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, TransactKey

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

logger = Logger(__name__)
enrollment_layer = 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']
    course = enrollment_layer.collection.get_items(
        TransactKey(new_image['id'])
        + SortKey('METADATA#COURSE', path_spec='cert', rename_key='cert')
        + SortKey('STARTED', path_spec='started_at', rename_key='started_at')
        + SortKey('COMPLETED', path_spec='completed_at', rename_key='completed_at'),
        flatten_top=False,
    )

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

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

    data = json.dumps(
        {
            'template_s3_uri': cert['s3_uri'],
            'template_vars': {
                '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'),
            },
        },
    )
    # Send template URI and data to Paperforge API to generate a PDF
    r = requests.post(PAPERFORGE_API, data=data)
    r.raise_for_status()

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

    try:
        s3_client.put_object(
            Bucket=BUCKET_NAME,
            Key=object_key,
            Body=r.content,
            ContentType='application/pdf',
        )
    except Exception as exc:
        logger.exception(exc)
        raise

    logger.debug(f'PDF uploaded successfully to {s3_uri}')

    return enrollment_layer.update_item(
        key=KeyPair(
            pk=enrollment_id,
            sk='0',
        ),
        update_expr='SET issued_cert = :issued_cert',
        expr_attr_values={
            ':issued_cert': {
                's3_uri': s3_uri,
                'issued_at': now_,
                'expires_at': cert_expires_at,
            },
        },
        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}'