"""Implements a config object with dot-indexing syntax."""
import os
from itertools import chain
from operator import truth

from envyaml import EnvYAML
from funcy import first, juxt, butlast, last

from pyinfra.locations import CONFIG_FILE


def _get_item_and_maybe_make_dotindexable(container, item):
    ret = container[item]
    return DotIndexable(ret) if isinstance(ret, dict) else ret


class DotIndexable:
    def __init__(self, x):
        self.x = x

    def __getattr__(self, item):
        return _get_item_and_maybe_make_dotindexable(self.x, item)

    def __repr__(self):
        return self.x.__repr__()

    def __getitem__(self, item):
        return self.__getattr__(item)

    def __setitem__(self, key, value):
        self.x[key] = value


class Config:
    def __init__(self, config_path):
        self.__config = EnvYAML(config_path)

    def __getattr__(self, item):
        if item in self.__config:
            return _get_item_and_maybe_make_dotindexable(self.__config, item)

    def __getitem__(self, item):
        return self.__getattr__(item)

    def __setitem__(self, key, value):
        self.__config.key = value



CONFIG = Config(CONFIG_FILE)


def parse_disjunction_string(disjunction_string):
    def try_parse_env_var(disjunction_string):
        try:
            return os.environ[disjunction_string]
        except KeyError:
            return None

    options = disjunction_string.split("|")
    identifiers, fallback_value = juxt(butlast, last)(options)
    return first(chain(filter(truth, map(try_parse_env_var, identifiers)), [fallback_value]))