feat(i18n): add localized navigation and news translations

apps/admin/src/app/navigation/page.tsx

@@ -5,6 +5,7 @@ import {
   listNavigationMenus,
   listPages,
   updateNavigationItem,
+  upsertNavigationItemTranslation,
 } from "@cms/db"
 import { Button } from "@cms/ui/button"
 import { revalidatePath } from "next/cache"
@@ -18,6 +19,9 @@ import { requirePermissionForRoute } from "@/lib/route-guards"
 export const dynamic = "force-dynamic"
 
 type SearchParamsInput = Record<string, string | string[] | undefined>
+const SUPPORTED_LOCALES = ["de", "en", "es", "fr"] as const
+
+type SupportedLocale = (typeof SUPPORTED_LOCALES)[number]
 
 function readFirstValue(value: string | string[] | undefined): string | null {
   if (Array.isArray(value)) {
@@ -53,6 +57,14 @@ function readInt(formData: FormData, field: string, fallback = 0): number {
   return parsed
 }
 
+function normalizeLocale(input: string | null): SupportedLocale {
+  if (input && SUPPORTED_LOCALES.includes(input as SupportedLocale)) {
+    return input as SupportedLocale
+  }
+
+  return "en"
+}
+
 function redirectWithState(params: { notice?: string; error?: string }) {
   const query = new URLSearchParams()
 
@@ -165,6 +177,31 @@ async function deleteItemAction(formData: FormData) {
   redirectWithState({ notice: "Navigation item deleted." })
 }
 
+async function upsertItemTranslationAction(formData: FormData) {
+  "use server"
+
+  await requirePermissionForRoute({
+    nextPath: "/navigation",
+    permission: "navigation:write",
+    scope: "team",
+  })
+
+  const locale = normalizeLocale(readInputString(formData, "locale"))
+
+  try {
+    await upsertNavigationItemTranslation({
+      navigationItemId: readInputString(formData, "navigationItemId"),
+      locale,
+      label: readInputString(formData, "label"),
+    })
+  } catch {
+    redirectWithState({ error: "Failed to save item translation." })
+  }
+
+  revalidatePath("/navigation")
+  redirectWithState({ notice: "Navigation item translation saved." })
+}
+
 export default async function NavigationManagementPage({
   searchParams,
 }: {
@@ -184,6 +221,7 @@ export default async function NavigationManagementPage({
 
   const notice = readFirstValue(resolvedSearchParams.notice)
   const error = readFirstValue(resolvedSearchParams.error)
+  const selectedLocale = normalizeLocale(readFirstValue(resolvedSearchParams.locale))
 
   return (
     <AdminShell
@@ -218,6 +256,22 @@ export default async function NavigationManagementPage({
       </section>
 
