"""
A component to submit data to thingspeak.

For more details about this component, please refer to the documentation at
https://home-assistant.io/components/thingspeak/
"""
import logging

from requests.exceptions import RequestException
import voluptuous as vol

from homeassistant.const import (
    CONF_API_KEY, CONF_ID, CONF_WHITELIST, STATE_UNAVAILABLE, STATE_UNKNOWN)
from homeassistant.helpers import state as state_helper
import homeassistant.helpers.config_validation as cv
import homeassistant.helpers.event as event

REQUIREMENTS = ['thingspeak==0.4.1']

_LOGGER = logging.getLogger(__name__)

DOMAIN = 'thingspeak'

TIMEOUT = 5

CONFIG_SCHEMA = vol.Schema({
    DOMAIN: vol.Schema({
        vol.Required(CONF_API_KEY): cv.string,
        vol.Required(CONF_ID): int,
        vol.Required(CONF_WHITELIST): cv.string
        }),
}, extra=vol.ALLOW_EXTRA)


def setup(hass, config):
    """Set up the Thingspeak environment."""
    import thingspeak

    conf = config[DOMAIN]
    api_key = conf.get(CONF_API_KEY)
    channel_id = conf.get(CONF_ID)
    entity = conf.get(CONF_WHITELIST)

    try:
        channel = thingspeak.Channel(
            channel_id, write_key=api_key, timeout=TIMEOUT)
        channel.get()
    except RequestException:
        _LOGGER.error("Error while accessing the ThingSpeak channel. "
                      "Please check that the channel exists and your "
                      "API key is correct.")
        return False

    def thingspeak_listener(entity_id, old_state, new_state):
        """Listen for new events and send them to Thingspeak."""
        if new_state is None or new_state.state in (
                STATE_UNKNOWN, '', STATE_UNAVAILABLE):
            return
        try:
            if new_state.entity_id != entity:
                return
            _state = state_helper.state_as_number(new_state)
        except ValueError:
            return
        try:
            channel.update({'field1': _state})
        except RequestException:
            _LOGGER.error(
                "Error while sending value '%s' to Thingspeak", _state)

    event.track_state_change(hass, entity, thingspeak_listener)

    return True