"""Support for binary sensor using the PiFace Digital I/O module on a RPi."""
import voluptuous as vol

from homeassistant.components import rpi_pfio
from homeassistant.components.binary_sensor import PLATFORM_SCHEMA, BinarySensorEntity
from homeassistant.const import CONF_NAME, DEVICE_DEFAULT_NAME
import homeassistant.helpers.config_validation as cv

CONF_INVERT_LOGIC = "invert_logic"
CONF_PORTS = "ports"
CONF_SETTLE_TIME = "settle_time"

DEFAULT_INVERT_LOGIC = False
DEFAULT_SETTLE_TIME = 20

PORT_SCHEMA = vol.Schema(
    {
        vol.Optional(CONF_NAME): cv.string,
        vol.Optional(CONF_SETTLE_TIME, default=DEFAULT_SETTLE_TIME): cv.positive_int,
        vol.Optional(CONF_INVERT_LOGIC, default=DEFAULT_INVERT_LOGIC): cv.boolean,
    }
)

PLATFORM_SCHEMA = PLATFORM_SCHEMA.extend(
    {vol.Optional(CONF_PORTS, default={}): vol.Schema({cv.positive_int: PORT_SCHEMA})}
)


def setup_platform(hass, config, add_entities, discovery_info=None):
    """Set up the PiFace Digital Input devices."""
    binary_sensors = []
    ports = config.get(CONF_PORTS)
    for port, port_entity in ports.items():
        name = port_entity.get(CONF_NAME)
        settle_time = port_entity[CONF_SETTLE_TIME] / 1000
        invert_logic = port_entity[CONF_INVERT_LOGIC]

        binary_sensors.append(
            RPiPFIOBinarySensor(hass, port, name, settle_time, invert_logic)
        )
    add_entities(binary_sensors, True)

    rpi_pfio.activate_listener(hass)


class RPiPFIOBinarySensor(BinarySensorEntity):
    """Represent a binary sensor that a PiFace Digital Input."""

    def __init__(self, hass, port, name, settle_time, invert_logic):
        """Initialize the RPi binary sensor."""
        self._port = port
        self._name = name or DEVICE_DEFAULT_NAME
        self._invert_logic = invert_logic
        self._state = None

        def read_pfio(port):
            """Read state from PFIO."""
            self._state = rpi_pfio.read_input(self._port)
            self.schedule_update_ha_state()

        rpi_pfio.edge_detect(hass, self._port, read_pfio, settle_time)

    @property
    def should_poll(self):
        """No polling needed."""
        return False

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

    @property
    def is_on(self):
        """Return the state of the entity."""
        return self._state != self._invert_logic

    def update(self):
        """Update the PFIO state."""
        self._state = rpi_pfio.read_input(self._port)
