<?php
    ob_start();
    require_once 'config.php';

    // 验证版本ID
    if (!isset($_GET['version_id']) || !is_numeric($_GET['version_id'])) {
        http_response_code(400);
        exit('无效的版本ID');
    }
    $versionId = $_GET['version_id'];

    // 获取版本信息
    $version = null;
    $getVersionSql = "SELECT * FROM app_versions WHERE id = ?";
    $stmt = $conn->prepare($getVersionSql);
    $stmt->bind_param("i", $versionId);
    $stmt->execute();
    $result = $stmt->get_result();
    if ($result->num_rows !== 1) {
        http_response_code(404);
        exit('版本不存在');
    }
    $version = $result->fetch_assoc();

    // 获取绝对文件路径
    $filePath = realpath(__DIR__ . '/' . $version['file_path']);

    // 验证文件存在性
    if (!$filePath || !file_exists($filePath)) {
        http_response_code(404);
        exit('文件不存在');
    }

    // 设置下载响应头
    $fileName = basename($filePath);
    $fileSize = filesize($filePath);

    // 清除输出缓冲区并发送 headers
    ob_end_clean();
    header('Content-Type: application/octet-stream');
    header('Content-Disposition: attachment; filename*=UTF-8\'\'' . rawurlencode($fileName));
    header('Content-Length: ' . $fileSize);
    header('Cache-Control: no-cache, must-revalidate');
    header('Expires: 0');
    header('Pragma: public');

    // 输出文件内容
    if (!readfile($filePath)) {
        http_response_code(500);
        exit('无法读取文件');
    }

    exit;
?>