<?php
namespace App\Core;

class I18n {
    private static $lang = 'en';
    private static $translations = [];
    private static $fallback = [];
    private static $loaded = false;

    // 支持的语言列表
    const LANGUAGES = [
        'en'  => 'English',
        'th'  => 'ไทย',
        'vi'  => 'Tiếng Việt',
        'zh'  => '中文',
        'ms'  => 'Bahasa Melayu',
        'fil' => 'Filipino',
        'bn'  => 'বাংলা',
    ];

    public static function init($db = null) {
        if (self::$loaded) return;

        // 优先级: URL参数 > Session > Cookie > 浏览器 > 默认en
        if (!empty($_GET['lang']) && isset(self::LANGUAGES[$_GET['lang']])) {
            self::$lang = $_GET['lang'];
        } elseif (!empty($_SESSION['lang'])) {
            self::$lang = $_SESSION['lang'];
        } elseif (!empty($_COOKIE['lang'])) {
            self::$lang = $_COOKIE['lang'];
        } else {
            self::$lang = self::detectBrowserLang();
        }

        $_SESSION['lang'] = self::$lang;
        setcookie('lang', self::$lang, time() + 86400 * 365, '/');

        self::loadFromFile();
        self::$loaded = true;
    }

    private static function detectBrowserLang(): string {
        $accept = $_SERVER['HTTP_ACCEPT_LANGUAGE'] ?? '';
        foreach (self::LANGUAGES as $code => $name) {
            if (stripos($accept, $code) !== false) return $code;
        }
        return 'en';
    }

    private static function loadFromFile() {
        $file = ROOT_PATH . 'Lang/' . self::$lang . '.php';
        if (file_exists($file)) {
            self::$translations = require $file;
        }
        // 始终加载英文作为fallback
        $enFile = ROOT_PATH . 'Lang/en.php';
        if (file_exists($enFile)) {
            self::$fallback = require $enFile;
        }
    }

    public static function t(string $key, array $params = []): string {
        $text = self::$translations[$key] ?? self::$fallback[$key] ?? $key;
        foreach ($params as $k => $v) {
            $text = str_replace(':' . $k, $v, $text);
        }
        return $text;
    }

    public static function getLang(): string { return self::$lang; }
    public static function setLang(string $lang) {
        if (isset(self::LANGUAGES[$lang])) {
            self::$lang = $lang;
            self::$loaded = false;
            self::init();
        }
    }
    public static function getLanguages(): array { return self::LANGUAGES; }
}

// 全局快捷函数
function __($key, $params = []) { return I18n::t($key, $params); }