"""
This model defines the database models to handle Celery AsyncResults.

"""
from __future__ import unicode_literals

from django.db import models
from django.utils.encoding import python_2_unicode_compatible
from django.utils.translation import ugettext as _

from gnuviechadmin.celery import app


class TaskResultManager(models.Manager):
    def create_task_result(self, creator, signature, notes=''):
        sigstr = str(signature)
        result = signature.apply_async()
        taskresult = self.create(
            task_id=result.task_id, creator=creator, signature=sigstr,
            notes=notes)
        return taskresult


@python_2_unicode_compatible
class TaskResult(models.Model):
    task_id = models.CharField(_('Task id'), max_length=36)
    signature = models.TextField(_('Task signature'))
    creator = models.TextField(_('Task creator'))
    notes = models.TextField(_('Task notes'))
    result = models.TextField(_('Task result'))
    finished = models.BooleanField(default=False)
    state = models.CharField(_('Task state'), max_length=16)

    objects = TaskResultManager()

    class Meta:
        verbose_name = _('Task result')
        verbose_name_plural = _('Task results')

    def __str__(self):
        return "{creator} ({task_id}): {finished}".format(
            creator=self.creator,
            task_id=self.task_id,
            finished=_('yes') if self.finished else _('no')
        )

    def fetch_result(self):
        if not self.finished:
            ar = app.AsyncResult(self.task_id)
            self.state = ar.state
            if ar.ready():
                res = ar.get()
                self.result = str(res)
                self.finished = True