"""Support for switch sensor using I2C MCP23017 chip."""
import logging

import voluptuous as vol

from homeassistant.components.switch import PLATFORM_SCHEMA
from homeassistant.const import DEVICE_DEFAULT_NAME
from homeassistant.helpers.entity import ToggleEntity
import homeassistant.helpers.config_validation as cv

_LOGGER = logging.getLogger(__name__)

CONF_INVERT_LOGIC = 'invert_logic'
CONF_I2C_ADDRESS = 'i2c_address'
CONF_PINS = 'pins'
CONF_PULL_MODE = 'pull_mode'

DEFAULT_INVERT_LOGIC = False
DEFAULT_I2C_ADDRESS = 0x20

_SWITCHES_SCHEMA = vol.Schema({
    cv.positive_int: cv.string,
})

PLATFORM_SCHEMA = PLATFORM_SCHEMA.extend({
    vol.Required(CONF_PINS): _SWITCHES_SCHEMA,
    vol.Optional(CONF_INVERT_LOGIC, default=DEFAULT_INVERT_LOGIC): cv.boolean,
    vol.Optional(CONF_I2C_ADDRESS, default=DEFAULT_I2C_ADDRESS):
    vol.Coerce(int),
})


def setup_platform(hass, config, add_entities, discovery_info=None):
    """Set up the MCP23017 devices."""
    import board
    import busio
    import adafruit_mcp230xx

    invert_logic = config.get(CONF_INVERT_LOGIC)
    i2c_address = config.get(CONF_I2C_ADDRESS)

    i2c = busio.I2C(board.SCL, board.SDA)
    mcp = adafruit_mcp230xx.MCP23017(i2c, address=i2c_address)

    switches = []
    pins = config.get(CONF_PINS)
    for pin_num, pin_name in pins.items():
        pin = mcp.get_pin(pin_num)
        switches.append(MCP23017Switch(pin_name, pin, invert_logic))
    add_entities(switches)


class MCP23017Switch(ToggleEntity):
    """Representation of a  MCP23017 output pin."""

    def __init__(self, name, pin, invert_logic):
        """Initialize the pin."""
        import digitalio
        self._name = name or DEVICE_DEFAULT_NAME
        self._pin = pin
        self._invert_logic = invert_logic
        self._state = False

        self._pin.direction = digitalio.Direction.OUTPUT
        self._pin.value = self._invert_logic

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

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

    @property
    def is_on(self):
        """Return true if device is on."""
        return self._state

    @property
    def assumed_state(self):
        """Return true if optimistic updates are used."""
        return True

    def turn_on(self, **kwargs):
        """Turn the device on."""
        self._pin.value = not self._invert_logic
        self._state = True
        self.schedule_update_ha_state()

    def turn_off(self, **kwargs):
        """Turn the device off."""
        self._pin.value = self._invert_logic
        self._state = False
        self.schedule_update_ha_state()
