"""Select entity for Xiaoxiang Smart BMS MOS gate control."""
from __future__ import annotations

from homeassistant.components.select import SelectEntity
from homeassistant.config_entries import ConfigEntry
from homeassistant.core import HomeAssistant
from homeassistant.helpers.entity_platform import AddEntitiesCallback
from homeassistant.helpers.update_coordinator import CoordinatorEntity

from .const import (
    DOMAIN,
    MOS_BOTH_OFF,
    MOS_CHARGE_OFF,
    MOS_DISCHARGE_OFF,
    MOS_NORMAL,
)
from .coordinator import BmsCoordinator

# Maps the human-readable option to the XX byte value in the write command
_OPTION_TO_VALUE: dict[str, int] = {
    "Normal":           MOS_NORMAL,
    "Charge Disabled":  MOS_CHARGE_OFF,
    "Discharge Disabled": MOS_DISCHARGE_OFF,
    "Both Disabled":    MOS_BOTH_OFF,
}
_OPTIONS = list(_OPTION_TO_VALUE)


async def async_setup_entry(
    hass: HomeAssistant,
    entry: ConfigEntry,
    async_add_entities: AddEntitiesCallback,
) -> None:
    coordinator: BmsCoordinator = hass.data[DOMAIN][entry.entry_id]
    async_add_entities([BmsMosSelect(coordinator)])


class BmsMosSelect(CoordinatorEntity[BmsCoordinator], SelectEntity):
    """Dropdown to control the BMS charge/discharge MOSFET gates.

    Current state is derived from the MOS status bits returned by the BMS
    on every poll.  Selecting an option sends the write command (0xE1)
    immediately and triggers a coordinator refresh so sensors update.
    """

    _attr_has_entity_name = True
    _attr_name = "MOS Control"
    _attr_options = _OPTIONS
    _attr_icon = "mdi:electric-switch"

    def __init__(self, coordinator: BmsCoordinator) -> None:
        super().__init__(coordinator)
        self._attr_unique_id = f"{coordinator.address}_mos_control"
        self._attr_device_info = coordinator.device_info

    @property
    def current_option(self) -> str | None:
        data = self.coordinator.data
        if not data:
            return None
        charge    = data.get("mos_charge_enabled", True)
        discharge = data.get("mos_discharge_enabled", True)
        if charge and discharge:
            return "Normal"
        if not charge and discharge:
            return "Charge Disabled"
        if charge and not discharge:
            return "Discharge Disabled"
        return "Both Disabled"

    async def async_select_option(self, option: str) -> None:
        value = _OPTION_TO_VALUE[option]
        await self.coordinator.async_write_mos(value)