       <section className="space-y-4">
+        <div className="flex flex-wrap gap-2">
+          {SUPPORTED_LOCALES.map((locale) => (
+            <a
+              key={locale}
+              href={`/navigation?locale=${locale}`}
+              className={`inline-flex rounded border px-3 py-1.5 text-xs ${
+                selectedLocale === locale
+                  ? "border-neutral-800 bg-neutral-900 text-white"
+                  : "border-neutral-300 text-neutral-700"
+              }`}
+            >
+              {locale.toUpperCase()}
+            </a>
+          ))}
+        </div>
+
         {menus.length === 0 ? (
           <article className="rounded-xl border border-neutral-200 p-6 text-sm text-neutral-600">
             No navigation menus yet.
@@ -238,94 +292,126 @@ export default async function NavigationManagementPage({
                 {menu.items.length === 0 ? (
                   <p className="text-sm text-neutral-600">No items in this menu.</p>
                 ) : (
-                  menu.items.map((item) => (
-                    <form
-                      key={item.id}
-                      action={updateItemAction}
-                      className="rounded-lg border border-neutral-200 p-3"
-                    >
-                      <input type="hidden" name="id" value={item.id} />
-                      <div className="grid gap-3 md:grid-cols-5">
-                        <label className="space-y-1 md:col-span-2">
-                          <span className="text-xs text-neutral-600">Label</span>
-                          <input
-                            name="label"
-                            defaultValue={item.label}
-                            className="w-full rounded border border-neutral-300 px-3 py-2 text-sm"
-                          />
-                        </label>
-                        <label className="space-y-1 md:col-span-2">
-                          <span className="text-xs text-neutral-600">Href</span>
-                          <input
-                            name="href"
-                            defaultValue={item.href ?? ""}
-                            className="w-full rounded border border-neutral-300 px-3 py-2 text-sm"
-                          />
-                        </label>
-                        <label className="space-y-1">
-                          <span className="text-xs text-neutral-600">Sort</span>
-                          <input
-                            name="sortOrder"
-                            type="number"
-                            min={0}
-                            defaultValue={item.sortOrder}
-                            className="w-full rounded border border-neutral-300 px-3 py-2 text-sm"
-                          />
-                        </label>
-                      </div>
+                  menu.items.map((item) => {
+                    const translation = item.translations.find(
+                      (entry) => entry.locale === selectedLocale,
+                    )
 
-                      <div className="mt-3 grid gap-3 md:grid-cols-2">
-                        <label className="space-y-1">
-                          <span className="text-xs text-neutral-600">Linked page</span>
-                          <select
-                            name="pageId"
-                            defaultValue={item.pageId ?? ""}
-                            className="w-full rounded border border-neutral-300 px-3 py-2 text-sm"
-                          >
-                            <option value="">(none)</option>
-                            {pages.map((page) => (
-                              <option key={page.id} value={page.id}>
-                                {page.title} (/{page.slug})
-                              </option>
-                            ))}
-                          </select>
-                        </label>
-                        <label className="space-y-1">
-                          <span className="text-xs text-neutral-600">Parent id</span>
-                          <input
-                            name="parentId"
-                            defaultValue={item.parentId ?? ""}
-                            className="w-full rounded border border-neutral-300 px-3 py-2 text-sm"
-                          />
-                        </label>
-                      </div>
+                    return (
+                      <div key={item.id} className="rounded-lg border border-neutral-200 p-3">
+                        <form action={updateItemAction}>
+                          <input type="hidden" name="id" value={item.id} />
+                          <div className="grid gap-3 md:grid-cols-5">
+                            <label className="space-y-1 md:col-span-2">
+                              <span className="text-xs text-neutral-600">Label</span>
+                              <input
+                                name="label"
+                                defaultValue={item.label}
+                                className="w-full rounded border border-neutral-300 px-3 py-2 text-sm"
+                              />
+                            </label>
+                            <label className="space-y-1 md:col-span-2">
+                              <span className="text-xs text-neutral-600">Href</span>
+                              <input
+                                name="href"
+                                defaultValue={item.href ?? ""}
+                                className="w-full rounded border border-neutral-300 px-3 py-2 text-sm"
+                              />
+                            </label>
+                            <label className="space-y-1">
+                              <span className="text-xs text-neutral-600">Sort</span>
+                              <input
+                                name="sortOrder"
+                                type="number"
+                                min={0}
+                                defaultValue={item.sortOrder}
+                                className="w-full rounded border border-neutral-300 px-3 py-2 text-sm"
+                              />
+                            </label>
+                          </div>
 
