From ac8c63d7902ad1201157f338d5dd63a293b66caf Mon Sep 17 00:00:00 2001
From: Quang Khai Nguyen <quang_khai.nguyen2@sbb.ch>
Date: Wed, 14 Oct 2026 06:22:26 +0200
Subject: [PATCH] optimize search engine

---
 index.html  | 54 +++++++++++++++++++++++++++-----
 sitemap.xml | 89 +++++++++++++++++++++++++++++++++++++++++++++++++++--
 2 files changed, 133 insertions(+), 10 deletions(-)

diff --git a/index.html b/index.html
index eb67411..f516a02 100755
--- a/index.html
+++ b/index.html
@@ -4,13 +4,20 @@
     <meta charset="UTF-8">
     <meta name="viewport" content="width=device-width, initial-scale=1.0">
     <title data-i18n="page_title">Nha Trang — Thiên đường du lịch biển Việt Nam | 芽庄 | Nha Trang | Нячанг</title>
-    <meta name="description" content="Khám phá Nha Trang: các điểm tham quan nổi bật, thời tiết theo mùa, ẩm thực địa phương và tour du lịch.">
-    <link rel="canonical" href="https://kyduyen.duckdns.org/">
+    <meta id="meta-description" name="description" content="Khám phá Nha Trang: điểm tham quan, thời tiết, ẩm thực địa phương và tour du lịch.">
+    <link id="canonical-url" rel="canonical" href="https://kyduyen.duckdns.org/?lang=vi">
+    <link rel="alternate" hreflang="vi" href="https://kyduyen.duckdns.org/?lang=vi">
+    <link rel="alternate" hreflang="ru" href="https://kyduyen.duckdns.org/?lang=ru">
+    <link rel="alternate" hreflang="en" href="https://kyduyen.duckdns.org/?lang=en">
+    <link rel="alternate" hreflang="zh" href="https://kyduyen.duckdns.org/?lang=zh">
+    <link rel="alternate" hreflang="de" href="https://kyduyen.duckdns.org/?lang=de">
+    <link rel="alternate" hreflang="fr" href="https://kyduyen.duckdns.org/?lang=fr">
+    <link rel="alternate" hreflang="x-default" href="https://kyduyen.duckdns.org/?lang=vi">
     <meta property="og:type" content="website">
-    <meta property="og:title" content="Nha Trang — Cẩm nang du lịch">
-    <meta property="og:description" content="Khám phá điểm đến, thời tiết, ẩm thực và trải nghiệm tại Nha Trang, Việt Nam.">
-    <meta property="og:url" content="https://kyduyen.duckdns.org/">
-    <meta property="og:locale" content="vi_VN">
+    <meta id="og-title" property="og:title" content="Nha Trang — Thiên đường du lịch biển Việt Nam">
+    <meta id="og-description" property="og:description" content="Khám phá Nha Trang: điểm tham quan, thời tiết, ẩm thực địa phương và tour du lịch.">
+    <meta id="og-url" property="og:url" content="https://kyduyen.duckdns.org/?lang=vi">
+    <meta id="og-locale" property="og:locale" content="vi_VN">
     <script type="application/ld+json">
         {
             "@context": "https://schema.org",
@@ -436,6 +443,7 @@
         const translations = {
             vi: {
                 page_title: "Nha Trang — Thiên đường du lịch biển Việt Nam",
+                meta_description: "Khám phá Nha Trang: điểm tham quan, thời tiết, ẩm thực địa phương và tour du lịch.",
                 logo_sub: "Paradise Bay",
                 nav_about: "Về Nha Trang",
                 nav_attractions: "Điểm đến",
@@ -525,6 +533,7 @@
             },
             ru: {
                 page_title: "Нячанг — Жемчужина Вьетнама",
+                meta_description: "Откройте для себя Нячанг: достопримечательности, погода, местная кухня и экскурсии.",
                 logo_sub: "Paradise Bay",
                 nav_about: "О Нячанге",
                 nav_attractions: "Достопримечательности",
@@ -614,6 +623,7 @@
             },
             en: {
                 page_title: "Nha Trang — Vietnam's Coastal Paradise",
+                meta_description: "Explore Nha Trang, Vietnam: top attractions, local weather, cuisine, and tours.",
                 logo_sub: "Paradise Bay",
                 nav_about: "About",
                 nav_attractions: "Attractions",
@@ -703,6 +713,7 @@
             },
             zh: {
                 page_title: "芽庄 — 越南海滨度假天堂",
+                meta_description: "探索越南芽庄：热门景点、天气、当地美食与旅游体验。",
                 logo_sub: "Paradise Bay",
                 nav_about: "关于芽庄",
                 nav_attractions: "热门景点",
@@ -792,6 +803,7 @@
             },
             de: {
                 page_title: "Nha Trang — Vietnams Küstenparadies",
+                meta_description: "Entdecken Sie Nha Trang: Sehenswürdigkeiten, Wetter, lokale Küche und Ausflüge.",
                 logo_sub: "Paradiesische Bucht",
                 nav_about: "Über Nha Trang",
                 nav_attractions: "Sehenswürdigkeiten",
@@ -881,6 +893,7 @@
             },
             fr: {
                 page_title: "Nha Trang — Le paradis côtier du Vietnam",
+                meta_description: "Découvrez Nha Trang : sites incontournables, météo, cuisine locale et excursions.",
                 logo_sub: "Baie paradisiaque",
                 nav_about: "À propos de Nha Trang",
                 nav_attractions: "Sites à découvrir",
@@ -970,6 +983,15 @@
             }
         };
 
