self._created_at = created_at

    @property
    def name(self):
        return self._name

    @property
    def created_at(self):
        return self._created_at

    def verify(self, token: str):
        totp = pyotp.TOTP(self._secret)
        return totp.verify(token)

    def to_dict(self):
        return {
                'secret': self._secret,
                'name': self._name,
                'created_at': int(self._created_at.timestamp())}

    @staticmethod
    def from_dict(data):
        return Totp(
                name=data['name'],
                secret=data['secret'],
                created_at=datetime.fromtimestamp(data['created_at']))


class TotpList(MutableSequence):
    def __init__(self, ldap_attr):
        super().__init__()
        self._ldap_attr = ldap_attr

    def __getitem__(self, ii):
        return Totp.from_dict(json.loads(self._ldap_attr[ii]))

    def __setitem__(self, ii, val: Totp):
        self._ldap_attr[ii] = json.dumps(val.to_dict()).encode()

    def __len__(self):
        return len(self._ldap_attr)

    def __delitem__(self, ii):
        del self._ldap_attr[ii]

    def delete(self, totp_name):
        for i in range(len(self)):
            if self[i].name == totp_name:
                self._ldap_attr.delete(self._ldap_attr[i])

    def insert(self, ii, val):
        self.append(val)

    def append(self, val):
        self._ldap_attr.add(json.dumps(val.to_dict()).encode())


class User(EntryBase):

    dn = "uid={uid},{base_dn}"
    base_dn = "ou=users,{_base_dn}"
    object_classes = ["top", "inetOrgPerson", "LenticularUser"]

    def __init__(self, ldap_object=None, **kwargs):
        super().__init__(ldap_object, **kwargs)
        self._totp_list = TotpList(ldap_object.totpSecret)

    @property
    def is_authenticated(self):
        return True  # TODO

    def get(self, key):
        print(f'getitem: {key}')

    def make_writeable(self):
        self._ldap_object = self._ldap_object.entry_writable()
        self._totp_list = TotpList(self._ldap_object.totpSecret)

    @property
    def entry_dn(self):
        return self._ldap_object.entry_dn

    @property
    def username(self):
        return self._ldap_object.uid

    @username.setter
    def username(self, value):
        self._ldap_object.uid = value

    @property
    def userPassword(self):
        return self._ldap_object.userPassword

    @property
    def fullname(self):
        return self._ldap_object.fullname

    @property
    def givenname(self):
        return self._ldap_object.givenname

    @property
    def surname(self):
        return self._ldap_object.surname

    @property
    def email(self):
        return self._ldap_object.mail

    @property
    def alternative_email(self):
        return self._ldap_object.altMail

    @property
    def auth_role(self):
        return self._ldap_object.authRole

    @property
    def gpg_public_key(self):
        return self._ldap_object.gpgPublicKey

    @property
    def totps(self):
        return self._totp_list

    class _query(EntryBase._query):

        def _mapping(self, ldap_object):
            return User(ldap_object=ldap_object)

        def by_username(self, username) -> 'User':
            result = self._query('(uid={username:s})'.format(username=escape_filter_chars(username)))
            if len(result) > 0:
                return result[0]
            else:
                return None



class Group(EntryBase):
    dn = "cn={cn},{base_dn}"
    base_dn = "ou=Users,{_base_dn}"
    object_classes = ["top"]

    fullname = AttrDef("cn")