"""DTO pubblico e sanificato dello stato del servizio.

Questa route non legge agent_tasks, sessioni operative o log. La tabella
public_dashboard_snapshot viene aggiornata dal backend con service_role e letta
qui tramite una whitelist di campi.
"""
from __future__ import annotations

import asyncio
import logging
from typing import Any

from fastapi import APIRouter

from .state import sb

_logger = logging.getLogger("agente_ai.api.public_status")
router = APIRouter(prefix="/api/public", tags=["public"])

_PUBLIC_FIELDS = (
    "singleton,service_status,active_sessions,queued_tasks,in_progress_tasks,"
    "app_version,updated_at"
)


@router.get("/status")
async def public_status() -> dict[str, Any]:
    """Restituisce esclusivamente lo snapshot deliberatamente pubblico."""
    client = sb()
    if client is None:
        return _degraded_snapshot("database_unavailable")

    def operation():
        return client.table("public_dashboard_snapshot").select(_PUBLIC_FIELDS).eq("singleton", True).limit(1).execute()

    try:
        result = await asyncio.to_thread(operation)
    except Exception as exc:
        _logger.warning("public status snapshot unavailable: %s", type(exc).__name__)
        return _degraded_snapshot("snapshot_unavailable")

    row = (result.data or [None])[0]
    if not row:
        return _degraded_snapshot("snapshot_not_initialized")

    return {
        "service_status": str(row.get("service_status") or "unknown"),
        "active_sessions": int(row.get("active_sessions") or 0),
        "queued_tasks": int(row.get("queued_tasks") or 0),
        "in_progress_tasks": int(row.get("in_progress_tasks") or 0),
        "app_version": row.get("app_version"),
        "updated_at": row.get("updated_at"),
    }


def _degraded_snapshot(reason: str) -> dict[str, Any]:
    """Safe public response while the operational snapshot is unavailable.

    The public endpoint is used by lightweight status surfaces. Returning a
    deliberate degraded state keeps those surfaces functional without
    exposing database errors, internal topology, or operational records.
    """
    return {
        "service_status": "degraded",
        "active_sessions": 0,
        "queued_tasks": 0,
        "in_progress_tasks": 0,
        "app_version": None,
        "updated_at": None,
        "degraded": True,
        "reason": reason,
    }