From 9ffd154a2a5544de49cea1fcd3406b66f723a054 Mon Sep 17 00:00:00 2001
From: VAIO73 <50487331+Vaso73@users.noreply.github.com>
Date: Tue, 20 Oct 2026 06:46:15 +0000
Subject: [PATCH] i18n: refine Slovak linked nodes and localize validation
 errors

---
 .github/scripts/run_offline_qualified.py      |   3 +
 AppImage/components/monitor-switcher.tsx      |  22 +--
 AppImage/lib/monitor-link-errors.ts           |  29 ++++
 AppImage/messages/en/common.json              |  13 +-
 AppImage/messages/sk/common.json              |  35 +++--
 .../scripts/flask_monitor_links_routes.py     |  19 ++-
 AppImage/scripts/monitor_links.py             |  27 ++--
 .../scripts/tests/test_monitor_links_i18n.py  | 138 ++++++++++++++++++
 tests/test_monitor_links_i18n.cjs             | 133 +++++++++++++++++
 9 files changed, 379 insertions(+), 40 deletions(-)
 create mode 100644 AppImage/lib/monitor-link-errors.ts
 create mode 100644 AppImage/scripts/tests/test_monitor_links_i18n.py
 create mode 100644 tests/test_monitor_links_i18n.cjs

diff --git a/.github/scripts/run_offline_qualified.py b/.github/scripts/run_offline_qualified.py
index 8a9548cd..4ee4eb95 100644
--- a/.github/scripts/run_offline_qualified.py
+++ b/.github/scripts/run_offline_qualified.py
@@ -13,6 +13,8 @@ import sys
 import tempfile
 
 PYTHON_FILES = (
+    "AppImage/scripts/tests/test_monitor_links_i18n.py",
+    "AppImage/scripts/tests/test_monitor_links.py",
     "AppImage/scripts/tests/test_local_app_icon_isolation.py",
     "AppImage/scripts/tests/test_local_app_icons.py",
     "AppImage/scripts/tests/test_docker_app_discovery.py",
@@ -28,6 +30,7 @@ PYTHON_FILES = (
     "AppImage/scripts/tests/test_health_persistence_recurrence.py",
 )
 NODE_FILES = (
+    "tests/test_monitor_links_i18n.cjs",
     "tests/lxc_updates/test_local_app_icons_ui.cjs",
     "tests/lxc_updates/test_docker_app_discovery_ui.cjs",
     "tests/lxc_updates/test_native_app_discovery_ui.cjs",
diff --git a/AppImage/components/monitor-switcher.tsx b/AppImage/components/monitor-switcher.tsx
index 89f8d249..7fb88eb9 100644
--- a/AppImage/components/monitor-switcher.tsx
+++ b/AppImage/components/monitor-switcher.tsx
@@ -14,6 +14,7 @@ import {
   DropdownMenu, DropdownMenuContent, DropdownMenuItem, DropdownMenuLabel, DropdownMenuSeparator, DropdownMenuTrigger,
 } from "./ui/dropdown-menu"
 import { fetchApi } from "../lib/api-config"
+import { monitorLinkError } from "../lib/monitor-link-errors"
 import { useT } from "../lib/i18n/provider"
 
 interface MonitorLink {
@@ -185,8 +186,9 @@ export function MonitorSwitcher({ nodeName, compact = false }: { nodeName: strin
       await refreshCache("/api/monitor-links")
       setOfferOrigin(false)
     } catch (err) {
-      await refreshCache("/api/monitor-links")
-      setAddError(err instanceof Error ? err.message : t("monitorLinks.saveFailed"))
+      setAddError(monitorLinkError(err, t))
+      try { await refreshCache("/api/monitor-links") }
+      catch { /* SWR shows the load error; keep the localized mutation error. */ }
     } finally { setAdding(false) }
   }
   const notNow = () => {
@@ -260,7 +262,7 @@ export function MonitorSwitcher({ nodeName, compact = false }: { nodeName: strin
     </DropdownMenu>
     {manageOpen && <ManageLinksDialog open={manageOpen} onOpenChange={setManageOpen} />}
     {origin && <Dialog open={offerOrigin} onOpenChange={open => { if (!open) notNow() }}>
-      <DialogContent className="max-w-md" onClick={event => event.stopPropagation()}>
+      <DialogContent className="grid-cols-1 max-w-md" onClick={event => event.stopPropagation()}>
         <DialogHeader>
           <DialogTitle>{t("monitorLinks.knownTitle")}</DialogTitle>
           <DialogDescription>{t("monitorLinks.knownBody", { name: origin.name })}</DialogDescription>
@@ -290,7 +292,7 @@ export function MonitorSwitcher({ nodeName, compact = false }: { nodeName: strin
 
 function ManageLinksDialog({ open, onOpenChange }: { open: boolean; onOpenChange: (open: boolean) => void }) {
   const t = useT()
-  const { data, mutate } = useSWR<MonitorLinks>("/api/monitor-links?all=1", fetcher, { revalidateOnFocus: false })
+  const { data, mutate, error: loadError, isLoading } = useSWR<MonitorLinks>("/api/monitor-links?all=1", fetcher, { revalidateOnFocus: false })
   const [form, setForm] = useState({ name: "", url: "", product: "pve" })
   const [addresses, setAddresses] = useState<Record<string, string>>({})
   const [editing, setEditing] = useState<string | null>(null)
@@ -304,14 +306,14 @@ function ManageLinksDialog({ open, onOpenChange }: { open: boolean; onOpenChange
       await mutate()
       await refreshCache("/api/monitor-links")
     } catch (err) {
-      setError(err instanceof Error ? err.message : t("monitorLinks.saveFailed"))
+      setError(monitorLinkError(err, t))
     } finally { setBusy(false) }
   }
   const send = (path: string, method: string, body?: unknown) =>
     fetchApi(path, { method, ...(body === undefined ? {} : { body: JSON.stringify(body) }) })
 
