Added protecting hooks

src/modules/hooks/preventDeleteSystemPage.ts

@@ -0,0 +1,45 @@
+import type { CollectionBeforeDeleteHook } from 'payload'
+
+import { APIError } from 'payload'
+
+/**
+ * Blocks deletion of a page assigned a System Page role (homepage,
+ * privacyPolicy, cookiePolicy, termsOfService). An editor deleting the privacy
+ * policy or homepage by accident would break routing and compliance links; this
+ * stops it with a clear error. They must unassign the role first (deliberate).
+ *
+ * Reads the role assignments from SiteSettings (which page holds which role).
+ *
+ *   hooks: { beforeDelete: [buildPreventDeleteSystemPage({ settingsSlug: 'site-settings' })] }
+ */
+export function buildPreventDeleteSystemPage(
+  args: { roleFields?: string[]; settingsSlug?: string } = {},
+): CollectionBeforeDeleteHook {
+  const settingsSlug = args.settingsSlug ?? 'site-settings'
+  const roleFields = args.roleFields ?? [
+    'homepage',
+    'privacyPolicy',
+    'cookiePolicy',
+    'termsOfService',
+  ]
+
+  return async ({ id, req }) => {
+    const settings = (await req.payload
+      .findGlobal({ slug: settingsSlug as never, depth: 0 })
+      .catch(() => null)) as null | Record<string, unknown>
+    if (!settings) {return}
+
+    for (const field of roleFields) {
+      const assigned = settings[field]
+      const assignedId =
+        assigned && typeof assigned === 'object' ? (assigned as { id?: unknown }).id : assigned
+      if (assignedId != null && String(assignedId) === String(id)) {
+        throw new APIError(
+          `Nie można usunąć strony przypisanej do roli systemowej "${field}". ` +
+            `Najpierw odłącz rolę w Site Settings.`,
+          400,
+        )
+      }
+    }
+  }
+}