bambuddy/backend/app/services/obico_detection.py

"""Obico AI print-failure detection service.

Polls a self-hosted Obico ML API with snapshots from each monitored printer
while a print is running, smooths scores over time, and dispatches a configured
action (notify / pause / pause_and_off) when a sustained failure is detected.

See `obico_smoothing.py` for the per-print EWM + rolling-mean math.
"""

import asyncio
import json
import logging
from collections import deque
from datetime import datetime, timedelta, timezone
from urllib.parse import urlencode

import httpx
from sqlalchemy import select

from backend.app.core.auth import (
    CAMERA_STREAM_TOKEN_EXPIRE_MINUTES,
    create_camera_stream_token,
)
from backend.app.core.database import async_session
from backend.app.models.settings import Settings
from backend.app.services.obico_smoothing import (
    PrintState,
    classify,
    score_from_detections,
    thresholds,
)

logger = logging.getLogger(__name__)

HISTORY_MAX = 50
HEALTH_TIMEOUT = 5.0
DETECTION_TIMEOUT = 30.0


class ObicoDetectionService:
    """Singleton service that polls the ML API and acts on sustained failures."""

    def __init__(self):
        self._task: asyncio.Task | None = None
        # printer_id -> PrintState (reset when a new print starts)
        self._states: dict[int, PrintState] = {}
        # printer_id -> task_name active when state was created (used to detect new prints)
        self._state_keys: dict[int, str] = {}
        # printer_id -> last classification ("safe"/"warning"/"failure")
        self._last_class: dict[int, str] = {}
        # printer_id -> whether an action has already been fired for the current print
        self._action_fired: dict[int, bool] = {}
        # Global detection event log (most-recent-first)
        self._history: deque = deque(maxlen=HISTORY_MAX)
        self._last_error: str | None = None
        # Cached camera-stream token so the ML API can fetch snapshots when
        # auth is enabled. Refreshed before expiry; harmless when auth is off.
        self._snapshot_token: str | None = None
        self._snapshot_token_expires_at: datetime | None = None

    # ---- lifecycle ----

    async def start(self):
        if self._task is not None:
            return
        logger.info("Starting Obico detection service")
        self._task = asyncio.create_task(self._loop())

    def stop(self):
        if self._task:
            self._task.cancel()
            self._task = None
            logger.info("Stopped Obico detection service")

    # ---- snapshot auth ----

    async def _get_snapshot_token(self) -> str:
        """Return a valid camera-stream token, refreshing it before expiry.

        The ML API fetches the snapshot URL directly, so when Bambuddy's auth
        is enabled the URL must carry a token (same scheme used by <img>-based
        camera consumers). When auth is disabled the token is simply ignored.
        """
        now = datetime.now(timezone.utc)
        refresh_before = timedelta(minutes=5)
        if (
            self._snapshot_token is None
            or self._snapshot_token_expires_at is None
            or self._snapshot_token_expires_at - now <= refresh_before
        ):
            self._snapshot_token = await create_camera_stream_token()
            self._snapshot_token_expires_at = now + timedelta(minutes=CAMERA_STREAM_TOKEN_EXPIRE_MINUTES)
        return self._snapshot_token

    # ---- settings ----

    async def _load_settings(self) -> dict:
        keys = [
            "obico_enabled",
            "obico_ml_url",
            "obico_sensitivity",
            "obico_action",
            "obico_poll_interval",
            "obico_enabled_printers",
            "external_url",
        ]
        async with async_session() as db:
            result = await db.execute(select(Settings).where(Settings.key.in_(keys)))
            rows = {r.key: r.value for r in result.scalars().all()}

        enabled_printers_raw = rows.get("obico_enabled_printers", "")
        if enabled_printers_raw:
            try:
                enabled_printers = set(json.loads(enabled_printers_raw))
            except json.JSONDecodeError:
                enabled_printers = set()
        else:
            enabled_printers = None  # None = all printers

        return {
            "enabled": rows.get("obico_enabled", "false").lower() == "true",
            "ml_url": (rows.get("obico_ml_url") or "").rstrip("/"),
            "sensitivity": rows.get("obico_sensitivity", "medium"),
            "action": rows.get("obico_action", "notify"),
            "poll_interval": int(rows.get("obico_poll_interval", "10")),
            "enabled_printers": enabled_printers,
            "external_url": (rows.get("external_url") or "").rstrip("/"),
        }

