"""
homeassistant.components.notify.command_line
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
command_line notification service.

For more details about this platform, please refer to the documentation at
https://home-assistant.io/components/notify.command_line/
"""
import logging
import subprocess
from homeassistant.helpers import validate_config
from homeassistant.components.notify import (
    DOMAIN, BaseNotificationService)

_LOGGER = logging.getLogger(__name__)


def get_service(hass, config):
    """ Get the Command Line notification service. """

    if not validate_config({DOMAIN: config},
                           {DOMAIN: ['command']},
                           _LOGGER):
        return None

    command = config['command']

    return CommandLineNotificationService(command)


# pylint: disable=too-few-public-methods
class CommandLineNotificationService(BaseNotificationService):
    """ Implements notification service for the Command Line service. """

    def __init__(self, command):
        self.command = command

    def send_message(self, message="", **kwargs):
        """ Send a message to a command_line. """

        try:
            proc = subprocess.Popen(self.command, universal_newlines=True,
                                    stdin=subprocess.PIPE, shell=True)
            proc.communicate(input=message)
            if proc.returncode != 0:
                _LOGGER.error('Command failed: %s', self.command)
        except subprocess.SubprocessError:
            _LOGGER.error('Error trying to exec Command: %s', self.command)