from datetime import datetime
from .. import configuration as config
from .. import docker_client, Session
from ..decorators import background
from ..models import Job, JobResult, NotificationData, NotificationEmailData
import docker
import logging
import json
import os


@background
def check_jobs():
    session = Session()
    jobs = session.query(Job).all()
    for job in filter(lambda job: job.status == 'submitted', jobs):
        __create_job_service(job)
    for job in filter(lambda job: job.status == 'queued', jobs):
        __checkout_job_service(job, session)
        __add_notification_data(job, 'queued', session)
    for job in filter(lambda job: job.status == 'running', jobs):
        __checkout_job_service(job, session)
        __add_notification_data(job, 'running', session)
    for job in filter(lambda job: job.status == 'complete', jobs):
        __add_notification_data(job, 'complete', session)
    for job in filter(lambda job: job.status == 'failed', jobs):
        __add_notification_data(job, 'failed', session)
    for job in filter(lambda job: job.status == 'canceling', jobs):
        __remove_job_service(job)
    session.commit()
    Session.remove()


def __add_notification_data(job, notified_on_status, session):
    # checks if user wants any notifications at all
    if (job.user.setting_job_status_mail_notifications == 'none'):
        return
    # checks if user wants only notification on completed jobs
    elif (job.user.setting_job_status_mail_notifications == 'end'
          and notified_on_status != 'complete'):
        return
    else:
        # check if a job already has associated NotificationData
        notification_exists = len(job.notification_data)
        # create notification_data for current job if there is none
        if (notification_exists == 0):
            notification_data = NotificationData(job_id=job.id)
            session.add(notification_data)
            # If no commit job will have no NotificationData
            session.commit()
        if (job.notification_data[0].notified_on != notified_on_status):
            notification_email_data = NotificationEmailData(job_id=job.id)
            notification_email_data.notify_status = notified_on_status
            notification_email_data.creation_date = datetime.utcnow()
            job.notification_data[0].notified_on = notified_on_status
            session.add(notification_email_data)


def __create_job_service(job):
    job_dir = os.path.join(config.DATA_DIR,
                           str(job.user_id),
                           'jobs',
                           str(job.id))
    cmd = '{} -i /files -o /files/output'.format(job.service)
    if job.service == 'file-setup':
        cmd += ' -f {}'.format(job.secure_filename)
    cmd += ' --log-dir /files'
    cmd += ' --zip [{}]_{}'.format(job.service, job.secure_filename)
    cmd += ' ' + ' '.join(json.loads(job.service_args))
    service_args = {'command': cmd,
                    'constraints': ['node.role==worker'],
                    'labels': {'origin': 'nopaque',
                               'type': 'service.{}'.format(job.service),
                               'job_id': str(job.id)},
                    'mounts': [job_dir + ':/files:rw'],
                    'name': 'job_{}'.format(job.id),
                    'resources': docker.types.Resources(
                        cpu_reservation=job.n_cores * (10 ** 9),
                        mem_reservation=job.mem_mb * (10 ** 6)),
                    'restart_policy': docker.types.RestartPolicy()}
    service_image = ('gitlab.ub.uni-bielefeld.de:4567/sfb1288inf/'
                     + job.service + ':' + job.service_version)
    try:
        service = docker_client.services.get(service_args['name'])
    except docker.errors.NotFound:
        pass
    except docker.errors.DockerException:
        return
    else:
        service.remove()
    try:
        docker_client.services.create(service_image, **service_args)
    except docker.errors.DockerException:
        job.status = 'failed'
    else:
        job.status = 'queued'


def __checkout_job_service(job, session):
    service_name = 'job_{}'.format(job.id)
    try:
        service = docker_client.services.get(service_name)
    except docker.errors.NotFound:
        logging.error('__checkout_job_service({}): '.format(job.id)
                      + 'The service does not exist. '
                      + '(status: {} -> failed)'.format(job.status))
        job.status = 'failed'
        return
    except docker.errors.DockerException:
        return
    service_tasks = service.tasks()
    if not service_tasks:
        return
    task_state = service_tasks[0].get('Status').get('State')
    if job.status == 'queued' and task_state != 'pending':
        job.status = 'running'
    elif (job.status == 'running'
          and (task_state == 'complete' or task_state == 'failed')):
        service.remove()
        job.end_date = datetime.utcnow()
        job.status = task_state
        if task_state == 'complete':
            results_dir = os.path.join(config.DATA_DIR,
                                       str(job.user_id),
                                       'jobs',
                                       str(job.id),
                                       'output')
            results = filter(lambda x: x.endswith('.zip'),
                             os.listdir(results_dir))
            for result in results:
                job_result = JobResult(dir=results_dir,
                                       filename=result,
                                       job_id=job.id)
                session.add(job_result)


def __remove_job_service(job):
    service_name = 'job_{}'.format(job.id)
    try:
        service = docker_client.services.get(service_name)
    except docker.errors.NotFound:
        job.status = 'canceled'
    except docker.errors.DockerException:
        return
    else:
        service.update(mounts=None)
        service.remove()