"""Support for RESTful API sensors."""
import json
import logging
from xml.parsers.expat import ExpatError

import httpx
from jsonpath import jsonpath
import voluptuous as vol
import xmltodict

from homeassistant.components.sensor import DEVICE_CLASSES_SCHEMA, PLATFORM_SCHEMA
from homeassistant.const import (
    CONF_AUTHENTICATION,
    CONF_DEVICE_CLASS,
    CONF_FORCE_UPDATE,
    CONF_HEADERS,
    CONF_METHOD,
    CONF_NAME,
    CONF_PARAMS,
    CONF_PASSWORD,
    CONF_PAYLOAD,
    CONF_RESOURCE,
    CONF_RESOURCE_TEMPLATE,
    CONF_TIMEOUT,
    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
from homeassistant.helpers.entity import Entity
from homeassistant.helpers.reload import async_setup_reload_service

from . import DOMAIN, PLATFORMS
from .data import DEFAULT_TIMEOUT, RestData

_LOGGER = logging.getLogger(__name__)

DEFAULT_METHOD = "GET"
DEFAULT_NAME = "REST Sensor"
DEFAULT_VERIFY_SSL = True
DEFAULT_FORCE_UPDATE = False


CONF_JSON_ATTRS = "json_attributes"
CONF_JSON_ATTRS_PATH = "json_attributes_path"
METHODS = ["POST", "GET"]

PLATFORM_SCHEMA = PLATFORM_SCHEMA.extend(
    {
        vol.Exclusive(CONF_RESOURCE, CONF_RESOURCE): cv.url,
        vol.Exclusive(CONF_RESOURCE_TEMPLATE, CONF_RESOURCE): cv.template,
        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_PARAMS): vol.Schema({cv.string: cv.string}),
        vol.Optional(CONF_JSON_ATTRS, default=[]): cv.ensure_list_csv,
        vol.Optional(CONF_METHOD, default=DEFAULT_METHOD): vol.In(METHODS),
        vol.Optional(CONF_NAME, default=DEFAULT_NAME): cv.string,
        vol.Optional(CONF_PASSWORD): cv.string,
        vol.Optional(CONF_PAYLOAD): cv.string,
        vol.Optional(CONF_UNIT_OF_MEASUREMENT): cv.string,
        vol.Optional(CONF_DEVICE_CLASS): DEVICE_CLASSES_SCHEMA,
        vol.Optional(CONF_USERNAME): cv.string,
        vol.Optional(CONF_JSON_ATTRS_PATH): cv.string,
        vol.Optional(CONF_VALUE_TEMPLATE): cv.template,
        vol.Optional(CONF_VERIFY_SSL, default=DEFAULT_VERIFY_SSL): cv.boolean,
        vol.Optional(CONF_FORCE_UPDATE, default=DEFAULT_FORCE_UPDATE): cv.boolean,
        vol.Optional(CONF_TIMEOUT, default=DEFAULT_TIMEOUT): cv.positive_int,
    }
)

PLATFORM_SCHEMA = vol.All(
    cv.has_at_least_one_key(CONF_RESOURCE, CONF_RESOURCE_TEMPLATE), PLATFORM_SCHEMA
)


async def async_setup_platform(hass, config, async_add_entities, discovery_info=None):
    """Set up the RESTful sensor."""
    await async_setup_reload_service(hass, DOMAIN, PLATFORMS)

    name = config.get(CONF_NAME)
    resource = config.get(CONF_RESOURCE)
    resource_template = config.get(CONF_RESOURCE_TEMPLATE)
    method = config.get(CONF_METHOD)
    payload = config.get(CONF_PAYLOAD)
    verify_ssl = config.get(CONF_VERIFY_SSL)
    username = config.get(CONF_USERNAME)
    password = config.get(CONF_PASSWORD)
    headers = config.get(CONF_HEADERS)
    params = config.get(CONF_PARAMS)
    unit = config.get(CONF_UNIT_OF_MEASUREMENT)
    device_class = config.get(CONF_DEVICE_CLASS)
    value_template = config.get(CONF_VALUE_TEMPLATE)
    json_attrs = config.get(CONF_JSON_ATTRS)
    json_attrs_path = config.get(CONF_JSON_ATTRS_PATH)
    force_update = config.get(CONF_FORCE_UPDATE)
    timeout = config.get(CONF_TIMEOUT)