-                      <div className="mt-3 flex flex-wrap items-center justify-between gap-3">
-                        <label className="inline-flex items-center gap-2 text-sm text-neutral-700">
-                          <input
-                            type="checkbox"
-                            name="isVisible"
-                            value="true"
-                            defaultChecked={item.isVisible}
-                            className="size-4"
-                          />
-                          Visible
-                        </label>
-                        <div className="flex items-center gap-2">
-                          <Button type="submit" size="sm">
-                            Save item
-                          </Button>
-                          <button
-                            type="submit"
-                            formAction={deleteItemAction}
-                            className="rounded-md border border-red-300 px-3 py-2 text-sm text-red-700"
-                          >
-                            Delete
-                          </button>
-                        </div>
+                          <div className="mt-3 grid gap-3 md:grid-cols-2">
+                            <label className="space-y-1">
+                              <span className="text-xs text-neutral-600">Linked page</span>
+                              <select
+                                name="pageId"
+                                defaultValue={item.pageId ?? ""}
+                                className="w-full rounded border border-neutral-300 px-3 py-2 text-sm"
+                              >
+                                <option value="">(none)</option>
+                                {pages.map((page) => (
+                                  <option key={page.id} value={page.id}>
+                                    {page.title} (/{page.slug})
+                                  </option>
+                                ))}
+                              </select>
+                            </label>
+                            <label className="space-y-1">
+                              <span className="text-xs text-neutral-600">Parent id</span>
+                              <input
+                                name="parentId"
+                                defaultValue={item.parentId ?? ""}
+                                className="w-full rounded border border-neutral-300 px-3 py-2 text-sm"
+                              />
+                            </label>
+                          </div>
+
+                          <div className="mt-3 flex flex-wrap items-center justify-between gap-3">
+                            <label className="inline-flex items-center gap-2 text-sm text-neutral-700">
+                              <input
+                                type="checkbox"
+                                name="isVisible"
+                                value="true"
+                                defaultChecked={item.isVisible}
+                                className="size-4"
+                              />
+                              Visible
+                            </label>
+                            <div className="flex items-center gap-2">
+                              <Button type="submit" size="sm">
+                                Save item
+                              </Button>
+                              <button
+                                type="submit"
+                                formAction={deleteItemAction}
+                                className="rounded-md border border-red-300 px-3 py-2 text-sm text-red-700"
+                              >
+                                Delete
+                              </button>
+                            </div>
+                          </div>
+                        </form>
+
+                        <form
+                          action={upsertItemTranslationAction}
+                          className="mt-3 rounded border border-neutral-200 p-3"
+                        >
+                          <input type="hidden" name="navigationItemId" value={item.id} />
+                          <input type="hidden" name="locale" value={selectedLocale} />
+
+                          <p className="text-xs text-neutral-600">
+                            Translation ({selectedLocale.toUpperCase()}) - saved locales:{" "}
+                            {item.translations.length > 0
+                              ? item.translations
+                                  .map((entry) => entry.locale.toUpperCase())
+                                  .join(", ")
+                              : "none"}
+                          </p>
+
+                          <div className="mt-2 flex gap-2">
+                            <input
+                              name="label"
+                              defaultValue={translation?.label ?? item.label}
+                              className="w-full rounded border border-neutral-300 px-3 py-2 text-sm"
+                            />
+                            <Button type="submit" size="sm" variant="secondary">
+                              Save translation
+                            </Button>
+                          </div>
+                        </form>
                       </div>
-                    </form>
-                  ))
+                    )
+                  })
                 )}
               </div>
             </article>

apps/admin/src/app/news/page.tsx

@@ -1,4 +1,10 @@
-import { createPost, deletePost, listPosts, updatePost } from "@cms/db"
+import {
+  createPost,
+  deletePost,
+  listPostsWithTranslations,
+  updatePost,
+  upsertPostTranslation,
+} from "@cms/db"
 import { Button } from "@cms/ui/button"
 import { revalidatePath } from "next/cache"
 import { redirect } from "next/navigation"
@@ -9,6 +15,9 @@ import { requirePermissionForRoute } from "@/lib/route-guards"
 export const dynamic = "force-dynamic"
 
 type SearchParamsInput = Record<string, string | string[] | undefined>
+const SUPPORTED_LOCALES = ["de", "en", "es", "fr"] as const
+
+type SupportedLocale = (typeof SUPPORTED_LOCALES)[number]
 
 function readFirstValue(value: string | string[] | undefined): string | null {
   if (Array.isArray(value)) {
@@ -28,6 +37,14 @@ function readNullableString(formData: FormData, field: string): string | undefin
   return value.length > 0 ? value : undefined
 }
 
