OPNexus/backend/app/services/notification_checks.py

"""Five detection functions, each returning {dedup_key: context} for
whatever's currently bad. Pure detection — no delivery, no state tracking
here (see notification_dedup.py for the open/resolved diffing that turns
these snapshots into actual notifications)."""
from collections import defaultdict
from datetime import datetime, timedelta, timezone

from sqlalchemy import select
from sqlalchemy.ext.asyncio import AsyncSession

from app.models.alias_deployment import AliasDeployment
from app.models.backup_settings import BackupSettings
from app.models.compliance_result import ComplianceResult
from app.models.host import OpnsenseHost
from app.models.host_operation import HostOperation
from app.models.one_to_one_deployment import OneToOneDeployment
from app.models.outbound_nat_deployment import OutboundNatDeployment
from app.models.port_forward_deployment import PortForwardDeployment
from app.models.rule_deployment import RuleDeployment
from app.models.scheduled_maintenance import ScheduledMaintenance
from app.services import backup_store, nat_drift_service, network_drift_service, rule_drift_service
from app.services.notification_dedup import Problems
from app.services.host_status_service import get_statuses
from app.services.live_certificates_service import get_live_certificates
from app.services.opnsense_client import OpnsenseAPIError

# (deployment_type, model, id_attr) — same shape audit_service.py's mapping
# uses, so a revert_failed row can point back at the underlying entity.
_DEPLOYMENT_MODELS = [
    ("rule", RuleDeployment, "rule_id"),
    ("alias", AliasDeployment, "alias_id"),
    ("port_forward", PortForwardDeployment, "port_forward_id"),
    ("outbound_nat", OutboundNatDeployment, "outbound_nat_id"),
    ("one_to_one", OneToOneDeployment, "one_to_one_id"),
]


async def _enabled_hosts(db: AsyncSession) -> list[OpnsenseHost]:
    result = await db.execute(select(OpnsenseHost).where(OpnsenseHost.enabled.is_(True)))
    return list(result.scalars().all())


async def check_host_offline(db: AsyncSession) -> dict[str, dict]:
    hosts = await _enabled_hosts(db)
    statuses = await get_statuses(hosts)
    problems: dict[str, dict] = {}
    for host in hosts:
        info = statuses.get(host.id, {})
        if info.get("status") != "offline":
            continue
        problems[str(host.id)] = {
            "host_id": str(host.id),
            "host_name": host.name,
            "detail": info.get("status_detail"),
        }
    return problems


async def check_certificates(db: AsyncSession) -> dict[str, dict]:
    hosts = await _enabled_hosts(db)
    problems = Problems()
    for host in hosts:
        try:
            certs = await get_live_certificates(host)
        except OpnsenseAPIError:
            # Unreachable — already reported by check_host_offline, no need
            # to double-report it here as a certificate problem. Its open
            # certificate problems stay as they are (not evaluable now).
            problems.preserve_prefixes.add(f"{host.id}:")
            continue
        for cert in certs:
            if cert.status not in ("expiring_soon", "expired"):
                continue
            key = f"{host.id}:{cert.uuid}"
            problems[key] = {
                "host_id": str(host.id),
                "host_name": host.name,
                "cert_descr": cert.descr,
                "common_name": cert.common_name,
                "status": cert.status,
                "days_until_expiry": cert.days_until_expiry,
            }
    return problems


async def check_rule_drift(db: AsyncSession) -> dict[str, dict]:
    hosts = await _enabled_hosts(db)
    by_cluster: dict[str, list[OpnsenseHost]] = defaultdict(list)
    for host in hosts:
        if host.cluster_name:
            by_cluster[host.cluster_name].append(host)

