from decimal import Decimal from typing import Iterable, Optional, Tuple, Type from django.conf import settings from django.core.validators import MinValueValidator from django.db import models from ..utils.autoupdate import inform_changed_data, inform_deleted_data from ..utils.models import SET_NULL_AND_AUTOUPDATE class BaseVote(models.Model): """ All subclasses must have option attribute with the related name "votes" """ weight = models.DecimalField( default=Decimal("1"), validators=[MinValueValidator(Decimal("-2"))], max_digits=15, decimal_places=6, ) value = models.CharField(max_length=1, choices=(("Y", "Y"), ("N", "N"), ("A", "A"))) user = models.ForeignKey( settings.AUTH_USER_MODEL, default=None, null=True, blank=True, on_delete=SET_NULL_AND_AUTOUPDATE, ) class Meta: abstract = True class BaseOption(models.Model): """ All subclasses must have poll attribute with the related name "options" """ vote_class: Optional[Type["BaseVote"]] = None class Meta: abstract = True @property def yes(self) -> Decimal: return self.sum_weight("Y") @property def no(self) -> Decimal: return self.sum_weight("N") @property def abstain(self) -> Decimal: return self.sum_weight("A") def sum_weight(self, value): # We could do this in a nice .aggregate(Sum...) querystatement, # but these might be expensive DB queries, because they are not preloaded. # With this in-logic-counting, we operate inmemory. weight_sum = Decimal(0) for vote in self.votes.all(): if vote.value == value: weight_sum += vote.weight return weight_sum @classmethod def get_vote_class(cls): if cls.vote_class is None: raise NotImplementedError( f"The option class {cls} has to have an attribute vote_class." ) return cls.vote_class class BasePoll(models.Model): option_class: Optional[Type["BaseOption"]] = None STATE_CREATED = 1 STATE_STARTED = 2 STATE_FINISHED = 3 STATE_PUBLISHED = 4 STATES = ( (STATE_CREATED, "Created"), (STATE_STARTED, "Started"), (STATE_FINISHED, "Finished"), (STATE_PUBLISHED, "Published"), ) state = models.IntegerField(choices=STATES, default=STATE_CREATED) TYPE_ANALOG = "analog" TYPE_NAMED = "named" TYPE_PSEUDOANONYMOUS = "pseudoanonymous" TYPES = ( (TYPE_ANALOG, "Analog"), (TYPE_NAMED, "Named"), (TYPE_PSEUDOANONYMOUS, "Pseudoanonymous"), ) type = models.CharField(max_length=64, blank=False, null=False, choices=TYPES) title = models.CharField(max_length=255, blank=True, null=False) groups = models.ManyToManyField(settings.AUTH_GROUP_MODEL, blank=True) voted = models.ManyToManyField(settings.AUTH_USER_MODEL, blank=True) db_votesvalid = models.DecimalField( null=True, blank=True, validators=[MinValueValidator(Decimal("-2"))], max_digits=15, decimal_places=6, ) db_votesinvalid = models.DecimalField( null=True, blank=True, validators=[MinValueValidator(Decimal("-2"))], max_digits=15, decimal_places=6, ) db_votescast = models.DecimalField( null=True, blank=True, validators=[MinValueValidator(Decimal("-2"))], max_digits=15, decimal_places=6, ) PERCENT_BASE_YN = "YN" PERCENT_BASE_YNA = "YNA" PERCENT_BASE_VALID = "valid" PERCENT_BASE_CAST = "cast" PERCENT_BASE_DISABLED = "disabled" PERCENT_BASES: Iterable[Tuple[str, str]] = ( (PERCENT_BASE_YN, "Yes/No per candidate"), (PERCENT_BASE_YNA, "Yes/No/Abstain per candidate"), (PERCENT_BASE_VALID, "All valid ballots"), (PERCENT_BASE_CAST, "All casted ballots"), (PERCENT_BASE_DISABLED, "Disabled (no percents)"), ) # type: ignore onehundred_percent_base = models.CharField( max_length=8, blank=False, null=False, choices=PERCENT_BASES ) MAJORITY_SIMPLE = "simple" MAJORITY_TWO_THIRDS = "two_thirds" MAJORITY_THREE_QUARTERS = "three_quarters" MAJORITY_DISABLED = "disabled" MAJORITY_METHODS = ( (MAJORITY_SIMPLE, "Simple majority"), (MAJORITY_TWO_THIRDS, "Two-thirds majority"), (MAJORITY_THREE_QUARTERS, "Three-quarters majority"), (MAJORITY_DISABLED, "Disabled"), ) majority_method = models.CharField( max_length=14, blank=False, null=False, choices=MAJORITY_METHODS ) class Meta: abstract = True def get_votesvalid(self): if self.type == self.TYPE_ANALOG: return self.db_votesvalid else: return Decimal(self.count_users_voted()) def set_votesvalid(self, value): if self.type != self.TYPE_ANALOG: raise ValueError("Do not set votesvalid for non analog polls") self.db_votesvalid = value votesvalid = property(get_votesvalid, set_votesvalid) def get_votesinvalid(self): if self.type == self.TYPE_ANALOG: return self.db_votesinvalid else: return Decimal(0) def set_votesinvalid(self, value): if self.type != self.TYPE_ANALOG: raise ValueError("Do not set votesinvalid for non analog polls") self.db_votesinvalid = value votesinvalid = property(get_votesinvalid, set_votesinvalid) def get_votescast(self): if self.type == self.TYPE_ANALOG: return self.db_votescast else: return Decimal(self.count_users_voted()) def set_votescast(self, value): if self.type != self.TYPE_ANALOG: raise ValueError("Do not set votescast for non analog polls") self.db_votescast = value votescast = property(get_votescast, set_votescast) def count_users_voted(self): return self.voted.all().count() def get_options(self): """ Returns the option objects for the poll. """ return self.get_option_class().objects.filter(poll=self) def create_options(self): """ Should be called after creation of this model. """ raise NotImplementedError() @classmethod def get_option_class(cls): if cls.option_class is None: raise NotImplementedError( f"The poll class {cls} has to have an attribute option_class." ) return cls.option_class @classmethod def get_vote_class(cls): return cls.get_option_class().get_vote_class() def get_votes(self): """ Return a QuerySet with all vote objects related to this poll. """ return self.get_vote_class().objects.filter(option__poll__id=self.id) def pseudoanonymize(self): for vote in self.get_votes(): vote.user = None vote.save() def reset(self): self.voted.clear() # Delete votes votes = self.get_votes() votes_id = [vote.id for vote in votes] votes.delete() collection = self.get_vote_class().get_collection_string() inform_deleted_data((collection, id) for id in votes_id) # update options inform_changed_data(self.get_options()) # Reset state self.state = BasePoll.STATE_CREATED if self.type == self.TYPE_ANALOG: self.votesvalid = None self.votesinvalid = None self.votescast = None self.save()