   return <Dialog open={open} onOpenChange={onOpenChange}>
-    <DialogContent className="max-w-2xl max-h-[85vh] overflow-y-auto bg-accent [&_input]:bg-background [&_textarea]:bg-background [&_[role=combobox]]:bg-background"
+    <DialogContent className="grid-cols-1 max-w-2xl max-h-[85vh] overflow-y-auto bg-accent [&_input]:bg-background [&_textarea]:bg-background [&_[role=combobox]]:bg-background"
       onClick={event => event.stopPropagation()}>
       <DialogHeader>
         <DialogTitle>{t("monitorLinks.dialogTitle")}</DialogTitle>
@@ -320,7 +322,7 @@ function ManageLinksDialog({ open, onOpenChange }: { open: boolean; onOpenChange
 
       <div className="space-y-3 rounded-lg border border-border p-4">
         <p className="text-sm font-medium">{t("monitorLinks.addTitle")}</p>
-        <div className="grid gap-3 sm:grid-cols-[1fr_1.5fr_auto]">
+        <div className="grid grid-cols-1 gap-3 sm:grid-cols-[1fr_1.5fr_auto]">
           <div className="space-y-1.5">
             <Label htmlFor="monitor-link-name">{t("monitorLinks.name")}</Label>
             <Input id="monitor-link-name" value={form.name} disabled={busy} onChange={event => setForm({ ...form, name: event.target.value })} />
@@ -350,6 +352,8 @@ function ManageLinksDialog({ open, onOpenChange }: { open: boolean; onOpenChange
       {error && <p role="alert" className="text-sm text-red-500">{error}</p>}
 
