"""
Base Feed Ingestion Work Flow.

Base Work Flow class that new Feed Ingestion flows should extend. Standardizes
how flow domain, name, and workflow_id are generated and adds default
on_exception method.

Flows should override the decider method.
"""

import datetime
import logging
import os

from garcon import activity
import raven


logger = logging.getLogger('garcon')


class FlowBase(object):
    """Base Garcon Workflow that other Flows can extend."""

    def __init__(self, *, swf_domain, flow_name, version):
        """Initialize Flow.

        Args:
            swf_domain (str):
            flow_name (str):
            version (str):
        """
        self.domain = swf_domain
        self.name = flow_name
        self.version = version
        self.create = activity.create(
            self.domain, self.name, version=self.version,
            on_exception=self.on_exception)

    def on_exception(self, actor, exception):
        """Capture an exception that has occurred in the application.

        Args:
            actor (ActivityWorker, DeciderWorker): The actor that has received
                the exception.
            exception (Exception): The exception to capture.
        """
        # client grabs sentry dns from SENTRY_DSN environment variable
        if os.environ.get('SENTRY_DSN'):
            client = raven.Client()
            client.captureException()

        if isinstance(actor, activity.Activity):
            actor.logger.error(exception, exc_info=True)
        else:
            logger.error(exception, exc_info=True)

    def workflow_id(self, initial_context):
        """Generate workflow id.

        Assumes a unique workflow is defined by it's context date and
        defaults to today's date. If that is not the case this method
        should be overridden.

        Args:
            initial_context (dict): The initial context for the flow.
        Returns:
            str: A unique identifier for a workflow being executed
                In the forms of '<self.flow_name>-YYYY-MM-DD', where
                YYYY-MM-DD is the context date or, if none passed the
                current date.
        """
        if 'context_date' not in initial_context:
            date = datetime.datetime.today().strftime('%Y-%m-%d')
        else:
            date = initial_context['context_date']

        return '{flow_name}-{date}'.format(flow_name=self.name, date=date)