<?php
/**
 * NY 问卷考试系统数据平台 - 后端接口
 */
declare(strict_types=1);

require __DIR__ . '/bootstrap.php';
require __DIR__ . '/lib/multi_export.php';

$action = (string)($_GET['action'] ?? $_POST['action'] ?? '');

function cfg(): array
{
    return ny_load_config();
}

/**
 * 按成绩排序（null 成绩恒排末尾，同分按提交时间降序）
 * @param bool $desc true=降序
 */
function ny_sort_by_score(array $rows, bool $desc): array
{
    $dir = $desc ? -1 : 1;
    usort($rows, static function (array $x, array $y) use ($dir): int {
        $xn = ($x['score'] ?? null) === null;
        $yn = ($y['score'] ?? null) === null;
        if ($xn && $yn) {
            return 0;
        }
        if ($xn) {
            return 1;
        }
        if ($yn) {
            return -1;
        }
        $d = ((float)$x['score'] <=> (float)$y['score']) * $dir;
        if ($d !== 0) {
            return $d;
        }
        return ((int)($y['submit_ts'] ?? 0)) <=> ((int)($x['submit_ts'] ?? 0));
    });
    return $rows;
}

/** 缺考名单工作表行（按学号升序） */
function ny_absent_sheet_rows(array $absent): array
{
    usort($absent, static function ($x, $y): int {
        $a = trim((string)($x['sid'] ?? ''));
        $b = trim((string)($y['sid'] ?? ''));
        if (is_numeric($a) && is_numeric($b)) {
            return $a <=> $b;
        }
        return strnatcmp($a, $b);
    });
    $out = [['学号', '姓名', '班级', '组别']];
    foreach ($absent as $r) {
        $out[] = [
            (string)($r['sid'] ?? ''),
            (string)($r['name'] ?? ''),
            (string)($r['cls'] ?? ''),
            (string)($r['grp'] ?? ''),
        ];
    }
    return $out;
}

/**
 * 多考试对比导出（成绩交叉矩阵）的纯逻辑见 lib/multi_export.php
 * （ny_exam_cell_score / ny_assemble_multi_exam_matrix），便于在 api.php 与单测中复用。
 */

/**
 * 带短期缓存的数据构建（含并发锁，避免多人同时刷新时重复打卷王造成惊群）
 *
 * 缓存 key 由「项目 + 姓名字段 + 连接/去重等配置 + 名单指纹」组成：
 * 名单一变指纹就变，因此不会出现"改了名单还显示旧数据"。
 * force=true 时跳过缓存（前端"立即刷新"按钮使用）。
 *
 * @return array{result:array,cached:bool,at:int}
 */
function ny_build_data(array $c, string $projectId, string $nameQid, bool $force = false): array
{
    $ttl = (int)($c['cache_ttl'] ?? 15);
    if ($ttl < 0) {
        $ttl = 0;
    }
    $key = DataCache::key([
        $projectId, $nameQid,
        (string)$c['base_url'], (string)$c['api_prefix'], (string)$c['username'],
        !empty($c['dedupe']) ? 1 : 0,
        !empty($c['include_temp_save']) ? 1 : 0,
        (string)($c['name_keywords'] ?? ''),
        (int)($c['page_size'] ?? 100),
        Roster::fingerprint(),
        // 本卷独立配置（免考名单/满分/合格率）变化也应让缓存失效，否则改免考后可能短暂看到旧数据
        json_encode(DataService::projectConfig($projectId) ?? []),
    ]);

    if ($ttl > 0 && !$force) {
        $hit = DataCache::read($key, $ttl);
        if ($hit !== null) {
            return ['result' => $hit['result'], 'cached' => true, 'at' => $hit['at']];
        }
    }

    // 并发锁：同一 key 只允许一个请求真正去拉卷王
    $lock = DataCache::acquireLock($key);
    if ($lock === null) {
        // 已有别的请求在构建：短暂等待其落盘后直接复用（允许略旧，总比同时压垮卷王好）
        for ($i = 0; $i < 15; $i++) {
            usleep(200000); // 200ms
            $hit = DataCache::read($key, max($ttl, 60));
            if ($hit !== null) {
                return ['result' => $hit['result'], 'cached' => true, 'at' => $hit['at']];
            }
        }
        // 等不到（构建很慢或锁不被支持）就自己构建，保证可用性
    }

    // try/finally：无论 build 是否抛异常都释放构建锁，避免异常时锁句柄挂到进程退出造成惊群
    $result = null;
    try {
        $result = DataService::build($c, $projectId, $nameQid);
        if ($ttl > 0) {
            DataCache::write($key, $result);
        }
    } finally {
        DataCache::releaseLock($lock);
    }

    return ['result' => $result, 'cached' => false, 'at' => time()];
}

// 会话保护：白名单外的动作未登录一律拒访。
// dashboard 进白名单是因为班级大屏要公开访问；它在 case 内部自己兜底——
// 未登录时必须带 ?class=，且只回传该班数据（全卷与其它班级一律不回）。
$PUBLIC_ACTIONS = ['auth_check', 'dashboard'];
if (!in_array($action, $PUBLIC_ACTIONS, true) && !ny_is_auth()) {
    ny_json(['ok' => false, 'msg' => '未登录或会话已过期，请重新登录'], 401);
    exit;
}

// CSRF 防护：所有写操作必须携带会话绑定的 token（GET 读取类接口不受影响）
$WRITE_ACTIONS = [
    'config_save', 'roster_save', 'roster_import', 'roster_clear',
    'unmatched_map', 'project_config_save',
];
if (in_array($action, $WRITE_ACTIONS, true) && !ny_csrf_ok()) {
    ny_json(['ok' => false, 'msg' => '安全校验失败（CSRF token 缺失或不匹配），请刷新页面后重试'], 403);
    exit;
}

try {
    switch ($action) {
        // 登录状态检查
        case 'auth_check':
            ny_ok(['auth' => ny_is_auth(), 'installed' => ny_is_installed()]);

