<?php

namespace App\Http\Middleware;

use Closure;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\App;
use Illuminate\Support\Facades\Session;

class SetLocaleFromRequest
{
    public function handle(Request $request, Closure $next)
    {
        $supportedLocales = $this->supportedLocales();

        $locale = (string) $request->route('locale');

        if (! $locale || ! in_array($locale, $supportedLocales, true)) {
            $preferred = Session::get('preferred_locale');

            if ($preferred && in_array($preferred, $supportedLocales, true)) {
                App::setLocale($preferred);
                Session::put('locale', $preferred);
                $request->attributes->set('preferred_locale', $preferred);
            }

            return $next($request);
        }

        App::setLocale($locale);
        Session::put('preferred_locale', $locale);
        Session::put('locale', $locale);
        $request->attributes->set('preferred_locale', $locale);

        return $next($request);
    }

    /**
     * @return array<int, string>
     */
    private function supportedLocales(): array
    {
        $configured = array_filter(array_map(
            static fn ($value) => trim((string) $value),
            explode(',', (string) env('APP_SUPPORTED_LOCALES', ''))
        ));

        if (empty($configured)) {
            $configured = array_filter([
                config('app.locale'),
                config('app.fallback_locale'),
            ]);
        }

        if (empty($configured)) {
            $configured = ['de', 'en'];
        }

        return array_values(array_unique($configured));
    }
}