"""
backend/api/hf_monitor.py — Monitoraggio centralizzato HF Spaces (ARCH-P5.2-MONITOR)

Aggrega salute e stato di tutti gli HF Spaces configurati:
  - Polling salute via /health endpoint di ogni Space
  - Stato runtime via HuggingFace API (RUNNING/SLEEPING/BUILDING)
  - Cache interna con TTL per evitare flooding degli endpoint
  - Background polling ogni 60s

Endpoints:
  GET  /api/hf-monitor/spaces          — stato aggregato tutti gli Space (cached)
  POST /api/hf-monitor/spaces/refresh  — forza aggiornamento immediato
  GET  /api/hf-monitor/ping/{space_id} — ping live singolo Space

Invarianti:
  - Zero crash se uno Space non risponde (tutto in try/except)
  - Token non esposto nei response
  - Cache aggiornata in background senza bloccare l'API
  - Idempotente: start_monitor() sicuro da chiamare più volte
"""
from __future__ import annotations

import asyncio
import logging
import os
import time
from dataclasses import dataclass, field, asdict
from typing import Any

import httpx
from fastapi import APIRouter, Depends, HTTPException

from .auth_guard import AuthRole, require_role

_logger = logging.getLogger("api.hf_monitor")
router  = APIRouter()

# ── Configurazione ──────────────────────────────────────────────────────────────
_PING_TIMEOUT_S   = 8.0    # timeout ping singolo Space
_HF_API_TIMEOUT_S = 6.0    # timeout HuggingFace runtime API
_CACHE_TTL_S      = 60.0   # TTL cache risultati
_POLL_INTERVAL_S  = 60.0   # intervallo background polling
_HF_API_BASE      = "https://huggingface.co/api/spaces"

# ── Tipi ────────────────────────────────────────────────────────────────────────

@dataclass
class SpaceConfig:
    space_id:   str    # ID univoco interno (es. "brain", "daemon")
    name:       str    # Nome display (es. "Brain / Backend")
    base_url:   str    # URL base dello Space
    hf_repo_id: str = ""  # ID repo HF (es. "arjanit98/terminal") — per API runtime
    role:       str = ""  # ruolo: brain | daemon | worker | compute

@dataclass
class SpaceStatus:
    space_id:    str
    name:        str
    base_url:    str
    role:        str
    # Health
    health:      str   = "unknown"   # ok | degraded | down | unknown
    latency_ms:  float = 0.0
    http_status: int   = 0
    # HF Runtime stage
    hf_stage:    str   = "unknown"   # RUNNING | SLEEPING | BUILDING | FAILED | unknown
    # Meta
    checked_at:  float = field(default_factory=time.time)
    error:       str   = ""


def _build_spaces_from_env() -> list[SpaceConfig]:
    """Legge configurazioni degli Space dalle env var. Zero crash su var mancanti."""
    spaces: list[SpaceConfig] = []

    def _add(space_id: str, name: str, env_url: str,
             hf_repo_id: str = "", role: str = "") -> None:
        url = os.getenv(env_url, "").rstrip("/")
        if url:
            spaces.append(SpaceConfig(
                space_id=space_id, name=name, base_url=url,
                hf_repo_id=hf_repo_id, role=role,
            ))
        else:
            _logger.debug("hf_monitor: %s non configurato (%s vuoto)", space_id, env_url)

    # Fleet — aggiungere nuove righe al crescere degli Space
    _add("brain",    "Brain / Backend",   "HF_SPACE_URL",        role="brain")
    _add("daemon",   "Daemon / Telegram", "HF_SPACE_B_URL",      role="daemon")
    _add("worker-a", "Worker A (Collab)", "HF_SPACE_C_URL",      role="worker")
    _add("worker-b", "Worker B",          "HF_SPACE_D_URL",      role="worker")
    _add("worker-c",       "Worker C",             "HF_SPACE_E_URL",         role="worker")
    # ── Ruoli futuri — skippati automaticamente se env var non configurata ──
    _add("executor",       "Brain Executor",        "HF_SPACE_EXECUTOR_URL",  role="executor")
    _add("browser-worker", "Browser Worker",        "HF_SPACE_BROWSER_URL",   role="browser-worker")
    _add("memory-worker",  "Memory Worker",         "HF_SPACE_MEMORY_URL",    role="memory-worker")
    _add("staging",        "Staging / Collab B",    "HF_SPACE_STAGING_URL",   role="staging")
    _add("oracle",         "Oracle Cloud VM",       "ORACLE_CLOUD_VM_URL",    role="compute")
    return spaces


# Singleton — letto all'import del modulo
_SPACES: list[SpaceConfig] = _build_spaces_from_env()

# ── Cache ────────────────────────────────────────────────────────────────────────
_cache:    dict[str, SpaceStatus] = {}
_cache_ts: float                  = 0.0
_poll_task: asyncio.Task | None   = None   # type: ignore[type-arg]


async def _ping_space(client: httpx.AsyncClient, cfg: SpaceConfig) -> SpaceStatus:
    """Ping /health di uno Space. Non solleva mai eccezioni."""
    t0 = time.time()
    status = SpaceStatus(
        space_id=cfg.space_id, name=cfg.name,
        base_url=cfg.base_url, role=cfg.role,
    )
    try:
        url  = f"{cfg.base_url}/health"
        resp = await client.get(url, timeout=_PING_TIMEOUT_S)
        ms   = (time.time() - t0) * 1000
        status.http_status = resp.status_code
        status.latency_ms  = round(ms, 1)
        if resp.status_code < 400:
            status.health = "ok"
        elif resp.status_code < 500:
            status.health = "degraded"
        else:
            status.health = "down"
    except httpx.TimeoutException:
        status.health     = "down"
        status.error      = "timeout"
        status.latency_ms = _PING_TIMEOUT_S * 1000
    except Exception as exc:
        status.health = "down"
        status.error  = str(exc)[:120]
    status.checked_at = time.time()
    return status


