OpenSlides/server/openslides/poll/models.py

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 ..core.config import config
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

    def get_votes(self):
        """
        Return a QuerySet with all vote objects related to this option.
        """
        return self.get_vote_class().objects.filter(option=self)

    def pseudoanonymize(self):
        for vote in self.get_votes():
            vote.user = None
            vote.save()

    def reset(self):
        # 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 self because the changed voted relation
        inform_changed_data(self)


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, "nominal"),
        (TYPE_PSEUDOANONYMOUS, "non-nominal"),
    )
    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"),
        (PERCENT_BASE_YNA, "Yes/No/Abstain"),
        (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.amount_users_voted_with_individual_weight())

    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.amount_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 amount_users_voted(self):
        return len(self.voted.all())

    def amount_users_voted_with_individual_weight(self):
        if config["users_activate_vote_weight"]:
            return sum(user.vote_weight for user in self.voted.all())
        else:
            return self.amount_users_voted()

    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

    def get_options(self):
        """
        Returns the option objects for the poll.
        """
        return self.options.all()

    @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 option in self.get_options():
            option.pseudoanonymize()

    def reset(self):
        for option in self.get_options():
            option.reset()

        self.voted.clear()

        # Reset state
        self.state = BasePoll.STATE_CREATED
        if self.type == self.TYPE_ANALOG:
            self.votesvalid = None
            self.votesinvalid = None
            self.votescast = None
        self.save()