"""Support for monitoring an OpenEVSE Charger."""
import logging

from requests import RequestException
import voluptuous as vol

import homeassistant.helpers.config_validation as cv
from homeassistant.components.sensor import PLATFORM_SCHEMA
from homeassistant.const import (
    TEMP_CELSIUS,
    CONF_HOST,
    ENERGY_KILO_WATT_HOUR,
    CONF_MONITORED_VARIABLES,
)
from homeassistant.helpers.entity import Entity

_LOGGER = logging.getLogger(__name__)

SENSOR_TYPES = {
    "status": ["Charging Status", None],
    "charge_time": ["Charge Time Elapsed", "minutes"],
    "ambient_temp": ["Ambient Temperature", TEMP_CELSIUS],
    "ir_temp": ["IR Temperature", TEMP_CELSIUS],
    "rtc_temp": ["RTC Temperature", TEMP_CELSIUS],
    "usage_session": ["Usage this Session", ENERGY_KILO_WATT_HOUR],
    "usage_total": ["Total Usage", ENERGY_KILO_WATT_HOUR],
}

PLATFORM_SCHEMA = PLATFORM_SCHEMA.extend(
    {
        vol.Required(CONF_HOST): cv.string,
        vol.Optional(CONF_MONITORED_VARIABLES, default=["status"]): vol.All(
            cv.ensure_list, [vol.In(SENSOR_TYPES)]
        ),
    }
)


def setup_platform(hass, config, add_entities, discovery_info=None):
    """Set up the OpenEVSE sensor."""
    import openevsewifi

    host = config.get(CONF_HOST)
    monitored_variables = config.get(CONF_MONITORED_VARIABLES)

    charger = openevsewifi.Charger(host)

    dev = []
    for variable in monitored_variables:
        dev.append(OpenEVSESensor(variable, charger))

    add_entities(dev, True)


class OpenEVSESensor(Entity):
    """Implementation of an OpenEVSE sensor."""

    def __init__(self, sensor_type, charger):
        """Initialize the sensor."""
        self._name = SENSOR_TYPES[sensor_type][0]
        self.type = sensor_type
        self._state = None
        self.charger = charger
        self._unit_of_measurement = SENSOR_TYPES[sensor_type][1]

    @property
    def name(self):
        """Return the name of the sensor."""
        return self._name

    @property
    def state(self):
        """Return the state of the sensor."""
        return self._state

    @property
    def unit_of_measurement(self):
        """Return the unit of measurement of this sensor."""
        return self._unit_of_measurement

    def update(self):
        """Get the monitored data from the charger."""
        try:
            if self.type == "status":
                self._state = self.charger.getStatus()
            elif self.type == "charge_time":
                self._state = self.charger.getChargeTimeElapsed() / 60
            elif self.type == "ambient_temp":
                self._state = self.charger.getAmbientTemperature()
            elif self.type == "ir_temp":
                self._state = self.charger.getIRTemperature()
            elif self.type == "rtc_temp":
                self._state = self.charger.getRTCTemperature()
            elif self.type == "usage_session":
                self._state = float(self.charger.getUsageSession()) / 1000
            elif self.type == "usage_total":
                self._state = float(self.charger.getUsageTotal()) / 1000
            else:
                self._state = "Unknown"
        except (RequestException, ValueError, KeyError):
            _LOGGER.warning("Could not update status for %s", self.name)