async def _get_hf_stage(client: httpx.AsyncClient,
                        repo_id: str, hf_token: str) -> str:
    """Recupera lo stage runtime da HF API. Ritorna 'unknown' su qualsiasi errore."""
    if not repo_id or not hf_token:
        return "unknown"
    try:
        url  = f"{_HF_API_BASE}/{repo_id}/runtime"
        hdrs = {"Authorization": f"Bearer {hf_token}"}
        resp = await client.get(url, headers=hdrs, timeout=_HF_API_TIMEOUT_S)
        if resp.status_code == 200:
            return str(resp.json().get("stage", "unknown"))
    except Exception as exc:
        _logger.debug("hf_monitor: HF runtime API %s: %s", repo_id, exc)
    return "unknown"


async def _refresh_all() -> dict[str, SpaceStatus]:
    """Aggiorna lo stato di tutti gli Space configurati in parallelo."""
    global _cache, _cache_ts
    if not _SPACES:
        return {}

    hf_token = os.getenv("HF_TOKEN", "")
    async with httpx.AsyncClient() as client:
        ping_results: list[SpaceStatus] = list(await asyncio.gather(
            *[_ping_space(client, cfg) for cfg in _SPACES],
            return_exceptions=False,
        ))
        stage_results: list[str] = list(await asyncio.gather(
            *[_get_hf_stage(client, cfg.hf_repo_id, hf_token) for cfg in _SPACES],
            return_exceptions=False,
        ))

    for status, stage in zip(ping_results, stage_results):
        status.hf_stage = stage

    new_cache = {s.space_id: s for s in ping_results}
    _cache    = new_cache
    _cache_ts = time.time()
    _logger.info(
        "hf_monitor: refresh OK — %d space: %s",
        len(ping_results),
        ", ".join(f"{s.space_id}={s.health}" for s in ping_results),
    )
    return new_cache


async def _background_poll() -> None:
    """Loop di polling in background — mai si ferma, mai solleva."""
    while True:
        try:
            await _refresh_all()
        except Exception as exc:
            _logger.warning("hf_monitor: errore polling: %s", exc)
        await asyncio.sleep(_POLL_INTERVAL_S)


def start_monitor() -> None:
    """Avvia il background polling. Idempotente: sicuro da chiamare più volte."""
    global _poll_task
    if _poll_task and not _poll_task.done():
        return
    _poll_task = asyncio.ensure_future(_background_poll())
    _logger.info("hf_monitor: polling avviato — %d space, ogni %ds",
                 len(_SPACES), int(_POLL_INTERVAL_S))


def _status_to_dict(s: SpaceStatus) -> dict[str, Any]:
    return asdict(s)


# ── Endpoints ───────────────────────────────────────────────────────────────────

@router.get(
    "/api/hf-monitor/spaces",
    summary="Stato aggregato di tutti gli HF Spaces monitorati (ARCH-P5.2)",
)
async def get_spaces_status(
    _auth: None = Depends(require_role(AuthRole.MACHINE)),
) -> dict[str, Any]:
    """
    Restituisce lo stato cached di tutti gli HF Spaces.
    La cache si aggiorna ogni 60s in background; la prima call forza un refresh.
    """
    global _cache, _cache_ts
    if not _cache:
        await _refresh_all()
    return {
        "spaces":            [_status_to_dict(s) for s in _cache.values()],
        "total":             len(_cache),
        "cache_age_s":       round(time.time() - _cache_ts, 1) if _cache_ts else None,
        "spaces_configured": len(_SPACES),
    }


@router.post(
    "/api/hf-monitor/spaces/refresh",
    summary="Forza aggiornamento immediato stato HF Spaces",
)
async def force_refresh(
    _auth: None = Depends(require_role(AuthRole.MACHINE)),
) -> dict[str, Any]:
    """Forza refresh sincrono di tutti gli Space. Può richiedere fino a 8s."""
    await _refresh_all()
    return {
        "spaces":       [_status_to_dict(s) for s in _cache.values()],
        "total":        len(_cache),
        "refreshed_at": time.time(),
    }


@router.get(
    "/api/hf-monitor/ping/{space_id}",
    summary="Ping live di un singolo HF Space",
)
async def ping_single_space(
    space_id: str,
    _auth: None = Depends(require_role(AuthRole.MACHINE)),
) -> dict[str, Any]:
    """Ping diretto e sincrono di un singolo Space (bypassa la cache)."""
    cfg = next((c for c in _SPACES if c.space_id == space_id), None)
    if not cfg:
        raise HTTPException(
            status_code=404,
            detail=f"Space '{space_id}' non configurato. "
                   f"Space disponibili: {[c.space_id for c in _SPACES]}",
        )
    hf_token = os.getenv("HF_TOKEN", "")
    async with httpx.AsyncClient() as client:
        status = await _ping_space(client, cfg)
        stage  = await _get_hf_stage(client, cfg.hf_repo_id, hf_token)
    status.hf_stage = stage
    return _status_to_dict(status)