"""Tasks for the chartmetric_monitor SWF workflow."""

import backoff
import datadog
from datadog.api import exceptions
from garcon import task
from snowflake.connector.errors import ProgrammingError
from snowflake_connector.etl_connector import SnowflakeSQLExecutor, SQLLoader

from swf_monitoring.flows.chartmetric_monitor import config

sqlloader = SQLLoader(__file__)


@backoff.on_exception(
    backoff.expo,
    (exceptions.ProxyError, exceptions.HTTPError,
     exceptions.HttpBackoff, exceptions.HttpTimeout))
def _send_event(event):
    """Send an event using backoff/retry decorator.

    Args:
        event (dict): An event to send.

    """
    res = datadog.api.Event.create(
        title=event['title'],
        text=event['text'],
        tags=event['tags'],
        alert_type='warning')
    if res.get('status') != 'ok':
        raise exceptions.HttpBackoff(5)  # will be handled by backoff


@task.decorate(timeout=60 * 15)
def check_tables(activity):
    """Populate shared_tables_stability table.

    And send an event to Datadog on each error.
    """
    datadog.initialize(**{'api_key': config.DATADOG_API_KEY})

    activity.logger.info('Populating shared_tables_stability table...')

    for table_name in config.TABLES_TO_MONITOR:
        params = {
            'db': config.SF_CONFIG['db'],
            'schema': config.SF_CONFIG['schema'],
            'database_name': config.TABLES_TO_MONITOR[table_name]['db'],
            'schema_name': config.TABLES_TO_MONITOR[table_name]['schema'],
            'table_name': table_name
        }

        with SnowflakeSQLExecutor(config.SF_CONFIG) as executor:
            try:
                executor.fetchone_query(sqlloader, 'insert_row_count', params)
            except ProgrammingError:
                with SnowflakeSQLExecutor(
                        config.SF_CONFIG) as executor:
                    activity.logger.info('Table {} is gone'.format(table_name))
                    executor.fetchall_query(
                        sqlloader, 'insert_row_count_error', params)
                    event = {
                        'title': 'CHARTMETRIC shared table '
                                 '{table_name} is gone'.format(
                                    table_name=table_name),
                        'text':
                            'Table {database_name}.{schema_name}.{table_name} '
                            'is not available'.format(
                                table_name=table_name,
                                database_name=config.TABLES_TO_MONITOR[
                                    table_name]['db'],
                                schema_name=config.TABLES_TO_MONITOR[
                                    table_name]['schema']),
                        'tags': ['chartmetric', 'swf_monitoring']
                    }
                    _send_event(event)
                    activity.logger.info(
                        'A warning about table {} sent to Datadog!'.format(
                            table_name))

            activity.logger.info('Check for {} finished'.format(table_name))

    activity.logger.info('All done!')