import os

SERVICE_ACCOUNT_TOKEN_PATH = '/var/run/secrets/kubernetes.io/serviceaccount/token'

DEFAULT_QE_NAMESPACE = 'quay-enterprise'
DEFAULT_QE_CONFIG_SECRET = 'quay-enterprise-config-secret'

# The name of the quay enterprise deployment (not config app) that is used to query & rollout
DEFAULT_QE_DEPLOYMENT_SELECTOR = 'app'


def get_k8s_namespace():
  return os.environ.get('QE_K8S_NAMESPACE', DEFAULT_QE_NAMESPACE)


class KubernetesConfig(object):
  def __init__(self, api_host='', service_account_token=SERVICE_ACCOUNT_TOKEN_PATH,
               qe_namespace=DEFAULT_QE_NAMESPACE,
               qe_config_secret=DEFAULT_QE_CONFIG_SECRET,
               qe_deployment_selector=DEFAULT_QE_DEPLOYMENT_SELECTOR):
    self.api_host = api_host
    self.qe_namespace = qe_namespace
    self.qe_config_secret = qe_config_secret
    self.qe_deployment_selector = qe_deployment_selector
    self.service_account_token = service_account_token

  @classmethod
  def from_env(cls):
    # Load the service account token from the local store.
    if not os.path.exists(SERVICE_ACCOUNT_TOKEN_PATH):
      raise Exception('Cannot load Kubernetes service account token')

    with open(SERVICE_ACCOUNT_TOKEN_PATH, 'r') as f:
      service_token = f.read()

    api_host = os.environ.get('KUBERNETES_SERVICE_HOST', '')
    port = os.environ.get('KUBERNETES_SERVICE_PORT')
    if port:
      api_host += ':' + port

    qe_namespace = get_k8s_namespace()
    qe_config_secret = os.environ.get('QE_K8S_CONFIG_SECRET', DEFAULT_QE_CONFIG_SECRET)
    qe_deployment_selector = os.environ.get('QE_DEPLOYMENT_SELECTOR', DEFAULT_QE_DEPLOYMENT_SELECTOR)

    return cls(api_host=api_host, service_account_token=service_token, qe_namespace=qe_namespace,
               qe_config_secret=qe_config_secret, qe_deployment_selector=qe_deployment_selector)