+        const languageLocales = {
+            vi: 'vi_VN',
+            ru: 'ru_RU',
+            en: 'en_US',
+            zh: 'zh_CN',
+            de: 'de_DE',
+            fr: 'fr_FR'
+        };
+
         let currentLang = 'vi';
         let currentWeatherCondition = 'weather_loading';
 
@@ -1028,7 +1050,13 @@
             return 'vi';
         }
 
+        function getRequestedLanguage() {
+            const requested = new URLSearchParams(window.location.search).get('lang');
+            return translations[requested] ? requested : null;
+        }
+
         function setLanguage(lang) {
+            if (!translations[lang]) lang = 'vi';
             currentLang = lang;
             document.querySelectorAll('[data-i18n]').forEach(el => {
                 const key = el.getAttribute('data-i18n');
@@ -1051,6 +1079,17 @@
             });
 
             document.documentElement.lang = lang;
+            const languageUrl = new URL(window.location.href);
+            languageUrl.searchParams.set('lang', lang);
+            history.replaceState(null, '', `${languageUrl.pathname}${languageUrl.search}${languageUrl.hash}`);
+
+            const canonicalUrl = new URL(`/?lang=${lang}`, window.location.origin).href;
+            document.getElementById('canonical-url').href = canonicalUrl;
+            document.getElementById('meta-description').content = translations[lang].meta_description;
+            document.getElementById('og-title').content = translations[lang].page_title;
+            document.getElementById('og-description').content = translations[lang].meta_description;
+            document.getElementById('og-url').content = canonicalUrl;
+            document.getElementById('og-locale').content = languageLocales[lang];
             renderWeatherCondition();
         }
 
@@ -1104,8 +1143,7 @@
             document.getElementById('success-modal').classList.add('hidden');
         }
 
