"""Configuration handling module."""

import os

from autonomic import logger
from autonomic.settings import AUTONOMIC_YAML
from autonomic.system import exit_with_msg
from autonomic.yaml import yaml

log = logger.get_logger(__name__)


def ensure_config():
    """Ensure the configuration exists."""
    if not os.path.exists(AUTONOMIC_YAML):
        msg = "{} is missing, run: autonomic init".format(AUTONOMIC_YAML)
        exit_with_msg(msg)


def add_to_config(data):
    """Add values to the autonomic.yml file."""
    ensure_config()

    with open(AUTONOMIC_YAML, "r") as handle:
        config = yaml.load(handle.read())

    if config is None:
        config = {}

    for key in data:
        config[key] = data[key]

    with open(AUTONOMIC_YAML, "w") as handle:
        yaml.dump(config, handle)


def get_from_config(key):
    """Get values from the autonomic.yml file."""
    ensure_config()

    with open(AUTONOMIC_YAML, "r") as handle:
        config = yaml.load(handle.read())

    try:
        return config[key]
    except KeyError:
        msg = "Unable to retrieve {} from {}".format(key, AUTONOMIC_YAML)
        exit_with_msg(msg)