    if value_template is not None:
        value_template.hass = hass

    if resource_template is not None:
        resource_template.hass = hass
        resource = resource_template.async_render(parse_result=False)

    if username and password:
        if config.get(CONF_AUTHENTICATION) == HTTP_DIGEST_AUTHENTICATION:
            auth = httpx.DigestAuth(username, password)
        else:
            auth = (username, password)
    else:
        auth = None
    rest = RestData(
        hass, method, resource, auth, headers, params, payload, verify_ssl, timeout
    )

    await rest.async_update()

    if rest.data is None:
        raise PlatformNotReady

    # Must update the sensor now (including fetching the rest resource) to
    # ensure it's updating its state.
    async_add_entities(
        [
            RestSensor(
                hass,
                rest,
                name,
                unit,
                device_class,
                value_template,
                json_attrs,
                force_update,
                resource_template,
                json_attrs_path,
            )
        ],
    )


class RestSensor(Entity):
    """Implementation of a REST sensor."""

    def __init__(
        self,
        hass,
        rest,
        name,
        unit_of_measurement,
        device_class,
        value_template,
        json_attrs,
        force_update,
        resource_template,
        json_attrs_path,
    ):
        """Initialize the REST sensor."""
        self._hass = hass
        self.rest = rest
        self._name = name
        self._state = None
        self._unit_of_measurement = unit_of_measurement
        self._device_class = device_class
        self._value_template = value_template
        self._json_attrs = json_attrs
        self._attributes = None
        self._force_update = force_update
        self._resource_template = resource_template
        self._json_attrs_path = json_attrs_path

    @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 device_class(self):
        """Return the class of this sensor."""
        return self._device_class

    @property
    def available(self):
        """Return if the sensor data are available."""
        return self.rest.data is not None

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

    @property
    def force_update(self):
        """Force update."""
        return self._force_update

    async def async_update(self):
        """Get the latest data from REST API and update the state."""
        if self._resource_template is not None:
            self.rest.set_url(self._resource_template.async_render(parse_result=False))

        await self.rest.async_update()
        self._update_from_rest_data()

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

    def _update_from_rest_data(self):
        """Update state from the rest data."""
        value = self.rest.data
        _LOGGER.debug("Data fetched from resource: %s", value)
        if self.rest.headers is not None:
            # If the http request failed, headers will be None
            content_type = self.rest.headers.get("content-type")

            if content_type and (
                content_type.startswith("text/xml")
                or content_type.startswith("application/xml")
                or content_type.startswith("application/xhtml+xml")
            ):
                try:
                    value = json.dumps(xmltodict.parse(value))
                    _LOGGER.debug("JSON converted from XML: %s", value)
                except ExpatError:
                    _LOGGER.warning(
                        "REST xml result could not be parsed and converted to JSON"
                    )
                    _LOGGER.debug("Erroneous XML: %s", value)

        if self._json_attrs:
            self._attributes = {}
            if value:
                try:
                    json_dict = json.loads(value)
                    if self._json_attrs_path is not None:
                        json_dict = jsonpath(json_dict, self._json_attrs_path)
                    # jsonpath will always store the result in json_dict[0]
                    # so the next line happens to work exactly as needed to
                    # find the result
                    if isinstance(json_dict, list):
                        json_dict = json_dict[0]
                    if isinstance(json_dict, dict):
                        attrs = {
                            k: json_dict[k] for k in self._json_attrs if k in json_dict
                        }
                        self._attributes = attrs
                    else:
                        _LOGGER.warning(
                            "JSON result was not a dictionary"
                            " or list with 0th element a dictionary"
                        )
                except ValueError:
                    _LOGGER.warning("REST result could not be parsed as JSON")
                    _LOGGER.debug("Erroneous JSON: %s", value)

            else:
                _LOGGER.warning("Empty reply found when expecting JSON data")

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

        self._state = value

    @property
    def device_state_attributes(self):
        """Return the state attributes."""
        return self._attributes