        // ---------------- 配置 ----------------
        case 'config_get':
            $c = cfg();
            $c['has_password'] = ((string)$c['password']) !== '';
            unset($c['password']);
            $c['csrf_token'] = ny_csrf_token();
            // 诊断信息：配置存在哪里、数据库通不通（登录卷王失败时优先看这里）
            $c['storage']       = ny_config_source();
            $c['db_driver']     = class_exists('Db') ? Db::driver() : '';
            $c['db_configured'] = class_exists('Db') && Db::isConfigured();
            $c['db_connected']  = class_exists('Db') && Db::isConnected();
            // 仅在未连接时回传错误详情（供前端诊断连接失败原因）；
            // 已连接时一律不回传 lastError，避免把 SQL/文件路径等内部信息泄露给客户端。
            $c['db_error']      = (class_exists('Db') && !Db::isConnected()) ? Db::lastError() : '';
            ny_ok($c);

        case 'config_save':
            $raw = ny_request_body();
            $in  = json_decode($raw, true);
            if (!is_array($in)) {
                $in = $_POST;
            }
            $old = cfg();
            // 合并规则统一放在 ny_apply_config_input（含"账号/密码不许被改空"的兜底），便于单测
            $applied      = ny_apply_config_input($old, $in);
            $new          = $applied['config'];
            $connChanged  = $applied['conn_changed'];
            ny_save_config($new);
            if ($connChanged) {
                @unlink(NY_DATA . '/cache/token.json');
            }
            // 返回的 config 不再带明文密码
            $outCfg = ny_load_config();
            $outCfg['has_password'] = ((string)$outCfg['password']) !== '';
            unset($outCfg['password']);
            $res = [
                'saved'        => true,
                'config'       => $outCfg,
                'conn_changed' => $connChanged,
                'storage'      => ny_config_source(),
            ];
            // 连接信息修改后自动测一次，给出明确结果（避免用户配置对错无从知晓）
            if ($connChanged) {
                try {
                    $client = new SurveyKingClient(ny_load_config());
                    $p = $client->ping();
                    $res['ping'] = ['ok' => true, 'projects' => $p['projects'], 'elapsed' => $p['elapsed']];
                } catch (Throwable $e) {
                    $res['ping'] = ['ok' => false, 'msg' => $e->getMessage()];
                }
            }
            ny_ok($res);

        // ---------------- 用弹窗内（未保存）的凭据测试连接 ----------------
        case 'config_test':
            $raw = ny_request_body();
            $in  = json_decode($raw, true);
            if (!is_array($in)) {
                $in = $_POST;
            }
            // 以已保存配置为基底，仅覆盖弹窗中填写的字段，避免漏填导致误测
            $test = ny_load_config();
            foreach (['base_url', 'api_prefix', 'username', 'verify_ssl', 'timeout'] as $k) {
                if (array_key_exists($k, $in)) {
                    $test[$k] = is_string($in[$k]) ? trim((string)$in[$k]) : $in[$k];
                }
            }
            if (array_key_exists('password', $in)) {
                $pwdIn = (string)$in['password'];
                if ($pwdIn !== '' && $pwdIn !== '******') {
                    $test['password'] = $pwdIn;
                }
            }
            $test['base_url']   = rtrim((string)($test['base_url'] ?? ''), '/');
            $test['api_prefix'] = '/' . trim((string)($test['api_prefix'] ?? '/api'), '/');
            try {
                $client = new SurveyKingClient($test);
                $p = $client->ping();
                ny_ok(['connected' => true, 'projects' => $p['projects'], 'elapsed' => $p['elapsed']]);
            } catch (Throwable $e) {
                ny_ok(['connected' => false, 'msg' => $e->getMessage()]);
            }

        // ---------------- 连接测试 ----------------
        case 'ping':
            $client = new SurveyKingClient(cfg());
            $res = $client->ping();
            $res['session'] = $client->sessionInfo();
            ny_ok($res);

        case 'diag':
            $client = new SurveyKingClient(cfg());
            ny_ok($client->diagnose());

        // ---------------- 问卷列表 ----------------
        case 'projects':
            $client = new SurveyKingClient(cfg());
            $list   = $client->listProjects();
            $out    = [];
            foreach ($list as $p) {
                if (!is_array($p)) {
                    continue;
                }
                $out[] = [
                    'id'        => ny_str($p['id'] ?? ''),
                    'name'      => ny_str($p['name'] ?? '') ?: '未命名',
                    'mode'      => ny_str($p['mode'] ?? ''),
                    'total'     => (int)($p['total'] ?? 0),
                    'status'    => (int)($p['status'] ?? 0),
                    'parent_id' => (string)($p['parentId'] ?? '0'),
                ];
            }
            ny_ok($out);

        // ---------------- 数据 ----------------
        case 'data':
            $projectId = (string)($_GET['projectId'] ?? '');
            if ($projectId === '') {
                ny_fail('请先选择问卷/考试');
            }
            $nameQid = (string)($_GET['nameQid'] ?? '');
            $c = cfg();
            $built  = ny_build_data($c, $projectId, $nameQid, !empty($_GET['force']));
            $result = $built['result'];
            // 满分：本卷独立优先，其次全局默认
            [$fs, $passRate] = ny_resolve_score_cfg($projectId, $c);
            $result['config'] = [
                'refresh_interval'  => (int)$c['refresh_interval'],
                'base_url'          => $c['base_url'],
                'full_score'        => $fs,
                'pass_rate'         => $passRate,
            ];
            // 缓存来源标记：便于前端/排查时知道这次是实时拉取还是命中短期缓存
            $result['_cache'] = ['cached' => $built['cached'], 'at' => $built['at']];
            ny_ok($result);

        // ---------------- 数据看板（按班级聚合，面向班主任/学生整体情况） ----------------
        case 'dashboard':
            $projectId = (string)($_GET['projectId'] ?? '');
            if ($projectId === '') {
                ny_fail('请先选择问卷/考试');
            }
            $nameQid = (string)($_GET['nameQid'] ?? '');
            $c = cfg();
            $built  = ny_build_data($c, $projectId, $nameQid, !empty($_GET['force']));
            $result = $built['result'];
            [$fs, $passRate] = ny_resolve_score_cfg($projectId, $c);

            $students = $result['roster'] ?: [];
            $rows     = $result['rows'] ?: [];

            /* 公开访问（未登录）只允许看指定班级，且只看这一个类的数据：
               名单、答卷都在服务端先按班级裁掉，不给前端任何"全卷"数据，
               避免公开链接顺手拿到其它班级甚至全校的成绩。 */
            $publicCls = '';
            if (!ny_is_auth()) {
                $publicCls = trim((string)($_GET['class'] ?? ''));
                if ($publicCls === '') {
                    ny_fail('缺少班级参数（公开访问需指定 ?class=）');
                }
                $inCls = static fn($x) => (trim((string)($x['cls'] ?? '')) ?: '（未分班）') === $publicCls;
                $students = array_values(array_filter($students, $inCls));
                $rows     = array_values(array_filter($rows, $inCls));
            }

