"""
Author: Michel Peltriaux
Organization: Struktur- und Genehmigungsdirektion Nord, Rhineland-Palatinate, Germany
Contact: michel.peltriaux@sgdnord.rlp.de
Created on: 16.11.21

"""
import shutil

from django.contrib import messages
from django.contrib.auth.models import User
from django.db import models, transaction
from django.db.models import QuerySet, Sum
from django.http import HttpRequest
from django.utils.translation import gettext_lazy as _

from compensation.managers import CompensationManager
from compensation.models import CompensationState, CompensationAction
from compensation.utils.quality import CompensationQualityChecker
from konova.models import BaseObject, AbstractDocument, Deadline, generate_document_file_upload_path, \
    GeoReferencedMixin
from konova.settings import DEFAULT_SRID_RLP, LANIS_LINK_TEMPLATE
from konova.utils.message_templates import DATA_UNSHARED_EXPLANATION
from user.models import UserActionLogEntry


class AbstractCompensation(BaseObject, GeoReferencedMixin):
    """
    Abstract compensation model which holds basic attributes, shared by subclasses like the regular Compensation,
    EMA or EcoAccount.

    """
    responsible = models.OneToOneField(
        "intervention.Responsibility",
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        help_text="Holds data on responsible organizations ('Zulassungsbehörde', 'Eintragungsstelle') and handler",
    )

    before_states = models.ManyToManyField(CompensationState, blank=True, related_name='+', help_text="Refers to 'Ausgangszustand Biotop'")
    after_states = models.ManyToManyField(CompensationState, blank=True, related_name='+', help_text="Refers to 'Zielzustand Biotop'")
    actions = models.ManyToManyField(CompensationAction, blank=True, help_text="Refers to 'Maßnahmen'")

    deadlines = models.ManyToManyField("konova.Deadline", blank=True, related_name="+")

    class Meta:
        abstract = True

    def add_deadline(self, form) -> Deadline:
        """ Adds a new deadline to the abstract compensation

        Args:
            form (NewDeadlineModalForm): The form holding all relevant data

        Returns:

        """
        form_data = form.cleaned_data
        user = form.user
        with transaction.atomic():
            created_action = UserActionLogEntry.get_created_action(user)
            edited_action = UserActionLogEntry.get_edited_action(user, _("Added deadline"))

            deadline = Deadline.objects.create(
                type=form_data["type"],
                date=form_data["date"],
                comment=form_data["comment"],
                created=created_action,
            )

            self.modified = edited_action
            self.save()
            self.log.add(edited_action)
            self.deadlines.add(deadline)
            return deadline

    def add_action(self, form) -> CompensationAction:
        """ Adds a new action to the compensation

        Args:
            form (NewActionModalForm): The form holding all relevant data

        Returns:

        """
        form_data = form.cleaned_data
        user = form.user
        with transaction.atomic():
            user_action = UserActionLogEntry.get_created_action(user)
            comp_action = CompensationAction.objects.create(
                action_type=form_data["action_type"],
                amount=form_data["amount"],
                unit=form_data["unit"],
                comment=form_data["comment"],
                created=user_action,
            )
            self.actions.add(comp_action)
            return comp_action

    def add_state(self, form, is_before_state: bool) -> CompensationState:
        """ Adds a new compensation state to the compensation

        Args:
            form (NewStateModalForm): The form, holding all relevant data
            is_before_state (bool): Whether this is a new before_state or after_state

        Returns:

        """
        form_data = form.cleaned_data
        with transaction.atomic():
            state = CompensationState.objects.create(
                biotope_type=form_data["biotope_type"],
                surface=form_data["surface"],
            )
            if is_before_state:
                self.before_states.add(state)
            else:
                self.after_states.add(state)
            return state

    def get_surface_after_states(self) -> float:
        """ Calculates the compensation's/account's surface

        Returns:
            sum_surface (float)
        """
        return self._calc_surface(self.after_states.all())

    def get_surface_before_states(self) -> float:
        """ Calculates the compensation's/account's surface

        Returns:
            sum_surface (float)
        """
        return self._calc_surface(self.before_states.all())

    def _calc_surface(self, qs: QuerySet):
        """ Calculates the surface sum of a given queryset

        Args:
            qs (QuerySet): The queryset containing CompensationState entries

        Returns:

        """
        return qs.aggregate(Sum("surface"))["surface__sum"] or 0

    def quality_check(self) -> CompensationQualityChecker:
        """ Performs data quality check

