Split auth UI module and load FAQ from markdown assets

wwwroot/js/i18n.js

@@ -4,7 +4,7 @@ const translationsAssetUrl = new URL(
     "../data/i18n/translations.json",
     import.meta.url,
 );
-const faqAssetUrl = new URL("../data/i18n/faq.json", import.meta.url);
+const faqBaseUrl = new URL("../data/i18n/faq/", import.meta.url);
 
 let currentLang = defaultLang;
 const listeners = [];
@@ -62,20 +62,6 @@ function validateTranslations(raw) {
     return raw;
 }
 
-function validateFaq(raw) {
-    if (!isRecord(raw) || typeof raw[defaultLang] !== "string") {
-        throw new Error(`Missing default FAQ language "${defaultLang}".`);
-    }
-
-    Object.entries(raw).forEach(([lang, value]) => {
-        if (typeof value !== "string") {
-            throw new Error(`Invalid FAQ value for "${lang}".`);
-        }
-    });
-
-    return raw;
-}
-
 async function loadJson(url, label) {
     const response = await fetch(url, { cache: "no-store" });
     if (!response.ok) {
@@ -85,18 +71,61 @@ async function loadJson(url, label) {
     return response.json();
 }
 
+async function loadText(url, label) {
+    const response = await fetch(url, { cache: "no-store" });
+    if (!response.ok) {
+        throw new Error(`Failed to load ${label}: ${response.status}`);
+    }
+
+    return response.text();
+}
+
+async function loadFaqMarkdownForLanguages(languages) {
+    if (!Array.isArray(languages) || languages.length === 0) {
+        throw new Error("No i18n languages available for FAQ loading.");
+    }
+
+    const faqByLanguage = {};
+    for (const lang of languages) {
+        const faqUrl = new URL(`${lang}.md`, faqBaseUrl);
+        try {
+            faqByLanguage[lang] = await loadText(faqUrl, `faq.${lang}`);
+        } catch (err) {
+            if (lang === defaultLang) {
+                throw err;
+            }
+        }
+    }
+
+    const fallback = faqByLanguage[defaultLang];
+    if (typeof fallback !== "string" || fallback.trim().length === 0) {
+        throw new Error(`Missing default FAQ language "${defaultLang}".`);
+    }
+
+    languages.forEach((lang) => {
+        const value = faqByLanguage[lang];
+        faqByLanguage[lang] =
+            typeof value === "string" && value.trim().length > 0
+                ? value
+                : fallback;
+    });
+
+    return faqByLanguage;
+}
+
 async function ensureAssetsLoaded() {
     if (assetsLoaded) return;
     if (assetsLoadingPromise) return assetsLoadingPromise;
 
     assetsLoadingPromise = (async () => {
-        const [translationsRaw, faqRaw] = await Promise.all([
-            loadJson(translationsAssetUrl, "translations"),
-            loadJson(faqAssetUrl, "faq"),
-        ]);
-
+        const translationsRaw = await loadJson(
+            translationsAssetUrl,
+            "translations",
+        );
         translations = validateTranslations(translationsRaw);
-        faqMarkdown = validateFaq(faqRaw);
+        faqMarkdown = await loadFaqMarkdownForLanguages(
+            Object.keys(translations),
+        );
         assetsLoaded = true;
     })().finally(() => {
         assetsLoadingPromise = null;