# -*- coding: utf-8 -*-
#
import uuid

from django.conf import settings
from django.contrib.auth import BACKEND_SESSION_KEY
from django.db import transaction
from django.db.models.signals import post_save, pre_save, m2m_changed, pre_delete
from django.dispatch import receiver
from django.utils import timezone, translation
from django.utils.functional import LazyObject
from django.utils.translation import ugettext_lazy as _
from rest_framework.renderers import JSONRenderer
from rest_framework.request import Request

from audits.handler import (
    get_instance_current_with_cache_diff, cache_instance_before_data,
    create_or_update_operate_log, get_instance_dict_from_cache
)
from audits.utils import model_to_dict_for_operate_log as model_to_dict
from authentication.signals import post_auth_failed, post_auth_success
from authentication.utils import check_different_city_login_if_need
from common.const.signals import POST_ADD, POST_REMOVE, POST_CLEAR, SKIP_SIGNAL
from common.utils import get_request_ip, get_logger, get_syslogger
from common.utils.encode import data_to_json
from jumpserver.utils import current_request
from terminal.backends.command.serializers import SessionCommandSerializer
from terminal.models import Session, Command
from terminal.serializers import SessionSerializer
from users.models import User
from users.signals import post_user_change_password
from . import models, serializers
from .const import MODELS_NEED_RECORD, ActionChoices
from .utils import write_login_log

logger = get_logger(__name__)
sys_logger = get_syslogger(__name__)
json_render = JSONRenderer()


class AuthBackendLabelMapping(LazyObject):
    @staticmethod
    def get_login_backends():
        backend_label_mapping = {}
        for source, backends in User.SOURCE_BACKEND_MAPPING.items():
            for backend in backends:
                backend_label_mapping[backend] = source.label
        backend_label_mapping[settings.AUTH_BACKEND_PUBKEY] = _("SSH Key")
        backend_label_mapping[settings.AUTH_BACKEND_MODEL] = _("Password")
        backend_label_mapping[settings.AUTH_BACKEND_SSO] = _("SSO")
        backend_label_mapping[settings.AUTH_BACKEND_AUTH_TOKEN] = _("Auth Token")
        backend_label_mapping[settings.AUTH_BACKEND_WECOM] = _("WeCom")
        backend_label_mapping[settings.AUTH_BACKEND_FEISHU] = _("FeiShu")
        backend_label_mapping[settings.AUTH_BACKEND_DINGTALK] = _("DingTalk")
        backend_label_mapping[settings.AUTH_BACKEND_TEMP_TOKEN] = _("Temporary token")
        return backend_label_mapping

    def _setup(self):
        self._wrapped = self.get_login_backends()


AUTH_BACKEND_LABEL_MAPPING = AuthBackendLabelMapping()

M2M_ACTION = {
    POST_ADD: ActionChoices.create,
    POST_REMOVE: ActionChoices.delete,
    POST_CLEAR: ActionChoices.delete,
}


@receiver(m2m_changed)
def on_m2m_changed(sender, action, instance, reverse, model, pk_set, **kwargs):
    if action not in M2M_ACTION:
        return
    if not instance:
        return

    resource_type = instance._meta.verbose_name
    current_instance = model_to_dict(instance, include_model_fields=False)

    instance_id = current_instance.get('id')
    log_id, before_instance = get_instance_dict_from_cache(instance_id)

    field_name = str(model._meta.verbose_name)
    objs = model.objects.filter(pk__in=pk_set)
    objs_display = [str(o) for o in objs]
    action = M2M_ACTION[action]
    changed_field = current_instance.get(field_name, [])

    after, before, before_value = None, None, None
    if action == ActionChoices.create:
        before_value = list(set(changed_field) - set(objs_display))
    elif action == ActionChoices.delete:
        before_value = list(
            set(changed_field).symmetric_difference(set(objs_display))
        )

    if changed_field:
        after = {field_name: changed_field}
    if before_value:
        before = {field_name: before_value}

    if sorted(str(before)) == sorted(str(after)):
        return

    create_or_update_operate_log(
        ActionChoices.update, resource_type,
        resource=instance, log_id=log_id, before=before, after=after
    )


def signal_of_operate_log_whether_continue(sender, instance, created, update_fields=None):
    condition = True
    if not instance:
        condition = False
    if instance and getattr(instance, SKIP_SIGNAL, False):
        condition = False
    # 终端模型的 create 事件由系统产生，不记录
    if instance._meta.object_name == 'Terminal' and created:
        condition = False
    # last_login 改变是最后登录日期, 每次登录都会改变
    if instance._meta.object_name == 'User' and \
            update_fields and 'last_login' in update_fields:
        condition = False
    # 不在记录白名单中，跳过
    if sender._meta.object_name not in MODELS_NEED_RECORD:
        condition = False
    return condition