       <div className="space-y-3">
+        {isLoading && <p className="text-sm text-muted-foreground">{t("monitorLinks.checking")}</p>}
+        {loadError && <p role="alert" className="text-sm text-amber-500">{t("monitorLinks.loadFailed")}</p>}
         {data?.links.length === 0 && <p className="text-sm text-muted-foreground">{t("monitorLinks.empty")}</p>}
         {data?.links.map(link => {
           const own = link.manual || link.custom_url
@@ -378,8 +382,8 @@ function ManageLinksDialog({ open, onOpenChange }: { open: boolean; onOpenChange
                   <span className="shrink-0 rounded border border-border px-1.5 py-0.5 text-[11px] text-muted-foreground">{t("monitorLinks.thisNode")}</span>
                 </div>
               : isEditing
-              ? <div className="flex gap-2">
-                  <Input value={draft} disabled={busy} autoFocus aria-label={t("monitorLinks.address")}
+              ? <div className="grid grid-cols-2 gap-2 sm:flex">
+                  <Input className="col-span-2 min-w-0 sm:flex-1" value={draft} disabled={busy} autoFocus aria-label={t("monitorLinks.address")}
                     placeholder={link.manual ? "" : `${t("monitorLinks.autoAddress")}${shown ? `: ${shown}` : ""}`}
                     onChange={event => setAddresses({ ...addresses, [link.key]: event.target.value })} />
                   <Button size="sm" className="h-10 bg-blue-600 text-white hover:bg-blue-700 disabled:bg-blue-600/50 disabled:text-white disabled:opacity-100"
diff --git a/AppImage/lib/monitor-link-errors.ts b/AppImage/lib/monitor-link-errors.ts
new file mode 100644
index 00000000..f186c227
--- /dev/null
+++ b/AppImage/lib/monitor-link-errors.ts
@@ -0,0 +1,29 @@
+type Translate = (key: string, params?: Record<string, string | number>) => string
+
+const ERROR_KEYS: Record<string, string> = {
+  monitor_link_address_required: "addressRequired",
+  monitor_link_invalid_address: "invalidAddress",
+  monitor_link_address_credentials: "addressCredentials",
+  monitor_link_invalid_port: "invalidPort",
+  monitor_link_invalid_request: "invalidRequest",
+  monitor_link_duplicate: "duplicate",
+  monitor_link_not_found: "notFound",
+  monitor_link_detected_remove: "detectedRemove",
+}
+
+// fetchApi preserves the structured response on Error.body. Never expose raw
+// server/network messages or treat arbitrary error codes as translation keys.
+export function monitorLinkError(error: unknown, t: Translate): string {
+  const fallback = () => t("monitorLinks.saveFailed")
+  if (!error || typeof error !== "object" || !("body" in error)) return fallback()
+  const body = error.body
+  if (!body || typeof body !== "object" || !("code" in body) || typeof body.code !== "string") return fallback()
+  if (body.code === "monitor_link_limit") {
+    const params = "params" in body ? body.params : null
+    const count = params && typeof params === "object" && "count" in params ? params.count : null
+    return typeof count === "number" && Number.isSafeInteger(count) && count > 0
+      ? t("monitorLinks.errors.limit", { count }) : fallback()
+  }
+  return Object.prototype.hasOwnProperty.call(ERROR_KEYS, body.code)
+    ? t(`monitorLinks.errors.${ERROR_KEYS[body.code]}`) : fallback()
+}
diff --git a/AppImage/messages/en/common.json b/AppImage/messages/en/common.json
index cb93dc90..aa4a5c4a 100644
--- a/AppImage/messages/en/common.json
+++ b/AppImage/messages/en/common.json
@@ -6616,6 +6616,17 @@
     "addSelected": "Add selected",
     "pbsWebInterface": "PBS web interface",
     "changeAddress": "Change address",
-    "cancel": "Cancel"
+    "cancel": "Cancel",
+    "errors": {
+      "addressRequired": "Enter the address of the Monitor.",
+      "invalidAddress": "The address must start with http:// or https:// and name a host.",
+      "addressCredentials": "The address must not contain a user or password.",
+      "invalidPort": "The port of the address is not valid.",
+      "invalidRequest": "The request is not valid. Reload the page and try again.",
+      "limit": "At most {count} nodes can be added.",
+      "duplicate": "This address is already in the list.",
+      "notFound": "The node was not found. Reload the list and try again.",
+      "detectedRemove": "Only nodes added by hand can be removed. Detected nodes can be hidden."
+    }
   }
 }
diff --git a/AppImage/messages/sk/common.json b/AppImage/messages/sk/common.json
index 18c9805b..29ea7bd2 100644
--- a/AppImage/messages/sk/common.json
+++ b/AppImage/messages/sk/common.json
@@ -7372,41 +7372,52 @@
   },
   "monitorLinks": {
     "groups": {
-      "cluster": "Cluster",
+      "cluster": "Klaster",
       "standalone": "Samostatné uzly",
       "pbs": "Proxmox Backup Server"
     },
     "thisNode": "Tento uzol",
     "checking": "Kontrolujú sa uzly…",
     "loadFailed": "Nepodarilo sa načítať zoznam uzlov.",
-    "empty": "Zatiaľ žiadne ďalšie uzly. Pridajte jeden, aby ste odtiaľto otvorili jeho Monitor.",
+    "empty": "Zatiaľ tu nie sú ďalšie uzly. Pridaj uzol a jeho Monitor otvoríš priamo odtiaľto.",
     "noResponse": "Žiadna odpoveď",
     "pbsInterface": "rozhranie PBS",
     "openNewTab": "Otvoriť na novej karte",
     "manage": "Pridať alebo spravovať uzly…",
     "dialogTitle": "Prepojené uzly",
-    "dialogDescription": "Uzly klastra a nakonfigurované Proxmox Backup Server sa zisťujú automaticky. Každý Monitor má vlastné prihlásenie.",
+    "dialogDescription": "Uzly klastra a nastavené servery Proxmox Backup Server sa zisťujú automaticky. Do Monitora každého uzla sa prihlasuješ samostatne.",
     "addTitle": "Pridať uzol",
-    "name": "Meno",
-    "address": "Adresa monitora",
+    "name": "Názov uzla",
+    "address": "Adresa Monitora",
     "type": "Typ",
     "add": "Pridať",
     "save": "Uložiť",
     "remove": "Odstrániť",
-    "visible": "Viditeľné",
+    "visible": "Zobraziť",
     "autoAddress": "Automaticky",
-    "detected": "Zistené",
-    "added": "Pridané",
+    "detected": "Zistený",
+    "added": "Pridaný",
     "saveFailed": "Nepodarilo sa uložiť zoznam uzlov.",
     "backTo": "Späť na {name}",
-    "cameFromTitle": "Pridať uzol monitora?",
-    "cameFromBody": "Pridajte {name} do prepojených uzlov tohto monitora.",
+    "cameFromTitle": "Pridať uzol Monitora?",
+    "cameFromBody": "Pridaj {name} medzi prepojené uzly tohto Monitora.",
     "notNow": "Teraz nie",
     "knownTitle": "Pridať prepojené uzly?",
-    "knownBody": "{name} prepája tieto monitory. Vyberte tie, ktoré chcete pridať do tohto monitora.",
+    "knownBody": "Uzol {name} má prepojené tieto uzly. Vyber tie, ktoré chceš pridať aj sem.",
     "addSelected": "Pridať vybrané",
     "pbsWebInterface": "Webové rozhranie PBS",
     "changeAddress": "Zmeniť adresu",
-    "cancel": "Zrušiť"
+    "cancel": "Zrušiť",
+    "errors": {
+      "addressRequired": "Zadaj adresu Monitora.",
+      "invalidAddress": "Adresa musí začínať na http:// alebo https:// a obsahovať názov hostiteľa alebo IP adresu.",
+      "addressCredentials": "Adresa nesmie obsahovať používateľské meno ani heslo.",
+      "invalidPort": "Port v adrese nie je platný. Zadaj číslo od 1 do 65535.",
+      "invalidRequest": "Požiadavka nie je platná. Obnov stránku a skús to znova.",
+      "limit": "Môžeš pridať najviac {count} uzlov.",
+      "duplicate": "Táto adresa už je v zozname.",
+      "notFound": "Uzol sa nenašiel. Obnov zoznam a skús to znova.",
+      "detectedRemove": "Odstrániť môžeš iba ručne pridané uzly. Automaticky zistené uzly môžeš skryť."
+    }
   }
 }
diff --git a/AppImage/scripts/flask_monitor_links_routes.py b/AppImage/scripts/flask_monitor_links_routes.py
index 24c7d3ee..bf150aae 100644
--- a/AppImage/scripts/flask_monitor_links_routes.py
+++ b/AppImage/scripts/flask_monitor_links_routes.py
@@ -7,6 +7,13 @@ from jwt_middleware import require_auth, require_admin_scope
 monitor_links_bp = Blueprint("monitor_links", __name__)
 
