import logging
import trollius

from autobahn.asyncio.wamp import RouterFactory, RouterSessionFactory
from autobahn.asyncio.websocket import WampWebSocketServerFactory
from autobahn.wamp import types

from aiowsgi import create_server as create_wsgi_server
from flask import Flask
from threading import Event
from trollius.coroutines import From
from datetime import timedelta

from buildman.jobutil.buildjob import BuildJob, BuildJobLoadException
from data import database
from data.queue import WorkQueue
from app import app

logger = logging.getLogger(__name__)

WORK_CHECK_TIMEOUT = 10
TIMEOUT_PERIOD_MINUTES = 20
JOB_TIMEOUT_SECONDS = 300
MINIMUM_JOB_EXTENSION = timedelta(minutes=2)

HEARTBEAT_PERIOD_SEC = 30

class BuildJobResult(object):
  """ Build job result enum """
  INCOMPLETE = 'incomplete'
  COMPLETE = 'complete'
  ERROR = 'error'

class BuilderServer(object):
  """ Server which handles both HTTP and WAMP requests, managing the full state of the build
      controller.
  """
  def __init__(self, registry_hostname, queue, build_logs, user_files, lifecycle_manager_klass,
               lifecycle_manager_config, manager_hostname):
    self._loop = None
    self._current_status = 'starting'
    self._current_components = []
    self._job_count = 0

    self._session_factory = RouterSessionFactory(RouterFactory())
    self._registry_hostname = registry_hostname
    self._queue = queue
    self._build_logs = build_logs
    self._user_files = user_files
    self._lifecycle_manager = lifecycle_manager_klass(
        self._register_component,
        self._unregister_component,
        self._job_heartbeat,
        self._job_complete,
        manager_hostname,
        HEARTBEAT_PERIOD_SEC,
    )
    self._lifecycle_manager_config = lifecycle_manager_config

    self._shutdown_event = Event()
    self._current_status = 'running'

    self._register_controller()

  def _register_controller(self):
    controller_app = Flask('controller')
    server = self

    @controller_app.route('/status')
    def status():
      return server._current_status

    self._controller_app = controller_app

  def run(self, host, websocket_port, controller_port, ssl=None):
    logger.debug('Initializing the lifecycle manager')
    self._lifecycle_manager.initialize(self._lifecycle_manager_config)

    logger.debug('Initializing all members of the event loop')
    loop = trollius.get_event_loop()

    logger.debug('Starting server on port %s, with controller on port %s', websocket_port,
                 controller_port)
    try:
      loop.run_until_complete(self._initialize(loop, host, websocket_port, controller_port, ssl))
    except KeyboardInterrupt:
      pass
    finally:
      loop.close()

  def close(self):
    logger.debug('Requested server shutdown')
    self._current_status = 'shutting_down'
    self._lifecycle_manager.shutdown()
    self._shutdown_event.wait()
    logger.debug('Shutting down server')

  def _register_component(self, realm, component_klass, **kwargs):
    """ Registers a component with the server. The component_klass must derive from
        BaseComponent.
    """
    logger.debug('Registering component with realm %s', realm)

    component = component_klass(types.ComponentConfig(realm=realm), realm=realm, **kwargs)
    component.server = self
    component.parent_manager = self._lifecycle_manager
    component.build_logs = self._build_logs
    component.user_files = self._user_files
    component.registry_hostname = self._registry_hostname

    self._current_components.append(component)
    self._session_factory.add(component)
    return component

  def _unregister_component(self, component):
    logger.debug('Unregistering component with realm %s and token %s',
                  component.builder_realm, component.expected_token)

    self._current_components.remove(component)
    self._session_factory.remove(component)

  def _job_heartbeat(self, build_job):
    self._queue.extend_processing(build_job.job_item, seconds_from_now=JOB_TIMEOUT_SECONDS,
                                  minimum_extension=MINIMUM_JOB_EXTENSION)

  def _job_complete(self, build_job, job_status):
    if job_status == BuildJobResult.INCOMPLETE:
      self._queue.incomplete(build_job.job_item, restore_retry=False, retry_after=30)
    else:
      self._queue.complete(build_job.job_item)

    self._job_count = self._job_count - 1

    if self._current_status == 'shutting_down' and not self._job_count:
      self._shutdown_event.set()

  @trollius.coroutine
  def _work_checker(self):
    while self._current_status == 'running':
      with database.CloseForLongOperation(app.config):
        yield From(trollius.sleep(WORK_CHECK_TIMEOUT))

      logger.debug('Checking for more work for %d active workers',
                   self._lifecycle_manager.num_workers())

      job_item = self._queue.get(processing_time=self._lifecycle_manager.setup_time())
      if job_item is None:
        logger.debug('No additional work found. Going to sleep for %s seconds', WORK_CHECK_TIMEOUT)
        continue

      try:
        build_job = BuildJob(job_item)
      except BuildJobLoadException as irbe:
        logger.exception(irbe)
        self._queue.incomplete(job_item, restore_retry=False)
        continue

      logger.debug('Build job found. Checking for an avaliable worker.')
      scheduled = yield From(self._lifecycle_manager.schedule(build_job))
      if scheduled:
        self._job_count = self._job_count + 1
        logger.debug('Build job scheduled. Running: %s', self._job_count)
      else:
        logger.debug('All workers are busy. Requeuing.')
        self._queue.incomplete(job_item, restore_retry=True, retry_after=0)



  @trollius.coroutine
  def _initialize(self, loop, host, websocket_port, controller_port, ssl=None):
    self._loop = loop

    # Create the WAMP server.
    transport_factory = WampWebSocketServerFactory(self._session_factory, debug_wamp=False)
    transport_factory.setProtocolOptions(failByDrop=True)

    # Initialize the controller server and the WAMP server
    create_wsgi_server(self._controller_app, loop=loop, host=host, port=controller_port, ssl=ssl)
    yield From(loop.create_server(transport_factory, host, websocket_port, ssl=ssl))

    # Initialize the work queue checker.
    yield From(self._work_checker())