    problems = Problems()
    for cluster_name, cluster_hosts in by_cluster.items():
        if len(cluster_hosts) < 2:
            continue
        names_by_id = {h.id: h.name for h in cluster_hosts}
        rows, reachable = await rule_drift_service.compute_cluster_drift_with_reachable(cluster_hosts)
        if len(reachable) < 2:
            # A member is down (reboot/update): drift cannot be judged, so keep
            # what is open instead of resolving it and re-opening it later.
            problems.preserve_prefixes.add(f"{cluster_name}:")
            continue
        for row in rows:
            key = f"{cluster_name}:{row['fingerprint']}"
            present_names = sorted(names_by_id[hid] for hid in row["present_on"])
            missing_names = sorted(
                names_by_id[hid] for hid in row["reachable_host_ids"] - row["present_on"]
            )
            problems[key] = {
                "cluster_name": cluster_name,
                "description": row["sample"].description,
                "present_on": present_names,
                "missing_from": missing_names,
            }
    return problems


_NAT_TYPE_LABELS = {"port_forward": "Port-Forward", "one_to_one": "1:1-NAT", "outbound_nat": "Outbound-NAT"}


async def check_nat_drift(db: AsyncSession) -> dict[str, dict]:
    hosts = await _enabled_hosts(db)
    by_cluster: dict[str, list[OpnsenseHost]] = defaultdict(list)
    for host in hosts:
        if host.cluster_name:
            by_cluster[host.cluster_name].append(host)

    problems = Problems()
    for cluster_name, cluster_hosts in by_cluster.items():
        if len(cluster_hosts) < 2:
            continue
        names_by_id = {h.id: h.name for h in cluster_hosts}
        for nat_type in _NAT_TYPE_LABELS:
            rows, reachable = await nat_drift_service.compute_cluster_drift_with_reachable(cluster_hosts, nat_type)
            if len(reachable) < 2:
                problems.preserve_prefixes.add(f"{cluster_name}:{nat_type}:")
                continue
            for row in rows:
                key = f"{cluster_name}:{nat_type}:{row['fingerprint']}"
                present_names = sorted(names_by_id[hid] for hid in row["present_on"])
                missing_names = sorted(
                    names_by_id[hid] for hid in row["reachable_host_ids"] - row["present_on"]
                )
                problems[key] = {
                    "cluster_name": cluster_name,
                    "nat_type": _NAT_TYPE_LABELS[nat_type],
                    "description": row["sample"].get("descr") or row["sample"].get("description"),
                    "present_on": present_names,
                    "missing_from": missing_names,
                }
    return problems


_NETWORK_LABELS = {
    "interfaces": "Schnittstelle", "vlans": "VLAN", "vips": "Virtuelle IP", "gateways": "Gateway", "routes": "Route",
    "dns_hosts": "DNS-Eintrag", "dhcp_hosts": "DHCP-Host", "kea_subnets": "DHCP-Subnetz", "kea_reservations": "DHCP-Reservierung",
}


async def check_network_drift(db: AsyncSession) -> dict[str, dict]:
    hosts = await _enabled_hosts(db)
    by_cluster: dict[str, list[OpnsenseHost]] = defaultdict(list)
    for host in hosts:
        if host.cluster_name:
            by_cluster[host.cluster_name].append(host)

    problems = Problems()
    for cluster_name, cluster_hosts in by_cluster.items():
        if len(cluster_hosts) < 2:
            continue
        differences, compared, _unreachable = await network_drift_service.compute_cluster(cluster_hosts)
        if len(compared) < 2:
            # Not evaluable right now (a node is down, which check_host_offline reports): keep what is open.
            problems.preserve_prefixes.add(f"{cluster_name}:")
            continue
        for row in differences:
            key = f"{cluster_name}:{row['category']}:{row['key']}"
            problems[key] = {
                "cluster_name": cluster_name,
                "object": f"{_NETWORK_LABELS.get(row['category'], row['category'])} {row['key']}",
                "status": "fehlt auf einem Knoten" if row["status"] == "missing" else "Einstellungen weichen ab",
                "present_on": row["present_on"],
                "missing_from": row["missing_from"],
            }
    return problems


