import json

from datetime import timedelta, datetime

from peewee import JOIN

from active_migration import ActiveDataMigration, ERTMigrationFlags
from data.database import (BuildTriggerService, RepositoryBuildTrigger, Repository, Namespace, User,
                           RepositoryBuild, BUILD_PHASE, db_random_func, UseThenDisconnect,
                           TRIGGER_DISABLE_REASON)
from data.model import (InvalidBuildTriggerException, InvalidRepositoryBuildException,
                        db_transaction, user as user_model, config)
from data.fields import DecryptedValue


PRESUMED_DEAD_BUILD_AGE = timedelta(days=15)
PHASES_NOT_ALLOWED_TO_CANCEL_FROM = (BUILD_PHASE.PUSHING, BUILD_PHASE.COMPLETE,
                                     BUILD_PHASE.ERROR, BUILD_PHASE.INTERNAL_ERROR)

ARCHIVABLE_BUILD_PHASES = [BUILD_PHASE.COMPLETE, BUILD_PHASE.ERROR, BUILD_PHASE.CANCELLED]


def update_build_trigger(trigger, config, auth_token=None, write_token=None):
  trigger.config = json.dumps(config or {})

  # TODO(remove-unenc): Remove legacy field.
  if auth_token is not None:
    if ActiveDataMigration.has_flag(ERTMigrationFlags.WRITE_OLD_FIELDS):
      trigger.auth_token = auth_token

    trigger.secure_auth_token = auth_token

  if write_token is not None:
    trigger.write_token = write_token

  trigger.save()


def create_build_trigger(repo, service_name, auth_token, user, pull_robot=None, config=None):
  service = BuildTriggerService.get(name=service_name)

  # TODO(remove-unenc): Remove legacy field.
  old_auth_token = None
  if ActiveDataMigration.has_flag(ERTMigrationFlags.WRITE_OLD_FIELDS):
    old_auth_token = auth_token

  secure_auth_token = DecryptedValue(auth_token) if auth_token else None
  trigger = RepositoryBuildTrigger.create(repository=repo, service=service,
                                          auth_token=old_auth_token,
                                          secure_auth_token=secure_auth_token,
                                          connected_user=user,
                                          pull_robot=pull_robot,
                                          config=json.dumps(config or {}))
  return trigger


def get_build_trigger(trigger_uuid):
  try:
    return (RepositoryBuildTrigger
            .select(RepositoryBuildTrigger, BuildTriggerService, Repository, Namespace)
            .join(BuildTriggerService)
            .switch(RepositoryBuildTrigger)
            .join(Repository)
            .join(Namespace, on=(Repository.namespace_user == Namespace.id))
            .switch(RepositoryBuildTrigger)
            .join(User, on=(RepositoryBuildTrigger.connected_user == User.id))
            .where(RepositoryBuildTrigger.uuid == trigger_uuid)
            .get())
  except RepositoryBuildTrigger.DoesNotExist:
    msg = 'No build trigger with uuid: %s' % trigger_uuid
    raise InvalidBuildTriggerException(msg)


def list_build_triggers(namespace_name, repository_name):
  return (RepositoryBuildTrigger
          .select(RepositoryBuildTrigger, BuildTriggerService, Repository)
          .join(BuildTriggerService)
          .switch(RepositoryBuildTrigger)
          .join(Repository)
          .join(Namespace, on=(Repository.namespace_user == Namespace.id))
          .where(Namespace.username == namespace_name, Repository.name == repository_name))


def list_trigger_builds(namespace_name, repository_name, trigger_uuid,
                        limit):
  return (list_repository_builds(namespace_name, repository_name, limit)
          .where(RepositoryBuildTrigger.uuid == trigger_uuid))


def get_repository_for_resource(resource_key):
  try:
    return (Repository
            .select(Repository, Namespace)
            .join(Namespace, on=(Repository.namespace_user == Namespace.id))
            .switch(Repository)
            .join(RepositoryBuild)
            .where(RepositoryBuild.resource_key == resource_key)
            .get())
  except Repository.DoesNotExist:
    return None