 
+def link_error(exc):
+    payload = {"error": str(exc), "code": exc.code}
+    if exc.params:
+        payload["params"] = exc.params
+    return jsonify(payload), 400
+
+
 @monitor_links_bp.after_request
 def no_cache(response):
     response.headers["Cache-Control"] = "no-store"
@@ -27,9 +34,9 @@ def add_link():
         monitor_links.refresh()
         return jsonify(success=True, key=key)
     except monitor_links.LinkError as exc:
-        return jsonify(error=str(exc)), 400
+        return link_error(exc)
     except OSError:
-        return jsonify(error="Could not save the node list."), 500
+        return jsonify(error="Could not save the node list.", code="monitor_links_save_failed"), 500
 
 
 @monitor_links_bp.route("/api/monitor-links/<path:key>", methods=["PATCH"])
@@ -40,9 +47,9 @@ def update_link(key):
         monitor_links.refresh()
         return jsonify(success=True)
     except monitor_links.LinkError as exc:
-        return jsonify(error=str(exc)), 400
+        return link_error(exc)
     except OSError:
-        return jsonify(error="Could not save the node list."), 500
+        return jsonify(error="Could not save the node list.", code="monitor_links_save_failed"), 500
 
 
 @monitor_links_bp.route("/api/monitor-links/<path:key>", methods=["DELETE"])
@@ -53,6 +60,6 @@ def delete_link(key):
         monitor_links.refresh()
         return jsonify(success=True)
     except monitor_links.LinkError as exc:
-        return jsonify(error=str(exc)), 400
+        return link_error(exc)
     except OSError:
-        return jsonify(error="Could not save the node list."), 500
+        return jsonify(error="Could not save the node list.", code="monitor_links_save_failed"), 500
diff --git a/AppImage/scripts/monitor_links.py b/AppImage/scripts/monitor_links.py
index 169ca0f0..6bf46ebc 100644
--- a/AppImage/scripts/monitor_links.py
+++ b/AppImage/scripts/monitor_links.py
@@ -39,7 +39,10 @@ _refresh_lock = threading.Lock()
 
 
 class LinkError(ValueError):
-    pass
+    def __init__(self, message, *, code="monitor_links_save_failed", params=None):
+        super().__init__(message)
+        self.code = code
+        self.params = params
 
 
 def _load():
@@ -63,19 +66,19 @@ def _save(data):
 def normalize_url(value):
     """Return the origin of an http(s) address, or raise LinkError."""
     if not isinstance(value, str) or not value.strip():
-        raise LinkError("Enter the address of the Monitor.")
+        raise LinkError("Enter the address of the Monitor.", code="monitor_link_address_required")
     text = value.strip()
     if "://" not in text:
         text = "https://" + text
     parsed = urllib.parse.urlsplit(text)
     if parsed.scheme not in ("http", "https") or not parsed.hostname:
-        raise LinkError("The address must start with http:// or https:// and name a host.")
+        raise LinkError("The address must start with http:// or https:// and name a host.", code="monitor_link_invalid_address")
     if parsed.username or parsed.password:
-        raise LinkError("The address must not contain a user or password.")
+        raise LinkError("The address must not contain a user or password.", code="monitor_link_address_credentials")
     try:
         port = parsed.port
     except ValueError as exc:
-        raise LinkError("The port of the address is not valid.") from exc
+        raise LinkError("The port of the address is not valid.", code="monitor_link_invalid_port") from exc
     host = parsed.hostname
     if ":" in host:
         host = f"[{host}]"
@@ -301,16 +304,16 @@ def start_prewarmer():
 
 def add_link(payload):
     if not isinstance(payload, dict):
-        raise LinkError("Invalid request.")
+        raise LinkError("Invalid request.", code="monitor_link_invalid_request")
     name = str(payload.get("name") or "").strip()[:64]
     url = normalize_url(payload.get("url"))
     product = payload.get("product") if payload.get("product") in PRODUCTS else "pve"
     with _lock:
         data = _load()
         if len(data["manual"]) >= MAX_MANUAL:
-            raise LinkError(f"At most {MAX_MANUAL} nodes can be added.")
+            raise LinkError(f"At most {MAX_MANUAL} nodes can be added.", code="monitor_link_limit", params={"count": MAX_MANUAL})
         if any(row.get("url") == url for row in data["manual"]):
-            raise LinkError("This address is already in the list.")
+            raise LinkError("This address is already in the list.", code="monitor_link_duplicate")
         identifier = secrets.token_hex(6)
         data["manual"].append({"id": identifier, "name": name or urllib.parse.urlsplit(url).hostname,
                                "url": url, "product": product})
@@ -320,13 +323,13 @@ def add_link(payload):
 
 def update_link(key, payload):
     if not isinstance(payload, dict):
-        raise LinkError("Invalid request.")
+        raise LinkError("Invalid request.", code="monitor_link_invalid_request")
     with _lock:
         data = _load()
         if key.startswith("manual:"):
             row = next((r for r in data["manual"] if f"manual:{r.get('id')}" == key), None)
             if row is None:
-                raise LinkError("Node not found.")
+                raise LinkError("Node not found.", code="monitor_link_not_found")
             if "name" in payload:
                 row["name"] = str(payload["name"] or "").strip()[:64] or row["name"]
             if payload.get("url"):
@@ -345,7 +348,7 @@ def update_link(key, payload):
             if not override:
                 data["overrides"].pop(key, None)
         else:
-            raise LinkError("Node not found.")
+            raise LinkError("Node not found.", code="monitor_link_not_found")
         _save(data)
 
