"""Light platform for LED Screen Controller (api_input CSS sources)."""
from __future__ import annotations

import logging
from typing import Any

from homeassistant.components.light import (
    ATTR_BRIGHTNESS,
    ATTR_RGB_COLOR,
    ColorMode,
    LightEntity,
)
from homeassistant.config_entries import ConfigEntry
from homeassistant.core import HomeAssistant
from homeassistant.helpers.entity_platform import AddEntitiesCallback
from homeassistant.helpers.restore_state import RestoreEntity
from homeassistant.helpers.update_coordinator import CoordinatorEntity

from .const import DOMAIN, DATA_COORDINATOR
from .coordinator import LedGrabCoordinator

_LOGGER = logging.getLogger(__name__)


async def async_setup_entry(
    hass: HomeAssistant,
    entry: ConfigEntry,
    async_add_entities: AddEntitiesCallback,
) -> None:
    """Set up LED Screen Controller api_input lights."""
    data = hass.data[DOMAIN][entry.entry_id]
    coordinator: LedGrabCoordinator = data[DATA_COORDINATOR]

    entities = []
    if coordinator.data:
        for source in coordinator.data.get("css_sources", []):
            if source.get("source_type") == "api_input":
                entities.append(
                    ApiInputLight(coordinator, source, entry.entry_id)
                )

    async_add_entities(entities)


class ApiInputLight(CoordinatorEntity, LightEntity, RestoreEntity):
    """Representation of an api_input CSS source as a light entity.

    The light's RGB color doubles as the source's ``fallback_color`` (the
    resting color shown when no API input arrives within ``timeout``).
    Turning the light off only pushes black segments — it does *not* zero
    ``fallback_color`` — so the chosen default color persists across off/on
    cycles. The on/off state itself is restored across HA restarts via
    ``RestoreEntity``.
    """

    _attr_has_entity_name = True
    _attr_color_mode = ColorMode.RGB
    _attr_supported_color_modes = {ColorMode.RGB}
    _attr_translation_key = "api_input_light"
    _attr_icon = "mdi:led-strip-variant"

    def __init__(
        self,
        coordinator: LedGrabCoordinator,
        source: dict[str, Any],
        entry_id: str,
    ) -> None:
        """Initialize the light."""
        super().__init__(coordinator)
        self._source_id: str = source["id"]
        self._source_name: str = source.get("name", self._source_id)
        self._entry_id = entry_id
        self._attr_unique_id = f"{self._source_id}_light"

        # Seed color from the source's current fallback_color; default to
        # white if it's unset/black so the picker has a sensible starting
        # value. is_on is provisional here and refined in async_added_to_hass
        # from RestoreEntity, since fallback_color alone no longer indicates
        # on/off.
        fallback = self._get_fallback_color()
        has_color = fallback != [0, 0, 0]
        self._rgb_color: tuple[int, int, int] = (
            tuple(fallback) if has_color else (255, 255, 255)  # type: ignore[arg-type]
        )
        self._is_on: bool = has_color
        self._brightness: int = 255

    async def async_added_to_hass(self) -> None:
        """Restore on/off state and last color from the previous HA session."""
        await super().async_added_to_hass()
        last_state = await self.async_get_last_state()
        if last_state is None:
            return
        self._is_on = last_state.state == "on"
        last_rgb = last_state.attributes.get("rgb_color")
        if (
            isinstance(last_rgb, (list, tuple))
            and len(last_rgb) == 3
            and all(isinstance(c, (int, float)) for c in last_rgb)
        ):
            self._rgb_color = tuple(int(c) for c in last_rgb)  # type: ignore[assignment]
        last_brightness = last_state.attributes.get("brightness")
        if isinstance(last_brightness, (int, float)):
            self._brightness = int(last_brightness)

    @property
    def device_info(self) -> dict[str, Any]:
        """Return device information — one virtual device per api_input source."""
        return {
            "identifiers": {(DOMAIN, self._source_id)},
            "name": self._source_name,
            "manufacturer": "LedGrab",
            "model": "API Input CSS Source",
        }

    @property
    def is_on(self) -> bool:
        """Return true if the light is on."""
        return self._is_on

    @property
    def rgb_color(self) -> tuple[int, int, int]:
        """Return the current RGB color."""
        return self._rgb_color

    @property
    def brightness(self) -> int:
        """Return the current brightness (0-255)."""
        return self._brightness

    async def async_turn_on(self, **kwargs: Any) -> None:
        """Turn on the light, optionally setting color and brightness."""
        if ATTR_RGB_COLOR in kwargs:
            self._rgb_color = kwargs[ATTR_RGB_COLOR]
        if ATTR_BRIGHTNESS in kwargs:
            self._brightness = kwargs[ATTR_BRIGHTNESS]

        # Scale RGB by brightness
        scale = self._brightness / 255
        r, g, b = self._rgb_color
        scaled = [round(r * scale), round(g * scale), round(b * scale)]

        await self.coordinator.push_segments(
            self._source_id,
            [{"start": 0, "length": 9999, "mode": "solid", "color": scaled}],
        )
        # Update fallback_color so the color persists beyond the timeout
        await self.coordinator.update_source(
            self._source_id, fallback_color=scaled,
        )
        self._is_on = True
        self.async_write_ha_state()

    async def async_turn_off(self, **kwargs: Any) -> None:
        """Turn off the light by pushing black segments.

        ``fallback_color`` is intentionally left untouched so the chosen
        default color survives off/on cycles.
        """
        await self.coordinator.push_segments(
            self._source_id,
            [{"start": 0, "length": 9999, "mode": "solid", "color": [0, 0, 0]}],
        )
        self._is_on = False
        self.async_write_ha_state()

    def _get_fallback_color(self) -> list[int]:
        """Read fallback_color from the source config in coordinator data."""
        if not self.coordinator.data:
            return [0, 0, 0]
        for source in self.coordinator.data.get("css_sources", []):
            if source.get("id") == self._source_id:
                fallback = source.get("fallback_color")
                if fallback and len(fallback) >= 3:
                    return list(fallback[:3])
                break
        return [0, 0, 0]