            $byCls = [];
            foreach ($students as $s) {
                $k = trim((string)($s['cls'] ?? '')) ?: '（未分班）';
                $byCls[$k][] = $s;
            }
            $rowsByCls = [];
            foreach ($rows as $r) {
                $k = trim((string)($r['cls'] ?? '')) ?: '（未分班）';
                $rowsByCls[$k][] = $r;
            }

            // 通用统计器：给定学生集合 + 答卷集合，算一组指标
            // 合格率阈值可配（全局 pass_rate 或本卷独立），不再写死 60%
            $statOf = static function (array $stu, array $rs, int $fs) use ($passRate): array {
                $total     = count($stu);
                $submitted = count($rs);
                $attempts  = array_sum(array_map(static fn($r) => (int)($r['attempts'] ?? 1), $rs));
                $scores    = array_values(array_filter(array_map(static fn($r) => $r['score'] ?? null, $rs), static fn($v) => $v !== null));
                $avg       = $scores !== [] ? round(array_sum($scores) / count($scores), 2) : null;
                $pass      = count(array_filter($rs, static fn($r) => ($r['score'] ?? null) !== null && ($r['score'] >= ($passRate / 100) * $fs)));
                $passRate  = $submitted > 0 ? round($pass / $submitted * 100, 1) : 0;
                $durs      = array_values(array_filter(array_map(static fn($r) => $r['duration'] ?? null, $rs), static fn($v) => $v !== null));
                $avgDur    = $durs !== [] ? (int)round(array_sum($durs) / count($durs)) : null;
                return [
                    'total'        => $total,
                    'submitted'    => $submitted,
                    'attempts'     => $attempts,
                    'absent'       => max(0, $total - $submitted),
                    'rate'         => $total > 0 ? round($submitted / $total * 100, 1) : 0,
                    'avg'          => $avg,
                    'pass_rate'    => $passRate,
                    'max'          => $scores !== [] ? max($scores) : null,
                    'min'          => $scores !== [] ? min($scores) : null,
                    'avg_duration' => $avgDur,
                ];
            };

            // 已提交成员榜：按成绩从高到低，缺成绩者排最后，并给出排名
            // 透传 attempts / attempts_list，供前端展示"同人多刷卷"
            $membersOf = static function (array $rs): array {
                $ms = [];
                foreach ($rs as $r) {
                    $ms[] = [
                        'sid'           => (string)($r['sid'] ?? ''),
                        'name'          => (string)($r['name'] ?? ''),
                        'score'         => ($r['score'] ?? null),
                        'attempts'      => (int)($r['attempts'] ?? 1),
                        'attempts_list' => $r['attempts_list'] ?? [],
                    ];
                }
                usort($ms, static function (array $a, array $b): int {
                    $as = $a['score'];
                    $bs = $b['score'];
                    if ($as === null && $bs === null) {
                        return 0;
                    }
                    if ($as === null) {
                        return 1;   // 无成绩排最后
                    }
                    if ($bs === null) {
                        return -1;
                    }
                    return $bs <=> $as;  // 成绩降序
                });
                foreach ($ms as $i => $m) {
                    $ms[$i]['rank'] = $i + 1;
                }
                return $ms;
            };

            $classes = [];
            foreach ($byCls as $k => $stu) {
                $rs  = $rowsByCls[$k] ?? [];
                $row = $statOf($stu, $rs, $fs);
                $row['class']   = $k;
                $row['members'] = $membersOf($rs);

                // 班级内按组别（A/B 等）再聚合，用于看板下钻对比
                $stuByGrp  = [];
                foreach ($stu as $s) {
                    $g = trim((string)($s['grp'] ?? '')) ?: '（未分组）';
                    $stuByGrp[$g][] = $s;
                }
                $rowsByGrp = [];
                foreach ($rs as $r) {
                    $g = trim((string)($r['grp'] ?? '')) ?: '（未分组）';
                    $rowsByGrp[$g][] = $r;
                }
                $groups = [];
                foreach ($stuByGrp as $g => $gstu) {
                    $gs = $statOf($gstu, $rowsByGrp[$g] ?? [], $fs);
                    $gs['group']   = $g;
                    $gs['members'] = $membersOf($rowsByGrp[$g] ?? []);
                    $groups[] = $gs;
                }
                usort($groups, static fn(array $a, array $b): int => strcmp((string)$a['group'], (string)$b['group']));
                $row['groups'] = $groups;

                $classes[] = $row;
            }
            usort($classes, static function (array $a, array $b): int {
                $an = is_numeric($a['class']) ? (int)$a['class'] : $a['class'];
                $bn = is_numeric($b['class']) ? (int)$b['class'] : $b['class'];
                if (is_int($an) && is_int($bn)) {
                    return $an <=> $bn;
                }
                return strcmp((string)$a['class'], (string)$b['class']);
            });

            $payload = [
                'project'    => $result['project'],
                'full_score' => $fs,
                'pass_rate'  => $passRate,
                'overall'    => $result['stats'],
                'classes'    => $classes,
                'updated_at' => $result['updated_at'],
            ];
            if ($publicCls !== '') {
                // 公开访问：overall 换成该班自己的汇总（保持 stats 原有键名，前端按 attempts_total 读取），
                // classes 只留这一个班，并打上 public 标记供前端展示"公开页面"
                $st = $statOf($students, $rows, $fs);
                $payload['overall'] = array_merge($result['stats'], [
                    'roster_total'   => $st['total'],
                    'submitted'      => $st['submitted'],
                    'absent'         => $st['absent'],
                    'submit_rate'    => $st['rate'],
                    'avg_score'      => $st['avg'],
                    'max_score'      => $st['max'],
                    'min_score'      => $st['min'],
                    'avg_duration'   => $st['avg_duration'],
                    'attempts_total' => $st['attempts'],
                ]);
                $payload['public'] = true;
            }
            ny_ok($payload);

