"""Support for the Environment Canada weather service."""
from datetime import datetime, timedelta
import logging
import re

from env_canada import ECData
import voluptuous as vol

from homeassistant.components.sensor import PLATFORM_SCHEMA
from homeassistant.const import (
    ATTR_ATTRIBUTION,
    ATTR_LOCATION,
    CONF_LATITUDE,
    CONF_LONGITUDE,
    TEMP_CELSIUS,
)
import homeassistant.helpers.config_validation as cv
from homeassistant.helpers.entity import Entity

_LOGGER = logging.getLogger(__name__)

SCAN_INTERVAL = timedelta(minutes=10)

ATTR_UPDATED = "updated"
ATTR_STATION = "station"
ATTR_TIME = "alert time"

CONF_ATTRIBUTION = "Data provided by Environment Canada"
CONF_STATION = "station"
CONF_LANGUAGE = "language"


def validate_station(station):
    """Check that the station ID is well-formed."""
    if station is None:
        return
    if not re.fullmatch(r"[A-Z]{2}/s0000\d{3}", station):
        raise vol.error.Invalid('Station ID must be of the form "XX/s0000###"')
    return station


PLATFORM_SCHEMA = PLATFORM_SCHEMA.extend(
    {
        vol.Required(CONF_LANGUAGE, default="english"): vol.In(["english", "french"]),
        vol.Optional(CONF_STATION): validate_station,
        vol.Inclusive(CONF_LATITUDE, "latlon"): cv.latitude,
        vol.Inclusive(CONF_LONGITUDE, "latlon"): cv.longitude,
    }
)


def setup_platform(hass, config, add_entities, discovery_info=None):
    """Set up the Environment Canada sensor."""

    if config.get(CONF_STATION):
        ec_data = ECData(
            station_id=config[CONF_STATION], language=config.get(CONF_LANGUAGE)
        )
    else:
        lat = config.get(CONF_LATITUDE, hass.config.latitude)
        lon = config.get(CONF_LONGITUDE, hass.config.longitude)
        ec_data = ECData(coordinates=(lat, lon), language=config.get(CONF_LANGUAGE))

    sensor_list = list(ec_data.conditions.keys()) + list(ec_data.alerts.keys())
    add_entities([ECSensor(sensor_type, ec_data) for sensor_type in sensor_list], True)


class ECSensor(Entity):
    """Implementation of an Environment Canada sensor."""

    def __init__(self, sensor_type, ec_data):
        """Initialize the sensor."""
        self.sensor_type = sensor_type
        self.ec_data = ec_data

        self._unique_id = None
        self._name = None
        self._state = None
        self._attr = None
        self._unit = None

    @property
    def unique_id(self) -> str:
        """Return the unique ID of the sensor."""
        return self._unique_id

    @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 device_state_attributes(self):
        """Return the state attributes of the device."""
        return self._attr

    @property
    def unit_of_measurement(self):
        """Return the units of measurement."""
        return self._unit

    def update(self):
        """Update current conditions."""
        self.ec_data.update()
        self.ec_data.conditions.update(self.ec_data.alerts)

        conditions = self.ec_data.conditions
        metadata = self.ec_data.metadata
        sensor_data = conditions.get(self.sensor_type)

        self._unique_id = f"{metadata['location']}-{self.sensor_type}"
        self._attr = {}
        self._name = sensor_data.get("label")
        value = sensor_data.get("value")

        if isinstance(value, list):
            self._state = " | ".join([str(s.get("title")) for s in value])[:255]
            self._attr.update(
                {ATTR_TIME: " | ".join([str(s.get("date")) for s in value])}
            )
        elif self.sensor_type == "tendency":
            self._state = str(value).capitalize()
        elif value is not None and len(value) > 255:
            self._state = value[:255]
            _LOGGER.info("Value for %s truncated to 255 characters", self._unique_id)
        else:
            self._state = value

        if sensor_data.get("unit") == "C" or self.sensor_type in [
            "wind_chill",
            "humidex",
        ]:
            self._unit = TEMP_CELSIUS
        else:
            self._unit = sensor_data.get("unit")

        timestamp = metadata.get("timestamp")
        if timestamp:
            updated_utc = datetime.strptime(timestamp, "%Y%m%d%H%M%S").isoformat()
        else:
            updated_utc = None

        self._attr.update(
            {
                ATTR_ATTRIBUTION: CONF_ATTRIBUTION,
                ATTR_UPDATED: updated_utc,
                ATTR_LOCATION: metadata.get("location"),
                ATTR_STATION: metadata.get("station"),
            }
        )
