# -*- coding: utf-8 -*-
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# regarding copyright ownership.  The ASF licenses this file
# to you under the Apache License, Version 2.0 (the
# "License"); you may not use this file except in compliance
# with the License.  You may obtain a copy of the License at
#
#   http://www.apache.org/licenses/LICENSE-2.0
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# Unless required by applicable law or agreed to in writing,
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from airflow.operators.http_operator import SimpleHttpOperator
from airflow.utils.decorators import apply_defaults
from airflow.contrib.hooks.slack_webhook_hook import SlackWebhookHook


class SlackWebhookOperator(SimpleHttpOperator):
    """
    This operator allows you to post messages to Slack using incoming webhooks.
    Takes both Slack webhook token directly and connection that has Slack webhook token.
    If both supplied, Slack webhook token will be used.

    Each Slack webhook token can be pre-configured to use a specific channel, username and
    icon. You can override these defaults in this hook.

    :param http_conn_id: connection that has Slack webhook token in the extra field
    :type http_conn_id: str
    :param webhook_token: Slack webhook token
    :type webhook_token: str
    :param message: The message you want to send on Slack
    :type message: str
    :param attachments: The attachments to send on Slack. Should be a list of
                        dictionaries representing Slack attachments.
    :type attachments: list
    :param channel: The channel the message should be posted to
    :type channel: str
    :param username: The username to post to slack with
    :type username: str
    :param icon_emoji: The emoji to use as icon for the user posting to Slack
    :type icon_emoji: str
    :param link_names: Whether or not to find and link channel and usernames in your
                       message
    :type link_names: bool
    :param proxy: Proxy to use to make the Slack webhook call
    :type proxy: str
    """

    @apply_defaults
    def __init__(self,
                 http_conn_id=None,
                 webhook_token=None,
                 message="",
                 attachments=None,
                 channel=None,
                 username=None,
                 icon_emoji=None,
                 link_names=False,
                 proxy=None,
                 *args,
                 **kwargs):
        super(SlackWebhookOperator, self).__init__(endpoint=webhook_token,
                                                   *args,
                                                   **kwargs)
        self.http_conn_id = http_conn_id
        self.webhook_token = webhook_token
        self.message = message
        self.attachments = attachments
        self.channel = channel
        self.username = username
        self.icon_emoji = icon_emoji
        self.link_names = link_names
        self.proxy = proxy
        self.hook = None

    def execute(self, context):
        """
        Call the SlackWebhookHook to post the provided Slack message
        """
        self.hook = SlackWebhookHook(
            self.http_conn_id,
            self.webhook_token,
            self.message,
            self.attachments,
            self.channel,
            self.username,
            self.icon_emoji,
            self.link_names,
            self.proxy
        )
        self.hook.execute()