def _get_build_base_query():
  return (RepositoryBuild
          .select(RepositoryBuild, RepositoryBuildTrigger, BuildTriggerService, Repository,
                  Namespace, User)
          .join(Repository)
          .join(Namespace, on=(Repository.namespace_user == Namespace.id))
          .switch(RepositoryBuild)
          .join(User, JOIN.LEFT_OUTER)
          .switch(RepositoryBuild)
          .join(RepositoryBuildTrigger, JOIN.LEFT_OUTER)
          .join(BuildTriggerService, JOIN.LEFT_OUTER)
          .order_by(RepositoryBuild.started.desc()))


def get_repository_build(build_uuid):
  try:
    return _get_build_base_query().where(RepositoryBuild.uuid == build_uuid).get()

  except RepositoryBuild.DoesNotExist:
    msg = 'Unable to locate a build by id: %s' % build_uuid
    raise InvalidRepositoryBuildException(msg)


def list_repository_builds(namespace_name, repository_name, limit,
                           include_inactive=True, since=None):
  query = (_get_build_base_query()
           .where(Repository.name == repository_name, Namespace.username == namespace_name)
           .limit(limit))

  if since is not None:
    query = query.where(RepositoryBuild.started >= since)

  if not include_inactive:
    query = query.where(RepositoryBuild.phase != BUILD_PHASE.ERROR,
                        RepositoryBuild.phase != BUILD_PHASE.COMPLETE)

  return query


def get_recent_repository_build(namespace_name, repository_name):
  query = list_repository_builds(namespace_name, repository_name, 1)
  try:
    return query.get()
  except RepositoryBuild.DoesNotExist:
    return None


def create_repository_build(repo, access_token, job_config_obj, dockerfile_id,
                            display_name, trigger=None, pull_robot_name=None):
  pull_robot = None
  if pull_robot_name:
    pull_robot = user_model.lookup_robot(pull_robot_name)

  return RepositoryBuild.create(repository=repo, access_token=access_token,
                                job_config=json.dumps(job_config_obj),
                                display_name=display_name, trigger=trigger,
                                resource_key=dockerfile_id,
                                pull_robot=pull_robot)


def get_pull_robot_name(trigger):
  if not trigger.pull_robot:
    return None

  return trigger.pull_robot.username


def _get_build_row(build_uuid):
  return RepositoryBuild.select().where(RepositoryBuild.uuid == build_uuid).get()


def update_phase_then_close(build_uuid, phase):
  """ A function to change the phase of a build """
  with UseThenDisconnect(config.app_config):
    try:
      build = _get_build_row(build_uuid)
    except RepositoryBuild.DoesNotExist:
      return False

    # Can't update a cancelled build
    if build.phase == BUILD_PHASE.CANCELLED:
      return False

    updated = (RepositoryBuild
               .update(phase=phase)
               .where(RepositoryBuild.id == build.id, RepositoryBuild.phase == build.phase)
               .execute())

    return updated > 0


def create_cancel_build_in_queue(build_phase, build_queue_id, build_queue):
  """ A function to cancel a build before it leaves the queue """

  def cancel_build():
    cancelled = False

    if build_queue_id is not None:
      cancelled = build_queue.cancel(build_queue_id)

    if build_phase != BUILD_PHASE.WAITING:
      return False

    return cancelled

  return cancel_build


def create_cancel_build_in_manager(build_phase, build_uuid, build_canceller):
  """ A function to cancel the build before it starts to push """

  def cancel_build():
    if build_phase in PHASES_NOT_ALLOWED_TO_CANCEL_FROM:
      return False

    return build_canceller.try_cancel_build(build_uuid)

  return cancel_build


def cancel_repository_build(build, build_queue):
  """ This tries to cancel the build returns true if request is successful false
      if it can't be cancelled """
  from app import build_canceller
  from buildman.jobutil.buildjob import BuildJobNotifier

