from datetime import datetime, date
from json import JSONEncoder

from flask import Flask

""" 程序入口"""


class Singleton(type):
    _instances = {}

    def __call__(cls, *args, **kwargs):
        if cls not in cls._instances:
            cls._instances[cls] = super(Singleton, cls).__call__(*args, **kwargs)
        return cls._instances[cls]


class App(Flask):
    __metaclass__ = Singleton

    def __init__(self, import_name=__name__, **kwargs):
        super().__init__(import_name, **kwargs)
        self.bootstrap()

    def bootstrap(self):
        pass


class CustomJSONEncoder(JSONEncoder):
    def default(self, obj):
        if isinstance(obj, datetime):
            return obj.strftime('%Y-%m-%d %H:%M:%S')
        elif isinstance(obj, date):
            return obj.strftime('%Y-%m-%d')
        else:
            return JSONEncoder.default(self, obj)


class ApiApp(App):
    def bootstrap(self):
        with self.app_context():
            import config
            import api
            from core.extensions import db, siwa
            self.config.from_object(config)
            # if config.SENTRY_DSN:
            #     sentry.init_app(self)

            # if config.CELERY_BROKER_URL:
            #     celery.init_app(self)

            db.init_app(self)

            siwa.init_app(self)

            api.init_logger(self)
            api.init_app(self)

            self.json_encoder = CustomJSONEncoder


class ClientApp(App):
    def bootstrap(self):
        super().bootstrap()
        with self.app_context():
            import config
            from core.extensions import db

            self.config.from_object(config)

            db.init_app(self)