feat(i18n): wire page translation editor and locale rendering

apps/admin/src/app/pages/[id]/page.tsx

@@ -1,4 +1,10 @@
-import { deletePage, getPageById, updatePage } from "@cms/db"
+import {
+  deletePage,
+  getPageById,
+  listPageTranslations,
+  updatePage,
+  upsertPageTranslation,
+} from "@cms/db"
 import { Button } from "@cms/ui/button"
 import Link from "next/link"
 import { redirect } from "next/navigation"
@@ -9,6 +15,8 @@ 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]
 
 type PageProps = {
   params: Promise<{ id: string }>
@@ -48,6 +56,14 @@ function redirectWithState(pageId: string, params: { notice?: string; error?: st
   redirect(value ? `/pages/${pageId}?${value}` : `/pages/${pageId}`)
 }
 
+function normalizeLocale(input: string | null): SupportedLocale {
+  if (input && SUPPORTED_LOCALES.includes(input as SupportedLocale)) {
+    return input as SupportedLocale
+  }
+
+  return "en"
+}
+
 export default async function PageEditorPage({ params, searchParams }: PageProps) {
   const role = await requirePermissionForRoute({
     nextPath: "/pages",
@@ -57,7 +73,11 @@ export default async function PageEditorPage({ params, searchParams }: PageProps
   const resolvedParams = await params
   const pageId = resolvedParams.id
 
-  const [resolvedSearchParams, pageRecord] = await Promise.all([searchParams, getPageById(pageId)])
+  const [resolvedSearchParams, pageRecord, translations] = await Promise.all([
+    searchParams,
+    getPageById(pageId),
+    listPageTranslations(pageId),
+  ])
 
   if (!pageRecord) {
     redirect("/pages?error=Page+not+found")
@@ -66,6 +86,8 @@ export default async function PageEditorPage({ params, searchParams }: PageProps
   const page = pageRecord
   const notice = readFirstValue(resolvedSearchParams.notice)
   const error = readFirstValue(resolvedSearchParams.error)
+  const selectedLocale = normalizeLocale(readFirstValue(resolvedSearchParams.locale))
+  const selectedTranslation = translations.find((entry) => entry.locale === selectedLocale)
 
   async function updatePageAction(formData: FormData) {
     "use server"
@@ -118,6 +140,34 @@ export default async function PageEditorPage({ params, searchParams }: PageProps
     redirect("/pages?notice=Page+deleted")
   }
 
+  async function upsertPageTranslationAction(formData: FormData) {
+    "use server"
+
+    await requirePermissionForRoute({
+      nextPath: "/pages",
+      permission: "pages:write",
+      scope: "team",
+    })
+
+    const locale = normalizeLocale(readInputString(formData, "locale"))
+
+    try {
+      await upsertPageTranslation({
+        pageId,
+        locale,
+        title: readInputString(formData, "title"),
+        summary: readNullableString(formData, "summary"),
+        content: readInputString(formData, "content"),
+        seoTitle: readNullableString(formData, "seoTitle"),
+        seoDescription: readNullableString(formData, "seoDescription"),
+      })
+    } catch {
+      redirect(`/pages/${pageId}?error=Failed+to+save+translation.&locale=${locale}`)
+    }
+
+    redirect(`/pages/${pageId}?notice=Translation+saved.&locale=${locale}`)
+  }
+
   return (
     <AdminShell
       role={role}
@@ -226,6 +276,132 @@ export default async function PageEditorPage({ params, searchParams }: PageProps
         </form>
       </section>
 
