# pylint: disable=too-few-public-methods

from datetime import datetime
from flask import Flask
from flask_smorest import Api
from .config import APISettings

class IsSingletonException(Exception):
    pass

class Application:
    """
    This is a singleton that can be accessed using get_instance()

    It has 2 properties
    - app: Used for WSGI servers and such
    - api: Used for Blueprints
    """

    __instance = None
    app = Flask(__name__)
    app.config.from_object(APISettings)
    api = None
    alive_since = None

    @staticmethod
    def get_instance():
        if Application.__instance is None:
            Application()
        return Application.__instance

    def __init__(self):
        if Application.__instance is not None:
            raise IsSingletonException("This class is a singleton")
        Application.__instance = self
        self.api = Api(self.app)
        self.alive_since = datetime.now()