bookwyrm/bookwyrm/models/status.py

""" models for storing different kinds of Activities """
from dataclasses import MISSING
import re

from django.apps import apps
from django.core.validators import MaxValueValidator, MinValueValidator
from django.db import models
from django.dispatch import receiver
from django.template.loader import get_template
from django.utils import timezone
from model_utils import FieldTracker
from model_utils.managers import InheritanceManager

from bookwyrm import activitypub
from bookwyrm.preview_images import generate_edition_preview_image_task
from bookwyrm.settings import ENABLE_PREVIEW_IMAGES
from .activitypub_mixin import ActivitypubMixin, ActivityMixin
from .activitypub_mixin import OrderedCollectionPageMixin
from .base_model import BookWyrmModel
from .fields import image_serializer
from .readthrough import ProgressMode
from . import fields


class Status(OrderedCollectionPageMixin, BookWyrmModel):
    """any post, like a reply to a review, etc"""

    user = fields.ForeignKey(
        "User", on_delete=models.PROTECT, activitypub_field="attributedTo"
    )
    content = fields.HtmlField(blank=True, null=True)
    mention_users = fields.TagField("User", related_name="mention_user")
    mention_books = fields.TagField("Edition", related_name="mention_book")
    local = models.BooleanField(default=True)
    content_warning = fields.CharField(
        max_length=500, blank=True, null=True, activitypub_field="summary"
    )
    privacy = fields.PrivacyField(max_length=255)
    sensitive = fields.BooleanField(default=False)
    # created date is different than publish date because of federated posts
    published_date = fields.DateTimeField(
        default=timezone.now, activitypub_field="published"
    )
    deleted = models.BooleanField(default=False)
    deleted_date = models.DateTimeField(blank=True, null=True)
    favorites = models.ManyToManyField(
        "User",
        symmetrical=False,
        through="Favorite",
        through_fields=("status", "user"),
        related_name="user_favorites",
    )
    reply_parent = fields.ForeignKey(
        "self",
        null=True,
        on_delete=models.PROTECT,
        activitypub_field="inReplyTo",
    )
    objects = InheritanceManager()

    activity_serializer = activitypub.Note
    serialize_reverse_fields = [("attachments", "attachment", "id")]
    deserialize_reverse_fields = [("attachments", "attachment")]

    class Meta:
        """default sorting"""

        ordering = ("-published_date",)

    def save(self, *args, **kwargs):
        """save and notify"""
        super().save(*args, **kwargs)

        notification_model = apps.get_model("bookwyrm.Notification", require_ready=True)

        if self.deleted:
            notification_model.objects.filter(related_status=self).delete()
            return

        if (
            self.reply_parent
            and self.reply_parent.user != self.user
            and self.reply_parent.user.local
        ):
            notification_model.objects.create(
                user=self.reply_parent.user,
                notification_type="REPLY",
                related_user=self.user,
                related_status=self,
            )
        for mention_user in self.mention_users.all():
            # avoid double-notifying about this status
            if not mention_user.local or (
                self.reply_parent and mention_user == self.reply_parent.user
            ):
                continue
            notification_model.objects.create(
                user=mention_user,
                notification_type="MENTION",
                related_user=self.user,
                related_status=self,
            )

    def delete(self, *args, **kwargs):  # pylint: disable=unused-argument
        """ "delete" a status"""
        if hasattr(self, "boosted_status"):
            # okay but if it's a boost really delete it
            super().delete(*args, **kwargs)
            return
        self.deleted = True
        self.deleted_date = timezone.now()
        self.save()

    @property
    def recipients(self):
        """tagged users who definitely need to get this status in broadcast"""
        mentions = [u for u in self.mention_users.all() if not u.local]
        if (
            hasattr(self, "reply_parent")
            and self.reply_parent
            and not self.reply_parent.user.local
        ):
            mentions.append(self.reply_parent.user)
        return list(set(mentions))

    @classmethod
    def ignore_activity(cls, activity):  # pylint: disable=too-many-return-statements
        """keep notes if they are replies to existing statuses"""
        if activity.type == "Announce":
            try:
                boosted = activitypub.resolve_remote_id(
                    activity.object, get_activity=True
                )
            except activitypub.ActivitySerializerError:
                # if we can't load the status, definitely ignore it
                return True
            # keep the boost if we would keep the status
            return cls.ignore_activity(boosted)