+function normalizeLocale(input: string | null): SupportedLocale {
+  if (input && SUPPORTED_LOCALES.includes(input as SupportedLocale)) {
+    return input as SupportedLocale
+  }
+
+  return "en"
+}
+
 function redirectWithState(params: { notice?: string; error?: string }) {
   const query = new URLSearchParams()
 
@@ -115,6 +132,34 @@ async function deleteNewsAction(formData: FormData) {
   redirectWithState({ notice: "Post deleted." })
 }
 
+async function upsertNewsTranslationAction(formData: FormData) {
+  "use server"
+
+  await requirePermissionForRoute({
+    nextPath: "/news",
+    permission: "news:write",
+    scope: "team",
+  })
+
+  const locale = normalizeLocale(readInputString(formData, "locale"))
+
+  try {
+    await upsertPostTranslation({
+      postId: readInputString(formData, "postId"),
+      locale,
+      title: readInputString(formData, "title"),
+      excerpt: readNullableString(formData, "excerpt") ?? null,
+      body: readInputString(formData, "body"),
+    })
+  } catch {
+    redirectWithState({ error: "Failed to save translation." })
+  }
+
+  revalidatePath("/news")
+  revalidatePath("/")
+  redirectWithState({ notice: "Post translation saved." })
+}
+
 export default async function NewsManagementPage({
   searchParams,
 }: {
@@ -126,10 +171,14 @@ export default async function NewsManagementPage({
     scope: "team",
   })
 
-  const [resolvedSearchParams, posts] = await Promise.all([searchParams, listPosts()])
+  const [resolvedSearchParams, posts] = await Promise.all([
+    searchParams,
+    listPostsWithTranslations(),
+  ])
 
   const notice = readFirstValue(resolvedSearchParams.notice)
   const error = readFirstValue(resolvedSearchParams.error)
+  const selectedLocale = normalizeLocale(readFirstValue(resolvedSearchParams.locale))
 
   return (
     <AdminShell
@@ -204,72 +253,146 @@ export default async function NewsManagementPage({
       </section>
 