        // ---------------- 名单 ----------------
        case 'roster':
            ny_ok(['students' => Roster::all(), 'meta' => Roster::meta()]);

        case 'roster_import':
            if (empty($_FILES['file']) || !is_uploaded_file($_FILES['file']['tmp_name'])) {
                ny_fail('请选择要导入的文件');
            }
            $f   = $_FILES['file'];
            $err = (int)($f['error'] ?? UPLOAD_ERR_OK);
            if ($err !== UPLOAD_ERR_OK) {
                ny_fail('上传失败（错误码 ' . $err . '）');
            }
            if ((int)($f['size'] ?? 0) > 20 * 1024 * 1024) {
                ny_fail('文件过大（上限 20MB）');
            }
            // 扩展名白名单：杜绝上传 .php/.phtml 等可执行后缀到 Web 目录
            $ext = strtolower(pathinfo((string)$f['name'], PATHINFO_EXTENSION));
            if (!in_array($ext, ['xlsx', 'xlsm', 'csv', 'txt'], true)) {
                ny_fail('仅支持 .xlsx / .xlsm / .csv / .txt 文件');
            }
            // 随机文件名：杜绝按时间枚举（原 roster_YYYYMMDD_HHMMSS.ext 可被遍历）
            $dir = NY_DATA . '/uploads';
            if (!is_dir($dir)) {
                @mkdir($dir, 0777, true);
            }
            $dest = $dir . '/' . bin2hex(random_bytes(16)) . '.' . $ext;
            if (!@move_uploaded_file($f['tmp_name'], $dest)) {
                ny_fail('文件保存失败，请检查 data/uploads 目录权限');
            }
            try {
                $res = Roster::importFile($dest, $ext);
            } catch (Throwable $e) {
                @unlink($dest);
                ny_fail($e->getMessage());
            }
            // 解析完立即删除：Web 目录下不再留存任何上传文件
            @unlink($dest);
            // 默认追加：与「导入名单默认为追加」一致（学号名单管理导入）
            $mode = (string)($_POST['mode'] ?? 'append');
            if ($mode === 'append') {
                // 追加：仅加入名单中尚不存在的成员（无学号时按姓名判重），避免重复行。
                // 学号与姓名分两套判重键：带学号者以 sid 判重，无学号者以姓名判重，
                // 避免「已存在带学号 A 的行」被「同名但空学号的导入行」误判为不重复而重复插入。
                $existing = Roster::all();
                $seenSid  = [];
                $seenName = [];
                foreach ($existing as $s) {
                    $sid  = strtolower(trim((string)($s['sid'] ?? '')));
                    $name = strtolower(trim((string)($s['name'] ?? '')));
                    if ($sid !== '') {
                        $seenSid[$sid] = true;
                    } elseif ($name !== '') {
                        $seenName[$name] = true;
                    }
                }
                $added = [];
                foreach ($res['students'] as $s) {
                    $sid  = strtolower(trim((string)($s['sid'] ?? '')));
                    $name = strtolower(trim((string)($s['name'] ?? '')));
                    $dup  = false;
                    if ($sid !== '') {
                        if (isset($seenSid[$sid])) { $dup = true; }
                        else { $seenSid[$sid] = true; }
                    } elseif ($name !== '') {
                        if (isset($seenName[$name])) { $dup = true; }
                        else { $seenName[$name] = true; }
                    }
                    if ($dup) {
                        continue;
                    }
                    $added[] = $s;
                }
                if (!Roster::save(array_merge($existing, $added))) {
                    ny_fail('名单追加失败：' . (class_exists('Db') ? Db::lastError() : '未知错误'));
                }
                $res['count'] = count($added);   // 仅计入真正新增的人数
            } else {
                if (!Roster::save($res['students'])) {
                    ny_fail('名单导入失败：' . (class_exists('Db') ? Db::lastError() : '未知错误'));
                }
            }
            ny_ok([
                'students'   => Roster::all(),
                'meta'       => Roster::meta(),
                'imported'   => $res['count'],
                'skipped'    => $res['skipped'] ?? 0,
                'duplicates' => $res['duplicates'] ?? 0,
            ]);

        // ---------------- 从卷王白名单导入待考名单（已移除）----------------
        // 现改为：DataService::build 自动读取每套试卷卷内设置的「答题白名单」，
        // 白名单成员即「应考名单」，未设置时回退到全名单（按现在的方案显示）。
        // 名单管理里的「⬇ 从白名单导入」按钮已删除。

        case 'roster_save':
            $raw = ny_request_body();
            $in  = json_decode($raw, true);
            if (!is_array($in) || !isset($in['students']) || !is_array($in['students'])) {
                ny_fail('参数错误');
            }
            $students = [];
            foreach ($in['students'] as $s) {
                if (!is_array($s)) {
                    continue;
                }
                $students[] = [
                    'sid'   => (string)($s['sid'] ?? ''),
                    'name'  => (string)($s['name'] ?? ''),
                    'cls'   => trim((string)($s['cls'] ?? '')),
                    'grp'   => trim((string)($s['grp'] ?? '')),
                    'login' => trim((string)($s['login'] ?? '')),
                ];
            }
            if (!Roster::save($students)) {
                ny_fail('名单保存失败：' . (class_exists('Db') ? Db::lastError() : '未知错误'));
            }
            ny_ok(['students' => Roster::all(), 'meta' => Roster::meta()]);

        case 'roster_clear':
            Roster::clear();
            ny_ok(['students' => [], 'meta' => Roster::meta()]);

        // ---------------- 未匹配答卷 → 加入名单 ----------------
        case 'unmatched_map':
            $raw = ny_request_body();
            $in  = json_decode($raw, true);
            if (!is_array($in)) {
                $in = $_POST;
            }
            $name = trim((string)($in['name'] ?? ''));
            $sid  = trim((string)($in['sid'] ?? ''));
            if ($name === '' || $sid === '') {
                ny_fail('姓名与学号必填');
            }
            $cls = trim((string)($in['cls'] ?? ''));
            $grp = trim((string)($in['grp'] ?? ''));
            $login = trim((string)($in['login'] ?? ''));
            $roster = Roster::all();
            // 若学号已存在则更新其姓名为该答卷姓名（映射到已有学生）；否则新增一行
            $found = false;
            foreach ($roster as &$s) {
                if (trim((string)($s['sid'] ?? '')) === $sid) {
                    $s['name'] = $name;
                    if ($cls !== '') { $s['cls'] = $cls; }
                    if ($grp !== '') { $s['grp'] = $grp; }
                    if ($login !== '') { $s['login'] = $login; }
                    $found = true;
                    break;
                }
            }
            unset($s);
            if (!$found) {
                $roster[] = ['sid' => $sid, 'name' => $name, 'cls' => $cls, 'grp' => $grp, 'login' => $login];
            }
            if (!Roster::save($roster)) {
                ny_fail('映射保存失败：' . (class_exists('Db') ? Db::lastError() : '未知错误'));
            }
            ny_ok(['students' => Roster::all(), 'meta' => Roster::meta(), 'mapped' => $name]);

