"""
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.auth.models import User
from django.db import models, transaction

from konova.models import BaseResource
from organisation.enums import RoleTypeEnum
from organisation.models import Organisation
from process.enums import ProcessStateEnum
from process.settings import PROCESS_STATE_STRINGS


class Process(BaseResource):
    """
    Process links compensation, intervention and eco accounts. These links are realized as ForeignKeys in their models.

    This process model therefore just holds further information on participated legal organizations.

    Attribute 'state' holds information on the current state of the process, which are defined in ProcessStateEnum
    """
    licensing_authority = models.ForeignKey(Organisation, on_delete=models.SET_NULL, null=True, blank=True, related_name="+")
    licensing_authority_document_identifier = models.CharField(max_length=500, null=True, blank=True)
    licensing_authority_comment = models.CharField(max_length=500, null=True, blank=True)
    registration_office_document_identifier = models.CharField(max_length=500, null=True, blank=True)
    registration_office = models.ForeignKey(Organisation, on_delete=models.SET_NULL, null=True, blank=True, related_name="+")
    registration_office_comment = models.CharField(max_length=500, null=True, blank=True)
    state = models.PositiveIntegerField(choices=ProcessStateEnum.as_choices(drop_empty_choice=True), default=0)

    def __str__(self) -> str:
        try:
            intervention = self.intervention
            title = intervention.title
        except AttributeError:
            title = "NO TITLE"
        return title

    def get_state_str(self):
        """
        Translates the numeric state into a string

        Returns:

        """
        return PROCESS_STATE_STRINGS.get(self.state, None)

    def deactivate(self):
        """ Deactivates a process and it's related elements

        Returns:

        """
        if self.is_active and not self.is_deleted:
            self.toggle_deletion()

    def activate(self):
        """ Activates a process and it's related elements

        Returns:

        """
        if not self.is_active and self.is_deleted:
            self.toggle_deletion()

    def toggle_deletion(self):
        """ Enables or disables a process

        Processes are not truly removed from the database, just toggled in their flags 'is_active' and 'is_deleted'

        Returns:

        """
        with transaction.atomic():
            self.is_active = not self.is_active
            self.is_deleted = not self.is_deleted
            self.save()

            # toggle related elements
            comps = self.compensation.all()
            elements = list(comps)
            if self.intervention is not None:
                elements.append(self.intervention)

            for elem in elements:
                elem.is_active = self.is_active
                elem.is_deleted = self.is_deleted
                elem.save()

    @staticmethod
    def get_role_objects(user: User, order_by: str = "-created_on"):
        """ Returns processes depending on the currently selected role of the user

            * REGISTRATIONOFFICE
                * User can see the processes where registration_office is set to the organisation of the currently selected role
                * User can see self-created processes
            * LICENSINGOFFICE
                * same
            * DATAPROVIDER
                * User can see only self-created processes

        Args:
            user (User): The performing user
            order_by (str): Order by which Process attribute

        Returns:

        """
        role = user.current_role
        if role is None:
            return Process.objects.none()
        _filter = {
            "is_deleted": False,
        }
        if role.role.type == RoleTypeEnum.REGISTRATIONOFFICE.value:
            _filter["registration_office"] = role.organisation
        elif role.role.type == RoleTypeEnum.LICENSINGAUTHORITY.value:
            _filter["licensing_authority"] = role.organisation
        elif role.role.type == RoleTypeEnum.DATAPROVIDER.value:
            # Nothing special
            _filter["created_by"] = user
        else:
            # None of the above
            pass

        other_processes = Process.objects.filter(
            **_filter
        )
        user_created_processes = Process.objects.filter(
            created_by=user,
            is_deleted=False,
        )
        qs = (other_processes | user_created_processes).distinct()
        qs = qs.order_by(order_by)
        return qs

    @staticmethod
    def create_from_intervention(intervention):
        """ Creates a process for an intervention, in case an intervention has been created without a process

        Args:
            intervention (Intervention): The intervention

        Returns:
            process (Process)
        """
        process = Process()
        process.identifier = intervention.identifier
        process.title = intervention.title
        process.created_by = intervention.created_by
        process.save()

        intervention.process = process
        intervention.save()
        return process