import abc
from collections import namedtuple
import typing

import boto3
from celery import shared_task
import structlog

from atlas_um.consts import SystemEvents
from atlas_um.settings import Settings
from . import schemas


class BaseAuditProcessor(abc.ABC):
    """
    Interface for audit log processors.

    Processors are observers that intended to handle audit events
    in any needed way, e.g. storage backends, message busses etc.
    """

    @abc.abstractmethod
    def process(self, event: SystemEvents, context: typing.Mapping, **kwargs):
        pass


class StructlogProcessor(BaseAuditProcessor):
    """
    Audit processor for writing events into system log via Structlog.
    """

    def __init__(self, logger_name):
        self._logger = structlog.get_logger(logger_name)

    def process(self, event: SystemEvents, context: typing.Mapping, **kwargs):
        self._logger.bind(**context, **kwargs).info(event.value)


BusConf = namedtuple("BusConf", ("detail_type", "detail_schema"))


class EventBridgeAsyncProcessor(BaseAuditProcessor):
    """
    Audit processor for pushing needed events to Amazon EventBridge.
    """

    EVENTS_SETTINGS = {
        SystemEvents.creating_dna_account: BusConf(
            "dna_account.create", schemas.DNAAccountDetail
        ),
        SystemEvents.updating_dna_account: BusConf(
            "dna_account.update", schemas.DNAAccountDetail
        ),
        SystemEvents.updating_dna_account_claims: BusConf(
            "dna_account.update", schemas.DNAAccountDetail
        ),
        SystemEvents.disabling_dna_account_claims: BusConf(
            "dna_account.update", schemas.DNAAccountDetail
        ),
        SystemEvents.sending_dna_invitation: BusConf(
            "dna_account.update", schemas.DNAAccountDetail
        ),
        SystemEvents.suspending_dna_account: BusConf(
            "dna_account.delete", schemas.DNAAccountDetail
        ),
    }

    def process(self, event: SystemEvents, context: typing.Mapping, **kwargs):
        event_settings = self.EVENTS_SETTINGS.get(event)
        if not event_settings:
            return
        event_data = {
            "Source": Settings.EVENT_BUS_SOURCE,
            "EventBusName": Settings.EVENT_BUS_NAME,
            "DetailType": event_settings.detail_type,
            "Detail": event_settings.detail_schema().dumps(kwargs),
        }
        self.send_to_event_bridge.delay(event_data)

    @staticmethod
    @shared_task
    def send_to_event_bridge(event_data):
        client = boto3.client(
            "events", region_name=Settings.AWS_DEFAULT_REGION
        )
        client.put_events(Entries=[event_data])