from django.db import models
from django.utils.translation import ugettext_lazy as _
from django.core.urlresolvers import reverse
from django.conf import settings


from counter.models import Counter, ProductType

class Stock(models.Model):
    """
    The Stock class, this one is used to know how many products are left for a specific counter
    """
    name = models.CharField(_('name'), max_length=64)
    counter = models.OneToOneField(Counter, verbose_name=_('counter'), related_name='stock')

    def __str__(self):
        return "%s (%s)" % (self.name, self.counter)

    def get_absolute_url(self):
        return reverse('stock:list')

    def can_be_viewed_by(self, user):
        return user.is_in_group(settings.SITH_GROUP_COUNTER_ADMIN_ID)

class StockItem(models.Model):
    """
    The StockItem class, element of the stock
    """
    name = models.CharField(_('name'), max_length=64)
    unit_quantity = models.IntegerField(_('unit quantity'), default=0, help_text=_('number of element in one box'))
    effective_quantity = models.IntegerField(_('effective quantity'), default=0, help_text=_('number of box'))
    minimal_quantity = models.IntegerField(_('minimal quantity'), default=1,
        help_text=_('if the effective quantity is less than the minimal, item is added to the shopping list'))
    type = models.ForeignKey(ProductType, related_name="stock_items", verbose_name=_("type"), null=True, blank=True,
        on_delete=models.SET_NULL)
    stock_owner = models.ForeignKey(Stock, related_name="items")

    def __str__(self):
        return "%s" % (self.name)

    def get_absolute_url(self):
        return reverse('stock:items_list', kwargs={'stock_id':self.stock_owner.id})

    def can_be_viewed_by(self, user):
        return user.is_in_group(settings.SITH_GROUP_COUNTER_ADMIN_ID)

class ShoppingList(models.Model):
    """
    The ShoppingList class, used to make an history of the shopping lists
    """
    date = models.DateTimeField(_('date'))
    name = models.CharField(_('name'), max_length=64)
    todo = models.BooleanField(_('todo'))
    comment = models.TextField(_('comment'), null=True, blank=True)
    stock_owner = models.ForeignKey(Stock, null=True, related_name="shopping_lists")

    def __str__(self):
        return "%s (%s)" % (self.name, self.date)

    def get_absolute_url(self):
        return reverse('stock:shoppinglist_list')

    def can_be_viewed_by(self, user):
        return user.is_in_group(settings.SITH_GROUP_COUNTER_ADMIN_ID)


class ShoppingListItem(models.Model):
    """
    """
    shopping_lists = models.ManyToManyField(ShoppingList, verbose_name=_("shopping lists"), related_name="shopping_items_to_buy")
    stockitem_owner = models.ForeignKey(StockItem, related_name="shopping_item", null=True)
    name = models.CharField(_('name'), max_length=64)
    type = models.ForeignKey(ProductType, related_name="shoppinglist_items", verbose_name=_("type"), null=True, blank=True,
        on_delete=models.SET_NULL)
    tobuy_quantity = models.IntegerField(_('quantity to buy'), default=6, help_text=_("quantity to buy during the next shopping session"))
    bought_quantity = models.IntegerField(_('quantity bought'), default=0, help_text=_("quantity bought during the last shopping session"))

    def __str__(self):
        return "%s - %s" % (self.name, self.shopping_lists.first())

    def can_be_viewed_by(self, user):
        return user.is_in_group(settings.SITH_GROUP_COUNTER_ADMIN_ID)

    def get_absolute_url(self):
        return reverse('stock:shoppinglist_list')