"""
https://docs.python.org/3/library/functions.html?highlight=property#property
https://docs.python.org/3/reference/datamodel.html#implementing-descriptors

Non utilise finalement
https://stackoverflow.com/questions/1325673/how-to-add-property-to-a-class-dynamically
"""

import logging
import os

logging.basicConfig(level=logging.INFO)

# Class variable : (parameter name, environment variable, description, defaut value)
DEFAULTS = {
        'NAME': ('name', 'HTTP_FETCHER_NAME', 'Name of the acquisition', None),
        'MODE': ('mode', 'HTTP_FETCHER_MODE', 'http method', 'GET'),
        'URL': ('url', 'HTTP_FETCHER_URL', 'URL to fetch', None),
        'DELAY': ('delay', 'HTTP_FETCHER_DELAY', 'Delay between requests in seconds', 3600),
        'FORMAT': ('format', 'HTTP_FETCHER_FORMAT', 'File format', 'json'),
        'MAXITEMS': ('maxitems', 'HTTP_FETCHER_MAXITEMS', 'Max number of fetches', -1)
        }


class ConfigParameter:

    def __set_name__(self, owner, name):
        """Called at the time the owning class "owner" is created.
        The descriptor has been assigned to "name".

        https://docs.python.org/3/reference/datamodel.html#object.__set_name__
        """
        self.public_name = name
        self.private_name = f'_{name}'

    def __get__(self, obj, objtype=None):
        value = getattr(obj, self.private_name)
        logging.info('Accessing %r giving %r', self.public_name, value)
        return value

    def __set__(self, obj, value):
        logging.info('Updating %r to %r', self.public_name, value)
        setattr(obj, self.private_name, value)


def define_config_parameters(cls):

    # https://stackoverflow.com/questions/2583620/dynamically-create-class-attributes

    for name, value in DEFAULTS.items():
        setattr(cls, name, ConfigParameter())

    return cls


@define_config_parameters
class Config:

    def __init__(self, **kwargs):
        for param, value in kwargs.items():
            setattr(self, param, value)


if __name__ == "__main__":
    print(f"vars(Config) = {vars(Config)}")

    for param in DEFAULTS.keys():
        print(f"vars(vars(Config)[{param}]) = {vars(vars(Config)[param])}")

    config_params = {}
    for k, v in DEFAULTS.items():
        config_params[k] = v[-1]

    print(f"config_params = {config_params}")

    c = Config(**config_params)

    for param in DEFAULTS.keys():
        print(f"vars(vars(Config)[{param}]) = {vars(vars(Config)[param])}")

    print(vars(c))