 
@@ -354,6 +357,6 @@ def delete_link(key):
         data = _load()
         remaining = [r for r in data["manual"] if f"manual:{r.get('id')}" != key]
         if len(remaining) == len(data["manual"]):
-            raise LinkError("Only nodes added by hand can be removed; detected ones can be hidden.")
+            raise LinkError("Only nodes added by hand can be removed; detected ones can be hidden.", code="monitor_link_detected_remove")
         data["manual"] = remaining
         _save(data)
diff --git a/AppImage/scripts/tests/test_monitor_links_i18n.py b/AppImage/scripts/tests/test_monitor_links_i18n.py
new file mode 100644
index 00000000..197096c2
--- /dev/null
+++ b/AppImage/scripts/tests/test_monitor_links_i18n.py
@@ -0,0 +1,138 @@
+"""Exercise the shipped routes and persistence; localization is additive."""
+import importlib.util
+import json
+from pathlib import Path
+import sys
+import tempfile
+import types
+import unittest
+from unittest import mock
+
+from flask import Flask
+
+ROOT = Path(__file__).resolve().parents[3]
+sys.path.insert(0, str(ROOT / "AppImage/scripts"))
+import monitor_links as links
+
+
+class MonitorLinksI18nTests(unittest.TestCase):
+    def setUp(self):
+        temporary = tempfile.TemporaryDirectory()
+        self.addCleanup(temporary.cleanup)
+        self.path = Path(temporary.name) / "links.json"
+        self.previous = {"manual": [{"id": "saved", "name": "Saved", "url": "https://saved.test", "product": "pve"}], "overrides": {}}
+        self.path.write_text(json.dumps(self.previous))
+        for patch in [mock.patch.object(links, "LINKS_FILE", self.path),
+                      mock.patch.object(links, "refresh"), mock.patch.object(links, "_probe")]:
+            patch.start()
+            self.addCleanup(patch.stop)
+        auth_provider = types.SimpleNamespace(
+            load_auth_config=lambda: {"enabled": True},
+            verify_token=lambda token: "fixture" if token in ("admin", "reader") else None,
+            verify_token_full=lambda token: ("fixture", "full_admin" if token == "admin" else "read_only")
+            if token in ("admin", "reader") else (None, None))
+        middleware_spec = importlib.util.spec_from_file_location("fixture_jwt_middleware", ROOT / "AppImage/scripts/jwt_middleware.py")
+        middleware = importlib.util.module_from_spec(middleware_spec)
+        # Execute the shipped decorators; only credential verification is faked.
+        with mock.patch.dict(sys.modules, {"auth_manager": auth_provider}):
+            middleware_spec.loader.exec_module(middleware)
+        spec = importlib.util.spec_from_file_location("fixture_monitor_links_routes", ROOT / "AppImage/scripts/flask_monitor_links_routes.py")
+        routes = importlib.util.module_from_spec(spec)
+        # Import isolation keeps the real JWT module and other suites untouched.
+        with mock.patch.dict(sys.modules, {"jwt_middleware": middleware}):
+            spec.loader.exec_module(routes)
+        app = Flask(__name__)
+        app.register_blueprint(routes.monitor_links_bp)
+        self.client = app.test_client()
+
+    def send(self, method, path="", payload=None, role="admin"):
+        return self.client.open("/api/monitor-links" + path, method=method,
+                                json=payload, headers={"Authorization": "Bearer " + role} if role else {})
+
+    def rejected(self, method, path, payload, message, code, params=None):
+        before = self.path.read_bytes()
+        with mock.patch.object(links, "_save") as save:
+            response = self.send(method, path, payload)
+        self.assertEqual(response.status_code, 400)
+        expected = {"error": message, "code": code}
+        if params:
+            expected["params"] = params
+        self.assertEqual(response.json, expected)
+        self.assertEqual(response.headers["Cache-Control"], "no-store")
+        save.assert_not_called()
+        links.refresh.assert_not_called()
+        links._probe.assert_not_called()
+        self.assertEqual(self.path.read_bytes(), before)
+
+    def test_validation_errors_preserve_english_status_and_have_stable_codes_without_effects(self):
+        cases = [
+            ("POST", "", None, "Invalid request.", "monitor_link_invalid_request"),
+            ("PATCH", "/manual:saved", [], "Invalid request.", "monitor_link_invalid_request"),
+            ("POST", "", {"url": " "}, "Enter the address of the Monitor.", "monitor_link_address_required"),
+            ("POST", "", {"url": "ftp://example.test"}, "The address must start with http:// or https:// and name a host.", "monitor_link_invalid_address"),
+            ("POST", "", {"url": "https://user:pass@example.test"}, "The address must not contain a user or password.", "monitor_link_address_credentials"),
+            ("PATCH", "/manual:saved", {"name": "Unsaved", "url": "https://example.test:99999"}, "The port of the address is not valid.", "monitor_link_invalid_port"),
