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

"""
import shutil

from django.contrib.auth.models import User
from django.contrib.gis.db import models
from django.db.models import QuerySet
from django.utils.timezone import localtime
from django.utils.translation import gettext_lazy as _

from codelist.models import KonovaCode
from codelist.settings import CODELIST_REGISTRATION_OFFICE_ID, CODELIST_CONSERVATION_OFFICE_ID, CODELIST_LAW_ID, \
    CODELIST_PROCESS_TYPE_ID
from konova.models import BaseObject, Geometry, UuidModel, BaseResource, AbstractDocument, \
    generate_document_file_upload_path
from konova.settings import DEFAULT_SRID_RLP, LANIS_LINK_TEMPLATE
from konova.sub_settings.django_settings import DEFAULT_DATE_TIME_FORMAT
from konova.utils import generators
from user.models import UserActionLogEntry


class ResponsibilityData(UuidModel):
    """
    Holds intervention data about responsible organizations and their file numbers for this case

    """
    registration_office = models.ForeignKey(
        KonovaCode,
        on_delete=models.SET_NULL,
        null=True,
        related_name="+",
        blank=True,
        limit_choices_to={
            "code_lists__in": [CODELIST_REGISTRATION_OFFICE_ID],
            "is_selectable": True,
            "is_archived": False,
        }
    )
    registration_file_number = models.CharField(max_length=1000, blank=True, null=True)
    conservation_office = models.ForeignKey(
        KonovaCode,
        on_delete=models.SET_NULL,
        null=True,
        related_name="+",
        blank=True,
        limit_choices_to={
            "code_lists__in": [CODELIST_CONSERVATION_OFFICE_ID],
            "is_selectable": True,
            "is_archived": False,
        }
    )
    conservation_file_number = models.CharField(max_length=1000, blank=True, null=True)
    handler = models.CharField(max_length=500, null=True, blank=True, help_text="Refers to 'Eingriffsverursacher' or 'Maßnahmenträger'")

    def __str__(self):
        return "ZB: {} | ETS: {} | Handler: {}".format(
            self.registration_office,
            self.conservation_office,
            self.handler
        )


class Revocation(BaseResource):
    """
    Holds revocation data e.g. for intervention objects
    """
    date = models.DateField(null=True, blank=True, help_text="Revocation from")
    comment = models.TextField(null=True, blank=True)

    def delete(self, *args, **kwargs):
        # Make sure related objects are being removed as well
        if self.document:
            self.document.delete(*args, **kwargs)
        super().delete()


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

    @property
    def intervention(self):
        """
        Shortcut for opening the related intervention

        Returns:
            intervention (Intervention)
        """
        return self.instance.legaldata.intervention

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

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

        Returns:

        """
        revoc_docs, other_intervention_docs = self.intervention.get_documents()

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

        # Always remove 'revocation' folder
        folder_path = self.file.path.split("/")
        try:
            shutil.rmtree("/".join(folder_path[:-1]))
        except FileNotFoundError:
            # Revocation subfolder seems to be missing already
            pass

        if other_intervention_docs.count() == 0:
            # If there are no further documents for the intervention, we can simply remove the whole folder as well!
            try:
                shutil.rmtree("/".join(folder_path[:-2]))
            except FileNotFoundError:
                # Folder seems to be missing already
                pass

class LegalData(UuidModel):
    """
    Holds intervention legal data such as important dates, laws or responsible handler
    """
    # Refers to "zugelassen am"
    registration_date = models.DateField(null=True, blank=True, help_text="Refers to 'Zugelassen am'")

