from datetime import datetime
from uuid import uuid4

from aws_lambda_powertools import Logger
from aws_lambda_powertools.utilities.data_classes import (
    EventBridgeEvent,
    event_source,
)
from aws_lambda_powertools.utilities.typing import LambdaContext
from layercake.dateutils import now
from layercake.dynamodb import DynamoDBPersistenceLayer, KeyPair

from boto3clients import dynamodb_client
from config import ENROLLMENT_TABLE, ORDER_TABLE
from enrollment import (
    Enrollment,
    Kind,
    LinkedEntity,
    Seat,
    Subscription,
    enroll,
)

logger = Logger(__name__)
dyn = DynamoDBPersistenceLayer(ENROLLMENT_TABLE, dynamodb_client)


@event_source(data_class=EventBridgeEvent)
@logger.inject_lambda_context
def lambda_handler(event: EventBridgeEvent, context: LambdaContext) -> bool:
    old_image = event.detail['old_image']
    now_ = now()
    # Key pattern `SCHEDULED#ORG#{org_id}`
    *_, org_id = old_image['id'].split('#')
    # Key pattern `{YYYY-MM-DD HH:MM:SS.mmmmmm}#{lock_hash}`
    sk = old_image['sk']
    _, lock_hash = sk.split('#')
    offset_days = old_image.get('dedup_window_offset_days')
    billing_day = old_image.get('subscription_billing_day')
    created_by = old_image.get('created_by')
    seat: Seat = old_image.get('seat', {})
    enrollment = Enrollment(
        id=old_image['enrollment_id'],
        course=old_image['course'],
        user=old_image['user'],
    )
    subscription: Subscription | None = (
        {
            'org_id': org_id,
            'billing_day': int(billing_day),
        }
        if billing_day
        else None
    )

    try:
        # The enrollment must know its source
        linked_entities = (
            frozenset(
                {
                    LinkedEntity(
                        id=seat['order_id'],
                        kind=Kind.ORDER,
                        table_name=ORDER_TABLE,
                    ),
                },
            )
            if seat
            else frozenset()
        )

        enroll(
            enrollment,
            org={
                'org_id': org_id,
                'name': old_image['org_name'],
            },
            subscription=subscription,
            cancel_policy=bool(subscription),
            created_by=created_by,
            seat=seat,
            scheduled_at=datetime.fromisoformat(old_image['scheduled_at']),
            # Transfer the deduplication window if it exists
            deduplication_window={'offset_days': offset_days} if offset_days else None,
            linked_entities=linked_entities,
            persistence_layer=dyn,
        )

        with dyn.transact_writer() as transact:
            transact.put(
                item={
                    'id': old_image['id'],
                    'sk': f'{sk}#EXECUTED',
                    'enrollment_id': enrollment.id,
                    'user': old_image['user'],
                    'course': old_image['course'],
                    'created_by': created_by,
                    'created_at': now_,
                }
            )
            transact.delete(
                key=KeyPair(
                    pk='LOCK#SCHEDULED',
                    sk=lock_hash,
                ),
            )
    except Exception as exc:
        dyn.put_item(
            item={
                'id': old_image['id'],
                'sk': f'{sk}#FAILED',
                'cause': {
                    'type': type(exc).__name__,
                    'message': str(exc),
                },
                'snapshot': old_image,
                'created_at': now_,
            }
        )

    return True