konova/konova/models/object.py

"""
Author: Michel Peltriaux
Organization: Struktur- und Genehmigungsdirektion Nord, Rhineland-Palatinate, Germany
Contact: michel.peltriaux@sgdnord.rlp.de
Created on: 15.11.21

"""

import uuid
from abc import abstractmethod

from django.contrib import messages
from django.contrib.auth.models import User
from django.core.exceptions import ObjectDoesNotExist
from django.http import HttpRequest
from django.utils.timezone import now
from django.db import models, transaction
from compensation.settings import COMPENSATION_IDENTIFIER_TEMPLATE, COMPENSATION_IDENTIFIER_LENGTH, \
    ECO_ACCOUNT_IDENTIFIER_TEMPLATE, ECO_ACCOUNT_IDENTIFIER_LENGTH
from ema.settings import EMA_ACCOUNT_IDENTIFIER_LENGTH, EMA_ACCOUNT_IDENTIFIER_TEMPLATE
from intervention.settings import INTERVENTION_IDENTIFIER_LENGTH, INTERVENTION_IDENTIFIER_TEMPLATE
from konova.utils import generators
from konova.utils.generators import generate_random_string
from konova.utils.message_templates import CHECKED_RECORDED_RESET, GEOMETRY_CONFLICT_WITH_TEMPLATE
from user.models import UserActionLogEntry, UserAction


class UuidModel(models.Model):
    """
    Encapsules identifying via uuid
    """
    id = models.UUIDField(
        primary_key=True,
        default=uuid.uuid4,
        editable=False,
    )

    class Meta:
        abstract = True


class BaseResource(UuidModel):
    """
    A basic resource model, which defines attributes for every derived model
    """
    created = models.ForeignKey(
        UserActionLogEntry,
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name='+'
    )
    modified = models.ForeignKey(
        UserActionLogEntry,
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name='+',
        help_text="Last modified"
    )

    class Meta:
        abstract = True

    def delete(self, using=None, keep_parents=False):
        """ Base deleting of a resource

        Args:
            using ():
            keep_parents ():

        Returns:

        """
        try:
            self.created.delete()
        except (ObjectDoesNotExist, AttributeError):
            # Object does not exist anymore - we can skip this
            pass
        super().delete()


class BaseObject(BaseResource):
    """
    A basic object model, which specifies BaseResource.

    Mainly used for intervention, compensation, ecoaccount
    """
    identifier = models.CharField(max_length=1000, null=True, blank=True)
    title = models.CharField(max_length=1000, null=True, blank=True)
    deleted = models.ForeignKey(UserActionLogEntry, on_delete=models.SET_NULL, null=True, blank=True, related_name='+')
    comment = models.TextField(null=True, blank=True)
    log = models.ManyToManyField(UserActionLogEntry, blank=True, help_text="Keeps all user actions of an object", editable=False)

    class Meta:
        abstract = True

    @abstractmethod
    def set_status_messages(self, request: HttpRequest):
        raise NotImplementedError

    def mark_as_deleted(self, user: User):
        """ Mark an entry as deleted

        Does not delete from database but sets a timestamp for being deleted on and which user deleted the object

        Args:
            user (User): The performing user

        Returns:

        """
        if self.deleted:
            # Nothing to do here
            return

        with transaction.atomic():
            action = UserActionLogEntry.get_deleted_action(user)
            self.deleted = action
            self.log.add(action)
            self.save()

    def add_log_entry(self, action: UserAction, user: User, comment: str):
        """ Wraps adding of UserActionLogEntry to log

        Args:
            action (UserAction): The performed UserAction
            user (User): Performing user
            comment (str): The optional comment

        Returns:

        """
        user_action = UserActionLogEntry.objects.create(
            user=user,
            action=action,
            comment=comment
        )
        self.log.add(user_action)

    def generate_new_identifier(self) -> str:
        """ Generates a new identifier for the intervention object

        Returns:
            str
        """
        from compensation.models import Compensation, EcoAccount
        from intervention.models import Intervention
        from ema.models import Ema

        definitions = {
            Intervention: {
                "length": INTERVENTION_IDENTIFIER_LENGTH,
                "template": INTERVENTION_IDENTIFIER_TEMPLATE,
            },
            Compensation: {
                "length": COMPENSATION_IDENTIFIER_LENGTH,
                "template": COMPENSATION_IDENTIFIER_TEMPLATE,
            },
            EcoAccount: {
                "length": ECO_ACCOUNT_IDENTIFIER_LENGTH,
                "template": ECO_ACCOUNT_IDENTIFIER_TEMPLATE,
            },
            Ema: {
                "length": EMA_ACCOUNT_IDENTIFIER_LENGTH,
                "template": EMA_ACCOUNT_IDENTIFIER_TEMPLATE,
            },
        }

        if self.__class__ not in definitions:
            # Not defined, yet. Create fallback identifier for this case
            return generate_random_string(10)

        _now = now()
        curr_month = str(_now.month)
        curr_year = str(_now.year)
        rand_str = generate_random_string(
            length=definitions[self.__class__]["length"],
            use_numbers=True,
            use_letters_lc=False,
            use_letters_uc=True,
        )
        _str = "{}{}-{}".format(curr_month, curr_year, rand_str)
        return definitions[self.__class__]["template"].format(_str)


class RecordableObjectMixin(models.Model):
    """ Wraps record related fields and functionality

    """
    # Refers to "verzeichnen"
    recorded = models.OneToOneField(
        UserActionLogEntry,
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        help_text="Holds data on user and timestamp of this action",
        related_name="+"
    )

    class Meta:
        abstract = True

    def set_unrecorded(self, user: User):
        """ Perform unrecording

        Args:
            user (User): Performing user

        Returns:

        """
        if not self.recorded:
            return None
        action = UserActionLogEntry.get_unrecorded_action(user)
        self.recorded = None
        self.save()
        self.log.add(action)
        return action

    def set_recorded(self, user: User):
        """ Perform recording

        Args:
            user (User): Performing user

        Returns:

        """
        if self.recorded:
            return None
        action = UserActionLogEntry.get_recorded_action(user)
        self.recorded = action
        self.save()
        self.log.add(action)
        return action

    def mark_as_edited(self, performing_user: User, request: HttpRequest = None, edit_comment: str = None):
        """ In case the object or a related object changed, internal processes need to be started, such as
        unrecord and uncheck

        Args:
            performing_user (User): The user which performed the editing action

        Returns:

        """
        action = UserActionLogEntry.get_edited_action(performing_user, edit_comment)
        self.modified = action
        self.log.add(action)
        self.save()

        if self.recorded:
            self.set_unrecorded(performing_user)
            if request:
                messages.info(
                    request,
                    CHECKED_RECORDED_RESET
                )


class CheckableObjectMixin(models.Model):
    # Checks - Refers to "Genehmigen" but optional
    checked = models.OneToOneField(
        UserActionLogEntry,
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        help_text="Holds data on user and timestamp of this action",
        related_name="+"
    )

    class Meta:
        abstract = True

    def set_unchecked(self) -> None:
        """ Perform unrecording

        Args:

        Returns:

        """
        if not self.checked:
            # Nothing to do
            return
        # Do not .delete() the checked attribute! Just set it to None, since a delete() would kill it out of the
        # log history, which is not what we want!
        self.checked = None
        self.save()
        return None

    def set_checked(self, user: User) -> UserActionLogEntry:
        """ Perform checking

        Args:
            user (User): Performing user

        Returns:

        """
        if self.checked:
            # Nothing to do
            return
        action = UserActionLogEntry.get_checked_action(user)
        self.checked = action
        self.save()
        self.log.add(action)
        return action


class ShareableObjectMixin(models.Model):
    # Users having access on this object
    users = models.ManyToManyField(User, help_text="Users having access (data shared with)")
    access_token = models.CharField(
        max_length=255,
        null=True,
        blank=True,
        help_text="Used for sharing access",
    )

    class Meta:
        abstract = True

    def generate_access_token(self, make_unique: bool = False, rec_depth: int = 5):
        """ Creates a new access token for the data

        Tokens are not used for identification of a table row. The share logic checks the intervention id as well
        as the given token. Therefore two different interventions can hold the same access_token without problems.
        For (possible) future changes to the share logic, the make_unique parameter may be used for checking whether
        the access_token is already used in any intervention. If so, tokens will be generated as long as a free token
        can be found.

        Args:
            make_unique (bool): Perform check on uniqueness over all intervention entries
            rec_depth (int): How many tries for generating a free random token (only if make_unique)

        Returns:

        """
        # Make sure we won't end up in an infinite loop of trying to generate access_tokens
        rec_depth = rec_depth - 1
        if rec_depth < 0 and make_unique:
            raise RuntimeError(
                "Access token generating for {} does not seem to find a free random token! Aborted!".format(self.id)
            )

        # Create random token
        token = generators.generate_random_string(15, True, True, False)
        # Check dynamically wheter there is another instance of that model, which holds this random access token
        _model = self._meta.concrete_model
        token_used_in = _model.objects.filter(access_token=token)
        # Make sure the token is not used anywhere as access_token, yet.
        # Make use of QuerySet lazy method for checking if it exists or not.
        if token_used_in and make_unique:
            self.generate_access_token(make_unique, rec_depth)
        else:
            self.access_token = token
            self.save()

    def is_shared_with(self, user: User):
        """ Access check

        Checks whether a given user has access to this object

        Args:
            user ():

        Returns:

        """
        return self.users.filter(id=user.id)

    def share_with(self, user: User):
        """ Adds user to list of shared access users

        Args:
            user (User): The user to be added to the object

        Returns:

        """
        if not self.is_shared_with(user):
            self.users.add(user)

    def share_with_list(self, user_list: list):
        """ Sets the list of shared access users

        Args:
            user_list (list): The users to be added to the object

        Returns:

        """
        self.users.set(user_list)

    def update_sharing_user(self, form):
        """ Adds a new user with shared access to the object

        Args:
            form (ShareModalForm): The form holding the data

        Returns:

        """
        form_data = form.cleaned_data

        keep_accessing_users = form_data["users"]
        new_accessing_users = list(form_data["user_select"].values_list("id", flat=True))
        accessing_users = keep_accessing_users + new_accessing_users
        users = User.objects.filter(
            id__in=accessing_users
        )
        self.share_with_list(users)


class GeoReferencedMixin(models.Model):
    geometry = models.ForeignKey("konova.Geometry", null=True, blank=True, on_delete=models.SET_NULL)

    class Meta:
        abstract = True

    def _set_geometry_conflict_message(self, request: HttpRequest):
        instance_objs = []
        add_message = False
        conflicts = self.geometry.conflicts_geometries.all()
        for conflict in conflicts:
            instance_objs += conflict.affected_geometry.get_data_objects()
            add_message = True
        conflicts = self.geometry.conflicted_by_geometries.all()
        for conflict in conflicts:
            instance_objs += conflict.conflicting_geometry.get_data_objects()
            add_message = True

        if add_message:
            instance_identifiers = [x.identifier for x in instance_objs]
            instance_identifiers = ", ".join(instance_identifiers)
            message_str = GEOMETRY_CONFLICT_WITH_TEMPLATE.format(instance_identifiers)
            messages.info(request, message_str)
        return request