       <section className="space-y-3">
-        {posts.map((post) => (
-          <form
-            key={post.id}
-            action={updateNewsAction}
-            className="rounded-xl border border-neutral-200 p-6"
-          >
-            <input type="hidden" name="id" value={post.id} />
-            <div className="grid gap-3 md:grid-cols-2">
-              <label className="space-y-1">
-                <span className="text-xs text-neutral-600">Title</span>
-                <input
-                  name="title"
-                  defaultValue={post.title}
-                  className="w-full rounded border border-neutral-300 px-3 py-2 text-sm"
-                />
-              </label>
-              <label className="space-y-1">
-                <span className="text-xs text-neutral-600">Slug</span>
-                <input
-                  name="slug"
-                  defaultValue={post.slug}
-                  className="w-full rounded border border-neutral-300 px-3 py-2 text-sm"
-                />
-              </label>
-            </div>
-            <label className="mt-3 block space-y-1">
-              <span className="text-xs text-neutral-600">Excerpt</span>
-              <input
-                name="excerpt"
-                defaultValue={post.excerpt ?? ""}
-                className="w-full rounded border border-neutral-300 px-3 py-2 text-sm"
-              />
-            </label>
-            <label className="mt-3 block space-y-1">
-              <span className="text-xs text-neutral-600">Body</span>
-              <textarea
-                name="body"
-                rows={4}
-                defaultValue={post.body}
-                className="w-full rounded border border-neutral-300 px-3 py-2 text-sm"
-              />
-            </label>
-            <div className="mt-3 flex flex-wrap items-center justify-between gap-3">
-              <select
-                name="status"
-                defaultValue={post.status}
-                className="rounded border border-neutral-300 px-3 py-2 text-sm"
+        <div className="flex flex-wrap gap-2">
+          {SUPPORTED_LOCALES.map((locale) => (
+            <a
+              key={locale}
+              href={`/news?locale=${locale}`}
+              className={`inline-flex rounded border px-3 py-1.5 text-xs ${
+                selectedLocale === locale
+                  ? "border-neutral-800 bg-neutral-900 text-white"
+                  : "border-neutral-300 text-neutral-700"
+              }`}
+            >
+              {locale.toUpperCase()}
+            </a>
+          ))}
+        </div>
+
+        {posts.map((post) => {
+          const translation = post.translations.find((entry) => entry.locale === selectedLocale)
+
+          return (
+            <div key={post.id} className="rounded-xl border border-neutral-200 p-6">
+              <form action={updateNewsAction}>
+                <input type="hidden" name="id" value={post.id} />
+                <div className="grid gap-3 md:grid-cols-2">
+                  <label className="space-y-1">
+                    <span className="text-xs text-neutral-600">Title</span>
+                    <input
+                      name="title"
+                      defaultValue={post.title}
+                      className="w-full rounded border border-neutral-300 px-3 py-2 text-sm"
+                    />
+                  </label>
+                  <label className="space-y-1">
+                    <span className="text-xs text-neutral-600">Slug</span>
+                    <input
+                      name="slug"
+                      defaultValue={post.slug}
+                      className="w-full rounded border border-neutral-300 px-3 py-2 text-sm"
+                    />
+                  </label>
+                </div>
+                <label className="mt-3 block space-y-1">
+                  <span className="text-xs text-neutral-600">Excerpt</span>
+                  <input
+                    name="excerpt"
+                    defaultValue={post.excerpt ?? ""}
+                    className="w-full rounded border border-neutral-300 px-3 py-2 text-sm"
+                  />
+                </label>
+                <label className="mt-3 block space-y-1">
+                  <span className="text-xs text-neutral-600">Body</span>
+                  <textarea
+                    name="body"
+                    rows={4}
+                    defaultValue={post.body}
+                    className="w-full rounded border border-neutral-300 px-3 py-2 text-sm"
+                  />
+                </label>
+                <div className="mt-3 flex flex-wrap items-center justify-between gap-3">
+                  <select
+                    name="status"
+                    defaultValue={post.status}
+                    className="rounded border border-neutral-300 px-3 py-2 text-sm"
+                  >
+                    <option value="draft">draft</option>
+                    <option value="published">published</option>
+                  </select>
+                  <div className="flex items-center gap-2">
+                    <Button type="submit" size="sm">
+                      Save
+                    </Button>
+                    <button
+                      type="submit"
+                      formAction={deleteNewsAction}
+                      className="rounded-md border border-red-300 px-3 py-2 text-sm text-red-700"
+                    >
+                      Delete
+                    </button>
+                  </div>
+                </div>
+              </form>
+
+              <form
+                action={upsertNewsTranslationAction}
+                className="mt-4 rounded-lg border border-neutral-200 p-4"
               >
-                <option value="draft">draft</option>
-                <option value="published">published</option>
-              </select>
-              <div className="flex items-center gap-2">
-                <Button type="submit" size="sm">
-                  Save
-                </Button>
-                <button
-                  type="submit"
-                  formAction={deleteNewsAction}
-                  className="rounded-md border border-red-300 px-3 py-2 text-sm text-red-700"
-                >
-                  Delete
-                </button>
-              </div>
+                <input type="hidden" name="postId" value={post.id} />
+                <input type="hidden" name="locale" value={selectedLocale} />
+
+                <h3 className="text-sm font-medium">
+                  Translation ({selectedLocale.toUpperCase()})
+                </h3>
+                <p className="mt-1 text-xs text-neutral-600">
+                  Missing fields fall back to base post content on public pages.
+                </p>
+                {post.translations.length > 0 ? (
+                  <p className="mt-2 text-xs text-neutral-600">
+                    Saved locales:{" "}
+                    {post.translations.map((entry) => entry.locale.toUpperCase()).join(", ")}
+                  </p>
+                ) : null}
+
+                <div className="mt-3 grid gap-3 md:grid-cols-2">
+                  <label className="space-y-1">
+                    <span className="text-xs text-neutral-600">Title</span>
+                    <input
+                      name="title"
+                      defaultValue={translation?.title ?? post.title}
+                      className="w-full rounded border border-neutral-300 px-3 py-2 text-sm"
+                    />
+                  </label>
+                  <label className="space-y-1">
+                    <span className="text-xs text-neutral-600">Excerpt</span>
+                    <input
+                      name="excerpt"
+                      defaultValue={translation?.excerpt ?? post.excerpt ?? ""}
+                      className="w-full rounded border border-neutral-300 px-3 py-2 text-sm"
+                    />
+                  </label>
+                </div>
+
+                <label className="mt-3 block space-y-1">
+                  <span className="text-xs text-neutral-600">Body</span>
+                  <textarea
+                    name="body"
+                    rows={4}
+                    defaultValue={translation?.body ?? post.body}
+                    className="w-full rounded border border-neutral-300 px-3 py-2 text-sm"
+                  />
+                </label>
+
+                <div className="mt-3">
+                  <Button type="submit" size="sm">
+                    Save translation
+                  </Button>
+                </div>
+              </form>
             </div>
-          </form>
-        ))}
+          )
+        })}
       </section>
     </AdminShell>
   )