-        // Initialize from browser language preferences
-        setLanguage(getPreferredLanguage());
+        setLanguage(getRequestedLanguage() || getPreferredLanguage());
         loadCurrentWeather();
         setInterval(loadCurrentWeather, 30 * 60 * 1000);
     </script>
diff --git a/sitemap.xml b/sitemap.xml
index b48c8e8..6c94fcb 100644
--- a/sitemap.xml
+++ b/sitemap.xml
@@ -1,6 +1,91 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
+<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"
+    xmlns:image="http://www.google.com/schemas/sitemap-image/1.1"
+    xmlns:xhtml="http://www.w3.org/1999/xhtml">
     <url>
-        <loc>https://kyduyen.duckdns.org/</loc>
+    <loc>https://kyduyen.duckdns.org/?lang=vi</loc>
+    <lastmod>2026-10-14</lastmod>
+    <xhtml:link rel="alternate" hreflang="vi" href="https://kyduyen.duckdns.org/?lang=vi" />
+    <xhtml:link rel="alternate" hreflang="ru" href="https://kyduyen.duckdns.org/?lang=ru" />
+    <xhtml:link rel="alternate" hreflang="en" href="https://kyduyen.duckdns.org/?lang=en" />
+    <xhtml:link rel="alternate" hreflang="zh" href="https://kyduyen.duckdns.org/?lang=zh" />
+    <xhtml:link rel="alternate" hreflang="de" href="https://kyduyen.duckdns.org/?lang=de" />
+    <xhtml:link rel="alternate" hreflang="fr" href="https://kyduyen.duckdns.org/?lang=fr" />
+    <xhtml:link rel="alternate" hreflang="x-default" href="https://kyduyen.duckdns.org/?lang=vi" />
+        <image:image>
+            <image:loc>https://kyduyen.duckdns.org/images/ThapBa.png</image:loc>
+            <image:caption>Tháp Bà Ponagar, quần thể kiến trúc đền tháp Champa cổ kính trên đồi cao hướng ra sông Cái.</image:caption>
+        </image:image>
+        <image:image>
+            <image:loc>https://kyduyen.duckdns.org/images/VinWonders.jpg</image:loc>
+            <image:caption>VinWonders Nha Trang trên đảo Hòn Tre, với cáp treo vượt biển, công viên nước và thủy cung.</image:caption>
+        </image:image>
+        <image:image>
+            <image:loc>https://kyduyen.duckdns.org/images/seafood.jpg</image:loc>
+            <image:caption>Hải sản tươi sống Nha Trang: tôm hùm, mực nướng và các loại ốc tại nhà hàng ven biển.</image:caption>
+        </image:image>
+        <image:image>
+            <image:loc>https://kyduyen.duckdns.org/images/BunCa.jpg</image:loc>
+            <image:caption>Phở và bún cá Nha Trang với hương vị thanh ngọt đặc trưng của biển.</image:caption>
+        </image:image>
+        <image:image>
+            <image:loc>https://kyduyen.duckdns.org/images/BanhXeoMuc.jpg</image:loc>
+            <image:caption>Bánh xèo mực Nha Trang giòn rụm, ăn kèm rau sống và nước mắm chua ngọt.</image:caption>
+        </image:image>
+    </url>
+    <url>
+        <loc>https://kyduyen.duckdns.org/?lang=ru</loc>
+        <lastmod>2026-10-14</lastmod>
+        <xhtml:link rel="alternate" hreflang="vi" href="https://kyduyen.duckdns.org/?lang=vi" />
+        <xhtml:link rel="alternate" hreflang="ru" href="https://kyduyen.duckdns.org/?lang=ru" />
+        <xhtml:link rel="alternate" hreflang="en" href="https://kyduyen.duckdns.org/?lang=en" />
+        <xhtml:link rel="alternate" hreflang="zh" href="https://kyduyen.duckdns.org/?lang=zh" />
+        <xhtml:link rel="alternate" hreflang="de" href="https://kyduyen.duckdns.org/?lang=de" />
+        <xhtml:link rel="alternate" hreflang="fr" href="https://kyduyen.duckdns.org/?lang=fr" />