async def check_revert_failed(db: AsyncSession) -> dict[str, dict]:
    problems: dict[str, dict] = {}
    for deployment_type, model, id_attr in _DEPLOYMENT_MODELS:
        result = await db.execute(select(model).where(model.status == "revert_failed"))
        for deployment in result.scalars().all():
            host = await db.get(OpnsenseHost, deployment.host_id)
            key = f"{deployment_type}:{deployment.id}"
            problems[key] = {
                "deployment_type": deployment_type,
                "deployment_id": str(deployment.id),
                "entity_id": str(getattr(deployment, id_attr)),
                "host_id": str(deployment.host_id),
                "host_name": host.name if host else None,
                "message": deployment.message,
            }
    return problems


async def check_carp_health(db: AsyncSession) -> dict[str, dict]:
    hosts = await _enabled_hosts(db)
    by_cluster: dict[str, list[OpnsenseHost]] = defaultdict(list)
    for host in hosts:
        if host.cluster_name:
            by_cluster[host.cluster_name].append(host)

    problems: dict[str, dict] = {}
    for cluster_name, cluster_hosts in by_cluster.items():
        if len(cluster_hosts) < 2:
            continue
        statuses = await get_statuses(cluster_hosts)
        online = [h for h in cluster_hosts if statuses.get(h.id, {}).get("status") == "online"]
        if len(online) < 2:
            # Can't tell split-brain from a simple outage with only one
            # reachable node — check_host_offline already reports that case.
            continue
        masters = [h for h in online if statuses.get(h.id, {}).get("carp_status") == "MASTER"]
        if len(masters) == 2:
            key = f"{cluster_name}:split_brain"
            problems[key] = {
                "cluster_name": cluster_name,
                "condition": "split_brain",
                "host_names": sorted(h.name for h in online),
            }
        elif len(masters) == 0:
            key = f"{cluster_name}:no_master"
            problems[key] = {
                "cluster_name": cluster_name,
                "condition": "no_master",
                "host_names": sorted(h.name for h in online),
            }
        problems.update(_carp_vip_problems(cluster_name, online, statuses, split_brain=len(masters) == 2))
    return problems


def _carp_vip_problems(cluster_name: str, online: list[OpnsenseHost], statuses: dict, split_brain: bool) -> dict[str, dict]:
    """Per-VHID checks. The host-level role is "MASTER" as soon as one VIP is, so a VIP that is down on a
    node (a node without the VIP never advertises it, the peer takes it over) looks healthy in the totals."""
    problems: dict[str, dict] = {}
    for host in online:
        vips = statuses.get(host.id, {}).get("carp_vips") or {}
        down = sorted(v for v, state in vips.items() if state not in ("MASTER", "BACKUP"))
        if down:
            problems[f"{cluster_name}:vip_down:{host.name}"] = {
                "cluster_name": cluster_name, "condition": "vip_down", "host_names": [host.name], "vhids": down,
            }
        # One node MASTER on some VHIDs and BACKUP on others: a partial failover. Already covered by the
        # split-brain alert when both nodes hold a MASTER.
        if not split_brain and {"MASTER", "BACKUP"} <= set(vips.values()):
            problems[f"{cluster_name}:role_mismatch:{host.name}"] = {
                "cluster_name": cluster_name, "condition": "role_mismatch", "host_names": [host.name],
                "vhids": sorted(v for v, state in vips.items() if state == "MASTER"),
            }
    return problems


async def check_maintenance_unknown(db: AsyncSession) -> dict[str, dict]:
    result = await db.execute(select(HostOperation).where(HostOperation.status == "unknown"))
    problems: dict[str, dict] = {}
    for operation in result.scalars().all():
        problems[str(operation.id)] = {
            "operation_id": str(operation.id),
            "host_id": str(operation.host_id),
            "host_name": operation.host_name,
            "action": operation.action,
            "message": operation.message,
        }
    return problems