apps/web/src/app/[locale]/news/[slug]/page.tsx

@@ -1,15 +1,15 @@
-import { getPostBySlug } from "@cms/db"
+import { getPostBySlugForLocale } from "@cms/db"
 import { notFound } from "next/navigation"
 
 export const dynamic = "force-dynamic"
 
 type PageProps = {
-  params: Promise<{ slug: string }>
+  params: Promise<{ locale: string; slug: string }>
 }
 
 export default async function PublicNewsDetailPage({ params }: PageProps) {
-  const { slug } = await params
-  const post = await getPostBySlug(slug)
+  const { locale, slug } = await params
+  const post = await getPostBySlugForLocale(slug, locale)
 
   if (!post || post.status !== "published") {
     notFound()

apps/web/src/app/[locale]/news/page.tsx

@@ -1,10 +1,15 @@
-import { listPosts } from "@cms/db"
+import { listPostsForLocale } from "@cms/db"
 import Link from "next/link"
 
 export const dynamic = "force-dynamic"
 
-export default async function PublicNewsIndexPage() {
-  const posts = await listPosts()
+type PublicNewsIndexPageProps = {
+  params: Promise<{ locale: string }>
+}
+
+export default async function PublicNewsIndexPage({ params }: PublicNewsIndexPageProps) {
+  const { locale } = await params
+  const posts = await listPostsForLocale(locale)
 
   return (
     <section className="mx-auto w-full max-w-4xl space-y-4 px-6 py-16">

apps/web/src/components/public-site-header.tsx

@@ -1,11 +1,13 @@
 import { listPublicNavigation } from "@cms/db"
+import { getLocale } from "next-intl/server"
 
 import { Link } from "@/i18n/navigation"
 
 import { LanguageSwitcher } from "./language-switcher"
 
 export async function PublicSiteHeader() {
-  const navItems = await listPublicNavigation("header")
+  const locale = await getLocale()
+  const navItems = await listPublicNavigation("header", locale)
 
   return (
     <header className="border-b border-neutral-200 bg-white/80 backdrop-blur">