<?php
/**
 * 多班级版班级管理系统 - Session 保存接口
 * 
 * 开发者: Canglan
 * 联系方式: admin@sea-studio.top
 * 版权归属: Sea Network Technology Studio
 * 许可证: Apache License 2.0
 * 
 * 版权所有 © Sea Network Technology Studio
 * 
 * 说明：登录成功后，前端调用此接口将用户信息同步到 PHP Session
 */

// 引入配置文件以初始化 Session
require_once __DIR__ . '/../config.php';

// 设置响应头
header('Content-Type: application/json; charset=utf-8');

// 仅允许同源请求
header('Access-Control-Allow-Methods: POST, OPTIONS');
header('Access-Control-Allow-Headers: Content-Type, Authorization');

// 处理预检请求
if ($_SERVER['REQUEST_METHOD'] === 'OPTIONS') {
    http_response_code(200);
    exit();
}
// 只允许 POST 请求
if ($_SERVER['REQUEST_METHOD'] !== 'POST') {
    http_response_code(405);
    echo json_encode([
        'success' => false,
        'message' => '仅支持 POST 请求'
    ]);
    exit();
}

// CSRF 防护：验证 Origin/Referer 头确保同源请求
$origin = $_SERVER['HTTP_ORIGIN'] ?? '';
$referer = $_SERVER['HTTP_REFERER'] ?? '';
$host = $_SERVER['HTTP_HOST'] ?? '';
$serverName = $_SERVER['SERVER_NAME'] ?? '';

if (!empty($origin)) {
    $parsedOrigin = parse_url($origin, PHP_URL_HOST);
    if ($parsedOrigin !== $host && $parsedOrigin !== $serverName) {
        http_response_code(403);
        echo json_encode([
            'success' => false,
            'message' => '跨域请求被拒绝'
        ]);
        exit();
    }
} elseif (!empty($referer)) {
    $parsedReferer = parse_url($referer, PHP_URL_HOST);
    if ($parsedReferer !== $host && $parsedReferer !== $serverName) {
        http_response_code(403);
        echo json_encode([
            'success' => false,
            'message' => '跨域请求被拒绝'
        ]);
        exit();
    }
}

// 获取原始输入
$input = file_get_contents('php://input');

if (empty($input)) {
    http_response_code(400);
    echo json_encode([
        'success' => false,
        'message' => '请求数据为空'
    ]);
    exit();
}

// 解析 JSON 数据
$data = json_decode($input, true);

if (json_last_error() !== JSON_ERROR_NONE) {
    http_response_code(400);
    echo json_encode([
        'success' => false,
        'message' => 'JSON 解析失败: ' . json_last_error_msg()
    ]);
    exit();
}

// 验证必要字段
$requiredFields = ['user_id', 'user_type', 'username'];
$missingFields = [];

foreach ($requiredFields as $field) {
    if (!isset($data[$field]) || empty($data[$field])) {
        $missingFields[] = $field;
    }
}

if (!empty($missingFields)) {
    http_response_code(400);
    echo json_encode([
        'success' => false,
        'message' => '缺少必要字段: ' . implode(', ', $missingFields)
    ]);
    exit();
}

// 验证 user_type 是否合法
$validUserTypes = ['student', 'parent', 'admin', 'super_admin'];
if (!in_array($data['user_type'], $validUserTypes)) {
    http_response_code(400);
    echo json_encode([
        'success' => false,
        'message' => '无效的用户类型'
    ]);
    exit();
}

// 验证 JWT Token
$authHeader = $_SERVER['HTTP_AUTHORIZATION'] ?? '';
if (empty($authHeader) || !preg_match('/^Bearer\s+(.+)$/i', $authHeader, $matches)) {
    http_response_code(401);
    echo json_encode([
        'success' => false,
        'message' => '缺少认证令牌'
    ]);
    exit();
}

$token = $matches[1];
$apiUrl = API_BASE_URL . '/api/auth/me';

$ch = curl_init();
curl_setopt_array($ch, [
    CURLOPT_URL => $apiUrl,
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_TIMEOUT => 10,
    CURLOPT_HTTPHEADER => [
        'Authorization: Bearer ' . $token,
        'Content-Type: application/json'
    ],
    CURLOPT_SSL_VERIFYPEER => true,
    CURLOPT_SSL_VERIFYHOST => 2
]);

$apiResponse = curl_exec($ch);
$httpCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
curl_close($ch);

if ($httpCode !== 200 || empty($apiResponse)) {
    http_response_code(401);
    echo json_encode([
        'success' => false,
        'message' => '认证令牌无效或已过期'
    ]);
    exit();
}

$tokenData = json_decode($apiResponse, true);
if (!$tokenData || !isset($tokenData['success']) || !$tokenData['success']) {
    http_response_code(401);
    echo json_encode([
        'success' => false,
        'message' => '认证验证失败'
    ]);
    exit();
}

// 验证 token 中的 user_id 与请求数据中的 user_id 一致
$tokenUserId = $tokenData['data']['user_id'] ?? null;
if ($tokenUserId === null || intval($tokenUserId) !== intval($data['user_id'])) {
    http_response_code(403);
    echo json_encode([
        'success' => false,
        'message' => '身份验证不匹配'
    ]);
    exit();
}

// 从后端 JWT 解析权威数据（不信任客户端传入的 user_type/role）
$tokenData_user = $tokenData['data'];
// 登录成功后重新生成 Session ID，防止 Session 固定攻击
session_regenerate_id(true);
$_SESSION['user_id'] = intval($tokenData_user['user_id']);
$_SESSION['user_type'] = $tokenData_user['user_type'];
$_SESSION['username'] = $tokenData_user['username'];
$_SESSION['real_name'] = $tokenData_user['real_name'] ?? '';
$_SESSION['role'] = $tokenData_user['role'] ?? '';
$_SESSION['class_id'] = $tokenData_user['class_id'] ?? null;
$_SESSION['class_name'] = $tokenData_user['class_name'] ?? '';
$_SESSION['login_time'] = time();
$_SESSION['jwt_token'] = $token;
// 如果是学生，额外设置 student_id（仅从 JWT 解析，不信任客户端传入值）
if ($_SESSION['user_type'] === 'student') {
    $studentId = $tokenData_user['student_id'] ?? null;
    if (empty($studentId)) {
        http_response_code(400);
        echo json_encode([
            'success' => false,
            'message' => '学生类型必须提供 student_id'
        ]);
        exit();
    }
    $_SESSION['student_id'] = $studentId;
}

// 保存 Session
session_write_close();

// 返回成功响应
http_response_code(200);
echo json_encode([
    'success' => true,
    'message' => 'Session 保存成功'
]);
exit();