    # Refers to "Bestandskraft am"
    binding_date = models.DateField(null=True, blank=True, help_text="Refers to 'Bestandskraft am'")

    process_type = models.ForeignKey(
        KonovaCode,
        on_delete=models.SET_NULL,
        null=True,
        related_name="+",
        blank=True,
        limit_choices_to={
            "code_lists__in": [CODELIST_PROCESS_TYPE_ID],
            "is_selectable": True,
            "is_archived": False,
        }
    )
    law = models.ForeignKey(
        KonovaCode,
        on_delete=models.SET_NULL,
        null=True,
        related_name="+",
        blank=True,
        limit_choices_to={
            "code_lists__in": [CODELIST_LAW_ID],
            "is_selectable": True,
            "is_archived": False,
        }
    )

    revocation = models.OneToOneField(Revocation, null=True, blank=True, help_text="Refers to 'Widerspruch am'", on_delete=models.SET_NULL)

    def __str__(self):
        return "{} | {} | {}".format(
            self.process_type,
            self.law,
            self.id
        )


class Intervention(BaseObject):
    """
    Interventions are e.g. construction sites where nature used to be.
    """
    responsible = models.OneToOneField(
        ResponsibilityData,
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        help_text="Holds data on responsible organizations ('Zulassungsbehörde', 'Eintragungsstelle')"
    )
    legal = models.OneToOneField(
        LegalData,
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        help_text="Holds data on legal dates or law"
    )
    geometry = models.ForeignKey(Geometry, null=True, blank=True, on_delete=models.SET_NULL)

    # 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="+"
    )

    # 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="+"
    )

    # 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",
    )

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

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

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

    def quality_check(self) -> list:
        """ Quality check

        Returns:
            ret_msgs (list): Holds error messages
        """
        ret_msgs = []

        self._check_quality_responsible_data(ret_msgs)
        self._check_quality_legal_data(ret_msgs)

        # ToDo: Extend for more!

        return ret_msgs

    def _check_quality_responsible_data(self, ret_msgs: list):
        """ Checks data quality of related ResponsibilityData

        Args:
            ret_msgs (dict): Holds error messages

        Returns:

        """
        try:
            # Check for file numbers
            if not self.responsible.registration_file_number or len(self.responsible.registration_file_number) == 0:
                ret_msgs.append(_("Registration office file number missing"))

            if not self.responsible.conservation_file_number or len(self.responsible.conservation_file_number) == 0:
                ret_msgs.append(_("Conversation office file number missing"))
        except AttributeError:
            # responsible data not found
            ret_msgs.append(_("Responsible data missing"))

    def _check_quality_legal_data(self, ret_msgs: list):
        """ Checks data quality of related LegalData

        Args:
            ret_msgs (dict): Holds error messages

        Returns:

        """
        try:
            # Check for a revocation
            if self.legal.revocation:
                ret_msgs.append(_("Revocation exists"))

            if self.legal.registration_date is None:
                ret_msgs.append(_("Registration date missing"))

            if self.legal.binding_date is None:
                ret_msgs.append(_("Binding on missing"))
        except AttributeError:
            ret_msgs.append(_("Legal data missing"))

    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,
        )

    @property
    def recorded_tooltip(self):
        tooltip = _("Not recorded yet")
        if self.recorded:
            value = self.recorded.timestamp
            value = localtime(value)
            on = value.strftime(DEFAULT_DATE_TIME_FORMAT)
            tooltip = _("Recorded on {} by {}").format(on, self.recorded.user)
        return tooltip

    def get_documents(self) -> (QuerySet, QuerySet):
        """ Getter for all documents of an intervention

        Returns:
            revoc_docs (QuerySet): The queryset of a revocation document
            regular_docs (QuerySet): The queryset of regular other documents
        """
        revoc_docs = RevocationDocument.objects.filter(
            instance=self.legal.revocation
        )
        regular_docs = InterventionDocument.objects.filter(
            instance=self
        )
        return revoc_docs, regular_docs


class InterventionDocument(AbstractDocument):
    """
    Specializes document upload for an intervention with certain path
    """
    instance = models.ForeignKey(
        Intervention,
        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 InterventionDocuments.
        Removes the folder from the file system if there are no further documents for this entry.

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

        Returns:

        """
        revoc_docs, other_intervention_docs = self.instance.get_documents()

        folder_path = None
        if revoc_docs.count() == 0 and other_intervention_docs.count() == 1:
            # The only file left for this intervention is the one which is currently processed and will be deleted
            # Make sure that the intervention 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