        # keep if it if it's a custom type
        if activity.type != "Note":
            return False
        # keep it if it's a reply to an existing status
        if cls.objects.filter(remote_id=activity.inReplyTo).exists():
            return False

        # keep notes if they mention local users
        if activity.tag == MISSING or activity.tag is None:
            return True
        tags = [l["href"] for l in activity.tag if l["type"] == "Mention"]
        user_model = apps.get_model("bookwyrm.User", require_ready=True)
        for tag in tags:
            if user_model.objects.filter(remote_id=tag, local=True).exists():
                # we found a mention of a known use boost
                return False
        return True

    @classmethod
    def replies(cls, status):
        """load all replies to a status. idk if there's a better way
        to write this so it's just a property"""
        return (
            cls.objects.filter(reply_parent=status)
            .select_subclasses()
            .order_by("published_date")
        )

    @property
    def status_type(self):
        """expose the type of status for the ui using activity type"""
        return self.activity_serializer.__name__

    @property
    def boostable(self):
        """you can't boost dms"""
        return self.privacy in ["unlisted", "public"]

    def to_replies(self, **kwargs):
        """helper function for loading AP serialized replies to a status"""
        return self.to_ordered_collection(
            self.replies(self),
            remote_id="%s/replies" % self.remote_id,
            collection_only=True,
            **kwargs
        ).serialize()

    def to_activity_dataclass(self, pure=False):  # pylint: disable=arguments-differ
        """return tombstone if the status is deleted"""
        if self.deleted:
            return activitypub.Tombstone(
                id=self.remote_id,
                url=self.remote_id,
                deleted=self.deleted_date.isoformat(),
                published=self.deleted_date.isoformat(),
            )
        activity = ActivitypubMixin.to_activity_dataclass(self)
        activity.replies = self.to_replies()

        # "pure" serialization for non-bookwyrm instances
        if pure and hasattr(self, "pure_content"):
            activity.content = self.pure_content
            if hasattr(activity, "name"):
                activity.name = self.pure_name
            activity.type = self.pure_type
            activity.attachment = [
                image_serializer(b.cover, b.alt_text)
                for b in self.mention_books.all()[:4]
                if b.cover
            ]
            if hasattr(self, "book") and self.book.cover:
                activity.attachment.append(
                    image_serializer(self.book.cover, self.book.alt_text)
                )
        return activity

    def to_activity(self, pure=False):  # pylint: disable=arguments-differ
        """json serialized activitypub class"""
        return self.to_activity_dataclass(pure=pure).serialize()


class GeneratedNote(Status):
    """these are app-generated messages about user activity"""

    @property
    def pure_content(self):
        """indicate the book in question for mastodon (or w/e) users"""
        message = self.content
        books = ", ".join(
            '<a href="%s">"%s"</a>' % (book.remote_id, book.title)
            for book in self.mention_books.all()
        )
        return "%s %s %s" % (self.user.display_name, message, books)

    activity_serializer = activitypub.GeneratedNote
    pure_type = "Note"


class Comment(Status):
    """like a review but without a rating and transient"""

    book = fields.ForeignKey(
        "Edition", on_delete=models.PROTECT, activitypub_field="inReplyToBook"
    )

    # this is it's own field instead of a foreign key to the progress update
    # so that the update can be deleted without impacting the status
    progress = models.IntegerField(
        validators=[MinValueValidator(0)], null=True, blank=True
    )
    progress_mode = models.CharField(
        max_length=3,
        choices=ProgressMode.choices,
        default=ProgressMode.PAGE,
        null=True,
        blank=True,
    )

    @property
    def pure_content(self):
        """indicate the book in question for mastodon (or w/e) users"""
        return '%s<p>(comment on <a href="%s">"%s"</a>)</p>' % (
            self.content,
            self.book.remote_id,
            self.book.title,
        )

    activity_serializer = activitypub.Comment
    pure_type = "Note"


class Quotation(Status):
    """like a review but without a rating and transient"""

    quote = fields.HtmlField()
    book = fields.ForeignKey(
        "Edition", on_delete=models.PROTECT, activitypub_field="inReplyToBook"
    )

