"""
Support for monitoring OctoPrint sensors.

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

import requests

from homeassistant.components.octoprint import (SENSOR_TYPES,
                                                DOMAIN as COMPONENT_DOMAIN)
from homeassistant.const import (TEMP_CELSIUS)
from homeassistant.helpers.entity import Entity

_LOGGER = logging.getLogger(__name__)

DEPENDENCIES = ['octoprint']
NOTIFICATION_ID = 'octoprint_notification'
NOTIFICATION_TITLE = 'OctoPrint sensor setup error'


def setup_platform(hass, config, add_entities, discovery_info=None):
    """Set up the available OctoPrint sensors."""
    if discovery_info is None:
        return

    name = discovery_info['name']
    base_url = discovery_info['base_url']
    monitored_conditions = discovery_info['sensors']
    octoprint_api = hass.data[COMPONENT_DOMAIN][base_url]
    tools = octoprint_api.get_tools()

    if "Temperatures" in monitored_conditions:
        if not tools:
            hass.components.persistent_notification.create(
                'Your printer appears to be offline.<br />'
                'If you do not want to have your printer on <br />'
                ' at all times, and you would like to monitor <br /> '
                'temperatures, please add <br />'
                'bed and/or number&#95of&#95tools to your config <br />'
                'and restart.',
                title=NOTIFICATION_TITLE,
                notification_id=NOTIFICATION_ID)

    devices = []
    types = ["actual", "target"]
    for octo_type in monitored_conditions:
        if octo_type == "Temperatures":
            for tool in tools:
                for temp_type in types:
                    new_sensor = OctoPrintSensor(
                        octoprint_api, temp_type, temp_type, name,
                        SENSOR_TYPES[octo_type][3], SENSOR_TYPES[octo_type][0],
                        SENSOR_TYPES[octo_type][1], tool)
                    devices.append(new_sensor)
        else:
            new_sensor = OctoPrintSensor(
                octoprint_api, octo_type, SENSOR_TYPES[octo_type][2],
                name, SENSOR_TYPES[octo_type][3], SENSOR_TYPES[octo_type][0],
                SENSOR_TYPES[octo_type][1], None, SENSOR_TYPES[octo_type][4])
            devices.append(new_sensor)
    add_entities(devices, True)


class OctoPrintSensor(Entity):
    """Representation of an OctoPrint sensor."""

    def __init__(self, api, condition, sensor_type, sensor_name, unit,
                 endpoint, group, tool=None, icon=None):
        """Initialize a new OctoPrint sensor."""
        self.sensor_name = sensor_name
        if tool is None:
            self._name = '{} {}'.format(sensor_name, condition)
        else:
            self._name = '{} {} {} {}'.format(
                sensor_name, condition, tool, 'temp')
        self.sensor_type = sensor_type
        self.api = api
        self._state = None
        self._unit_of_measurement = unit
        self.api_endpoint = endpoint
        self.api_group = group
        self.api_tool = tool
        self._icon = icon
        _LOGGER.debug("Created OctoPrint sensor %r", self)

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

    @property
    def state(self):
        """Return the state of the sensor."""
        sensor_unit = self.unit_of_measurement
        if sensor_unit in (TEMP_CELSIUS, "%"):
            # API sometimes returns null and not 0
            if self._state is None:
                self._state = 0
            return round(self._state, 2)
        return self._state

    @property
    def unit_of_measurement(self):
        """Return the unit of measurement of this entity, if any."""
        return self._unit_of_measurement

    def update(self):
        """Update state of sensor."""
        try:
            self._state = self.api.update(
                self.sensor_type, self.api_endpoint, self.api_group,
                self.api_tool)
        except requests.exceptions.ConnectionError:
            # Error calling the api, already logged in api.update()
            return

    @property
    def icon(self):
        """Icon to use in the frontend."""
        return self._icon