import typing

# circuitpython
import busio
import digitalio
import adafruit_mcp3xxx.analog_in
import adafruit_mcp3xxx.mcp3008

import homeassistant.const
import homeassistant.core
import homeassistant.helpers.entity


class MCP3008Channel(homeassistant.helpers.entity.Entity):
    def __init__(self, adc: adafruit_mcp3xxx.mcp3008.MCP3008, channel: int) -> None:
        self._input = adafruit_mcp3xxx.analog_in.AnalogIn(adc, channel)
        self._channel = channel
        self._state: typing.Optional[float] = None

    # https://developers.home-assistant.io/docs/core/entity/#generic-properties

    @property
    def name(self) -> str:
        return f"MCP3008 Channel #{self._channel}"

    @property
    def unique_id(self) -> str:
        return f"mcp3008-ch{self._channel}"

    # https://developers.home-assistant.io/docs/core/entity/sensor/#properties

    @property
    def state(self) -> typing.Optional[float]:
        return self._state

    @property
    def device_class(self) -> str:
        return "voltage"

    @property
    def unit_of_measurement(self) -> str:
        return homeassistant.const.VOLT

    def update(self) -> None:
        self._state = self._input.voltage


def setup_platform(
    hass: homeassistant.core.HomeAssistant,
    config: dict,
    add_entities: typing.Callable,
    discovery_info=None,
):
    board = __import__("board")  # raises NotImplementedError
    spi = busio.SPI(clock=board.SCK, MISO=board.MISO, MOSI=board.MOSI)
    spi_chip_select = digitalio.DigitalInOut(board.D5)
    adc = adafruit_mcp3xxx.mcp3008.MCP3008(
        spi_bus=spi, cs=spi_chip_select, ref_voltage=3.3
    )
    add_entities(
        [
            MCP3008Channel(adc=adc, channel=c)
            for c in [
                adafruit_mcp3xxx.mcp3008.P0,
                adafruit_mcp3xxx.mcp3008.P1,
                adafruit_mcp3xxx.mcp3008.P2,
                adafruit_mcp3xxx.mcp3008.P3,
                adafruit_mcp3xxx.mcp3008.P4,
                adafruit_mcp3xxx.mcp3008.P5,
                adafruit_mcp3xxx.mcp3008.P6,
                adafruit_mcp3xxx.mcp3008.P7,
            ]
        ]
    )