"""Everything to do with Apps"""

import os

from sqlalchemy import ForeignKey, Integer, String
from sqlalchemy.orm import relationship
from database import db
import helpers.kubernetes as k8s
from .apps import APPS_WITHOUT_OAUTH, APP_NOT_INSTALLED_STATUS


class App(db.Model):
    """
    The App object, interact with the App database object. Data is stored in
    the local database.
    """

    id = db.Column(Integer, primary_key=True)
    name = db.Column(String(length=64))
    slug = db.Column(String(length=64), unique=True)

    def __repr__(self):
        return f"{self.id} <{self.name}>"

    def get_kustomization_status(self):
        """Returns True if the kustomization for this App is ready"""
        kustomization = k8s.get_kustomization(self.slug)
        if kustomization is None:
            return None
        return kustomization['status']

    def get_helmrelease_status(self):
        """Returns True if the kustomization for this App is ready"""
        helmrelease = k8s.get_helmrelease(self.slug, self.namespace)
        if helmrelease is None:
            return None
        return helmrelease['status']

    def get_status(self):
        """Returns a string that describes the app state in the cluster"""
        ks_status = self.get_kustomization_status()
        if ks_status is not None:
            ks_ready, ks_message = App.check_condition(ks_status)
        else:
            ks_ready = None
        hr_status = self.get_helmrelease_status()
        if hr_status is not None:
            hr_ready, hr_message = App.check_condition(hr_status)
        else:
            hr_ready = None
        if ks_ready is None:
            return APP_NOT_INSTALLED_STATUS
        # *Should* not happen, but just in case:
        if (ks_ready is None and hr_ready is not None) or \
                (hr_ready is None and ks_ready is not None):
            return ("This app is in a strange state. Contact a Stackspin"
                " administrator if this status stays for longer than 5 minutes")
        if ks_ready and hr_ready:
            return "App installed and running"
        if not hr_ready:
            return f"App HelmRelease status: {hr_message}"
        if not ks_ready:
            return f"App Kustomization status: {ks_message}"
        return "App is installing..."


    def install(self):
        """Creates a Kustomization in the Kubernetes cluster that installs this application"""
        # Generate the necessary passwords, etc. from a template
        self.__generate_secrets()
        # Create add-<app> kustomization
        self.__create_kustomization()

    def delete(self):
        """
        Fully deletes an application

        This includes user roles, all kubernetes objects and also PVCs, so your
        data will be *gone*
        """
        # Delete all roles first
        for role in self.roles:
            db.session.delete(role)

        # Delete the kustomization
        if self.__delete_kustomization():

        # TODO: This is where we might want to poll for status changes in the
        # app, so that only once the kustomization and all its stuff (other ks,
        # helmrelease, etc.) is deleted, we continue

        # If the kustomization delete went well, commit DB changes.
            db.session.commit()
            # Then delete the app
            db.session.delete(self)
            db.session.commit()
            return True
        return False

    def __generate_secrets(self):
        """Generates passwords for app installation"""
        # Create app variables secret
        if self.variables_template_filepath:
            k8s.create_variables_secret(self.slug, self.variables_template_filepath)
        # Create a secret that contains the oauth variables for Hydra Maester
        if self.slug not in APPS_WITHOUT_OAUTH:
            k8s.create_variables_secret(
                self.slug,
                os.path.join(self.__get_templates_dir(),
                    "stackspin-oauth-variables.yaml.jinja"))

    def __create_kustomization(self):
        """Creates the `add-{app_slug}` kustomization in the Kubernetes cluster"""
        kustomization_template_filepath = \
            os.path.join(self.__get_templates_dir(),
                "add-app-kustomization.yaml.jinja")
        k8s.store_kustomization(kustomization_template_filepath, self.slug)

    def __delete_kustomization(self):
        """Deletes kustomization for this app"""
        k8s.delete_kustomization(f"add-{self.slug}")


    @property
    def variables_template_filepath(self):
        """Path to the variables template used to generate secrets the app needs"""
        variables_template_filepath = os.path.join(self.__get_templates_dir(),
                f"stackspin-{self.slug}-variables.yaml.jinja")
        if os.path.exists(variables_template_filepath):
            return variables_template_filepath
        return None

    @property
    def namespace(self):
        """
        Returns the Kubernetes namespace of this app

        FIXME: This should probably become a database field.
        """
        if self.slug in ['nextcloud', 'wordpress', 'wekan', 'zulip']:
            return 'stackspin-apps'
        return 'stackspin'

    @property
    def roles(self):
        """
        All roles that are linked to this app
        """
        return AppRole.query.filter_by(
            app_id=self.id
        ).all()

    @staticmethod
    def __get_templates_dir():
        """Returns directory that contains the Jinja templates used to create app secrets."""
        return os.path.join(os.path.dirname(os.path.realpath(__file__)), "templates")

    @staticmethod
    def check_condition(status):
        """
        Returns a tuple that has true/false for readiness and a message

        Ready, in this case means that the condition's type == "Ready" and its
        status == "True". If the condition type "Ready" does not exist, the
        status is interpreted as not ready.

        The message that is returned is the message that comes with the
        condition with type "Ready"

        :param status: Kubernetes resource's "status" object.
        :type status: dict
        """
        for condition in status["conditions"]:
            if condition["type"] == "Ready":
                return condition["status"] == "True", condition["message"]
        return False


class AppRole(db.Model):  # pylint: disable=too-few-public-methods
    """
    The AppRole object, stores the roles Users have on Apps
    """

    user_id = db.Column(String(length=64), primary_key=True)
    app_id = db.Column(Integer, ForeignKey("app.id"), primary_key=True)
    role_id = db.Column(Integer, ForeignKey("role.id"))

    role = relationship("Role")

    def __repr__(self):
        return (f"role_id: {self.role_id}, user_id: {self.user_id},"
                f" app_id: {self.app_id}, role: {self.role}")