+            ("PATCH", "/cluster:node", {"url": "ftp://example.test"}, "The address must start with http:// or https:// and name a host.", "monitor_link_invalid_address"),
+            ("POST", "", {"url": "https://saved.test/path"}, "This address is already in the list.", "monitor_link_duplicate"),
+            ("PATCH", "/manual:absent", {"url": "https://new.test"}, "Node not found.", "monitor_link_not_found"),
+            ("PATCH", "/other:node", {}, "Node not found.", "monitor_link_not_found"),
+            ("DELETE", "/cluster:node", None, "Only nodes added by hand can be removed; detected ones can be hidden.", "monitor_link_detected_remove"),
+        ]
+        for case in cases:
+            with self.subTest(case=case):
+                self.rejected(*case)
+
+    def test_limit_uses_actual_count_and_preserves_previous_file(self):
+        with mock.patch.object(links, "MAX_MANUAL", 1):
+            self.rejected("POST", "", {"url": "https://new.test"}, "At most 1 nodes can be added.",
+                          "monitor_link_limit", {"count": 1})
+
+    def test_write_failure_is_localizable_without_leaking_filesystem_details(self):
+        for method, path, payload in [("POST", "", {"url": "https://new.test"}),
+                                      ("PATCH", "/manual:saved", {"name": "Unsaved"}),
+                                      ("DELETE", "/manual:saved", None)]:
+            with self.subTest(method=method), mock.patch.object(links.os, "replace", side_effect=OSError("private path details")):
+                before = self.path.read_bytes()
+                response = self.send(method, path, payload)
+                self.assertEqual(response.status_code, 500)
+                self.assertEqual(response.json, {"error": "Could not save the node list.", "code": "monitor_links_save_failed"})
+                self.assertEqual(self.path.read_bytes(), before)
+                links.refresh.assert_not_called()
+                links._probe.assert_not_called()
+
+    def test_successful_crud_and_detected_hide_reset_keep_existing_contract(self):
+        response = self.send("POST", payload={"name": "New", "url": "new.test:8008/path", "product": "pbs"})
+        self.assertEqual(response.status_code, 200)
+        self.assertEqual(set(response.json), {"success", "key"})
+        key = response.json["key"]
+        self.assertTrue(key.startswith("manual:"))
+        row = links._load()["manual"][-1]
+        self.assertEqual((row["url"], row["product"]), ("https://new.test:8008", "pbs"))
+        self.assertEqual(self.send("PATCH", "/" + key, {"url": "http://changed.test"}).json, {"success": True})
+        self.assertEqual(links._load()["manual"][-1]["url"], "http://changed.test")
+        self.assertEqual(self.send("PATCH", "/cluster:node", {"url": "https://override.test", "hidden": True}).json, {"success": True})
+        self.assertEqual(self.send("PATCH", "/cluster:node", {"url": "", "hidden": False}).json, {"success": True})
+        self.assertEqual(links._load()["overrides"], {"cluster:node": {"hidden": False}})
+        self.assertEqual(self.send("DELETE", "/" + key).json, {"success": True})
+        self.assertEqual(links._load()["manual"], self.previous["manual"])
+        self.assertEqual(self.path.stat().st_mode & 0o777, 0o600)
+        self.assertEqual(links.refresh.call_count, 5)
+        links._probe.assert_not_called()
+
+    def test_existing_read_and_admin_decorators_still_guard_routes_before_effects(self):
+        with mock.patch.object(links, "cached_links", return_value={"self": {}, "links": []}) as cached, \
+                mock.patch.object(links, "_save") as save:
+            for method, path in [("POST", ""), ("PATCH", "/manual:saved"), ("DELETE", "/manual:saved")]:
+                for role, status in [(None, 401), ("reader", 403)]:
+                    self.assertEqual(self.send(method, path, {"url": "https://new.test"}, role).status_code, status)
+            self.assertEqual(self.send("GET", role=None).status_code, 401)
+            self.assertEqual(self.send("GET", "?all=1", role="reader").status_code, 200)
+            cached.assert_called_once_with(include_hidden=True)
+            save.assert_not_called()
+            links.refresh.assert_not_called()
+            links._probe.assert_not_called()
+        self.assertEqual(json.loads(self.path.read_text()), self.previous)
+
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/tests/test_monitor_links_i18n.cjs b/tests/test_monitor_links_i18n.cjs
new file mode 100644
index 00000000..46c566f4
--- /dev/null
+++ b/tests/test_monitor_links_i18n.cjs
@@ -0,0 +1,133 @@
+// Run the shipped translation adapter, transport and both dialog components.
+const assert = require('node:assert/strict');
+const fs = require('node:fs');
+const vm = require('node:vm');
+const ts = require('typescript');
+const compile = source => ts.transpileModule(source, {compilerOptions: {
+  module: ts.ModuleKind.CommonJS, target: ts.ScriptTarget.ES2020, jsx: ts.JsxEmit.ReactJSX,
+}}).outputText;