@receiver(pre_save)
def on_object_pre_create_or_update(sender, instance=None, raw=False, using=None, update_fields=None, **kwargs):
    ok = signal_of_operate_log_whether_continue(
        sender, instance, False, update_fields
    )
    if not ok:
        return
    instance_before_data = {'id': instance.id}
    raw_instance = type(instance).objects.filter(pk=instance.id).first()
    if raw_instance:
        instance_before_data = model_to_dict(raw_instance)
    operate_log_id = str(uuid.uuid4())
    instance_before_data['operate_log_id'] = operate_log_id
    setattr(instance, 'operate_log_id', operate_log_id)
    cache_instance_before_data(instance_before_data)


@receiver(post_save)
def on_object_created_or_update(sender, instance=None, created=False, update_fields=None, **kwargs):
    ok = signal_of_operate_log_whether_continue(
        sender, instance, created, update_fields
    )
    if not ok:
        return

    log_id, before, after = None, None, None
    if created:
        action = models.ActionChoices.create
        after = model_to_dict(instance)
        log_id = getattr(instance, 'operate_log_id', None)
    else:
        action = ActionChoices.update
        current_instance = model_to_dict(instance)
        log_id, before, after = get_instance_current_with_cache_diff(current_instance)

    resource_type = sender._meta.verbose_name
    create_or_update_operate_log(
        action, resource_type, resource=instance,
        log_id=log_id, before=before, after=after
    )


@receiver(pre_delete)
def on_object_delete(sender, instance=None, **kwargs):
    ok = signal_of_operate_log_whether_continue(sender, instance, False)
    if not ok:
        return

    resource_type = sender._meta.verbose_name
    create_or_update_operate_log(
        ActionChoices.delete, resource_type,
        resource=instance, before=model_to_dict(instance)
    )


@receiver(post_user_change_password, sender=User)
def on_user_change_password(sender, user=None, **kwargs):
    if not current_request:
        remote_addr = '127.0.0.1'
        change_by = 'System'
    else:
        remote_addr = get_request_ip(current_request)
        if not current_request.user.is_authenticated:
            change_by = str(user)
        else:
            change_by = str(current_request.user)
    with transaction.atomic():
        models.PasswordChangeLog.objects.create(
            user=str(user), change_by=change_by,
            remote_addr=remote_addr,
        )


def on_audits_log_create(sender, instance=None, **kwargs):
    if sender == models.UserLoginLog:
        category = "login_log"
        serializer_cls = serializers.UserLoginLogSerializer
    elif sender == models.FTPLog:
        category = "ftp_log"
        serializer_cls = serializers.FTPLogSerializer
    elif sender == models.OperateLog:
        category = "operation_log"
        serializer_cls = serializers.OperateLogSerializer
    elif sender == models.PasswordChangeLog:
        category = "password_change_log"
        serializer_cls = serializers.PasswordChangeLogSerializer
    elif sender == Session:
        category = "host_session_log"
        serializer_cls = SessionSerializer
    elif sender == Command:
        category = "session_command_log"
        serializer_cls = SessionCommandSerializer
    else:
        return

    serializer = serializer_cls(instance)
    data = data_to_json(serializer.data, indent=None)
    msg = "{} - {}".format(category, data)
    sys_logger.info(msg)


def get_login_backend(request):
    backend = request.session.get('auth_backend', '') or \
              request.session.get(BACKEND_SESSION_KEY, '')

    backend_label = AUTH_BACKEND_LABEL_MAPPING.get(backend, None)
    if backend_label is None:
        backend_label = ''
    return backend_label


def generate_data(username, request, login_type=None):
    user_agent = request.META.get('HTTP_USER_AGENT', '')
    login_ip = get_request_ip(request) or '0.0.0.0'

    if login_type is None and isinstance(request, Request):
        login_type = request.META.get('HTTP_X_JMS_LOGIN_TYPE', 'U')
    if login_type is None:
        login_type = 'W'

    with translation.override('en'):
        backend = str(get_login_backend(request))

    data = {
        'username': username,
        'ip': login_ip,
        'type': login_type,
        'user_agent': user_agent[0:254],
        'datetime': timezone.now(),
        'backend': backend,
    }
    return data


@receiver(post_auth_success)
def on_user_auth_success(sender, user, request, login_type=None, **kwargs):
    logger.debug('User login success: {}'.format(user.username))
    check_different_city_login_if_need(user, request)
    data = generate_data(user.username, request, login_type=login_type)
    request.session['login_time'] = data['datetime'].strftime("%Y-%m-%d %H:%M:%S")
    data.update({'mfa': int(user.mfa_enabled), 'status': True})
    write_login_log(**data)


@receiver(post_auth_failed)
def on_user_auth_failed(sender, username, request, reason='', **kwargs):
    logger.debug('User login failed: {}'.format(username))
    data = generate_data(username, request)
    data.update({'reason': reason[:128], 'status': False})
    write_login_log(**data)