<?php
// $Id$

$uri  = parse_url($_SERVER["REQUEST_URI"], PHP_URL_PATH);
$file = $_SERVER["DOCUMENT_ROOT"] . $uri;

if (is_file($file)) {
    $ext = strtolower(pathinfo($file, PATHINFO_EXTENSION));

    // 仅对真正的静态资源注入缓存头，其余走原逻辑
    $cacheExts = [
        'js', 'css', 'png', 'jpg', 'jpeg', 'gif', 'svg', 'ico', 'webp',
        'woff', 'woff2', 'ttf', 'eot', 'otf', 'map',
        'json', 'xml', 'pdf', 'zip', 'mp3', 'mp4', 'wav', 'avi',
    ];

    if (in_array($ext, $cacheExts)) {
        $realPath = realpath($file);
        $docRoot  = realpath($_SERVER["DOCUMENT_ROOT"]);

        // 路径穿越防护
        if ($realPath === false || !str_starts_with($realPath, $docRoot)) {
            http_response_code(403);
            exit;
        }

        $etag = '"' . filemtime($file) . '-' . filesize($file) . '"';

        // 304 Not Modified
        if (
            (isset($_SERVER['HTTP_IF_NONE_MATCH']) && $_SERVER['HTTP_IF_NONE_MATCH'] === $etag) ||
            (isset($_SERVER['HTTP_IF_MODIFIED_SINCE']) && strtotime($_SERVER['HTTP_IF_MODIFIED_SINCE']) >= filemtime($file))
        ) {
            http_response_code(304);
            exit;
        }

        header('ETag: ' . $etag);
        header('Last-Modified: ' . gmdate('D, d M Y H:i:s', filemtime($file)) . ' GMT');
        header('Cache-Control: public, max-age=86400');
        header('X-Content-Type-Options: nosniff');

        $mimeMap = [
            'js'   => 'application/javascript',
            'css'  => 'text/css',
            'png'  => 'image/png',
            'jpg'  => 'image/jpeg',
            'jpeg' => 'image/jpeg',
            'gif'  => 'image/gif',
            'svg'  => 'image/svg+xml',
            'ico'  => 'image/x-icon',
            'webp' => 'image/webp',
            'woff'  => 'font/woff',
            'woff2' => 'font/woff2',
            'ttf'   => 'font/ttf',
            'eot'   => 'application/vnd.ms-fontobject',
            'otf'   => 'font/otf',
            'map'   => 'application/json',
            'json'  => 'application/json',
            'xml'   => 'application/xml',
            'pdf'   => 'application/pdf',
            'zip'   => 'application/zip',
            'mp3'   => 'audio/mpeg',
            'mp4'   => 'video/mp4',
            'wav'   => 'audio/wav',
            'avi'   => 'video/x-msvideo',
        ];
        header('Content-Type: ' . ($mimeMap[$ext] ?? 'application/octet-stream'));
        readfile($file);
        exit;
    }

    // PHP、HTML 等文件交给 PHP 内置服务器处理
    return false;
} else {
    require __DIR__ . "/index.php";
}