+const translations = Object.fromEntries(['en', 'sk'].map(locale => [locale, JSON.parse(fs.readFileSync(`AppImage/messages/${locale}/common.json`))]));
+const translate = locale => (key, params = {}) => {
+  const value = key.split('.').reduce((tree, part) => tree?.[part], translations[locale]);
+  assert.equal(typeof value, 'string', key);
+  return value.replace(/\{(\w+)\}/g, (match, key) => params[key] ?? match);
+};
+const adapter = {exports: {}};
+vm.runInNewContext(compile(fs.readFileSync('AppImage/lib/monitor-link-errors.ts', 'utf8')), adapter);
+const {monitorLinkError} = adapter.exports;
+const codes = {
+  monitor_link_address_required: 'addressRequired', monitor_link_invalid_address: 'invalidAddress',
+  monitor_link_address_credentials: 'addressCredentials', monitor_link_invalid_port: 'invalidPort',
+  monitor_link_invalid_request: 'invalidRequest', monitor_link_duplicate: 'duplicate',
+  monitor_link_not_found: 'notFound', monitor_link_detected_remove: 'detectedRemove',
+};
+const failure = (code, params) => Object.assign(new Error('RAW ENGLISH SECRET DETAILS'), {body: {error: 'RAW ENGLISH SECRET DETAILS', code, params}});
+
+const flatten = tree => !tree || typeof tree === 'boolean' ? [] : Array.isArray(tree) ? tree.flatMap(flatten)
+  : typeof tree === 'object' ? [tree, ...flatten(tree.props?.children)] : [tree];
+const text = tree => flatten(tree).filter(n => typeof n === 'string' || typeof n === 'number').join('');
+const jsx = (type, props) => ({type, props});
+const source = compile(fs.readFileSync('AppImage/components/monitor-switcher.tsx', 'utf8') + '\nexport {ManageLinksDialog};');
+
+function fixture({locale = 'sk', links = [], origin = false, loadError = false, loading = false} = {}) {
+  let slots = [], cursor = 0, effects = [], tree, responseError, refreshFailure = false;
+  const calls = [], refreshes = [], storage = new Map();
+  const candidates = [{u: 'https://other.test', n: 'Other', p: 'pve'}];
+  const carried = Buffer.from(JSON.stringify(candidates)).toString('base64url');
+  const location = {origin: 'https://current.test', hostname: 'current.test', pathname: '/', hash: '',
+    search: origin ? `?pmx_from=https%3A%2F%2Fsource.test&pmx_name=Source&pmx_links=${carried}` : ''};
+  const react = {
+    useState(initial) {const slot = cursor++; if (!(slot in slots)) slots[slot] = typeof initial === 'function' ? initial() : initial;
+      return [slots[slot], value => {slots[slot] = typeof value === 'function' ? value(slots[slot]) : value;}];},
+    useEffect(fn, deps) {const slot = cursor++; const old = slots[slot];
+      if (!old || deps.some((dep, i) => dep !== old[i])) effects.push(fn);
+      slots[slot] = deps;
+    },
+  };
+  const exported = {};
+  vm.runInNewContext(source, {exports: exported, URL, URLSearchParams, escape, unescape,
+    atob: value => Buffer.from(value, 'base64').toString('binary'), btoa: value => Buffer.from(value, 'binary').toString('base64'),
+    window: {location, history: {replaceState() {location.search = ''}}},
+    sessionStorage: {getItem: key => storage.get(key) || null, setItem: (key, value) => storage.set(key, value)},
+    require(name) {
+      if (name === 'react') return react;
+      if (name === 'react/jsx-runtime') return {jsx, jsxs: jsx, Fragment: 'Fragment'};
+      if (name === 'swr') return {default: () => ({data: {self: {name: 'Current', product: 'pve'}, links}, error: loadError, isLoading: loading,
+        mutate: async () => refreshes.push('all')}), mutate: async key => {refreshes.push(key); if (refreshFailure) throw new Error('RAW REFRESH ERROR');}};
+      if (name.includes('i18n/provider')) return {useT: () => translate(locale)};
+      if (name.includes('monitor-link-errors')) return {monitorLinkError};
+      if (name.includes('api-config')) return {fetchApi: async (path, options) => {calls.push({path, ...options}); if (responseError) throw responseError; return {success: true};}};
+      return new Proxy({}, {get: (_, key) => key});
+    },
+  });
+  return {
+    render(component = 'ManageLinksDialog') {cursor = 0; effects = []; tree = exported[component]({open: true, onOpenChange() {}, nodeName: 'Current'}); effects.forEach(fn => fn()); return tree;},
+    button(label) {const node = flatten(tree).find(n => n.type === 'Button' && (text(n) === label || n.props['aria-label'] === label)); assert.ok(node, label); return node;},
+    input(id) {const node = flatten(tree).find(n => n.type === 'Input' && (n.props.id === id || n.props['aria-label'] === id)); assert.ok(node, id); return node;},
+    nodes: () => flatten(tree), text: () => text(tree), fail: error => {responseError = error;}, failRefresh: () => {refreshFailure = true;}, calls, refreshes, storage,
+  };
+}
+
+async function main() {
+  for (const locale of ['en', 'sk']) {
+    const t = translate(locale);
+    for (const [code, key] of Object.entries(codes)) assert.equal(monitorLinkError(failure(code), t), t(`monitorLinks.errors.${key}`));
