"""
external library imports
"""
import logging

from celery.task import task
from datetime import timedelta
from time import sleep

"""
django imports
"""
from django.conf import settings
from django.contrib.auth.models import User
from django.core.mail import send_mail
from notification.engine import send_all
from notification import models as notification

"""
regluit imports
"""
from regluit.core import (
    bookloader,
    models,
    goodreads, 
    librarything
)
from regluit.core.models import Campaign
from regluit.core.signals import deadline_impending

from regluit.utils.localdatetime import now, date_today

logger = logging.getLogger(__name__)

@task 
def populate_edition(isbn):
    """given an edition this task will populate the database with additional
    information about related editions and subjects related to this edition
    """
    bookloader.add_related(isbn)
    edition=models.Edition.get_by_isbn(isbn)
    if edition:
        bookloader.add_openlibrary(edition.work)
    return edition

@task
def load_goodreads_shelf_into_wishlist(user_id, shelf_name='all', goodreads_user_id=None, max_books=None,
                                       expected_number_of_books=None):
    user=User.objects.get(id=user_id)
    return goodreads.load_goodreads_shelf_into_wishlist(user,shelf_name,goodreads_user_id,max_books, expected_number_of_books)

@task
def load_librarything_into_wishlist(user_id, lt_username, max_books=None):
    user=User.objects.get(id=user_id)
    return librarything.load_librarything_into_wishlist(user, lt_username, max_books)
    
@task
def fac(n, sleep_interval=None):
    # used to test celery task execution 
    if not(isinstance(n,int) and n >= 0):
        raise Exception("You can't calculate a factorial of %s " % (str(n)))
    if n <= 1:
        return 1
    else:
        res = 1
        for i in xrange(2,n+1):
            res = res*i
            fac.update_state(state="PROGRESS", meta={"current": i, "total": n})
            if sleep_interval is not None:
                sleep(sleep_interval)
        return res


@task
def send_mail_task(subject, message, from_email, recipient_list,
            fail_silently=False, auth_user=None, auth_password=None,
            connection=None, override_from_email=True):
    """a task to drop django.core.mail.send_mail into """
    # NOTE:  since we are currently using Amazon SES, which allows email to be sent only from validated email
    # addresses, we force from_email to be one of the validated address unless override_from_email is FALSE
    try:
        if override_from_email:
            try:
                from_email = settings.DEFAULT_FROM_EMAIL
            except:
                pass
        r= send_mail(subject, message, from_email, recipient_list, fail_silently=False, auth_user=auth_user,
                     auth_password=auth_password, connection=connection)
    except:
        r=logger.info('failed to send message:' + message)
    return r
    
#task to update the status of active campaigns
@task
def update_active_campaign_status():
    """update the status of all active campaigns -- presumed to be run at midnight Eastern time"""
    return [c.update_status(send_notice=True, ignore_deadline_for_success=True, process_transactions=True) for c in Campaign.objects.filter(status='Active') ]

@task
def emit_notifications():
    logger.info('notifications emitting' )
    return send_all()
    
@task
def report_new_ebooks(created=None):   #created= creation date
    if created:
        period = (created, created+timedelta(days=1))
    else:
        period = (date_today()-timedelta(days=1), date_today())
    works = models.Work.objects.filter(editions__ebooks__created__range = period).distinct()
    for work in works:
        notification.send_now(work.wished_by(), "wishlist_unglued_book_released", {'work':work}, True)
        
@task
def notify_ending_soon():
    c_active = Campaign.objects.filter(status='Active')
    for c in c_active:
        if c.deadline - now() < timedelta(7) and c.deadline - now() >= timedelta(6):
            """
            if the campaign is still active and there's only a week left until it closes, send reminder notification
            """
            deadline_impending.send(sender=None, campaign=c)

@task
def watermark_acq(acq):
    acq.get_watermarked()