from django.core.management.base import BaseCommand, CommandError
from django.core.mail import send_mass_mail
from django.utils import timezone, translation
from django.template import Context, loader
from django.conf import settings

from edt.models import Group, Subscription, Course
from edt.utils import get_week, group_courses

import datetime


class Command(BaseCommand):
    help = "Sends emails to subscribed users"

    def handle(self, *args, **options):
        translation.activate(settings.LANGUAGE_CODE)

        year, week, day = timezone.now().isocalendar()
        if day >= 6:
            year, week, _ = (timezone.now() + datetime.timedelta(weeks=1)).isocalendar()

        start, end = get_week(year, week)

        subscriptions = Subscription.objects.filter(active=True)
        content = {}
        mails = []

        print("Generating messages...")
        for subscription in subscriptions:
            if subscription.group.id not in content:
                courses = Course.objects.get_courses_for_group(subscription.group, begin__gte=start, begin__lt=end)
                grouped_courses = group_courses(courses)

                template = loader.get_template("mail/mail_timetable.txt")
                context = Context({"subscription": subscription, "courses": grouped_courses, "week": week})
                content[subscription.group.id] = template.render(context)

            footer = loader.get_template("mail/mail_footer.txt")
            context = Context({"admins": settings.ADMINS, "token": subscription.token})
            mail_content = content[subscription.group.id] + footer.render(context)

            mails.append(("{0} - {1} - Semaine {2}".format(subscription.group.timetable.name, subscription.group.name, week), mail_content, settings.DEFAULT_FROM_EMAIL, [subscription.email],))

        print("Sending mails...")
        send_mass_mail(mails)
        self.stdout.write(self.style.SUCCESS("Done."))