import time

import httpx
from fastapi import APIRouter

from config import LITELLM_HEALTH_API_KEY, LITELLM_URL

router = APIRouter()


@router.get("/health")
async def litellm_health():
    timeout = httpx.Timeout(2.0)
    checks = ("/health", "/v1/models")

    api_key = (LITELLM_HEALTH_API_KEY or "").strip()
    headers = {}
    if api_key:
        headers = {
            "Authorization": f"Bearer {api_key}",
            "X-API-Key": api_key,
        }

    last_error = None
    async with httpx.AsyncClient(timeout=timeout) as client:
        for path in checks:
            url = f"{LITELLM_URL.rstrip('/')}{path}"
            started = time.perf_counter()
            try:
                response = await client.get(url, headers=headers)
                latency_ms = round((time.perf_counter() - started) * 1000, 1)

                if response.is_success:
                    return {
                        "ok": True,
                        "status": "up",
                        "latency_ms": latency_ms,
                        "endpoint": path,
                        "http_status": response.status_code,
                    }

                if response.status_code == 401 and not api_key:
                    return {
                        "ok": True,
                        "status": "auth_required",
                        "latency_ms": latency_ms,
                        "endpoint": path,
                        "http_status": response.status_code,
                    }

                if response.status_code == 401 and api_key:
                    last_error = f"{path} returned 401 with configured health auth"
                else:
                    last_error = f"{path} returned {response.status_code}"
            except Exception as exc:
                last_error = str(exc)

    return {
        "ok": False,
        "status": "down",
        "latency_ms": None,
        "endpoint": None,
        "error": last_error or "health check failed",
    }