"""Support for getting data from websites with scraping."""
import logging

from bs4 import BeautifulSoup
from requests.auth import HTTPBasicAuth, HTTPDigestAuth
import voluptuous as vol

from homeassistant.components.rest.data import RestData
from homeassistant.components.sensor import PLATFORM_SCHEMA, SensorEntity
from homeassistant.const import (
    CONF_AUTHENTICATION,
    CONF_HEADERS,
    CONF_NAME,
    CONF_PASSWORD,
    CONF_RESOURCE,
    CONF_UNIT_OF_MEASUREMENT,
    CONF_USERNAME,
    CONF_VALUE_TEMPLATE,
    CONF_VERIFY_SSL,
    HTTP_BASIC_AUTHENTICATION,
    HTTP_DIGEST_AUTHENTICATION,
)
from homeassistant.exceptions import PlatformNotReady
import homeassistant.helpers.config_validation as cv

_LOGGER = logging.getLogger(__name__)

CONF_ATTR = "attribute"
CONF_SELECT = "select"
CONF_INDEX = "index"

DEFAULT_NAME = "Web scrape"
DEFAULT_VERIFY_SSL = True

PLATFORM_SCHEMA = PLATFORM_SCHEMA.extend(
    {
        vol.Required(CONF_RESOURCE): cv.string,
        vol.Required(CONF_SELECT): cv.string,
        vol.Optional(CONF_ATTR): cv.string,
        vol.Optional(CONF_INDEX, default=0): cv.positive_int,
        vol.Optional(CONF_AUTHENTICATION): vol.In(
            [HTTP_BASIC_AUTHENTICATION, HTTP_DIGEST_AUTHENTICATION]
        ),
        vol.Optional(CONF_HEADERS): vol.Schema({cv.string: cv.string}),
        vol.Optional(CONF_NAME, default=DEFAULT_NAME): cv.string,
        vol.Optional(CONF_PASSWORD): cv.string,
        vol.Optional(CONF_UNIT_OF_MEASUREMENT): cv.string,
        vol.Optional(CONF_USERNAME): cv.string,
        vol.Optional(CONF_VALUE_TEMPLATE): cv.template,
        vol.Optional(CONF_VERIFY_SSL, default=DEFAULT_VERIFY_SSL): cv.boolean,
    }
)


async def async_setup_platform(hass, config, async_add_entities, discovery_info=None):
    """Set up the Web scrape sensor."""
    name = config.get(CONF_NAME)
    resource = config.get(CONF_RESOURCE)
    method = "GET"
    payload = None
    headers = config.get(CONF_HEADERS)
    verify_ssl = config.get(CONF_VERIFY_SSL)
    select = config.get(CONF_SELECT)
    attr = config.get(CONF_ATTR)
    index = config.get(CONF_INDEX)
    unit = config.get(CONF_UNIT_OF_MEASUREMENT)
    username = config.get(CONF_USERNAME)
    password = config.get(CONF_PASSWORD)
    value_template = config.get(CONF_VALUE_TEMPLATE)
    if value_template is not None:
        value_template.hass = hass

    if username and password:
        if config.get(CONF_AUTHENTICATION) == HTTP_DIGEST_AUTHENTICATION:
            auth = HTTPDigestAuth(username, password)
        else:
            auth = HTTPBasicAuth(username, password)
    else:
        auth = None
    rest = RestData(hass, method, resource, auth, headers, None, payload, verify_ssl)
    await rest.async_update()

    if rest.data is None:
        raise PlatformNotReady

    async_add_entities(
        [ScrapeSensor(rest, name, select, attr, index, value_template, unit)], True
    )


class ScrapeSensor(SensorEntity):
    """Representation of a web scrape sensor."""

    def __init__(self, rest, name, select, attr, index, value_template, unit):
        """Initialize a web scrape sensor."""
        self.rest = rest
        self._name = name
        self._state = None
        self._select = select
        self._attr = attr
        self._index = index
        self._value_template = value_template
        self._unit_of_measurement = unit

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

    @property
    def unit_of_measurement(self):
        """Return the unit the value is expressed in."""
        return self._unit_of_measurement

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

    def _extract_value(self):
        """Parse the html extraction in the executor."""
        raw_data = BeautifulSoup(self.rest.data, "html.parser")
        _LOGGER.debug(raw_data)

        if self._attr is not None:
            value = raw_data.select(self._select)[self._index][self._attr]
        else:
            tag = raw_data.select(self._select)[self._index]
            if tag.name in ("style", "script", "template"):
                value = tag.string
            else:
                value = tag.text
        _LOGGER.debug(value)
        return value

    async def async_update(self):
        """Get the latest data from the source and updates the state."""
        await self.rest.async_update()
        await self._async_update_from_rest_data()

    async def async_added_to_hass(self):
        """Ensure the data from the initial update is reflected in the state."""
        await self._async_update_from_rest_data()

    async def _async_update_from_rest_data(self):
        """Update state from the rest data."""
        if self.rest.data is None:
            _LOGGER.error("Unable to retrieve data for %s", self.name)
            return

        try:
            value = await self.hass.async_add_executor_job(self._extract_value)
        except IndexError:
            _LOGGER.error("Unable to extract data from HTML for %s", self.name)
            return

        if self._value_template is not None:
            self._state = self._value_template.async_render_with_possible_json_value(
                value, None
            )
        else:
            self._state = value