  cancel_builds = [create_cancel_build_in_queue(build.phase, build.queue_id, build_queue),
                   create_cancel_build_in_manager(build.phase, build.uuid, build_canceller), ]
  for cancelled in cancel_builds:
    if cancelled():
      updated = update_phase_then_close(build.uuid, BUILD_PHASE.CANCELLED)
      if updated:
        BuildJobNotifier(build.uuid).send_notification("build_cancelled")

      return updated

  return False


def get_archivable_build():
  presumed_dead_date = datetime.utcnow() - PRESUMED_DEAD_BUILD_AGE

  candidates = (RepositoryBuild
                .select(RepositoryBuild.id)
                .where((RepositoryBuild.phase << ARCHIVABLE_BUILD_PHASES) |
                       (RepositoryBuild.started < presumed_dead_date),
                       RepositoryBuild.logs_archived == False)
                .limit(50)
                .alias('candidates'))

  try:
    found_id = (RepositoryBuild
                .select(candidates.c.id)
                .from_(candidates)
                .order_by(db_random_func())
                .get())
    return RepositoryBuild.get(id=found_id)
  except RepositoryBuild.DoesNotExist:
    return None


def mark_build_archived(build_uuid):
  """ Mark a build as archived, and return True if we were the ones who actually
      updated the row. """
  return (RepositoryBuild
          .update(logs_archived=True)
          .where(RepositoryBuild.uuid == build_uuid,
                  RepositoryBuild.logs_archived == False)
          .execute()) > 0


def toggle_build_trigger(trigger, enabled, reason=TRIGGER_DISABLE_REASON.USER_TOGGLED):
  """ Toggles the enabled status of a build trigger. """
  trigger.enabled = enabled

  if not enabled:
    trigger.disabled_reason = RepositoryBuildTrigger.disabled_reason.get_id(reason)
    trigger.disabled_datetime = datetime.utcnow()

  trigger.save()


def update_trigger_disable_status(trigger, final_phase):
  """ Updates the disable status of the given build trigger. If the build trigger had a
      failure, then the counter is increased and, if we've reached the limit, the trigger is
      automatically disabled. Otherwise, if the trigger succeeded, it's counter is reset. This
      ensures that triggers that continue to error are eventually automatically disabled.
  """
  with db_transaction():
    try:
      trigger = RepositoryBuildTrigger.get(id=trigger.id)
    except RepositoryBuildTrigger.DoesNotExist:
      # Already deleted.
      return

    # If the build completed successfully, then reset the successive counters.
    if final_phase == BUILD_PHASE.COMPLETE:
      trigger.successive_failure_count = 0
      trigger.successive_internal_error_count = 0
      trigger.save()
      return

    # Otherwise, increment the counters and check for trigger disable.
    if final_phase == BUILD_PHASE.ERROR:
      trigger.successive_failure_count = trigger.successive_failure_count + 1
      trigger.successive_internal_error_count = 0
    elif final_phase == BUILD_PHASE.INTERNAL_ERROR:
      trigger.successive_internal_error_count = trigger.successive_internal_error_count + 1

    # Check if we need to disable the trigger.    
    failure_threshold = config.app_config.get('SUCCESSIVE_TRIGGER_FAILURE_DISABLE_THRESHOLD')
    error_threshold = config.app_config.get('SUCCESSIVE_TRIGGER_INTERNAL_ERROR_DISABLE_THRESHOLD')

    if failure_threshold and trigger.successive_failure_count >= failure_threshold:
      toggle_build_trigger(trigger, False, TRIGGER_DISABLE_REASON.BUILD_FALURES)
    elif (error_threshold and
          trigger.successive_internal_error_count >= error_threshold):
      toggle_build_trigger(trigger, False, TRIGGER_DISABLE_REASON.INTERNAL_ERRORS)
    else:
      # Save the trigger changes.
      trigger.save()