import json
from datetime import datetime, timedelta

import requests
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 fromisoformat, now
from layercake.dynamodb import DynamoDBPersistenceLayer, KeyPair, SortKey

from boto3clients import dynamodb_client, s3_client
from config import BUCKET_NAME, ENROLLMENT_TABLE, PAPERFORGE_API, SIGNATURE_URI

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:
    new_image = event.detail['new_image']
    now_ = now()
    enrollment_id = new_image['id']
    cert = dyn.collection.get_item(
        KeyPair(
            pk=new_image['id'],
            sk=SortKey('METADATA#COURSE', path_spec='cert', rename_key='cert'),
        ),
        raise_on_error=False,
        default=False,
    )

    if not cert:
        logger.debug('Certificate not found')
        # There is no certificate to issue from metadata
        return False

    started_at: datetime = fromisoformat(new_image['started_at'])  # type: ignore
    completed_at: datetime = fromisoformat(new_image['completed_at'])  # type: ignore
    cert_expires_at = completed_at + timedelta(days=int(cert['exp_interval']))

    try:
        # Send template URI and data to Paperforge API to generate a PDF
        r = requests.post(
            PAPERFORGE_API,
            data=json.dumps(
                {
                    'template_uri': cert['s3_uri'],
                    'sign_uri': SIGNATURE_URI,
                    'args': {
                        'name': new_image['user']['name'],
                        'cpf': _cpffmt(new_image['user']['cpf']),
                        'score': new_image['score'],
                        'started_at': started_at.strftime('%d/%m/%Y'),
                        'completed_at': completed_at.strftime('%d/%m/%Y'),
                        'today': _datefmt(now_),
                        'year': now_.strftime('%Y'),
                    },
                },
            ),
        )
        r.raise_for_status()

        object_key = f'issuedcerts/{enrollment_id}.pdf'
        s3_uri = f's3://{BUCKET_NAME}/{object_key}'

        s3_client.put_object(
            Bucket=BUCKET_NAME,
            Key=object_key,
            Body=r.content,
            ContentType='application/pdf',
        )

        logger.debug(f'PDF uploaded successfully to {s3_uri}')
    except KeyError:
        # PDF generation fails if template URI is missing
        s3_uri = None
        logger.debug('Template URI is missing')
    except requests.exceptions.RequestException as exc:
        logger.exception(exc)
        raise

    return dyn.update_item(
        key=KeyPair(
            pk=enrollment_id,
            sk='0',
        ),
        update_expr='SET issued_cert = :issued_cert, uploaded_at = :now',
        expr_attr_values={
            ':now': now_,
            ':issued_cert': {
                'issued_at': now_,
                'expires_at': cert_expires_at,
            }
            | ({'s3_uri': s3_uri} if s3_uri else {}),
        },
        cond_expr='attribute_exists(sk)',
    )


def _cpffmt(s: str) -> str:
    return '{}.{}.{}-{}'.format(s[:3], s[3:6], s[6:9], s[9:])


def _datefmt(dt: datetime) -> str:
    months = [
        'Janeiro',
        'Fevereiro',
        'Março',
        'Abril',
        'Maio',
        'Junho',
        'Julho',
        'Agosto',
        'Setembro',
        'Outubro',
        'Novembro',
        'Dezembro',
    ]
    return f'{dt.day:02d} de {months[dt.month - 1]} de {dt.year}'