"""Support for Zyxel Keenetic NDMS2 based routers."""
import logging

from ndms2_client import Client, ConnectionException, TelnetConnection
import voluptuous as vol

from homeassistant.components.device_tracker import (
    DOMAIN,
    PLATFORM_SCHEMA,
    DeviceScanner,
)
from homeassistant.const import CONF_HOST, CONF_PASSWORD, CONF_PORT, CONF_USERNAME
import homeassistant.helpers.config_validation as cv

_LOGGER = logging.getLogger(__name__)

# Interface name to track devices for. Most likely one will not need to
# change it from default 'Home'. This is needed not to track Guest WI-FI-
# clients and router itself
CONF_INTERFACE = "interface"

DEFAULT_INTERFACE = "Home"
DEFAULT_PORT = 23


PLATFORM_SCHEMA = PLATFORM_SCHEMA.extend(
    {
        vol.Required(CONF_HOST): cv.string,
        vol.Required(CONF_USERNAME): cv.string,
        vol.Required(CONF_PORT, default=DEFAULT_PORT): cv.port,
        vol.Required(CONF_PASSWORD): cv.string,
        vol.Required(CONF_INTERFACE, default=DEFAULT_INTERFACE): cv.string,
    }
)


def get_scanner(_hass, config):
    """Validate the configuration and return a Keenetic NDMS2 scanner."""
    scanner = KeeneticNDMS2DeviceScanner(config[DOMAIN])

    return scanner if scanner.success_init else None


class KeeneticNDMS2DeviceScanner(DeviceScanner):
    """This class scans for devices using keenetic NDMS2 web interface."""

    def __init__(self, config):
        """Initialize the scanner."""

        self.last_results = []

        self._interface = config[CONF_INTERFACE]

        self._client = Client(
            TelnetConnection(
                config.get(CONF_HOST),
                config.get(CONF_PORT),
                config.get(CONF_USERNAME),
                config.get(CONF_PASSWORD),
            )
        )

        self.success_init = self._update_info()
        _LOGGER.info("Scanner initialized")

    def scan_devices(self):
        """Scan for new devices and return a list with found device IDs."""
        self._update_info()

        return [device.mac for device in self.last_results]

    def get_device_name(self, device):
        """Return the name of the given device or None if we don't know."""
        name = next(
            (result.name for result in self.last_results if result.mac == device), None
        )
        return name

    def get_extra_attributes(self, device):
        """Return the IP of the given device."""
        attributes = next(
            ({"ip": result.ip} for result in self.last_results if result.mac == device),
            {},
        )
        return attributes

    def _update_info(self):
        """Get ARP from keenetic router."""
        _LOGGER.debug("Fetching devices from router...")

        try:
            self.last_results = [
                dev
                for dev in self._client.get_devices()
                if dev.interface == self._interface
            ]
            _LOGGER.debug("Successfully fetched data from router")
            return True

        except ConnectionException:
            _LOGGER.error("Error fetching data from router")
            return False