import json

from peewee import JOIN_LEFT_OUTER
from datetime import timedelta, datetime

from data.database import (BuildTriggerService, RepositoryBuildTrigger, Repository, Namespace, User,
                           RepositoryBuild, BUILD_PHASE, db_for_update, db_random_func)
from data.model import (InvalidBuildTriggerException, InvalidRepositoryBuildException,
                        db_transaction, user as user_model)


PRESUMED_DEAD_BUILD_AGE = timedelta(days=15)


def update_build_trigger(trigger, config, auth_token=None):
  trigger.config = json.dumps(config or {})
  if auth_token is not None:
    trigger.auth_token = auth_token
  trigger.save()


def create_build_trigger(repo, service_name, auth_token, user, pull_robot=None, config=None):
  config = config or {}
  service = BuildTriggerService.get(name=service_name)
  trigger = RepositoryBuildTrigger.create(repository=repo, service=service,
                                          auth_token=auth_token,
                                          connected_user=user,
                                          pull_robot=pull_robot,
                                          config=json.dumps(config))
  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)
            .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 update_phase(build_uuid, phase):
  """ A function to change the phase of a build """
  with db_transaction():
    try:
      build = get_repository_build(build_uuid)
      build.phase = phase
      build.save()
      return True
    except InvalidRepositoryBuildException:
      return False


def create_cancel_build_in_queue(build, build_queue):
  """ A function to cancel a build before it leaves the queue """
  def cancel_build():
    if build.phase != BUILD_PHASE.WAITING or not build.queue_id:
      return False

    cancelled = build_queue.cancel(build.queue_id)
    if cancelled:
      # Delete the build row.
      build.delete_instance()
    return cancelled

  return cancel_build


def create_cancel_build_in_manager(build):
  """ A function to cancel the build before it starts to push """
  def cancel_build():
    return False
  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 """
  with db_transaction():
    # Reload the build for update.
    # We are loading the build for update so checks should be as quick as possible.
    try:
      build = db_for_update(RepositoryBuild.select().where(RepositoryBuild.id == build.id)).get()
    except RepositoryBuild.DoesNotExist:
      return False

    cancel_builds = [create_cancel_build_in_queue(build, build_queue),
                     create_cancel_build_in_manager(build), ]
    for cancelled in cancel_builds:
      if cancelled():
        return True

    return False


def get_archivable_build():
  presumed_dead_date = datetime.utcnow() - PRESUMED_DEAD_BUILD_AGE
  candidates = (RepositoryBuild
                .select(RepositoryBuild.id)
                .where((RepositoryBuild.phase == BUILD_PHASE.COMPLETE) |
                       (RepositoryBuild.phase == BUILD_PHASE.ERROR) |
                       (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