    # ---- main loop ----

    async def _loop(self):
        """Poll active printers while enabled. Adjusts interval from settings each cycle."""
        while True:
            try:
                settings = await self._load_settings()
                interval = max(5, settings.get("poll_interval", 10))
                if not settings["enabled"] or not settings["ml_url"]:
                    await asyncio.sleep(interval)
                    continue
                if not settings["external_url"]:
                    # Without a reachable base URL, the ML API can't fetch snapshots.
                    self._last_error = "external_url not set — ML API cannot reach snapshot endpoint"
                    await asyncio.sleep(interval)
                    continue

                await self._poll_once(settings)
                await asyncio.sleep(interval)
            except asyncio.CancelledError:
                break
            except Exception as e:
                logger.error("Obico detection loop error: %s", e)
                self._last_error = str(e)
                await asyncio.sleep(30)

    async def _poll_once(self, settings: dict):
        # Late import to avoid cycles at module load time
        from backend.app.services.printer_manager import printer_manager

        statuses = printer_manager.get_all_statuses()
        for printer_id, status in list(statuses.items()):
            if settings["enabled_printers"] is not None and printer_id not in settings["enabled_printers"]:
                continue
            if not printer_manager.is_connected(printer_id):
                continue
            if not status or getattr(status, "state", None) != "RUNNING":
                # Reset state when not printing so the next print starts fresh
                self._states.pop(printer_id, None)
                self._state_keys.pop(printer_id, None)
                self._action_fired.pop(printer_id, None)
                continue

            await self._check_printer(printer_id, status, settings)

    async def _check_printer(self, printer_id: int, status, settings: dict):
        task_name = getattr(status, "task_name", None) or getattr(status, "subtask_name", "") or ""
        key = f"{task_name}"
        if self._state_keys.get(printer_id) != key:
            self._states[printer_id] = PrintState()
            self._state_keys[printer_id] = key
            self._action_fired[printer_id] = False

        token = await self._get_snapshot_token()
        snapshot_url = (
            f"{settings['external_url']}/api/v1/printers/{printer_id}/camera/snapshot?{urlencode({'token': token})}"
        )
        ml_url = f"{settings['ml_url']}/p/"

        try:
            async with httpx.AsyncClient(timeout=DETECTION_TIMEOUT) as client:
                resp = await client.get(ml_url, params={"img": snapshot_url})
                resp.raise_for_status()
                payload = resp.json()
        except Exception as e:
            self._last_error = f"ML API call failed for printer {printer_id}: {e}"
            logger.warning(self._last_error)
            return

        detections = payload.get("detections", []) if isinstance(payload, dict) else []
        current_p = score_from_detections(detections)
        state = self._states[printer_id]
        score = state.update(current_p)
        verdict = classify(score, settings["sensitivity"])
        self._last_class[printer_id] = verdict

        # Log every non-safe sample — safe samples would flood history
        if verdict != "safe" or detections:
            self._history.appendleft(
                {
                    "printer_id": printer_id,
                    "task_name": task_name,
                    "timestamp": datetime.now(timezone.utc).isoformat(),
                    "current_p": round(current_p, 4),
                    "score": round(score, 4),
                    "class": verdict,
                    "detections": len(detections),
                }
            )

        if verdict == "failure" and not self._action_fired.get(printer_id):
            self._action_fired[printer_id] = True
            await self._dispatch_action(printer_id, settings["action"], task_name, score)

    async def _dispatch_action(self, printer_id: int, action: str, task_name: str, score: float):
        from backend.app.services.obico_actions import execute_action

        logger.warning(
            "Obico: failure detected on printer %s (task=%r score=%.3f) — action=%s",
            printer_id,
            task_name,
            score,
            action,
        )
        try:
            await execute_action(printer_id, action, task_name, score)
        except Exception as e:
            self._last_error = f"Action dispatch failed: {e}"
            logger.error(self._last_error)

    # ---- queries ----

    def get_status(self) -> dict:
        low, high = thresholds("medium")
        return {
            "is_running": self._task is not None and not self._task.done(),
            "last_error": self._last_error,
            "per_printer": {
                pid: {
                    "class": self._last_class.get(pid, "safe"),
                    "frame_count": state.frame_count,
                    "score": round(state.ewm_mean, 4),
                }
                for pid, state in self._states.items()
            },
            "thresholds": {"low": low, "high": high},
            "history": list(self._history),
        }

    async def test_connection(self, url: str) -> dict:
        """Ping the ML API health endpoint. Returns {ok, status_code, body, error}."""
        target = f"{url.rstrip('/')}/hc/"
        try:
            async with httpx.AsyncClient(timeout=HEALTH_TIMEOUT) as client:
                resp = await client.get(target)
            body = resp.text.strip()
            return {
                "ok": resp.status_code == 200 and body.lower() == "ok",
                "status_code": resp.status_code,
                "body": body,
                "error": None,
            }
        except Exception as e:
            return {"ok": False, "status_code": None, "body": None, "error": str(e)}


obico_detection_service = ObicoDetectionService()