from __future__ import annotations

from typing import Any

import aiohttp


class HAClient:
    """Async Home Assistant REST API client using long-lived token auth."""

    def __init__(self, base_url: str, token: str, timeout: float = 10.0) -> None:
        self._base_url = base_url.rstrip("/")
        self._headers = {
            "Authorization": f"Bearer {token}",
            "Content-Type": "application/json",
        }
        self._timeout = aiohttp.ClientTimeout(total=timeout)
        self._session: aiohttp.ClientSession | None = None

    async def __aenter__(self) -> "HAClient":
        self._session = aiohttp.ClientSession(
            headers=self._headers,
            timeout=self._timeout,
        )
        return self

    async def __aexit__(self, *_: Any) -> None:
        if self._session:
            await self._session.close()
            self._session = None

    def _session_or_raise(self) -> aiohttp.ClientSession:
        if self._session is None:
            raise RuntimeError("HAClient must be used as an async context manager")
        return self._session

    async def get_api_status(self) -> dict[str, Any]:
        """GET /api/ — returns {"message": "API running."} when HA is up."""
        async with self._session_or_raise().get(f"{self._base_url}/api/") as resp:
            resp.raise_for_status()
            return await resp.json()

    async def get_states(self) -> list[dict[str, Any]]:
        """GET /api/states — full entity state list."""
        async with self._session_or_raise().get(f"{self._base_url}/api/states") as resp:
            resp.raise_for_status()
            return await resp.json()

    async def get_system_health(self) -> dict[str, Any]:
        """GET /api/system_health — per-integration health summary."""
        async with self._session_or_raise().get(
            f"{self._base_url}/api/system_health"
        ) as resp:
            resp.raise_for_status()
            return await resp.json()

    async def get_config(self) -> dict[str, Any]:
        """GET /api/config — HA configuration including version."""
        async with self._session_or_raise().get(f"{self._base_url}/api/config") as resp:
            resp.raise_for_status()
            return await resp.json()

    async def get_automation_traces(self, automation_id: str) -> list[dict[str, Any]]:
        """GET /api/trace/automation/<id> — last run traces for an automation."""
        url = f"{self._base_url}/api/trace/automation/{automation_id}"
        async with self._session_or_raise().get(url) as resp:
            resp.raise_for_status()
            return await resp.json()

    async def get_error_log(self) -> str:
        """GET /api/error_log — plaintext error log."""
        async with self._session_or_raise().get(
            f"{self._base_url}/api/error_log"
        ) as resp:
            resp.raise_for_status()
            return await resp.text()