        // ---------------- 试卷独立配置（满分 / 合格率 / 免考名单）——仅对当前试卷生效 ----------------
        case 'project_config':
            $projectId = (string)($_GET['projectId'] ?? '');
            if ($projectId === '') {
                ny_fail('请先选择问卷/考试');
            }
            $c = cfg();
            [$fs, $pr] = ny_resolve_score_cfg($projectId, $c);
            $pc = DataService::projectConfig($projectId);
            ny_ok([
                'project_id' => $projectId,
                'cfg'        => $pc,
                // 解析后的生效值（前端回显用；null 表示"跟随全局"）
                'effective'  => ['full_score' => $fs, 'pass_rate' => $pr],
                'global'     => [
                    'full_score' => (int)($c['full_score'] ?? 100),
                    'pass_rate'  => (float)($c['pass_rate'] ?? 60),
                ],
            ]);

        case 'project_config_save':
            $projectId = (string)($_GET['projectId'] ?? $_POST['projectId'] ?? '');
            if ($projectId === '') {
                ny_fail('请先选择问卷/考试');
            }
            $raw = ny_request_body();
            $in  = json_decode($raw, true);
            if (!is_array($in)) {
                $in = $_POST;
            }
            $old = DataService::projectConfig($projectId);
            // 满分：留空/0 = 清除（跟随全局）
            $fsIn = $in['full_score'] ?? null;
            $fs   = ($fsIn === null || $fsIn === '' || (int)$fsIn < 1) ? null : (int)$fsIn;
            // 合格率：留空 = 清除（跟随全局）；否则夹到 1~100
            $prIn = $in['pass_rate'] ?? null;
            $pr   = ($prIn === null || $prIn === '') ? null : max(1, min(100, (float)$prIn));
            // 免考名单：支持数组或逗号/换行分隔的字符串
            $exIn = $in['exempt'] ?? null;
            $exempt = [];
            if (is_array($exIn)) {
                foreach ($exIn as $v) {
                    $v = trim((string)$v);
                    if ($v !== '') {
                        $exempt[] = $v;
                    }
                }
            } elseif (is_string($exIn) && trim($exIn) !== '') {
                foreach (preg_split('/[,，\s]+/u', trim($exIn)) ?: [] as $v) {
                    $v = trim($v);
                    if ($v !== '') {
                        $exempt[] = $v;
                    }
                }
            }
            $new = [
                'full_score' => $fs,
                'pass_rate'  => $pr,
                'exempt'     => array_values(array_unique($exempt)),
            ];
            DataService::projectConfigSave($projectId, $new);
            $c2 = cfg();
            [$effFs, $effPr] = ny_resolve_score_cfg($projectId, $c2);
            ny_ok([
                'cfg'       => $new,
                'effective' => ['full_score' => $effFs, 'pass_rate' => $effPr],
            ]);

        // ---------------- 导出（支持按班级 / 组别筛选，与页面当前筛选保持一致） ----------------
        case 'export':
        case 'export_absent':
            $projectId = (string)($_GET['projectId'] ?? '');
            if ($projectId === '') {
                ny_fail('请先选择问卷/考试');
            }
            $nameQid = (string)($_GET['nameQid'] ?? '');
            $clsFilter = trim((string)($_GET['cls'] ?? ''));
            $grpFilter = trim((string)($_GET['grp'] ?? ''));

            // 命中筛选：未选班级/组别时全部通过
            $hit = static function (array $r) use ($clsFilter, $grpFilter): bool {
                if ($clsFilter !== '' && trim((string)($r['cls'] ?? '')) !== $clsFilter) {
                    return false;
                }
                if ($grpFilter !== '' && trim((string)($r['grp'] ?? '')) !== $grpFilter) {
                    return false;
                }
                return true;
            };

            $c = cfg();
            // 复用与 data 接口相同的结果缓存：导出不必再全量拉一次卷王
            $built  = ny_build_data($c, $projectId, $nameQid, !empty($_GET['force']));
            $result = $built['result'];

            $rows = array_values(array_filter((array)($result['rows'] ?? []), $hit));

            // 缺考口径与页面完全保持一致：筛选后名单 − 筛选后已提交（按学号匹配）
            $roster = array_values(array_filter((array)($result['roster'] ?? []), $hit));
            if ($roster !== []) {
                $submitted = [];
                foreach ($rows as $r) {
                    $sid = trim((string)($r['sid'] ?? ''));
                    if ($sid !== '') {
                        $submitted[$sid] = true;
                    }
                }
                $absent = array_values(array_filter(
                    $roster,
                    static fn(array $s): bool => !isset($submitted[trim((string)($s['sid'] ?? ''))])
                ));
            } else {
                // 未导入名单时退回后端自带的缺考数组（同样按筛选过滤）
                $absent = array_values(array_filter((array)($result['absent'] ?? []), $hit));
            }

            // 文件名附带班级 / 组别，便于分辨
            $safe = static fn(string $s): string => preg_replace('/[\\\\\/:*?"<>|]/u', '_', $s) ?? '';
            $clsLabel = $clsFilter === '' ? ''
                : (mb_strpos($clsFilter, '班') === false ? $clsFilter . '班' : $clsFilter);
            $grpLabel = $grpFilter === '' ? ''
                : (mb_strpos($grpFilter, '组') === false ? $grpFilter . '组' : $grpFilter);
            $tag = ($clsLabel !== '' ? '_' . $safe($clsLabel) : '')
                . ($grpLabel !== '' ? '_' . $safe($grpLabel) : '');