        Returns:
            checker (CompensationQualityChecker): Holds validity data and error messages
        """
        checker = CompensationQualityChecker(self)
        checker.run_check()
        return checker

    def set_status_messages(self, request: HttpRequest):
        """ Setter for different information that need to be rendered

        Adds messages to the given HttpRequest

        Args:
            request (HttpRequest): The incoming request

        Returns:
            request (HttpRequest): The modified request
        """
        if not self.is_shared_with(request.user):
            messages.info(request, DATA_UNSHARED_EXPLANATION)
        request = self.set_geometry_conflict_message(request)
        return request


class CEFMixin(models.Model):
    """ Provides CEF flag as Mixin

    """
    is_cef = models.BooleanField(
        blank=True,
        null=True,
        default=False,
        help_text="Flag if compensation is a 'CEF-Maßnahme'"
    )

    class Meta:
        abstract = True


class CoherenceMixin(models.Model):
    """ Provides coherence keeping flag as Mixin

    """
    is_coherence_keeping = models.BooleanField(
        blank=True,
        null=True,
        default=False,
        help_text="Flag if compensation is a 'Kohärenzsicherung'"
    )

    class Meta:
        abstract = True


class Compensation(AbstractCompensation, CEFMixin, CoherenceMixin):
    """
    Regular compensation, linked to an intervention
    """
    intervention = models.ForeignKey(
        "intervention.Intervention",
        on_delete=models.CASCADE,
        null=True,
        blank=True,
        related_name='compensations'
    )

    objects = CompensationManager()

    def __str__(self):
        return "{}".format(self.identifier)

    def save(self, *args, **kwargs):
        if self.identifier is None or len(self.identifier) == 0:
            # Create new identifier is none was given
            self.identifier = self.generate_new_identifier()

        # Before saving, make sure a given identifier has not been taken already in the meanwhile
        while Compensation.objects.filter(identifier=self.identifier).exclude(id=self.id).exists():
            self.identifier = self.generate_new_identifier()
        super().save(*args, **kwargs)

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

        Checks whether a given user has access to this object

        Args:
            user (User): The user to be checked

        Returns:

        """
        # Compensations inherit their shared state from the interventions
        return self.intervention.is_shared_with(user)

    def get_LANIS_link(self) -> str:
        """ Generates a link for LANIS depending on the geometry

        Returns:

        """
        try:
            geom = self.geometry.geom.transform(DEFAULT_SRID_RLP, clone=True)
            x = geom.centroid.x
            y = geom.centroid.y
            zoom_lvl = 16
        except AttributeError:
            # If no geometry has been added, yet.
            x = 1
            y = 1
            zoom_lvl = 6
        return LANIS_LINK_TEMPLATE.format(
            zoom_lvl,
            x,
            y,
        )

    def get_documents(self) -> QuerySet:
        """ Getter for all documents of a compensation

        Returns:
            docs (QuerySet): The queryset of all documents
        """
        docs = CompensationDocument.objects.filter(
            instance=self
        )
        return docs

    def mark_as_edited(self, user: User, request: HttpRequest = None, edit_comment: str = None):
        """ Performs internal logic for setting the recordedd/checked state of the related intervention

        Args:
            user (User): The performing user
            request (HttpRequest): The performing request

        Returns:

        """
        self.intervention.mark_as_edited(user, request, edit_comment)


class CompensationDocument(AbstractDocument):
    """
    Specializes document upload for revocations with certain path
    """
    instance = models.ForeignKey(
        Compensation,
        on_delete=models.CASCADE,
        related_name="documents",
    )
    file = models.FileField(
        upload_to=generate_document_file_upload_path,
        max_length=1000,
    )

    def delete(self, *args, **kwargs):
        """
        Custom delete functionality for CompensationDocuments.
        Removes the folder from the file system if there are no further documents for this entry.

        Args:
            *args ():
            **kwargs ():

        Returns:

        """
        comp_docs = self.instance.get_documents()

        folder_path = None
        if comp_docs.count() == 1:
            # The only file left for this compensation is the one which is currently processed and will be deleted
            # Make sure that the compensation folder itself is deleted as well, not only the file
            # Therefore take the folder path from the file path
            folder_path = self.file.path.split("/")[:-1]
            folder_path = "/".join(folder_path)

        # Remove the file itself
        super().delete(*args, **kwargs)

        # If a folder path has been set, we need to delete the whole folder!
        if folder_path is not None:
            try:
                shutil.rmtree(folder_path)
            except FileNotFoundError:
                # Folder seems to be missing already...
                pass