"""WebSocket connection manager for Key Colors target color streams."""
from __future__ import annotations

import asyncio
import contextlib
import json
import logging
from collections.abc import Callable
from typing import Any

import aiohttp

from homeassistant.core import HomeAssistant
from homeassistant.helpers.aiohttp_client import async_get_clientsession

from .const import WS_RECONNECT_DELAY, WS_MAX_RECONNECT_DELAY

_LOGGER = logging.getLogger(__name__)


class KeyColorsWebSocketManager:
    """Manages WebSocket connections for Key Colors target color streams."""

    def __init__(
        self,
        hass: HomeAssistant,
        server_url: str,
        api_key: str,
    ) -> None:
        self._hass = hass
        self._server_url = server_url
        self._api_key = api_key
        self._connections: dict[str, asyncio.Task] = {}
        self._callbacks: dict[str, list[Callable]] = {}
        self._latest_colors: dict[str, dict[str, dict[str, int]]] = {}
        self._shutting_down = False

    def _get_ws_url(self, target_id: str) -> str:
        """Build WebSocket URL for a target."""
        ws_base = self._server_url.replace("http://", "ws://").replace(
            "https://", "wss://"
        )
        return f"{ws_base}/api/v1/output-targets/{target_id}/ws?token={self._api_key}"

    async def start_listening(self, target_id: str) -> None:
        """Start WebSocket connection for a target."""
        if target_id in self._connections:
            return
        task = self._hass.async_create_background_task(
            self._ws_loop(target_id),
            f"wled_screen_controller_ws_{target_id}",
        )
        self._connections[target_id] = task

    async def stop_listening(self, target_id: str) -> None:
        """Stop WebSocket connection for a target."""
        task = self._connections.pop(target_id, None)
        if task:
            task.cancel()
            with contextlib.suppress(asyncio.CancelledError):
                await task
        self._latest_colors.pop(target_id, None)

    def register_callback(
        self, target_id: str, callback: Callable
    ) -> Callable[[], None]:
        """Register a callback for color updates. Returns unregister function."""
        self._callbacks.setdefault(target_id, []).append(callback)

        def unregister() -> None:
            cbs = self._callbacks.get(target_id)
            if cbs and callback in cbs:
                cbs.remove(callback)

        return unregister

    def get_latest_colors(self, target_id: str) -> dict[str, dict[str, int]]:
        """Get latest colors for a target."""
        return self._latest_colors.get(target_id, {})

    async def _ws_loop(self, target_id: str) -> None:
        """WebSocket connection loop with reconnection."""
        delay = WS_RECONNECT_DELAY
        session = async_get_clientsession(self._hass)

        while not self._shutting_down:
            try:
                url = self._get_ws_url(target_id)
                async with session.ws_connect(url) as ws:
                    delay = WS_RECONNECT_DELAY  # reset on successful connect
                    _LOGGER.debug("WS connected for target %s", target_id)
                    async for msg in ws:
                        if msg.type == aiohttp.WSMsgType.TEXT:
                            self._handle_message(target_id, msg.data)
                        elif msg.type in (
                            aiohttp.WSMsgType.CLOSED,
                            aiohttp.WSMsgType.ERROR,
                        ):
                            break
            except asyncio.CancelledError:
                raise
            except (aiohttp.ClientError, asyncio.TimeoutError, OSError) as err:
                _LOGGER.debug("WS connection error for %s: %s", target_id, err)
            except Exception as err:
                _LOGGER.error("Unexpected WS error for %s: %s", target_id, err)

            if self._shutting_down:
                break

            await asyncio.sleep(delay)
            delay = min(delay * 2, WS_MAX_RECONNECT_DELAY)

    def _handle_message(self, target_id: str, raw: str) -> None:
        """Handle incoming WebSocket message."""
        try:
            data = json.loads(raw)
        except json.JSONDecodeError:
            return

        if data.get("type") != "colors_update":
            return

        colors: dict[str, Any] = data.get("colors", {})
        self._latest_colors[target_id] = colors

        for cb in self._callbacks.get(target_id, []):
            try:
                cb(colors)
            except Exception:
                _LOGGER.exception("Error in WS color callback for %s", target_id)

    async def shutdown(self) -> None:
        """Stop all WebSocket connections."""
        self._shutting_down = True
        for target_id in list(self._connections):
            await self.stop_listening(target_id)