from django.db import models
from django.utils.translation import gettext_lazy as _
from django.conf import settings
from django.urls import reverse
from mailer.mailutils import prepend_base_url
from .constants import WEEKDAYS

class Group(models.Model):
    """
    Represents one group of the association
    e.g: J1, J2, Jugendleiter, etc.
    """
    name = models.CharField(max_length=50, verbose_name=_('name'))  # e.g: J1
    description = models.TextField(verbose_name=_('description'), default='', blank=True)
    show_website = models.BooleanField(verbose_name=_('show on website'), default=False)
    year_from = models.IntegerField(verbose_name=_('lowest year'), default=2010)
    year_to = models.IntegerField(verbose_name=_('highest year'), default=2011)
    leiters = models.ManyToManyField('members.Member', verbose_name=_('youth leaders'),
                                     related_name='leited_groups', blank=True)
    weekday = models.IntegerField(verbose_name=_('week day'), choices=WEEKDAYS, null=True, blank=True)
    start_time = models.TimeField(verbose_name=_('Starting time'), null=True, blank=True)
    end_time = models.TimeField(verbose_name=_('Ending time'), null=True, blank=True)
    contact_email = models.ForeignKey('mailer.EmailAddress',
                                      verbose_name=_('Contact email'),
                                      null=True,
                                      blank=True,
                                      on_delete=models.SET_NULL)

    def __str__(self):
        """String representation"""
        return self.name

    class Meta:
        verbose_name = _('group')
        verbose_name_plural = _('groups')
        
    @property
    def sorted_members(self):
        """Returns the members of this group sorted by their last name."""
        return self.member_set.all().order_by('lastname')

    def has_time_info(self):
        # return if the group has all relevant time slot information filled
        return self.weekday and self.start_time and self.end_time

    def get_time_info(self):
        if self.has_time_info():
            return settings.GROUP_TIME_AVAILABLE_TEXT.format(weekday=WEEKDAYS[self.weekday][1],
                                                             start_time=self.start_time.strftime('%H:%M'),
                                                             end_time=self.end_time.strftime('%H:%M'))
        else:
            return ""
    
    def has_age_info(self):
        return self.year_from and self.year_to
    
    def get_age_info(self):
        if self.has_age_info():
            return _("years %(from)s to %(to)s") % {'from':self.year_from, 'to':self.year_to}
        return ""

    def get_invitation_text_template(self):
        """The text template used to invite waiters to this group. This contains
        placeholders for the name of the waiter and personalized links."""
        if self.show_website:
            group_link = '({url}) '.format(url=prepend_base_url(reverse('startpage:gruppe_detail', args=[self.name])))
        else:
            group_link = ''
        if self.has_time_info():
            group_time = self.get_time_info()
        else:
            group_time = settings.GROUP_TIME_UNAVAILABLE_TEXT.format(contact_email=self.contact_email)
        if self.has_age_info():
            group_age = self.get_age_info()
        else:
            group_age = _("no information available")

        return settings.INVITE_TEXT.format(group_time=group_time,
                                           group_name=self.name,
                                           group_age=group_age,
                                           group_link=group_link,
                                           contact_email=self.contact_email)