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"""This module contains AWS SNS hook"""
import json
from typing import Dict, Optional, Union

from airflow.providers.amazon.aws.hooks.base_aws import AwsBaseHook


def _get_message_attribute(o):
    if isinstance(o, bytes):
        return {"DataType": "Binary", "BinaryValue": o}
    if isinstance(o, str):
        return {"DataType": "String", "StringValue": o}
    if isinstance(o, (int, float)):
        return {"DataType": "Number", "StringValue": str(o)}
    if hasattr(o, "__iter__"):
        return {"DataType": "String.Array", "StringValue": json.dumps(o)}
    raise TypeError(
        "Values in MessageAttributes must be one of bytes, str, int, float, or iterable; "
        f"got {type(o)}"
    )


class AwsSnsHook(AwsBaseHook):
    """
    Interact with Amazon Simple Notification Service.

    Additional arguments (such as ``aws_conn_id``) may be specified and
    are passed down to the underlying AwsBaseHook.

    .. seealso::
        :class:`~airflow.providers.amazon.aws.hooks.base_aws.AwsBaseHook`
    """

    def __init__(self, *args, **kwargs):
        super().__init__(client_type="sns", *args, **kwargs)

    def publish_to_target(
        self,
        target_arn: str,
        message: str,
        subject: Optional[str] = None,
        message_attributes: Optional[dict] = None,
    ):
        """
        Publish a message to a topic or an endpoint.

        :param target_arn: either a TopicArn or an EndpointArn
        :type target_arn: str
        :param message: the default message you want to send
        :param message: str
        :param subject: subject of message
        :type subject: str
        :param message_attributes: additional attributes to publish for message filtering. This should be
            a flat dict; the DataType to be sent depends on the type of the value:

            - bytes = Binary
            - str = String
            - int, float = Number
            - iterable = String.Array

        :type message_attributes: dict
        """
        publish_kwargs: Dict[str, Union[str, dict]] = {
            "TargetArn": target_arn,
            "MessageStructure": "json",
            "Message": json.dumps({"default": message}),
        }

        # Construct args this way because boto3 distinguishes from missing args and those set to None
        if subject:
            publish_kwargs["Subject"] = subject
        if message_attributes:
            publish_kwargs["MessageAttributes"] = {
                key: _get_message_attribute(val)
                for key, val in message_attributes.items()
            }

        return self.get_conn().publish(**publish_kwargs)