+      <section className="rounded-xl border border-neutral-200 p-6">
+        <div className="space-y-1">
+          <h3 className="text-xl font-medium">Translations</h3>
+          <p className="text-sm text-neutral-600">
+            Add locale-specific page content. Missing locales fall back to base page fields.
+          </p>
+        </div>
+
+        <div className="mt-4 flex flex-wrap gap-2">
+          {SUPPORTED_LOCALES.map((locale) => {
+            const isActive = locale === selectedLocale
+            const hasTranslation = translations.some((entry) => entry.locale === locale)
+
+            return (
+              <Link
+                key={locale}
+                href={`/pages/${pageId}?locale=${locale}`}
+                className={`inline-flex items-center gap-2 rounded border px-3 py-1.5 text-xs ${
+                  isActive
+                    ? "border-neutral-800 bg-neutral-900 text-white"
+                    : "border-neutral-300 text-neutral-700"
+                }`}
+              >
+                <span>{locale.toUpperCase()}</span>
+                <span className={isActive ? "text-neutral-200" : "text-neutral-500"}>
+                  {hasTranslation ? "saved" : "missing"}
+                </span>
+              </Link>
+            )
+          })}
+        </div>
+
+        {translations.length > 0 ? (
+          <div className="mt-4 rounded border border-neutral-200">
+            <table className="min-w-full text-left text-sm">
+              <thead className="text-xs uppercase tracking-wide text-neutral-500">
+                <tr>
+                  <th className="px-3 py-2">Locale</th>
+                  <th className="px-3 py-2">Title</th>
+                  <th className="px-3 py-2">Updated</th>
+                </tr>
+              </thead>
+              <tbody>
+                {translations.map((translation) => (
+                  <tr key={translation.id} className="border-t border-neutral-200">
+                    <td className="px-3 py-2">{translation.locale.toUpperCase()}</td>
+                    <td className="px-3 py-2">{translation.title}</td>
+                    <td className="px-3 py-2 text-neutral-600">
+                      {translation.updatedAt.toLocaleDateString("en-US")}
+                    </td>
+                  </tr>
+                ))}
+              </tbody>
+            </table>
+          </div>
+        ) : null}
+
+        <form action={upsertPageTranslationAction} className="mt-6 space-y-3">
+          <label className="space-y-1">
+            <span className="text-xs text-neutral-600">Locale</span>
+            <select
+              name="locale"
+              defaultValue={selectedLocale}
+              className="w-full rounded border border-neutral-300 px-3 py-2 text-sm"
+            >
+              {SUPPORTED_LOCALES.map((locale) => (
+                <option key={locale} value={locale}>
+                  {locale.toUpperCase()}
+                </option>
+              ))}
+            </select>
+          </label>
+
+          <label className="space-y-1">
+            <span className="text-xs text-neutral-600">Title</span>
+            <input
+              name="title"
+              defaultValue={selectedTranslation?.title ?? page.title}
+              required
+              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">Summary</span>
+            <input
+              name="summary"
+              defaultValue={selectedTranslation?.summary ?? page.summary ?? ""}
+              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">Content</span>
+            <textarea
+              name="content"
+              rows={8}
+              defaultValue={selectedTranslation?.content ?? page.content}
+              required
+              className="w-full rounded border border-neutral-300 px-3 py-2 text-sm"
+            />
+          </label>
+
+          <div className="grid gap-3 md:grid-cols-2">
+            <label className="space-y-1">
+              <span className="text-xs text-neutral-600">SEO title</span>
+              <input
+                name="seoTitle"
+                defaultValue={selectedTranslation?.seoTitle ?? page.seoTitle ?? ""}
+                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">SEO description</span>
+              <input
+                name="seoDescription"
+                defaultValue={selectedTranslation?.seoDescription ?? page.seoDescription ?? ""}
+                className="w-full rounded border border-neutral-300 px-3 py-2 text-sm"
+              />
+            </label>
+          </div>
+
+          <Button type="submit">Save translation</Button>
+        </form>
+      </section>
+
       <section className="rounded-xl border border-red-300 bg-red-50 p-6">
         <h3 className="text-lg font-medium text-red-800">Danger Zone</h3>
         <p className="mt-1 text-sm text-red-700">