"""Module for working with status notifications."""
import datetime
import json

import boto3

from . import common_config
from .util import boto3_error_handling


client = boto3.client('sns', region_name=common_config.AWS_REGION)


@boto3_error_handling
def send_notification(topic_arn, message_payload):
    """Send SNS message.

    Args:
        topic_arn (str): SNS topic ARN.
        message_payload (dict): SNS message data.

    Returns:
        dict: Info about published message.

    """
    return client.publish(
        TopicArn=topic_arn,
        Message=json.dumps(message_payload))


def _remove_none_entries(source):
    """Remove entries with None values from dictionary.

    Args:
        source (dict): Source dictionary containing entries with None values.

    Returns:
        dict: Return a new dictionary with None values filtered out.

    """
    return {key: val for key, val in source.items() if val is not None}


def send_general_status(function, status_name, filename, bucket, errors=None):
    """Send general status notification about asset file processing by lambda.

    Args:
        function (str): Status source lambda function name.
        status_name (str): Status.
        filename (str): Current processed asset filename.
        bucket (str): Current processed asset source bucket name.
        errors (dict): An object of errors if present.

    Returns:
        dict: Info about published status message.

    """
    message = {
        'function': function,
        'status': status_name,
        'filename': filename,
        'bucket': bucket,
        'status_time': datetime.datetime.now().strftime('%Y-%m-%dT%H:%M:%S.%fZ'),
        'errors': errors
    }
    return send_notification(common_config.SNS_GENERAL_STATUS_TOPIC_ARN, _remove_none_entries(message))


def send_encoding_status(status_name, key, bucket, errors=None, final_assets=None):
    """Send encoding status notification about asset file processing by lambda.

    Args:
        status_name (str): Status.
        key (str): S3 object key.
        bucket (str): S3 bucket name.
        errors (dict): Errors if any description.
        final_assets (list): List of final assets bodies.

     Returns:
        dict: Info about published status message.

    """
    message = {
        'status': status_name,
        'errors': errors,
        'final_assets': final_assets,
        'input': {
            'key': key,
            'bucket': bucket
        }
    }
    return send_notification(common_config.SNS_ENCODING_STATUS_TOPIC_ARN, _remove_none_entries(message))