async def check_carp_auto_revert_failed(db: AsyncSession) -> dict[str, dict]:
    from app.models.carp_maintenance_window import CarpMaintenanceWindow

    result = await db.execute(select(CarpMaintenanceWindow).where(CarpMaintenanceWindow.status == "revert_failed"))
    problems: dict[str, dict] = {}
    for window in result.scalars().all():
        problems[str(window.id)] = {
            "window_id": str(window.id),
            "host_id": str(window.host_id),
            "host_name": window.host_name,
            "message": window.message,
        }
    return problems


# A failed scheduled run never turns "fixed" by itself, so it is reported as an event:
# open for this long after its planned time, then closed without a "resolved" message
# (see notification_service._NO_RESOLVED_NOTICE).
SCHEDULED_FAILURE_WINDOW = timedelta(days=3)


async def check_scheduled_maintenance_failed(db: AsyncSession) -> dict[str, dict]:
    since = datetime.now(timezone.utc) - SCHEDULED_FAILURE_WINDOW
    result = await db.execute(
        select(ScheduledMaintenance).where(
            ScheduledMaintenance.status == "failed", ScheduledMaintenance.run_at >= since
        )
    )
    problems: dict[str, dict] = {}
    for sched in result.scalars().all():
        problems[str(sched.id)] = {
            "schedule_id": str(sched.id),
            "host_id": str(sched.host_id),
            "host_name": sched.host_name,
            "action": sched.action,
            "run_at": sched.run_at.isoformat(),
            "message": (sched.result or {}).get("error"),
        }
    return problems


async def check_backup_stale(db: AsyncSession) -> dict[str, dict]:
    """Scheduled backups are on but a host has no recent one: three missed intervals
    (at least 6 hours) cover a reboot or a short outage without crying wolf."""
    cfg = await db.get(BackupSettings, 1)
    if cfg is not None and not cfg.scheduled_enabled:
        return {}
    interval = cfg.interval_hours if cfg is not None else 24
    limit = timedelta(hours=max(3 * interval, 6))
    now = datetime.now(timezone.utc)
    problems: dict[str, dict] = {}
    for host in await _enabled_hosts(db):
        snapshots = backup_store.list_snapshots(host.id)
        newest = snapshots[0]["created_at"] if snapshots else None
        if (newest is None and now - host.created_at > limit) or (newest is not None and now - newest > limit):
            problems[str(host.id)] = {
                "host_id": str(host.id), "host_name": host.name,
                "last_backup": newest.isoformat() if newest else "noch nie",
            }
    return problems


async def check_backup_offsite(db: AsyncSession) -> dict[str, dict]:
    cfg = await db.get(BackupSettings, 1)
    if cfg is None or not cfg.offsite_enabled or not cfg.last_offsite_error:
        return {}
    return {"offsite": {"message": cfg.last_offsite_error}}


async def check_compliance(db: AsyncSession) -> dict[str, dict]:
    """Critical and high findings of the last security check, one problem per (host, check); resolved when it passes."""
    from app.services import compliance_service as cs
    hosts = {h.id: h for h in await _enabled_hosts(db)}
    problems: dict[str, dict] = {}
    for row in (await db.scalars(select(ComplianceResult))).all():
        host = hosts.get(row.host_id)
        if host is None or row.error:
            continue
        for finding in row.findings:
            if finding["passed"] is False and finding["severity"] in ("critical", "high"):
                params = finding.get("params") or {}
                problems[f"{host.id}:{finding['id']}"] = {
                    "host_id": str(host.id), "host_name": host.name, "check": finding["id"],
                    "befund": cs.TITLES_DE.get(finding["id"], finding["id"]),
                    "schweregrad": cs.SEVERITIES_DE[finding["severity"]],
                    "beispiele": ", ".join(params.get("examples", [])) or None,
                }
    return problems