"""
homeassistant.components.automation
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Allows to setup simple automation rules via the config file.
"""
import logging
import json

from homeassistant.loader import get_component
from homeassistant.helpers import config_per_platform
from homeassistant.util import convert, split_entity_id
from homeassistant.const import ATTR_ENTITY_ID

DOMAIN = "automation"

DEPENDENCIES = ["group"]

CONF_ALIAS = "alias"
CONF_SERVICE = "execute_service"
CONF_SERVICE_ENTITY_ID = "service_entity_id"
CONF_SERVICE_DATA = "service_data"

_LOGGER = logging.getLogger(__name__)


def setup(hass, config):
    """ Sets up automation. """

    for p_type, p_config in config_per_platform(config, DOMAIN, _LOGGER):
        platform = get_component('automation.{}'.format(p_type))

        if platform is None:
            _LOGGER.error("Unknown automation platform specified: %s", p_type)
            continue

        if platform.register(hass, p_config, _get_action(hass, p_config)):
            _LOGGER.info(
                "Initialized %s rule %s", p_type, p_config.get(CONF_ALIAS, ""))
        else:
            _LOGGER.error(
                "Error setting up rule %s", p_config.get(CONF_ALIAS, ""))

    return True


def _get_action(hass, config):
    """ Return an action based on a config. """

    def action():
        """ Action to be executed. """
        _LOGGER.info("Executing rule %s", config.get(CONF_ALIAS, ""))

        if CONF_SERVICE in config:
            domain, service = split_entity_id(config[CONF_SERVICE])

            service_data = convert(
                config.get(CONF_SERVICE_DATA), json.loads, {})

            if not isinstance(service_data, dict):
                _LOGGER.error(
                    "%s should be a serialized JSON object", CONF_SERVICE_DATA)
                service_data = {}

            if CONF_SERVICE_ENTITY_ID in config:
                service_data[ATTR_ENTITY_ID] = \
                    config[CONF_SERVICE_ENTITY_ID].split(",")

            hass.services.call(domain, service, service_data)

    return action