    @property
    def pure_content(self):
        """indicate the book in question for mastodon (or w/e) users"""
        quote = re.sub(r"^<p>", '<p>"', self.quote)
        quote = re.sub(r"</p>$", '"</p>', quote)
        return '%s <p>-- <a href="%s">"%s"</a></p>%s' % (
            quote,
            self.book.remote_id,
            self.book.title,
            self.content,
        )

    activity_serializer = activitypub.Quotation
    pure_type = "Note"


class Review(Status):
    """a book review"""

    name = fields.CharField(max_length=255, null=True)
    book = fields.ForeignKey(
        "Edition", on_delete=models.PROTECT, activitypub_field="inReplyToBook"
    )
    rating = fields.DecimalField(
        default=None,
        null=True,
        blank=True,
        validators=[MinValueValidator(1), MaxValueValidator(5)],
        decimal_places=2,
        max_digits=3,
    )

    field_tracker = FieldTracker(fields=["rating"])

    @property
    def pure_name(self):
        """clarify review names for mastodon serialization"""
        template = get_template("snippets/generated_status/review_pure_name.html")
        return template.render(
            {"book": self.book, "rating": self.rating, "name": self.name}
        ).strip()

    @property
    def pure_content(self):
        """indicate the book in question for mastodon (or w/e) users"""
        return self.content

    activity_serializer = activitypub.Review
    pure_type = "Article"


class ReviewRating(Review):
    """a subtype of review that only contains a rating"""

    def save(self, *args, **kwargs):
        if not self.rating:
            raise ValueError("ReviewRating object must include a numerical rating")
        return super().save(*args, **kwargs)

    @property
    def pure_content(self):
        template = get_template("snippets/generated_status/rating.html")
        return template.render({"book": self.book, "rating": self.rating}).strip()

    activity_serializer = activitypub.Rating
    pure_type = "Note"


class Boost(ActivityMixin, Status):
    """boost'ing a post"""

    boosted_status = fields.ForeignKey(
        "Status",
        on_delete=models.PROTECT,
        related_name="boosters",
        activitypub_field="object",
    )
    activity_serializer = activitypub.Announce

    def save(self, *args, **kwargs):
        """save and notify"""
        # This constraint can't work as it would cross tables.
        # class Meta:
        #     unique_together = ('user', 'boosted_status')
        if (
            Boost.objects.filter(boosted_status=self.boosted_status, user=self.user)
            .exclude(id=self.id)
            .exists()
        ):
            return

        super().save(*args, **kwargs)
        if not self.boosted_status.user.local or self.boosted_status.user == self.user:
            return

        notification_model = apps.get_model("bookwyrm.Notification", require_ready=True)
        notification_model.objects.create(
            user=self.boosted_status.user,
            related_status=self.boosted_status,
            related_user=self.user,
            notification_type="BOOST",
        )

    def delete(self, *args, **kwargs):
        """delete and un-notify"""
        notification_model = apps.get_model("bookwyrm.Notification", require_ready=True)
        notification_model.objects.filter(
            user=self.boosted_status.user,
            related_status=self.boosted_status,
            related_user=self.user,
            notification_type="BOOST",
        ).delete()
        super().delete(*args, **kwargs)

    def __init__(self, *args, **kwargs):
        """the user field is "actor" here instead of "attributedTo" """
        super().__init__(*args, **kwargs)

        reserve_fields = ["user", "boosted_status", "published_date", "privacy"]
        self.simple_fields = [f for f in self.simple_fields if f.name in reserve_fields]
        self.activity_fields = self.simple_fields
        self.many_to_many_fields = []
        self.image_fields = []
        self.deserialize_reverse_fields = []

    # This constraint can't work as it would cross tables.
    # class Meta:
    #     unique_together = ('user', 'boosted_status')


# pylint: disable=unused-argument
@receiver(models.signals.post_save)
def preview_image(instance, sender, *args, **kwargs):
    """Updates book previews if the rating has changed"""
    if not ENABLE_PREVIEW_IMAGES or sender not in (Review, ReviewRating):
        return

    changed_fields = instance.field_tracker.changed()

    if len(changed_fields) > 0:
        edition = instance.book
        generate_edition_preview_image_task.delay(edition.id)