konova/compensation/models.py

"""
Author: Michel Peltriaux
Organization: Struktur- und Genehmigungsdirektion Nord, Rhineland-Palatinate, Germany
Contact: michel.peltriaux@sgdnord.rlp.de
Created on: 17.11.20

"""
from django.contrib.gis.db import models
from django.utils.timezone import now

from compensation.settings import COMPENSATION_IDENTIFIER_LENGTH, COMPENSATION_IDENTIFIER_TEMPLATE
from konova.models import BaseObject, BaseResource, Geometry
from konova.utils.generators import generate_random_string
from organisation.models import Organisation


class CompensationControl(BaseResource):
    """
    Holds data on how a compensation shall be controlled
    """
    deadline = models.ForeignKey("konova.Deadline", on_delete=models.SET_NULL, null=True, blank=True)
    type = models.CharField(max_length=500, null=True, blank=True)
    expected_result = models.CharField(max_length=500, null=True, blank=True, help_text="The expected outcome, that needs to be controlled")
    by_authority = models.ForeignKey(Organisation, null=True, blank=True, on_delete=models.SET_NULL)
    comment = models.TextField()


class CompensationState(models.Model):
    """
    Compensations must define the state of an area before and after the compensation.
    """
    biotope_type = models.CharField(max_length=500, null=True, blank=True)
    surface = models.FloatField()


class CompensationAction(BaseResource):
    """
    Compensations include actions like planting trees, refreshing rivers and so on.
    """
    action_type = models.CharField(max_length=500, null=True, blank=True)
    amount = models.FloatField()
    unit = models.CharField(max_length=100, null=True, blank=True)
    control = models.ForeignKey(CompensationControl, on_delete=models.SET_NULL, null=True, blank=True)


class Compensation(BaseObject):
    """
    The compensation holds information about which actions have to be performed until which date, who is in charge
    of this, which legal authority is the point of contact, and so on.
    """
    registration_office = models.ForeignKey(Organisation, on_delete=models.SET_NULL, null=True)
    conservation_office = models.ForeignKey(Organisation, on_delete=models.SET_NULL, null=True)

    ground_definitions = models.CharField(max_length=500, null=True, blank=True)  # ToDo: Need to be M2M to laws!
    action_definitions = models.CharField(max_length=500, null=True, blank=True)  # ToDo: Need to be M2M to laws!

    before_states = models.ManyToManyField(CompensationState, blank=True, related_name='+')
    after_states = models.ManyToManyField(CompensationState, blank=True, related_name='+')
    actions = models.ManyToManyField(CompensationAction)

    deadline_creation = models.ForeignKey("konova.Deadline", on_delete=models.SET_NULL, null=True, blank=True, related_name="deadline_creation")
    deadline_maintaining = models.ForeignKey("konova.Deadline", on_delete=models.SET_NULL, null=True, blank=True, related_name="deadline_maintaining")

    geometry = models.ForeignKey(Geometry, null=True, blank=True, on_delete=models.SET_NULL)
    documents = models.ManyToManyField("konova.Document", blank=True)

    @staticmethod
    def __generate_new_identifier() -> str:
        """ Generates a new identifier for the intervention object

        Returns:
            str
        """
        curr_month = str(now().month)
        curr_year = str(now().year)
        rand_str = generate_random_string(
            length=COMPENSATION_IDENTIFIER_LENGTH,
            only_numbers=True,
        )
        _str = "{}{}{}".format(curr_month, curr_year, rand_str)
        return COMPENSATION_IDENTIFIER_TEMPLATE.format(_str)

    def save(self, *args, **kwargs):
        if self.identifier is None or len(self.identifier) == 0:
            # Create new identifier
            new_id = self.__generate_new_identifier()
            while Compensation.objects.filter(identifier=new_id).exists():
                new_id = self.__generate_new_identifier()
            self.identifier = new_id
        super().save(*args, **kwargs)


class EcoAccount(Compensation):
    """
    An eco account is a kind of 'prepaid' compensation. It can be compared to an account that already has been filled
    with some kind of currency. From this account one is able to 'withdraw' currency for current projects.

    'Withdrawing' can only be applied by shrinking the size of the available geometry and declaring the withdrawed
    geometry as a compensation for a process.
    """
    handler = models.CharField(max_length=500, null=True, blank=True, help_text="Who is responsible for handling the actions")