<?php

namespace App\Http\Middleware;

use Closure;
use Illuminate\Http\Request;
use Symfony\Component\HttpFoundation\AcceptHeader;
use Symfony\Component\HttpFoundation\Response;

class SetLocale
{
    public function handle(Request $request, Closure $next): Response
    {
        app()->setLocale($this->resolve($request));
        $response = $next($request);
        $response->headers->set('Content-Language', app()->getLocale());
        $response->setVary(array_filter(['Accept-Language', 'Cookie', config('localization.country_header')]), false);

        return $response;
    }

    private function resolve(Request $request): string
    {
        $supported = config('localization.supported');
        $choice = $request->cookie('moonwell_locale');
        if (in_array($choice, $supported, true)) {
            return $choice;
        }

        $languages = AcceptHeader::fromString($request->header('Accept-Language', ''));
        foreach ($languages->all() as $language) {
            if ($language->getQuality() <= 0) {
                continue;
            }
            $locale = strtolower(explode('-', str_replace('_', '-', $language->getValue()))[0]);
            if (in_array($locale, $supported, true)) {
                return $locale;
            }
        }

        $header = config('localization.country_header');
        $country = $header ? strtoupper((string) $request->header($header, '')) : '';
        if (preg_match('/^[A-Z]{2}$/D', $country)) {
            return in_array($country, config('localization.russian_countries'), true) ? 'ru' : 'en';
        }

        return $languages->all() ? 'en' : config('localization.fallback');
    }
}