import logging
import boto


logger = logging.getLogger(__name__)


class NullReporter(object):
  def report(self, running_count, total_count):
    pass


class CloudWatchReporter(object):
  def __init__(self, aws_access_key, aws_secret_key, namespace, name):
    self._connection = boto.connect_cloudwatch(aws_access_key, aws_secret_key)
    self._namespace = namespace
    self._name = name

  def report(self, running_count, total_count):
    logger.debug('Worker indicated %s running count and %s total count', running_count,
                 total_count)
    need_capacity_count = total_count - running_count
    self._connection.put_metric_data(self._namespace, self._name, need_capacity_count,
                                     unit='Count')


class QueueMetrics(object):
  def __init__(self, app=None):
    self.app = app
    if app is not None:
      self.state = self.init_app(app)
    else:
      self.state = None

  def init_app(self, app):
    analytics_type = app.config.get('QUEUE_METRICS_TYPE', 'Null')

    if analytics_type == 'CloudWatch':
      access_key = app.config.get('QUEUE_METRICS_AWS_ACCESS_KEY', '')
      secret_key = app.config.get('QUEUE_METRICS_AWS_SECRET_KEY', '')
      namespace = app.config.get('QUEUE_METRICS_NAMESPACE', '')
      name = app.config.get('QUEUE_METRICS_NAME', '')
      reporter = CloudWatchReporter(access_key, secret_key, namespace, name)
    else:
      reporter = NullReporter()

    # register extension with app
    app.extensions = getattr(app, 'extensions', {})
    app.extensions['queuemetrics'] = reporter
    return reporter

  def __getattr__(self, name):
    return getattr(self.state, name, None)