feat: add locale extraction and sanitization methods

- Implemented `extract_locale_from_accept_language_header` to
  retrieve the user's preferred language from the request.
- Added `sanitize_locale` for validating and sanitizing locale
  inputs against available locales.
- Updated `set_locale` method to prepare for incorporating
  browser language preference handling.

These changes enhance the application's ability to set the locale
based on the user's browser settings, paving the way for better
internationalization support.

app/controllers/application_controller.rb

@@ -79,6 +79,30 @@ class ApplicationController < ActionController::Base
   def set_locale
     I18n.locale = extract_locale || I18n.default_locale
     I18n.fallbacks[I18n.locale] = [ I18n.locale, I18n.default_locale ].uniq
+    # 如果URL已经包含语言前缀，跳过处理
+    # return if params[:locale].present?
+    # 获取浏览器语言并转换为支持的语言代码
+    # locale = sanitize_locale(extract_locale_from_accept_language_header)
+    # I18n.with_locale(locale, &action)
+    # 重定向到带有语言前缀的相同路径
+    # redirect_to "/#{locale}#{request.fullpath}"
+  end
+
+  def extract_locale_from_accept_language_header
+    accept_language = request.env["HTTP_ACCEPT_LANGUAGE"].to_s
+    # 修改正则表达式以匹配 'zh-CN' 这样的格式
+    if (full_locale = accept_language.scan(/^[a-z]{2}-[A-Z]{2}/).first)
+      full_locale
+    else
+      # 否则只匹配语言代码 (例如 'en')
+      accept_language.scan(/^[a-z]{2}/).first || I18n.default_locale.to_s
+    end
+  end
+
+  def sanitize_locale(locale)
+    # 直接使用 I18n.available_locales
+    locale = locale.to_sym
+    I18n.available_locales.include?(locale) ? locale : I18n.default_locale
   end
 
   def extract_locale