            $mode     = ((string)($_GET['mode'] ?? '') === 'latest') ? 'latest' : 'all';
            $splitCls = ((string)($_GET['split'] ?? '') === 'cls');
            $isLatest = ($mode === 'latest');
            // 每人一行时的成绩口径：latest（默认，最近一次真实提交）| best（最高分）
            // 「成绩明细」的显示选项就是这一项——默认最新成绩，可选最高成绩。
            $rowScoreMode = ((string)($_GET['scoreMode'] ?? '') === 'best') ? 'best' : 'latest';
            // skipTemp=1：每次考试一行时排除暂存草稿（草稿不是有效成绩）；includeTemp=1 可保留
            $skipTemp = (!empty($_GET['skipTemp']) || !empty($_GET['skip_temp']))
                && empty($_GET['includeTemp']) && empty($_GET['include_temp']);
            $scoreTag = $isLatest ? ($rowScoreMode === 'best' ? '_最高成绩' : '_最新成绩') : '_每次考试';
            $filename = ($action === 'export_absent' ? '缺考名单' : '成绩明细')
                . '_' . $safe((string)$result['project']['name'])
                . $tag
                . $scoreTag
                . '_' . date('Ymd_His') . '.xlsx';

            // ---------------- 列定义（可通过 cols= 参数挑选） ----------------
            $colLabels = [
                'sid'          => '学号',
                'name'         => '姓名',
                'cls'          => '班级',
                'grp'          => '组别',
                'score'        => $isLatest ? ($rowScoreMode === 'best' ? '最高成绩' : '最新成绩') : '成绩',
                'best_score'   => '最高分',
                'attempts'     => '考试次数',
                'idx'          => '第几次',
                'is_best'      => '是否最高分',
                'submit_at'    => $isLatest ? '最近提交时间' : '提交时间',
                'duration_txt' => '考试时长',
                'duration'     => '考试时长(秒)',
            ];
            $defaultCols = $isLatest
                ? ['sid', 'name', 'cls', 'grp', 'score', 'best_score', 'attempts', 'submit_at', 'duration_txt', 'duration']
                : ['sid', 'name', 'cls', 'grp', 'score', 'best_score', 'attempts', 'idx', 'is_best', 'submit_at', 'duration_txt', 'duration'];
            $want = array_values(array_filter(
                array_map('trim', explode(',', (string)($_GET['cols'] ?? ''))),
                static fn($v): bool => $v !== ''
            ));
            $cols = $want !== [] ? array_values(array_intersect($defaultCols, $want)) : $defaultCols;
            if ($cols === []) {
                $cols = $defaultCols;
            }

            // ---------------- 数据行 ----------------
            $sortMode = (string)($_GET['sort'] ?? '');
            if ($isLatest) {
                // 每人一行：成绩按「最新成绩」（最近一次真实提交）或「最高成绩」（best_score），
                // 并附最高分与考试次数。
                // 注意：include_temp_save 开启时 attempts_list 可能含暂存草稿，取最新成绩应跳过 temp_save，
                // 否则导出的"最新成绩"可能是一份草稿分。
                $all = [];
                foreach ($rows as $r) {
                    $list = array_values((array)($r['attempts_list'] ?? []));
                    $last = null;
                    for ($i = count($list) - 1; $i >= 0; $i--) {
                        if (empty($list[$i]['temp_save'])) {
                            $last = $list[$i];
                            break;
                        }
                    }
                    if ($last === null && $list !== []) {
                        $last = $list[count($list) - 1]; // 全是暂存时退回最后一份
                    }
                    // best 口径：优先用聚合行 best_score；缺失时从 attempts_list 现算，
                    // 保证「最高成绩」列与代表成绩一致（避免出现"最高分比成绩还低"的怪表）。
                    $bestScore = $r['best_score'] ?? null;
                    if ($rowScoreMode === 'best') {
                        if ($bestScore === null || $bestScore === '') {
                            foreach ($list as $a) {
                                $sv = $a['score'] ?? null;
                                if ($sv === null || $sv === '') {
                                    continue;
                                }
                                if ($bestScore === null || (float)$sv > (float)$bestScore) {
                                    $bestScore = $sv;
                                }
                            }
                        }
                    }
                    // 最高分所在那次（用于「提交时间 / 时长」跟随口径，避免最高分配了别次的耗时）
                    $bestRow = null;
                    if ($rowScoreMode === 'best' && $bestScore !== null && $bestScore !== '') {
                        foreach ($list as $a) {
                            if ((string)($a['score'] ?? '') === (string)$bestScore) {
                                $bestRow = $a;
                                break;
                            }
                        }
                    }
                    $useRow = ($rowScoreMode === 'best') ? ($bestRow ?: $last) : $last;
                    $all[] = [
                        'sid'          => (string)($r['sid'] ?? ''),
                        'name'         => (string)($r['name'] ?? ''),
                        'cls'          => (string)($r['cls'] ?? ''),
                        'grp'          => (string)($r['grp'] ?? ''),
                        'score'        => ($rowScoreMode === 'best')
                            ? (($bestScore === null || $bestScore === '') ? null : $bestScore)
                            : ($useRow !== null ? ($useRow['score'] ?? null) : ($r['score'] ?? null)),
                        'best_score'   => $bestScore,
                        'attempts'     => (int)($r['attempts'] ?? 1),
                        'idx'          => (int)($r['attempts'] ?? 1),
                        'submit_ts'    => ($useRow !== null && isset($useRow['submit_ts']))
                            ? (int)$useRow['submit_ts']
                            : (int)($r['last_submit_ts'] ?? 0),
                        'submit_at'    => (string)($useRow['submit_at'] ?? ($r['last_submit_at'] ?? ($r['submit_at'] ?? '-'))),
                        'duration_txt' => (string)($useRow['duration_txt'] ?? ($r['duration_txt'] ?? '-')),
                        'duration'     => $useRow['duration'] ?? ($r['duration'] ?? null),
                    ];
                }
                if ($sortMode === 'score_desc' || $sortMode === 'score_asc') {
                    $all = ny_sort_by_score($all, $sortMode === 'score_desc');
                } else {
                    $all = DataService::sortForExport($all, ($sortMode === 'sid') ? 'sid' : 'time');
                }
            } else {
                // 每次考试一行（同一学号考了 N 次就有 N 行）
                $all = DataService::expandAttempts($rows, true);
                if ($skipTemp) {
                    $all = array_values(array_filter($all, static fn(array $r): bool => empty($r['temp_save'])));
                }
                if ($sortMode === 'score_desc' || $sortMode === 'score_asc') {
                    $all = ny_sort_by_score($all, $sortMode === 'score_desc');
                } else {
                    $all = DataService::sortForExport($all, ($sortMode === 'sid') ? 'sid' : 'time');
                }
            }

