255 lines
9.8 KiB
Python
255 lines
9.8 KiB
Python
from django.db import models
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from django.core.exceptions import ValidationError
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from django.db.models import Q
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import hashlib
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from cards.models import Card
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from accounts.models import FriendCode
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class TradeOffer(models.Model):
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id = models.AutoField(primary_key=True)
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manually_closed = models.BooleanField(default=False)
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hash = models.CharField(max_length=8, editable=False)
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initiated_by = models.ForeignKey(
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"accounts.FriendCode",
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on_delete=models.PROTECT,
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related_name='initiated_trade_offers'
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)
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# Use custom through models to support multiples.
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want_cards = models.ManyToManyField(
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"cards.Card",
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related_name='trade_offers_want',
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through="TradeOfferWantCard"
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)
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have_cards = models.ManyToManyField(
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"cards.Card",
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related_name='trade_offers_have',
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through="TradeOfferHaveCard"
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)
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created_at = models.DateTimeField(auto_now_add=True)
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updated_at = models.DateTimeField(auto_now=True)
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def __str__(self):
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want_names = ", ".join([x.name for x in self.want_cards.all()])
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have_names = ", ".join([x.name for x in self.have_cards.all()])
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return f"Want: {want_names} -> Have: {have_names}"
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def save(self, *args, **kwargs):
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is_new = self.pk is None
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super().save(*args, **kwargs)
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if is_new and not self.hash:
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self.hash = hashlib.md5(str(self.id).encode('utf-8')).hexdigest()[:8]
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super().save(update_fields=["hash"])
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@property
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def is_closed(self):
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if self.manually_closed:
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return True
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from .models import TradeAcceptance # local import to avoid circular dependencies
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active_states = [
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TradeAcceptance.AcceptanceState.ACCEPTED,
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TradeAcceptance.AcceptanceState.SENT,
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TradeAcceptance.AcceptanceState.RECEIVED,
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TradeAcceptance.AcceptanceState.COMPLETED
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]
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closed_have = True
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for through_obj in self.trade_offer_have_cards.all():
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accepted_count = self.acceptances.filter(
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requested_card=through_obj.card,
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state__in=active_states
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).count()
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if accepted_count < through_obj.quantity:
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closed_have = False
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break
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closed_want = True
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for through_obj in self.trade_offer_want_cards.all():
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accepted_count = self.acceptances.filter(
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offered_card=through_obj.card,
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state__in=active_states
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).count()
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if accepted_count < through_obj.quantity:
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closed_want = False
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break
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return closed_have or closed_want
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class TradeOfferHaveCard(models.Model):
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"""
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Through model for TradeOffer.have_cards.
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Represents the card the initiator is offering along with the quantity available.
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"""
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trade_offer = models.ForeignKey(
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TradeOffer,
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on_delete=models.CASCADE,
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related_name='trade_offer_have_cards'
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)
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card = models.ForeignKey("cards.Card", on_delete=models.PROTECT)
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quantity = models.PositiveIntegerField(default=1)
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def __str__(self):
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return f"{self.card.name} x{self.quantity} (Have side for offer {self.trade_offer.hash})"
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class Meta:
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unique_together = ("trade_offer", "card")
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class TradeOfferWantCard(models.Model):
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"""
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Through model for TradeOffer.want_cards.
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Represents the card the initiator is requesting along with the quantity requested.
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"""
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trade_offer = models.ForeignKey(
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TradeOffer,
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on_delete=models.CASCADE,
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related_name='trade_offer_want_cards'
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)
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card = models.ForeignKey("cards.Card", on_delete=models.PROTECT)
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quantity = models.PositiveIntegerField(default=1)
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def __str__(self):
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return f"{self.card.name} x{self.quantity} (Want side for offer {self.trade_offer.hash})"
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class Meta:
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unique_together = ("trade_offer", "card")
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class TradeAcceptance(models.Model):
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class AcceptanceState(models.TextChoices):
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ACCEPTED = 'ACCEPTED', 'Accepted'
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SENT = 'SENT', 'Sent'
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RECEIVED = 'RECEIVED', 'Received'
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COMPLETED = 'COMPLETED', 'Completed'
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REJECTED_BY_INITIATOR = 'REJECTED_BY_INITIATOR', 'Rejected by Initiator'
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REJECTED_BY_ACCEPTOR = 'REJECTED_BY_ACCEPTOR', 'Rejected by Acceptor'
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trade_offer = models.ForeignKey(
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TradeOffer,
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on_delete=models.CASCADE,
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related_name='acceptances'
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)
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accepted_by = models.ForeignKey(
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"accounts.FriendCode",
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on_delete=models.PROTECT,
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related_name='trade_acceptances'
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)
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# The acceptor selects one card the initiator is offering (from have_cards)
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requested_card = models.ForeignKey(
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"cards.Card",
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on_delete=models.PROTECT,
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related_name='accepted_requested'
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)
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# And one card from the initiator's wanted cards (from want_cards)
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offered_card = models.ForeignKey(
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"cards.Card",
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on_delete=models.PROTECT,
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related_name='accepted_offered'
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)
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state = models.CharField(
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max_length=25,
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choices=AcceptanceState.choices,
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default=AcceptanceState.ACCEPTED
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)
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created_at = models.DateTimeField(auto_now_add=True)
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updated_at = models.DateTimeField(auto_now=True)
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def clean(self):
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"""
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Validate that:
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- The requested_card is associated with the trade offer's have_cards (via the through model).
