added lang "auto-detect" instead of random lang

main.go

@@ -17,7 +17,7 @@ type LanguageOption struct {
 var settings UserSettings
 
 var languageOptions = []LanguageOption{
-	{Code: "", Name: "Any Language"},
+	{Code: "", Name: "Auto-detect"},
 	{Code: "en", Name: "English"},
 	{Code: "af", Name: "Afrikaans"},
 	{Code: "ar", Name: "العربية (Arabic)"},
@@ -70,25 +70,31 @@ func handleSearch(w http.ResponseWriter, r *http.Request) {
 	query, safe, lang, searchType, page := parseSearchParams(r)
 
 	// Load user settings
-	settings = loadUserSettings(r)
+	settings = loadUserSettings(w, r)
 
-	// Update the theme, safe search, and language based on query parameters or use existing settings
+	// Update theme if provided, or use existing settings
 	theme := r.URL.Query().Get("theme")
 	if theme != "" {
 		settings.Theme = theme
-		saveUserSettings(w, settings)
+		saveUserSettings(w, settings) // Save if theme is updated
 	} else if settings.Theme == "" {
 		settings.Theme = "dark" // Default theme
 	}
 
+	// Update safe search if provided, or use existing settings
 	if safe != "" && safe != settings.SafeSearch {
 		settings.SafeSearch = safe
-		saveUserSettings(w, settings)
+		saveUserSettings(w, settings) // Save if safe search is updated
 	}
 
+	// Update language if provided, or use existing settings
 	if lang != "" && lang != settings.Language {
 		settings.Language = lang
-		saveUserSettings(w, settings)
+		saveUserSettings(w, settings) // Save if language is updated
+	} else if settings.Language == "" {
+		// If no language set, auto-detect from browser or default to "en"
+		settings.Language = normalizeLangCode(r.Header.Get("Accept-Language"))
+		saveUserSettings(w, settings) // Save if language is auto-detected
 	}
 
 	// This will do for now (to handle Dark Reader addon)

user-settings.go

@@ -3,6 +3,7 @@ package main
 import (
 	"html/template"
 	"net/http"
+	"strings"
 	"time"
 )
 
@@ -13,21 +14,35 @@ type UserSettings struct {
 	IsThemeDark bool
 }
 
-func loadUserSettings(r *http.Request) UserSettings {
+func loadUserSettings(w http.ResponseWriter, r *http.Request) UserSettings {
 	var settings UserSettings
+	saveRequired := false // Track if we need to save settings back
 
 	// Load theme
 	if cookie, err := r.Cookie("theme"); err == nil {
 		settings.Theme = cookie.Value
 	} else {
 		settings.Theme = "dark" // Default theme
+		saveRequired = true     // No cookie found, need to save this later
 	}
 
 	// Load language
 	if cookie, err := r.Cookie("language"); err == nil {
 		settings.Language = cookie.Value
 	} else {
-		settings.Language = "en" // Default language
+		settings.Language = "" // Set language to empty, handled later
+	}
+
+	// If language is empty, get it from the Accept-Language header
+	if settings.Language == "" {
+		acceptLang := r.Header.Get("Accept-Language")
+		if acceptLang != "" {
+			// Get the first language from Accept-Language header and normalize
+			settings.Language = normalizeLangCode(strings.Split(acceptLang, ",")[0])
+		} else {
+			settings.Language = "en" // Default language if Accept-Language is not present
+		}
+		saveRequired = true // No language cookie found, need to save
 	}
 
 	// Load safe search
@@ -35,6 +50,12 @@ func loadUserSettings(r *http.Request) UserSettings {
 		settings.SafeSearch = cookie.Value
 	} else {
 		settings.SafeSearch = "" // Default safe search off
+		saveRequired = true      // No safe search cookie found, need to save
+	}
+
+	// Save settings if required (no cookie found for any of the settings)
+	if saveRequired {
+		saveUserSettings(w, settings)
 	}
 
 	return settings
@@ -74,7 +95,7 @@ func saveUserSettings(w http.ResponseWriter, settings UserSettings) {
 func handleSaveSettings(w http.ResponseWriter, r *http.Request) {
 	if r.Method == "POST" {
 		// Load current settings
-		settings := loadUserSettings(r)
+		settings := loadUserSettings(w, r)
 
 		// Update only the settings that were submitted in the form
 		if theme := r.FormValue("theme"); theme != "" {
@@ -82,6 +103,12 @@ func handleSaveSettings(w http.ResponseWriter, r *http.Request) {
 		}
 		if lang := r.FormValue("lang"); lang != "" {
 			settings.Language = lang
+		} else {
+			// If lang is empty, try to get from Accept-Language header
+			acceptLang := r.Header.Get("Accept-Language")
+			if acceptLang != "" {
+				settings.Language = strings.Split(acceptLang, ",")[0]
+			}
 		}
 		if safe := r.FormValue("safe"); safe != "" {
 			settings.SafeSearch = safe
@@ -97,7 +124,7 @@ func handleSaveSettings(w http.ResponseWriter, r *http.Request) {
 
 func handleSettings(w http.ResponseWriter, r *http.Request) {
 	// Load user settings
-	settings = loadUserSettings(r)
+	settings = loadUserSettings(w, r)
 
 	data := struct {
 		LanguageOptions []LanguageOption
@@ -129,3 +156,36 @@ func handleSettings(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 }
+
+// Helper function to normalize language codes
+func normalizeLangCode(lang string) string {
+	lang = strings.ToLower(lang)
+
+	// First, check if the language code is already valid
+	if isValidLangCode(lang) {
+		return lang
+	}
+
+	// Strip regional codes (e.g., en-US -> en)
+	if strings.Contains(lang, "-") {
+		lang = strings.Split(lang, "-")[0]
+	}
+
+	// Re-check if the normalized version is valid
+	if isValidLangCode(lang) {
+		return lang
+	}
+
+	// If the language is not recognized, default to "en"
+	return "en"
+}
+
+// Helper function to check if a language code exists in the language options
+func isValidLangCode(lang string) bool {
+	for _, opt := range languageOptions {
+		if opt.Code == lang {
+			return true
+		}
+	}
+	return false
+}