+        <xhtml:link rel="alternate" hreflang="x-default" href="https://kyduyen.duckdns.org/?lang=vi" />
+    </url>
+    <url>
+        <loc>https://kyduyen.duckdns.org/?lang=en</loc>
+        <lastmod>2026-10-14</lastmod>
+        <xhtml:link rel="alternate" hreflang="vi" href="https://kyduyen.duckdns.org/?lang=vi" />
+        <xhtml:link rel="alternate" hreflang="ru" href="https://kyduyen.duckdns.org/?lang=ru" />
+        <xhtml:link rel="alternate" hreflang="en" href="https://kyduyen.duckdns.org/?lang=en" />
+        <xhtml:link rel="alternate" hreflang="zh" href="https://kyduyen.duckdns.org/?lang=zh" />
+        <xhtml:link rel="alternate" hreflang="de" href="https://kyduyen.duckdns.org/?lang=de" />
+        <xhtml:link rel="alternate" hreflang="fr" href="https://kyduyen.duckdns.org/?lang=fr" />
+        <xhtml:link rel="alternate" hreflang="x-default" href="https://kyduyen.duckdns.org/?lang=vi" />
+    </url>
+    <url>
+        <loc>https://kyduyen.duckdns.org/?lang=zh</loc>
+        <lastmod>2026-10-14</lastmod>
+        <xhtml:link rel="alternate" hreflang="vi" href="https://kyduyen.duckdns.org/?lang=vi" />
+        <xhtml:link rel="alternate" hreflang="ru" href="https://kyduyen.duckdns.org/?lang=ru" />
+        <xhtml:link rel="alternate" hreflang="en" href="https://kyduyen.duckdns.org/?lang=en" />
+        <xhtml:link rel="alternate" hreflang="zh" href="https://kyduyen.duckdns.org/?lang=zh" />
+        <xhtml:link rel="alternate" hreflang="de" href="https://kyduyen.duckdns.org/?lang=de" />
+        <xhtml:link rel="alternate" hreflang="fr" href="https://kyduyen.duckdns.org/?lang=fr" />
+        <xhtml:link rel="alternate" hreflang="x-default" href="https://kyduyen.duckdns.org/?lang=vi" />
+    </url>
+    <url>
+        <loc>https://kyduyen.duckdns.org/?lang=de</loc>
+        <lastmod>2026-10-14</lastmod>
+        <xhtml:link rel="alternate" hreflang="vi" href="https://kyduyen.duckdns.org/?lang=vi" />
+        <xhtml:link rel="alternate" hreflang="ru" href="https://kyduyen.duckdns.org/?lang=ru" />
+        <xhtml:link rel="alternate" hreflang="en" href="https://kyduyen.duckdns.org/?lang=en" />
+        <xhtml:link rel="alternate" hreflang="zh" href="https://kyduyen.duckdns.org/?lang=zh" />
+        <xhtml:link rel="alternate" hreflang="de" href="https://kyduyen.duckdns.org/?lang=de" />
+        <xhtml:link rel="alternate" hreflang="fr" href="https://kyduyen.duckdns.org/?lang=fr" />
+        <xhtml:link rel="alternate" hreflang="x-default" href="https://kyduyen.duckdns.org/?lang=vi" />
+    </url>
+    <url>
+        <loc>https://kyduyen.duckdns.org/?lang=fr</loc>
+        <lastmod>2026-10-14</lastmod>
+        <xhtml:link rel="alternate" hreflang="vi" href="https://kyduyen.duckdns.org/?lang=vi" />
+        <xhtml:link rel="alternate" hreflang="ru" href="https://kyduyen.duckdns.org/?lang=ru" />
+        <xhtml:link rel="alternate" hreflang="en" href="https://kyduyen.duckdns.org/?lang=en" />
+        <xhtml:link rel="alternate" hreflang="zh" href="https://kyduyen.duckdns.org/?lang=zh" />
+        <xhtml:link rel="alternate" hreflang="de" href="https://kyduyen.duckdns.org/?lang=de" />
+        <xhtml:link rel="alternate" hreflang="fr" href="https://kyduyen.duckdns.org/?lang=fr" />
+        <xhtml:link rel="alternate" hreflang="x-default" href="https://kyduyen.duckdns.org/?lang=vi" />
     </url>
 </urlset>