from django.core.exceptions import ValidationError
from django.db.models.signals import m2m_changed, post_save, post_delete
from django.dispatch import receiver
from .models import TradeOffer
from cards.models import Card
from trades.models import TradeOfferHaveCard, TradeOfferWantCard, TradeAcceptance

def check_trade_offer_rarity(instance):
    combined_cards = list(instance.have_cards.all()) + list(instance.want_cards.all())
    # Use the normalized rarity from each card
    rarities = {card.normalized_rarity for card in combined_cards}
    if len(rarities) > 1:
        raise ValidationError("All cards in a trade offer must have the same rarity.")

@receiver(m2m_changed, sender=TradeOffer.have_cards.through)
def validate_have_cards_rarity(sender, instance, action, **kwargs):
    if action == "post_add":
        check_trade_offer_rarity(instance)

@receiver(m2m_changed, sender=TradeOffer.want_cards.through)
def validate_want_cards_rarity(sender, instance, action, **kwargs):
    if action == "post_add":
        check_trade_offer_rarity(instance)

@receiver(post_save, sender=TradeOfferHaveCard)
@receiver(post_delete, sender=TradeOfferHaveCard)
def update_aggregates_from_have_card(sender, instance, **kwargs):
    trade_offer = instance.trade_offer
    if trade_offer and hasattr(trade_offer, 'update_aggregates'):
        trade_offer.update_aggregates()

@receiver(post_save, sender=TradeOfferWantCard)
@receiver(post_delete, sender=TradeOfferWantCard)
def update_aggregates_from_want_card(sender, instance, **kwargs):
    trade_offer = instance.trade_offer
    if trade_offer and hasattr(trade_offer, 'update_aggregates'):
        trade_offer.update_aggregates()

@receiver(post_save, sender=TradeAcceptance)
@receiver(post_delete, sender=TradeAcceptance)
def update_aggregates_from_acceptance(sender, instance, **kwargs):
    trade_offer = instance.trade_offer
    if trade_offer and hasattr(trade_offer, 'update_aggregates'):
        trade_offer.update_aggregates()