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- The offered_card is associated with the trade offer's want_cards (via the through model).
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- The trade offer is not already closed.
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- The total number of active acceptances for each chosen card does not exceed the available quantity.
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"""
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# Validate that requested_card is in trade_offer.have_cards
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try:
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have_through_obj = self.trade_offer.trade_offer_have_cards.get(card=self.requested_card)
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except TradeOfferHaveCard.DoesNotExist:
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raise ValidationError("The requested card must be one of the trade offer's available cards (have_cards).")
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# Validate that offered_card is in trade_offer.want_cards
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try:
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want_through_obj = self.trade_offer.trade_offer_want_cards.get(card=self.offered_card)
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except TradeOfferWantCard.DoesNotExist:
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raise ValidationError("The offered card must be one of the trade offer's requested cards (want_cards).")
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# For new acceptances, do not allow creation if the trade offer is closed.
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if not self.pk and self.trade_offer.is_closed:
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raise ValidationError("This trade offer is closed. No more acceptances are allowed.")
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active_states = [
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self.AcceptanceState.ACCEPTED,
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self.AcceptanceState.SENT,
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self.AcceptanceState.RECEIVED,
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self.AcceptanceState.COMPLETED,
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]
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active_acceptances = self.trade_offer.acceptances.filter(state__in=active_states)
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if self.pk:
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active_acceptances = active_acceptances.exclude(pk=self.pk)
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# Count active acceptances for the requested card.
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requested_count = active_acceptances.filter(requested_card=self.requested_card).count()
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if requested_count >= have_through_obj.quantity:
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raise ValidationError("This requested card has been fully accepted.")
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# Count active acceptances for the offered card.
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offered_count = active_acceptances.filter(offered_card=self.offered_card).count()
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if offered_count >= want_through_obj.quantity:
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raise ValidationError("This offered card has already been fully used.")
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def update_state(self, new_state):
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"""
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Update the trade acceptance state.
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Allowed transitions:
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- ACCEPTED -> SENT
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- SENT -> RECEIVED
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- RECEIVED -> COMPLETED
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Additionally, from any active state a transition to:
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REJECTED_BY_INITIATOR or REJECTED_BY_ACCEPTOR is allowed.
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Once in COMPLETED or any rejection state, no further transitions are allowed.
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"""
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if new_state not in [choice[0] for choice in self.AcceptanceState.choices]:
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raise ValueError(f"'{new_state}' is not a valid state.")
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# Terminal states: no further transitions allowed.
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if self.state in [
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self.AcceptanceState.COMPLETED,
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self.AcceptanceState.REJECTED_BY_INITIATOR,
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self.AcceptanceState.REJECTED_BY_ACCEPTOR
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]:
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raise ValueError(f"No transitions allowed from the terminal state '{self.state}'.")
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allowed_transitions = {
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self.AcceptanceState.ACCEPTED: {
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self.AcceptanceState.SENT,
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self.AcceptanceState.REJECTED_BY_INITIATOR,
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self.AcceptanceState.REJECTED_BY_ACCEPTOR,
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},
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self.AcceptanceState.SENT: {
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self.AcceptanceState.RECEIVED,
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self.AcceptanceState.REJECTED_BY_INITIATOR,
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self.AcceptanceState.REJECTED_BY_ACCEPTOR,
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},
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self.AcceptanceState.RECEIVED: {
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self.AcceptanceState.COMPLETED,
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self.AcceptanceState.REJECTED_BY_INITIATOR,
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self.AcceptanceState.REJECTED_BY_ACCEPTOR,
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},
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}
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if new_state not in allowed_transitions.get(self.state, {}):
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raise ValueError(f"Transition from {self.state} to {new_state} is not allowed.")
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self.state = new_state
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self.save(update_fields=["state"])
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def __str__(self):
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return (f"TradeAcceptance(offer_hash={self.trade_offer.hash}, "
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f"accepted_by={self.accepted_by}, "
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f"requested_card={self.requested_card}, "
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f"offered_card={self.offered_card}, state={self.state})")
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class Meta:
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# Unique constraints have been removed because validations now allow
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# multiple active acceptances per card based on the available quantity.
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pass
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