"""Light platform for ninlight lamps."""

from __future__ import annotations

from typing import Any

from homeassistant.components.light import (
    ATTR_BRIGHTNESS,
    ATTR_COLOR_TEMP_KELVIN,
    ATTR_RGB_COLOR,
    ATTR_TRANSITION,
    ColorMode,
    LightEntity,
    LightEntityFeature,
)
from homeassistant.core import HomeAssistant
from homeassistant.helpers.entity_platform import AddConfigEntryEntitiesCallback

from .const import MAX_TRANSITION_MS
from .coordinator import NinlightConfigEntry, NinlightCoordinator
from .entity import NinlightEntity

PARALLEL_UPDATES = 0  # the coordinator lock serializes per lamp

_FALLBACK_KELVIN = (2700, 6500)


def ha_to_lamp_brightness(value: int) -> int:
    """HA 1-255 -> lamp 1-100. Never 0: 0 would switch the lamp off."""
    return max(1, min(100, round(value * 100 / 255)))


def lamp_to_ha_brightness(value: int) -> int:
    """Lamp 1-100 -> HA 1-255; round-trips back to the same lamp value."""
    return max(1, min(255, round(value * 255 / 100)))


def transition_ms(seconds: float) -> int:
    return max(0, min(MAX_TRANSITION_MS, round(seconds * 1000)))


async def async_setup_entry(
    hass: HomeAssistant,
    entry: NinlightConfigEntry,
    async_add_entities: AddConfigEntryEntitiesCallback,
) -> None:
    async_add_entities([NinlightLight(entry.runtime_data)])


class NinlightLight(NinlightEntity, LightEntity):
    """The lamp itself."""

    _attr_name = None
    _attr_supported_features = LightEntityFeature.TRANSITION

    def __init__(self, coordinator: NinlightCoordinator) -> None:
        super().__init__(coordinator, "light")

    @property
    def _state(self) -> dict[str, Any]:
        return self.coordinator.data.state

    @property
    def is_on(self) -> bool:
        return bool(self._state["on"])

    @property
    def brightness(self) -> int:
        return lamp_to_ha_brightness(int(self._state["brightness"]))

    @property
    def supported_color_modes(self) -> set[ColorMode]:
        if self._state["capabilities"].get("color"):
            return {ColorMode.RGB, ColorMode.COLOR_TEMP}
        return {ColorMode.COLOR_TEMP}

    @property
    def color_mode(self) -> ColorMode:
        if self._state.get("mode") == "color" and ColorMode.RGB in self.supported_color_modes:
            return ColorMode.RGB
        return ColorMode.COLOR_TEMP

    @property
    def rgb_color(self) -> tuple[int, int, int] | None:
        color = self._state.get("color")
        if not isinstance(color, dict):
            return None
        return (int(color["r"]), int(color["g"]), int(color["b"]))

    @property
    def color_temp_kelvin(self) -> int | None:
        value = self._state.get("color_temp")
        return int(value) if value is not None else None

    def _kelvin_range(self) -> tuple[int, int]:
        value = self._state["capabilities"].get("color_temp")
        if isinstance(value, list) and len(value) == 2:
            return (int(value[0]), int(value[1]))
        return _FALLBACK_KELVIN

    @property
    def min_color_temp_kelvin(self) -> int:
        return self._kelvin_range()[0]

    @property
    def max_color_temp_kelvin(self) -> int:
        return self._kelvin_range()[1]

    async def async_turn_on(self, **kwargs: Any) -> None:
        fields: dict[str, Any] = {"on": True}
        if ATTR_BRIGHTNESS in kwargs:
            fields["brightness"] = ha_to_lamp_brightness(kwargs[ATTR_BRIGHTNESS])
        if ATTR_RGB_COLOR in kwargs:
            red, green, blue = kwargs[ATTR_RGB_COLOR]
            fields["color"] = {"r": red, "g": green, "b": blue}
        if ATTR_COLOR_TEMP_KELVIN in kwargs:
            fields["color_temp"] = int(kwargs[ATTR_COLOR_TEMP_KELVIN])
        if ATTR_TRANSITION in kwargs:
            fields["transition"] = transition_ms(kwargs[ATTR_TRANSITION])
        await self.coordinator.async_set_state(**fields)

    async def async_turn_off(self, **kwargs: Any) -> None:
        fields: dict[str, Any] = {"on": False}
        if ATTR_TRANSITION in kwargs:
            fields["transition"] = transition_ms(kwargs[ATTR_TRANSITION])
        await self.coordinator.async_set_state(**fields)