PacketStation/server/packetstation/notify/events.py

"""Raise and resolve notification events inside the caller's transaction. No I/O here: notify-send mails them.

A standing condition stays open (resolved_at null) until it clears. Raising it again while open only counts it.
Clearing it closes the row and adds a recovery row that goes to the same rule. A one-shot is inserted resolved.
"""

from __future__ import annotations

import json
import logging
from typing import Any

from psycopg.types.json import Jsonb

from .catalog import EVENT_TYPES

log = logging.getLogger(__name__)

SEVERITIES = ("info", "warning", "critical")
TITLE_MAX = 200
BODY_MAX = 8000
SUBJECT_MAX = 200


def _jsonable(value: Any) -> Any:
    return json.loads(json.dumps(value if value is not None else {}, default=str))


def _clip(text: str | None, n: int) -> str:
    t = (text or "").strip()
    return t if len(t) <= n else t[: n - 1] + "…"


def raise_event(
    conn: Any,
    event_type: str,
    *,
    subject: str,
    title: str,
    body: str = "",
    detail: dict[str, Any] | None = None,
    dept_code: str | None = None,
    severity: str = "warning",
    condition: bool = False,
    dedupe_minutes: int = 0,
) -> int | None:
    """Record one event. Returns the new row's id, or None when it was deduped (or could not be recorded).

    Never raises: a notification must not break a sign-in, a reject or a job. A failure is logged.
    """
    if event_type not in EVENT_TYPES:
        log.error("raise_event: unknown event type %r; not recorded", event_type)
        return None
    if severity not in SEVERITIES:
        severity = "warning"
    subj = _clip(subject, SUBJECT_MAX)
    args = (_clip(title, TITLE_MAX), _clip(body, BODY_MAX), Jsonb(_jsonable(detail)), dept_code)
    try:
        with conn.transaction():
            if condition:
                row = conn.execute(
                    "INSERT INTO notification_events (kind, event_type, severity, subject, title, body, detail,"
                    " dept_code) VALUES (%s, %s, %s, %s, %s, %s, %s, %s)"
                    " ON CONFLICT (kind, coalesce(subject, '')) WHERE resolved_at IS NULL DO UPDATE SET"
                    " raised_count = notification_events.raised_count + 1, last_raised_at = now(),"
                    " detail = EXCLUDED.detail, body = EXCLUDED.body"
                    " RETURNING id, (xmax = 0) AS inserted",
                    (event_type, event_type, severity, subj, *args),
                ).fetchone()
                return int(row[0]) if row is not None and row[1] else None
            if dedupe_minutes > 0:
                recent = conn.execute(
                    "SELECT 1 FROM notification_events WHERE event_type = %s AND subject = %s"
                    " AND created_at > now() - make_interval(mins => %s) LIMIT 1",
                    (event_type, subj, int(dedupe_minutes)),
                ).fetchone()
                if recent is not None:
                    return None
            row = conn.execute(
                "INSERT INTO notification_events (kind, event_type, severity, subject, title, body, detail,"
                " dept_code, resolved_at) VALUES (%s, %s, %s, %s, %s, %s, %s, %s, now()) RETURNING id",
                (event_type, event_type, severity, subj, *args),
            ).fetchone()
            return int(row[0])
    except Exception:
        log.exception("raise_event %s failed; not recorded", event_type)
        return None


def resolve_event(conn: Any, event_type: str, *, subject: str, title: str | None = None, body: str = "") -> int | None:
    """Close the open condition for (event_type, subject) and add its recovery row. Returns the recovery row's id,
    or None when nothing was open. Never raises."""
    if event_type not in EVENT_TYPES:
        log.error("resolve_event: unknown event type %r", event_type)
        return None
    subj = _clip(subject, SUBJECT_MAX)
    try:
        with conn.transaction():
            row = conn.execute(
                "UPDATE notification_events SET resolved_at = now() WHERE kind = %s AND coalesce(subject, '') = %s"
                " AND resolved_at IS NULL RETURNING id, title, dept_code",
                (event_type, subj),
            ).fetchone()
            if row is None:
                return None
            open_id, open_title, dept = row
            base = title or open_title or EVENT_TYPES[event_type].label
            rec = conn.execute(
                "INSERT INTO notification_events (kind, event_type, severity, subject, title, body, detail,"
                " dept_code, resolved_at, recovery_of) VALUES (%s, %s, 'info', %s, %s, %s, %s, %s, now(), %s)"
                " RETURNING id",
                (
                    event_type,
                    event_type,
                    subj,
                    _clip(f"Cleared: {base}", TITLE_MAX),
                    _clip(body, BODY_MAX),
                    Jsonb({"recovery_of": open_id}),
                    dept,
                    open_id,
                ),
            ).fetchone()
            return int(rec[0])
    except Exception:
        log.exception("resolve_event %s failed", event_type)
        return None


def open_event(conn: Any, event_type: str, subject: str) -> int | None:
    row = conn.execute(
        "SELECT id FROM notification_events WHERE kind = %s AND coalesce(subject, '') = %s AND resolved_at IS NULL",
        (event_type, subject),
    ).fetchone()
    return int(row[0]) if row else None