            // 合格线：本卷满分 × 合格率（0 表示本卷没配满分，不判定合格）
            [$effFs, $effPr] = ny_resolve_score_cfg($projectId, $c);
            $passLineVal = ($effFs > 0 && $effPr > 0) ? ($effFs * $effPr / 100.0) : 0.0;
            $scoreColIdx = array_search('score', $cols, true);

            // ---------------- 组装工作表 ----------------
            // 出表方式 = 「每次考试一行」时，成绩达合格线的行标绿底（与多考试块表的口径一致）。
            // $marks 每次调用先重置，因此分班级多工作表时各表的标记不会串到别的表里。
            $marks = [];
            $toRows = static function (array $list) use ($cols, $colLabels, $mode, $passLineVal, $scoreColIdx, &$marks): array {
                $marks = [];
                $head  = [];
                foreach ($cols as $c) {
                    $head[] = $colLabels[$c];
                }
                $out = [$head];
                $rn  = 1;                       // 工作表内行号（1-based，与 cell_styles 一致）
                foreach ($list as $r) {
                    $rn++;
                    $line = [];
                    foreach ($cols as $i => $c) {
                        $v = $r[$c] ?? null;
                        $line[] = ($v === null || $v === '') ? '' : (string)$v;
                        if ($i === $scoreColIdx && $mode !== 'latest' && $passLineVal > 0
                            && $v !== null && $v !== '' && is_numeric($v) && (float)$v >= $passLineVal) {
                            $marks[$rn . ',' . ($i + 1)] = 'green';
                        }
                    }
                    $out[] = $line;
                }
                return $out;
            };
            $widths = [];
            foreach ($cols as $c) {
                $widths[] = in_array($c, ['sid', 'submit_at'], true) ? 20 : ($c === 'name' ? 14 : 11);
            }

            $sheets = [];
            if ($action === 'export_absent') {
                $sheets[] = ['name' => '缺考名单', 'rows' => ny_absent_sheet_rows($absent), 'widths' => [16, 14, 16, 10]];
            } else {
                if ($splitCls) {
                    // 按班级分表（班级名即工作表名）
                    $byCls = [];
                    foreach ($all as $r) {
                        $byCls[trim((string)($r['cls'] ?? '')) ?: '（未分班）'][] = $r;
                    }
                    ksort($byCls, SORT_NATURAL | SORT_FLAG_CASE);
                    foreach ($byCls as $clsName => $list) {
                        $sheets[] = [
                            'name'        => (string)$clsName,
                            'rows'        => $toRows($list),
                            'widths'      => $widths,
                            'cell_styles' => $marks,
                        ];
                    }
                } else {
                    $sheets[] = [
                        'name'        => $isLatest ? ($rowScoreMode === 'best' ? '成绩明细(最高)' : '成绩明细(最新)') : '成绩明细',
                        'rows'        => $toRows($all),
                        'widths'      => $widths,
                        'cell_styles' => $marks,
                    ];
                }
                // 附加：缺考名单 / 未匹配答卷（仅非空时输出）
                // noAbsent=1 时不附缺考名单（"成绩明细只导成绩"的场景）
                $noAbsent = !empty($_GET['noAbsent']) || !empty($_GET['no_absent']);
                if ($absent !== [] && !$noAbsent) {
                    $sheets[] = ['name' => '缺考名单', 'rows' => ny_absent_sheet_rows($absent), 'widths' => [16, 14, 16, 10]];
                }
                $unmatched = array_values((array)($result['unmatched'] ?? []));
                if ($unmatched !== []) {
                    $um = [['姓名', '成绩', '提交时间']];
                    foreach ($unmatched as $u) {
                        $um[] = [
                            (string)($u['name'] ?? ''),
                            ($u['score'] ?? null) === null ? '' : (string)$u['score'],
                            (string)($u['submit_at'] ?? ''),
                        ];
                    }
                    $sheets[] = ['name' => '未匹配答卷', 'rows' => $um, 'widths' => [16, 10, 20]];
                }
            }

            /* format=json：不下载文件，直接回传装配结果。
               「打印成绩明细 / 打印缺考名单」走的就是这条，前端拿它渲染打印视图；
               否则前端会拿到 xlsx 二进制再 res.json()，报 "Unexpected token 'P'"。
               缺考名单工作表也在 $sheets 里，所以勾选「附缺考名单」时打印同样看得到。 */
            if (in_array($action, ['export', 'export_absent'], true)
                && (string)($_GET['format'] ?? '') === 'json') {
                ny_ok([
                    'sheets' => $sheets,
                    'meta'   => [
                        'projectName' => (string)($result['project']['name'] ?? ''),
                        'passLine'    => $passLineVal,
                        'passRate'    => $effPr,
                        'fullScore'   => $effFs,
                    ],
                ]);
            }

            // 说明：所有单元格按「共享字符串 + 文本格式」写入，
            // 既不会把长学号变成科学计数法，也不会把 = + - @ 开头的内容当公式执行（规避 CSV 公式注入）
            $bin = XlsxWriter::renderMulti($sheets);

            header('Content-Type: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet');
            header('Content-Disposition: attachment; filename="export.xlsx"; filename*=UTF-8\'\'' . rawurlencode($filename));
            header('Content-Length: ' . strlen($bin));
            header('Cache-Control: no-store');
            echo $bin;
            exit;

        // ---------------- 多考试对比导出（横向交叉表） ----------------
        case 'export_multi':
            $idsRaw = (string)($_GET['projectIds'] ?? '');
            $ids = array_values(array_unique(array_filter(
                array_map('trim', explode(',', $idsRaw)),
                static fn($v): bool => $v !== ''
            )));
            if ($ids === []) {
                ny_fail('请至少选择一个问卷 / 考试');
            }
            $nameQid   = (string)($_GET['nameQid'] ?? '');
            $scoreMode = ((string)($_GET['scoreMode'] ?? '') === 'highest') ? 'highest' : 'latest';
            $c = cfg();

            // 班级 / 组别筛选（支持多选，逗号分隔；空 = 全部），与单考试导出口径一致
            $multiVals = static function (string $raw): array {
                return array_values(array_unique(array_filter(
                    array_map('trim', explode(',', $raw)),
                    static function ($v): bool { return $v !== ''; }
                )));
            };
            $clsPick = $multiVals((string)($_GET['cls'] ?? ''));
            $grpPick = $multiVals((string)($_GET['grp'] ?? ''));
            $hit = static function (array $r) use ($clsPick, $grpPick): bool {
                if ($clsPick !== [] && !in_array(trim((string)($r['cls'] ?? '')), $clsPick, true)) {
                    return false;
                }
                if ($grpPick !== [] && !in_array(trim((string)($r['grp'] ?? '')), $grpPick, true)) {
                    return false;
                }
                return true;
            };

