"""Lambda podcast_chartable function module."""

from datetime import datetime
from datetime import timedelta

import boto3
from botocore.exceptions import ClientError
import config
from common import sentry

OWS_PODCAST = 'ows-podcast'

s3_client = boto3.client('s3')


def file_exists(file_path):
    """Check if file exists in s3 bucket."""
    try:
        s3_object = s3_client.get_object(
            Bucket=config.CHARTABLE_BUCKET, Key=file_path)
        file_size = s3_object['ContentLength']
        if file_size > 20:  # file is not empty
            return True
    except ClientError as e:
        error = e.response['Error']['Code']
        if error != 'NoSuchKey':
            raise e
    return False


def get_missing_files(report_date, include_lag):
    """Get missing files for given date (and accounting for chartable lag)."""
    missing_files = []
    for file_type, file_info in config.FILES.items():

        if include_lag:
            report_date = report_date - timedelta(days=file_info[1])
        formatted_date = report_date.strftime('%Y-%m-%d')
        formatted_file_name = file_info[0].format(date=formatted_date)

        if not file_exists(formatted_file_name):
            missing_files.append('{}-{}'.format(file_type, formatted_date))
    return missing_files


def handler(event, context):
    """Lambda entry point."""
    try:
        report_date = datetime.now()
        include_lag = True
        if event.get('event_date'):
            report_date = datetime.strptime(
                event['event_date'], '%Y-%m-%dT%H:%M:%S.%f%z')
            include_lag = False

        missing_files = get_missing_files(report_date, include_lag)
        if len(missing_files):
            sentry_message = 'Missing files: {}'.format(
                ','.join(missing_files))
            sentry.capture_message(sentry_message)
    except Exception as e:
        config.logger.exception(str(e))
        raise e