"""Health check and error metrics endpoints."""

import logging

from fastapi import APIRouter, Depends, HTTPException, status
from sqlalchemy import text
from sqlalchemy.ext.asyncio import AsyncSession

from cartsnitch_api.auth.dependencies import verify_service_key
from cartsnitch_api.database import get_db
from cartsnitch_api.middleware.error_handler import get_error_monitor

logger = logging.getLogger(__name__)

router = APIRouter(tags=["health"])


@router.get("/health")
async def health(db: AsyncSession = Depends(get_db)):
    """Liveness + DB connectivity probe.

    Returns HTTP 200 when the API process is responsive *and* the database
    is reachable, so Kubernetes readiness probes can correctly route traffic
    away from pods that have lost their database connection.

    Returns HTTP 503 when the database is unreachable so K8s marks the pod
    unhealthy and stops sending traffic to it.
    """
    try:
        await db.execute(text("SELECT 1"))
    except Exception as exc:
        logger.exception("Health check failed: database unreachable")
        raise HTTPException(
            status_code=status.HTTP_503_SERVICE_UNAVAILABLE,
            detail={"status": "unavailable", "database": "disconnected"},
        ) from exc
    return {"status": "ok", "database": "connected"}


@router.get("/internal/error-stats", dependencies=[Depends(verify_service_key)])
async def error_stats():
    """Error monitoring stats — internal only (requires X-Service-Key)."""
    monitor = get_error_monitor()
    return monitor.get_stats()