"""
Base Aggregation Workflow class.

Base class that new 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

from analytics_aggregation import base_config


PROD_DOMAIN = 'prod_analytics_aggregation'
QA_DOMAIN = 'qa_analytics_aggregation'
TEST_DOMAIN = 'test'
SHADOW_DOMAIN = 'shadow_swf_feed_ingestion'
DEV_DOMAIN = os.environ.get('DEV_DOMAIN', 'dev')

logger = logging.getLogger('garcon')


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

    def __init__(self, feed_name, version):
        """Initialize Flow.

        Initializes the Flow's:
            domain - 'prod_analytics_aggregation' or 'dev
            feed_name - name of feed used in the status table
            name - '<feed_name>_analytics_aggregation' ex.
                spotify_sos_analytics_aggregation
                (this is the workflow name as opposed to the feed name)

        Args:
            feed_name (str): Name of the feed the workflow is processing,
                with underscores replacing spaces. ex. 'spotify_sos'
            version (str): Version of the workflow type to filter on. should
                be a 'x.x' float (ex. 1.0, 1.1, etc.)
        """
        self.domain = get_domain()
        self.name = generate_feed_name(feed_name)  # name = workflow_name
        self.feed_name = feed_name  # feed name verified in generate_feed_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)

    def decider(self, schedule):
        """Activity decider.

        Args:
            schedule (callable): The scheduler method.
        """
        raise NotImplementedError()


def generate_feed_name(feed_name):
    """Generate workflow name.

    Args:
        feed_name (str): Name of the feed the work flow is processing,
            must be lower case and have spaces replaced with underscores.
            ex. 'spotify_sos'
    Returns:
        str: SWF name in the format of '<feed_name>_analytics_aggregation'.
    """
    assert feed_name.islower() and ' ' not in feed_name, (
        'feed name must be lower case with no spaces')

    return '{feed_name}_analytics_aggregation'.format(feed_name=feed_name)


def get_domain():
    """Get workflow domain.

    Returns:
        str: SWF domain the workflow should use.
    """
    if base_config.environment == 'prod':
        return PROD_DOMAIN
    elif base_config.environment == 'test':
        return TEST_DOMAIN
    elif base_config.environment == 'qa':
        return QA_DOMAIN
    elif base_config.environment == 'shadow':
        return SHADOW_DOMAIN
    else:
        return DEV_DOMAIN