<?php

$staticLangDir = __DIR__ . '/lang';
$runtimeLangDir = getenv('WEBSITE_LANG_WRITE_DIR') ?: null;
$langFiles = glob($staticLangDir . '/*.php') ?: [];
if ($runtimeLangDir && is_dir($runtimeLangDir)) {
    $langFiles = array_merge($langFiles, glob($runtimeLangDir . '/*.php') ?: []);
}

$availableLangs = array_values(array_unique(array_map(
    fn($f) => basename($f, '.php'),
    $langFiles
)));

function getLang($supported) {
    if (isset($_GET['lang']) && in_array($_GET['lang'], $supported)) {
        return $_GET['lang'];
    }
    $browser = substr($_SERVER['HTTP_ACCEPT_LANGUAGE'] ?? 'nah', 0, 2);
    return in_array($browser, $supported) ? $browser : 'nah';
}

$lang = getLang($availableLangs);

$file = $runtimeLangDir ? "$runtimeLangDir/$lang.php" : '';
if (!$file || !file_exists($file)) {
    $file = "$staticLangDir/$lang.php";
}
if (!file_exists($file)) {
    $lang = 'nah';
    $file = "$staticLangDir/nah.php";
}

$en = include "$staticLangDir/en.php";
$text = array_replace($en, include $file);