feat: drill-down filters on overview and outdated agent version highlight

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/app/services/agent_version.py

@@ -0,0 +1,80 @@
+"""Сравнение версий агентов (ssh-monitor / rdp-login-monitor, формат X.Y.Z-SAC)."""
+
+from __future__ import annotations
+
+import re
+from dataclasses import dataclass
+
+from sqlalchemy import select
+from sqlalchemy.orm import Session
+
+from app.models import Host
+
+_VERSION_RE = re.compile(r"^(\d+)\.(\d+)\.(\d+)(?:-SAC)?$", re.IGNORECASE)
+_DEFAULT_LAG_THRESHOLD = 3
+
+
+@dataclass(frozen=True, order=True)
+class ParsedAgentVersion:
+    major: int
+    minor: int
+    patch: int
+
+
+def parse_agent_version(raw: str | None) -> ParsedAgentVersion | None:
+    if not raw:
+        return None
+    text = raw.strip()
+    match = _VERSION_RE.match(text)
+    if not match:
+        return None
+    return ParsedAgentVersion(
+        major=int(match.group(1)),
+        minor=int(match.group(2)),
+        patch=int(match.group(3)),
+    )
+
+
+def agent_version_lag(host: ParsedAgentVersion, latest: ParsedAgentVersion) -> int | None:
+    """Отставание от latest: patch при том же major.minor, иначе None (любое отставание)."""
+    if host > latest:
+        return 0
+    if host.major != latest.major or host.minor != latest.minor:
+        return None
+    return latest.patch - host.patch
+
+
+def is_agent_version_outdated(
+    host_version: str | None,
+    latest_version: str | None,
+    *,
+    lag_threshold: int = _DEFAULT_LAG_THRESHOLD,
+) -> bool:
+    host = parse_agent_version(host_version)
+    latest = parse_agent_version(latest_version)
+    if host is None or latest is None or host >= latest:
+        return False
+    lag = agent_version_lag(host, latest)
+    if lag is None:
+        return True
+    return lag >= lag_threshold
+
+
+def latest_agent_versions_by_product(db: Session) -> dict[str, str]:
+    rows = db.execute(
+        select(Host.product, Host.product_version).where(
+            Host.product_version.isnot(None),
+            Host.product_version != "",
+        )
+    ).all()
+    best: dict[str, ParsedAgentVersion] = {}
+    best_raw: dict[str, str] = {}
+    for product, version in rows:
+        parsed = parse_agent_version(version)
+        if parsed is None:
+            continue
+        current = best.get(product)
+        if current is None or parsed > current:
+            best[product] = parsed
+            best_raw[product] = version.strip()
+    return best_raw