feat: add hreflang tags and international sitemap for SEO

- Added hreflang alternates to root layout for all locales (sr, en, de, fr)
- Added hreflang alternates to [locale] layout for all locales
- Updated sitemap to include all locale variants for every page
- Google will now properly index all language versions

src/app/[locale]/layout.tsx

@@ -1,11 +1,36 @@
+import { Metadata } from "next";
 import { NextIntlClientProvider } from "next-intl";
 import { getMessages, setRequestLocale } from "next-intl/server";
 import { routing } from "@/i18n/routing";
 
+const baseUrl = process.env.NEXT_PUBLIC_SITE_URL || "https://dev.manoonoils.com";
+
 export function generateStaticParams() {
   return routing.locales.map((locale) => ({ locale }));
 }
 
+export async function generateMetadata({
+  params,
+}: {
+  params: Promise<{ locale: string }>;
+}): Promise<Metadata> {
+  const { locale } = await params;
+  const localePrefix = locale === "sr" ? "" : `/${locale}`;
+
+  const languages: Record<string, string> = {};
+  for (const loc of routing.locales) {
+    const prefix = loc === "sr" ? "" : `/${loc}`;
+    languages[loc] = `${baseUrl}${prefix}`;
+  }
+
+  return {
+    alternates: {
+      canonical: `${baseUrl}${localePrefix}`,
+      languages,
+    },
+  };
+}
+
 export default async function LocaleLayout({
   children,
   params,

src/app/layout.tsx

@@ -2,6 +2,8 @@ import "./globals.css";
 import type { Metadata, Viewport } from "next";
 import ErrorBoundary from "@/components/providers/ErrorBoundary";
 
+const baseUrl = process.env.NEXT_PUBLIC_SITE_URL || "https://dev.manoonoils.com";
+
 export const metadata: Metadata = {
   title: {
     default: "ManoonOils - Premium Natural Oils for Hair & Skin",
@@ -9,6 +11,15 @@ export const metadata: Metadata = {
   },
   description: "Discover our premium collection of natural oils for hair and skin care.",
   robots: "index, follow",
+  alternates: {
+    canonical: baseUrl,
+    languages: {
+      sr: baseUrl,
+      en: `${baseUrl}/en`,
+      de: `${baseUrl}/de`,
+      fr: `${baseUrl}/fr`,
+    },
+  },
   openGraph: {
     title: "ManoonOils - Premium Natural Oils for Hair & Skin",
     description: "Discover our premium collection of natural oils for hair and skin care.",

src/app/sitemap.ts

@@ -1,48 +1,121 @@
 import { MetadataRoute } from "next";
 import { getProducts } from "@/lib/saleor";
 
-export default async function sitemap(): Promise<MetadataRoute.Sitemap> {
+const LOCALES = ["sr", "en", "de", "fr"] as const;
 const baseUrl = process.env.NEXT_PUBLIC_SITE_URL || "https://dev.manoonoils.com";
 
+interface SitemapEntry {
+  url: string;
+  lastModified: Date;
+  changeFrequency: "always" | "hourly" | "daily" | "weekly" | "monthly" | "yearly" | "never";
+  priority: number;
+  alternates?: {
+    languages?: Record<string, string>;
+  };
+}
+
+export default async function sitemap(): Promise<SitemapEntry[]> {
   let products: any[] = [];
   try {
     products = await getProducts("SR", 100);
   } catch (e) {
-    console.log('Failed to fetch products for sitemap during build');
+    console.log("Failed to fetch products for sitemap during build");
   }
 
-  const productUrls = products.map((product) => ({
-    url: `${baseUrl}/products/${product.slug}`,
-    lastModified: new Date(),
-    changeFrequency: "weekly" as const,
-    priority: 0.8,
-  }));
-
-  return [
+  const staticPages: SitemapEntry[] = [
     {
       url: baseUrl,
       lastModified: new Date(),
       changeFrequency: "daily",
       priority: 1,
+      alternates: {
+        languages: {
+          sr: `${baseUrl}`,
+          en: `${baseUrl}/en`,
+          de: `${baseUrl}/de`,
+          fr: `${baseUrl}/fr`,
+        },
+      },
     },
     {
       url: `${baseUrl}/products`,
       lastModified: new Date(),
       changeFrequency: "daily",
       priority: 0.9,
+      alternates: {
+        languages: {
+          sr: `${baseUrl}/products`,
+          en: `${baseUrl}/en/products`,
+          de: `${baseUrl}/de/products`,
+          fr: `${baseUrl}/fr/products`,
+        },
+      },
     },
     {
       url: `${baseUrl}/about`,
       lastModified: new Date(),
       changeFrequency: "monthly",
       priority: 0.6,
+      alternates: {
+        languages: {
+          sr: `${baseUrl}/about`,
+          en: `${baseUrl}/en/about`,
+          de: `${baseUrl}/de/about`,
+          fr: `${baseUrl}/fr/about`,
+        },
+      },
     },
     {
       url: `${baseUrl}/contact`,
       lastModified: new Date(),
       changeFrequency: "monthly",
       priority: 0.6,
+      alternates: {
+        languages: {
+          sr: `${baseUrl}/contact`,
+          en: `${baseUrl}/en/contact`,
+          de: `${baseUrl}/de/contact`,
+          fr: `${baseUrl}/fr/contact`,
+        },
+      },
+    },
+    {
+      url: `${baseUrl}/checkout`,
+      lastModified: new Date(),
+      changeFrequency: "monthly",
+      priority: 0.5,
+      alternates: {
+        languages: {
+          sr: `${baseUrl}/checkout`,
+          en: `${baseUrl}/en/checkout`,
+          de: `${baseUrl}/de/checkout`,
+          fr: `${baseUrl}/fr/checkout`,
+        },
+      },
     },
-    ...productUrls,
   ];
+
+  const productUrls: SitemapEntry[] = [];
+
+  for (const product of products) {
+    for (const locale of LOCALES) {
+      const localePrefix = locale === "sr" ? "" : `/${locale}`;
+      productUrls.push({
+        url: `${baseUrl}${localePrefix}/products/${product.slug}`,
+        lastModified: new Date(),
+        changeFrequency: "weekly",
+        priority: 0.8,
+        alternates: {
+          languages: {
+            sr: `${baseUrl}/products/${product.slug}`,
+            en: `${baseUrl}/en/products/${product.slug}`,
+            de: `${baseUrl}/de/products/${product.slug}`,
+            fr: `${baseUrl}/fr/products/${product.slug}`,
+          },
+        },
+      });
+    }
+  }
+
+  return [...staticPages, ...productUrls];
 }