+    assert.equal(monitorLinkError(failure('monitor_link_limit', {count: 64}), t), t('monitorLinks.errors.limit', {count: 64}));
+    for (const error of [null, undefined, 'raw', new Error('raw'), {body: null}, {body: {}},
+      ...['constructor', '__proto__', 'toString', 'unknown', 'monitor_links_save_failed'].map(code => failure(code)),
+      ...[undefined, null, '64', 0, -1, 1.5, NaN, Infinity, 2 ** 54].map(count => failure('monitor_link_limit', {count}))]) {
+      assert.equal(monitorLinkError(error, t), t('monitorLinks.saveFailed'));
+    }
+    const f = fixture({locale, links: [{key: 'manual:saved', name: 'Saved', url: 'https://saved.test', manual: true}]});
+    f.render(); f.button(t('monitorLinks.changeAddress')).props.onClick(); f.render();
+    f.input(t('monitorLinks.address')).props.onChange({target: {value: 'https://unsaved.test'}}); f.render();
+    f.button(t('monitorLinks.cancel')).props.onClick(); f.render();
+    assert.equal(f.calls.length, 0, 'Cancel must not write');
+    f.button(t('monitorLinks.changeAddress')).props.onClick(); f.render();
+    assert.equal(f.input(t('monitorLinks.address')).props.value, 'https://saved.test', 'Cancel discards address draft');
+    f.input(t('monitorLinks.address')).props.onChange({target: {value: 'https://changed.test'}}); f.render();
+    await f.button(t('monitorLinks.save')).props.onClick(); f.render();
+    assert.equal(f.calls[0].method, 'PATCH'); assert.deepEqual(JSON.parse(f.calls[0].body), {url: 'https://changed.test'});
+    assert.equal(f.button(t('monitorLinks.add')).props.disabled, true, 'Blank address cannot be submitted');
+    f.input('monitor-link-url').props.onChange({target: {value: 'ftp://bad.test'}}); f.render();
+    f.fail(failure('monitor_link_invalid_address')); await f.button(t('monitorLinks.add')).props.onClick(); f.render();
+    assert.ok(f.text().includes(t('monitorLinks.errors.invalidAddress')));
+    assert.equal(f.input('monitor-link-url').props.value, 'ftp://bad.test', 'Failure retains draft');
+    assert.ok(!f.text().includes('RAW ENGLISH'));
+    f.fail(new Error('raw network details')); await f.button(t('monitorLinks.remove')).props.onClick(); f.render();
+    assert.ok(f.text().includes(t('monitorLinks.saveFailed')));
+    const failedRead = fixture({locale, loadError: new Error('raw')}); failedRead.render();
+    assert.ok(failedRead.text().includes(t('monitorLinks.loadFailed')));
+    const pendingRead = fixture({locale, loading: true}); pendingRead.render();
+    assert.ok(pendingRead.text().includes(t('monitorLinks.checking')));
+
+    const declined = fixture({locale, origin: true});
+    for (let n = 0; n < 3; n++) declined.render('MonitorSwitcher');
+    declined.button(t('monitorLinks.notNow')).props.onClick(); declined.render('MonitorSwitcher');
+    assert.equal(declined.calls.length, 0, 'Not now must not write');
+    const carried = fixture({locale, origin: true});
+    for (let n = 0; n < 3; n++) carried.render('MonitorSwitcher');
+    const boxes = carried.nodes().filter(n => n.type === 'Checkbox'); assert.equal(boxes.length, 2);
+    boxes[1].props.onCheckedChange(false); carried.render('MonitorSwitcher');
+    carried.fail(failure('monitor_link_duplicate'));
+    carried.failRefresh();
+    await carried.button(t('monitorLinks.addSelected')).props.onClick(); carried.render('MonitorSwitcher');
+    assert.equal(carried.calls.length, 1, 'Only selected origin is attempted');
+    assert.equal(JSON.parse(carried.calls[0].body).url, 'https://source.test');
+    assert.ok(carried.text().includes(t('monitorLinks.errors.duplicate')));
+    assert.equal(carried.refreshes.length, 1, 'Failed/partially successful batch refreshes the visible list');
+  }
+  // Real authenticated transport preserves additive fields for the adapter.
+  const api = {exports: {}, process: {env: {}}, fetch: async () => new Response(JSON.stringify({error: 'Original English error', code: 'monitor_link_duplicate'}), {status: 400, headers: {'Content-Type': 'application/json'}})};
+  vm.runInNewContext(compile(fs.readFileSync('AppImage/lib/api-config.ts', 'utf8')), api);
+  try {await api.exports.fetchApi('/api/monitor-links', {method: 'POST'}); assert.fail('expected rejection');}
+  catch (error) {assert.equal(error.status, 400); assert.equal(error.message, 'Original English error'); assert.equal(monitorLinkError(error, translate('sk')), translations.sk.monitorLinks.errors.duplicate);}
+  const en = translations.en.monitorLinks, sk = translations.sk.monitorLinks;
+  assert.deepEqual(Object.keys(en.errors).sort(), Object.keys(sk.errors).sort());
+  for (const key of Object.keys(en.errors)) {
+    assert.ok(sk.errors[key]);
+    assert.deepEqual(en.errors[key].match(/\{\w+\}/g), sk.errors[key].match(/\{\w+\}/g), key);
+  }
+  console.log('PASS: EN/SK known/unknown errors, real transport, both dialogs, Cancel/Not now zero writes, draft persistence, selected-only batch, localized loading/failure');
+}
+main().catch(error => {console.error(error); process.exitCode = 1;});