models.py

from django.conf import settings
from django.contrib.contenttypes.fields import GenericForeignKey
from django.contrib.contenttypes.models import ContentType
from django.db import models
from django.db.models import Case, When, Value
from django.db.models.functions import Concat

from .options import MESSAGES


COMMENT = 'comment'
ACTION = 'action'

ACTIVITY_TYPES = {
    COMMENT: 'Comment',
    ACTION: 'Action',
}
PRIVATE = 'private'
PUBLIC = 'public'
REVIEWER = 'reviewers'
INTERNAL = 'internal'


VISIBILILTY_HELP_TEXT = {
    PRIVATE: 'Visible to applicant and staff.',
    REVIEWER: 'Visible to reviewers and staff.',
    INTERNAL: 'Visible only to staff.',
    PUBLIC: 'Visible to all users of the application system.',
}


VISIBILITY = {
    PRIVATE: 'Private',
    REVIEWER: 'Reviewers and Staff',
    INTERNAL: 'Internal',
    PUBLIC: 'Public',
}


class BaseActivityQuerySet(models.QuerySet):
    def visible_to(self, user):
        return self.filter(visibility__in=self.model.visibility_for(user))

    def newer(self, activity):
        return self.filter(timestamp__gt=activity.timestamp)


class ActivityQuerySet(BaseActivityQuerySet):
    def comments(self):
        return self.filter(type=COMMENT)

    def actions(self):
        return self.filter(type=ACTION)


class ActivityBaseManager(models.Manager):
    def create(self, **kwargs):
        kwargs.update(type=self.type)
        return super().create(**kwargs)

    def get_queryset(self):
        return super().get_queryset().filter(
            type=self.type,
            current=True,
        )


class CommentQueryset(BaseActivityQuerySet):
    pass


class CommentManger(ActivityBaseManager):
    type = COMMENT


class ActionQueryset(BaseActivityQuerySet):
    pass


class ActionManager(ActivityBaseManager):
    type = ACTION


class Activity(models.Model):
    timestamp = models.DateTimeField()
    type = models.CharField(choices=ACTIVITY_TYPES.items(), max_length=30)
    user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.PROTECT)
    submission = models.ForeignKey('funds.ApplicationSubmission', related_name='activities', on_delete=models.CASCADE)
    message = models.TextField()
    visibility = models.CharField(choices=list(VISIBILITY.items()), default=PUBLIC, max_length=10)

    # Fields for handling versioning of the comment activity models
    edited = models.DateTimeField(default=None, null=True)
    current = models.BooleanField(default=True)
    previous = models.ForeignKey("self", on_delete=models.CASCADE, null=True)

    # Fields for generic relations to other objects. related_object should implement `get_absolute_url`
    content_type = models.ForeignKey(ContentType, blank=True, null=True, on_delete=models.CASCADE)
    object_id = models.PositiveIntegerField(blank=True, null=True)
    related_object = GenericForeignKey('content_type', 'object_id')

    objects = models.Manager.from_queryset(ActivityQuerySet)()
    comments = CommentManger.from_queryset(CommentQueryset)()
    actions = ActionManager.from_queryset(ActionQueryset)()

    class Meta:
        ordering = ['-timestamp']
        base_manager_name = 'objects'

    @property
    def priviledged(self):
        # Not visible to applicant
        return self.visibility not in [PUBLIC, PRIVATE]

    @property
    def private(self):
        # not visible to all
        return self.visibility not in [PUBLIC]

    def __str__(self):
        return '{}: for "{}"'.format(self.get_type_display(), self.submission)

    @classmethod
    def visibility_for(cls, user):
        if user.is_apply_staff:
            return [PRIVATE, REVIEWER, INTERNAL, PUBLIC]
        if user.is_reviewer:
            return [REVIEWER, PUBLIC]
        return [PRIVATE, PUBLIC]

    @classmethod
    def visibility_choices_for(cls, user):
        return [(choice, VISIBILITY[choice]) for choice in cls.visibility_for(user)]


class Event(models.Model):
    """Model to track when messages are triggered"""

    when = models.DateTimeField(auto_now_add=True)
    type = models.CharField(choices=MESSAGES.choices(), max_length=50)
    by = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.PROTECT)
    submission = models.ForeignKey('funds.ApplicationSubmission', related_name='+', on_delete=models.CASCADE)

    def __str__(self):
        return ' '.join([self.get_type_display(), 'by:', str(self.by), 'on:', self.submission.title])


class MessagesQueryset(models.QuerySet):
    def update_status(self, status):
        if status:
            return self.update(
                status=Case(
                    When(status='', then=Value(status)),
                    default=Concat('status', Value('<br />' + status))
                )
            )

    update_status.queryset_only = True


class Message(models.Model):
    """Model to track content of messages sent from an event"""

    type = models.CharField(max_length=15)
    content = models.TextField()
    recipient = models.CharField(max_length=250)
    event = models.ForeignKey(Event, on_delete=models.CASCADE)
    status = models.TextField()
    external_id = models.CharField(max_length=75, null=True, blank=True)  # Stores the id of the object from an external system

    objects = MessagesQueryset.as_manager()

    def update_status(self, status):
        if status:
            self.status = Case(
                When(status='', then=Value(status)),
                default=Concat('status', Value('<br />' + status))
            )
            self.save()