cms/app/Http/Middleware/SetLocaleMiddleware.php

<?php

namespace App\Http\Middleware;

use App\Services\TranslationManager;
use Closure;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\Auth;
use Symfony\Component\HttpFoundation\Response;

class SetLocaleMiddleware
{
    protected TranslationManager $translationManager;

    public function __construct(TranslationManager $translationManager)
    {
        $this->translationManager = $translationManager;
    }

    /**
     * Handle an incoming request.
     *
     * @param  \Closure(\Illuminate\Http\Request): (\Symfony\Component\HttpFoundation\Response)  $next
     */
    public function handle(Request $request, Closure $next): Response
    {
        $settingService = app(\App\Services\SettingService::class);
        $locale = $this->determineLocale($request, $settingService);

        app()->setLocale($locale);
        $this->translationManager->setLocale($locale);

        return $next($request);
    }

    protected function determineLocale(Request $request, \App\Services\SettingService $settingService): string
    {
        // 1. User Preference (Authenticated)
        if (Auth::check() && Auth::user()->preferred_locale) {
            return Auth::user()->preferred_locale;
        }

        // 2. URL Prefix (e.g., /en/about-us)
        $segments = $request->segments();
        $availableLocales = $settingService->getSupportedLocales();

        // In test or some scenarios, segments might be different
        if (count($segments) > 0 && in_array($segments[0], $availableLocales)) {
            return $segments[0];
        }

        // Handle case where it might be in route parameters directly
        $routeLocale = $request->route('locale');
        if ($routeLocale && in_array($routeLocale, $availableLocales)) {
            return $routeLocale;
        }

        // 3. Session
        if (session()->has('locale')) {
            return session()->get('locale');
        }

        // 4. Request Header
        $acceptLanguage = $request->server('HTTP_ACCEPT_LANGUAGE');
        if ($acceptLanguage) {
            $headerLocale = substr($acceptLanguage, 0, 2);
            if (in_array($headerLocale, $availableLocales)) {
                return $headerLocale;
            }
        }

        // 5. Global Default
        return $settingService->get('default_locale', config('app.locale'));
    }
}