feat: improve Bible version selection logic and language switching

- Auto-select appropriate version when switching languages
- Prioritize favorite version only if it matches current locale
- Fall back to locale-specific default version
- Redirect Bible pages to reader root when changing language to allow proper version selection

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

app/[locale]/bible/reader.tsx

@@ -350,12 +350,15 @@ export default function BibleReaderNew({ initialVersion, initialBook, initialCha
         if (data.success && data.versions) {
           setVersions(data.versions)
 
-          // Only auto-select if there's NO current selection
+          // Check if current version is available in the new locale's versions
-          if (!selectedVersion) {
+          const currentVersionAvailable = selectedVersion && data.versions.find((v: BibleVersion) => v.id === selectedVersion)
-            // Try to load user's favorite version first
+
+          // Auto-select if there's NO current selection OR if current version is not available in new locale
+          if (!selectedVersion || (!showAllVersions && !currentVersionAvailable)) {
             let versionToSelect = null
 
-            if (user) {
+            // Try to load user's favorite version first, but only if it matches the current locale
+            if (user && !showAllVersions) {
               const token = localStorage.getItem('authToken')
               if (token) {
                 try {
@@ -365,6 +368,7 @@ export default function BibleReaderNew({ initialVersion, initialBook, initialCha
                   const favoriteData = await favoriteRes.json()
 
                   if (favoriteData.success && favoriteData.favoriteBibleVersion) {
+                    // Check if favorite version is in the current locale's versions
                     const favoriteVersion = data.versions.find((v: BibleVersion) => v.id === favoriteData.favoriteBibleVersion)
                     if (favoriteVersion) {
                       versionToSelect = favoriteVersion
@@ -376,9 +380,11 @@ export default function BibleReaderNew({ initialVersion, initialBook, initialCha
               }
             }
 
-            // Fall back to default version or first version
+            // Fall back to default version for this locale or first version
             if (!versionToSelect) {
-              versionToSelect = data.versions.find((v: BibleVersion) => v.isDefault) || data.versions[0]
+              versionToSelect = data.versions.find((v: BibleVersion) => v.isDefault && v.language.toLowerCase() === locale.toLowerCase())
+                || data.versions.find((v: BibleVersion) => v.isDefault)
+                || data.versions[0]
             }
 
             if (versionToSelect) {

components/layout/language-switcher.tsx

@@ -33,12 +33,22 @@ export function LanguageSwitcher() {
     setAnchorEl(null)
   }
 
-  const handleLanguageChange = (newLocale: string) => {
+  const handleLanguageChange = async (newLocale: string) => {
-    // Remove current locale from pathname and add new one
+    // Check if we're on a Bible page
-    const pathWithoutLocale = pathname.replace(`/${locale}`, '') || '/'
+    const isBiblePage = pathname.includes('/bible/')
-    const newPath = `/${newLocale}${pathWithoutLocale === '/' ? '' : pathWithoutLocale}`
+
+    if (isBiblePage) {
+      // For Bible pages, redirect to Bible reader without specific version
+      // Let the reader component select appropriate version for the new language
+      const newPath = `/${newLocale}/bible`
+      router.push(newPath)
+    } else {
+      // For other pages, just change the locale in the URL
+      const pathWithoutLocale = pathname.replace(`/${locale}`, '') || '/'
+      const newPath = `/${newLocale}${pathWithoutLocale === '/' ? '' : pathWithoutLocale}`
+      router.push(newPath)
+    }
 
-    router.push(newPath)
     handleClose()
   }