            // 逐场考试取数（复用与 data 接口相同的缓存），按选择顺序组装交叉矩阵
            $exams     = [];
            $seenCls   = [];
            $seenGrp   = [];
            foreach ($ids as $pid) {
                $built  = ny_build_data($c, $pid, $nameQid, !empty($_GET['force']));
                $result = $built['result'];
                $rows   = array_values(array_filter((array)($result['rows'] ?? []), $hit));
                foreach ($rows as $r) {
                    $cv = trim((string)($r['cls'] ?? ''));
                    $gv = trim((string)($r['grp'] ?? ''));
                    if ($cv !== '') { $seenCls[$cv] = true; }
                    if ($gv !== '') { $seenGrp[$gv] = true; }
                }
                $exams[$pid] = [
                    'name' => (string)($result['project']['name'] ?? $pid),
                    'rows' => $rows,
                ];
            }

            // 导出形态：
            //   block   = 两行表头的「每次考试」块表（默认；需求截图版式）
            //   summary = 成绩对比（一行一个学生、一列一场考试，取最新 / 最高）
            //   both    = 块表 + 成绩对比，一次出
            // 兼容旧参数：matrix→summary、merged / attempts→block
            $modeRaw = (string)($_GET['mode'] ?? '');
            $modeMap = [
                'summary'  => 'summary',
                'matrix'   => 'summary',
                'block'    => 'block',
                'merged'   => 'block',
                'attempts' => 'block',
                'att'      => 'block',
                'both'     => 'both',
            ];
            $mode = $modeMap[$modeRaw] ?? 'block';

            // 每次考试明细默认跳过暂存草稿（草稿不是有效成绩）；includeTemp=1 可保留
            $includeTemp = !empty($_GET['includeTemp']) || !empty($_GET['include_temp']);

            // 合格线 / 合格次数阈值：用于「合格次数」行（达标绿底）与最高分标红
            // 合格线 = 每场考试各自的满分 × 合格率；判「合格次数」时按各场分别算，
            // 因此这里逐场解析（本卷独立配置优先，其次全局默认）。
            $passTimesIn = $_GET['passTimes'] ?? null;
            $passTimes   = ($passTimesIn === null || $passTimesIn === '') ? 1 : max(1, (int)$passTimesIn);
            $markBest    = !array_key_exists('markBest', $_GET) || !empty($_GET['markBest']);
            $passRow     = !array_key_exists('passRow', $_GET) || !empty($_GET['passRow']);

            // 每场考试的合格线（pid => float），随 $exams 一起传进装配函数
            $passLineOf  = [];
            foreach ($ids as $pid) {
                [$fsP, $prP] = ny_resolve_score_cfg($pid, $c);
                $passLineOf[$pid] = round($fsP * $prP / 100, 4);
            }

            // 班级 / 组别列：选了多班级 / 多组别才补出（只选 1 个班级且未选组别 → 两列都不出）
            $colFlags = ny_multi_col_flags($clsPick, $grpPick, array_keys($seenCls), array_keys($seenGrp));
            if (array_key_exists('withCls', $_GET)) {
                $colFlags['with_cls'] = !empty($_GET['withCls']);
            }
            if (array_key_exists('withGrp', $_GET)) {
                $colFlags['with_grp'] = !empty($_GET['withGrp']);
            }

            // 单场 + 明细列不含耗时/时间 → 走「宽表」版式（学号|姓名|第1次…第N次|合格次数），
            // 与需求截图二一致；带了耗时/时间则每人一行放不下，退回两行表头块表。
            $wantWide = !empty($_GET['wide']);

            $sheets = [];
            $block  = null;
            if ($mode === 'block' || $mode === 'both') {
                if ($wantWide && count($ids) === 1) {
                    $pid    = $ids[0];
                    $widRes = ny_assemble_attempt_wide_sheet($exams[$pid], [
                        'skip_temp' => !$includeTemp,
                        'pass_line' => $passLineOf[$pid],
                        'pass_times'=> $passTimes,
                        'mark_best' => $markBest,
                        'pass_row'  => $passRow,
                    ]);
                    $sheets[] = [
                        'name'         => '每次考试',
                        'rows'         => $widRes['rows'],
                        'widths'       => $widRes['widths'],
                        'merges'       => $widRes['merges'],
                        'header_rows'  => $widRes['header_rows'],
                        'cell_styles'  => $widRes['cell_styles'],
                    ];
                    $block = $widRes;
                } else {
                    // 多场：各场合格线可能不同，装配函数按「单条合格线」设计，
                    // 这里取各场合格线中的最低值作为汇总口径（避免把某场算得过严），
                    // 并在 meta 里回报每场各自的合格线供前端说明。
                    $lines = array_values($passLineOf);
                    $minLine = $lines === [] ? null : min($lines);
                    $block = ny_assemble_block_sheet($exams, [
                        'skip_temp'  => !$includeTemp,
                        'with_cls'   => $colFlags['with_cls'],
                        'with_grp'   => $colFlags['with_grp'],
                        'pass_line'  => $passRow ? $minLine : null,
                        'pass_times' => $passTimes,
                        'mark_best'  => $markBest,
                        'pass_row'   => $passRow,
                    ]);
                    $sheets[] = [
                        'name'        => '每次考试',
                        'rows'        => $block['rows'],
                        'widths'      => $block['widths'],
                        'merges'      => $block['merges'],
                        'header_rows' => $block['header_rows'],
                        'cell_styles' => $block['cell_styles'],
                    ];
                }
            }
            if ($mode === 'summary' || $mode === 'both') {
                $matrix    = ny_assemble_multi_exam_matrix($exams, $scoreMode);
                $sheetRows = array_merge([$matrix['head']], $matrix['rows']);
                $widths    = array_merge([20, 14], array_fill(0, count($matrix['exam_order']), 12));
                $sheets[]  = ['name' => '成绩对比', 'rows' => $sheetRows, 'widths' => $widths, 'header_rows' => 1];
            }
            if ($sheets === []) {
                $sheets[] = ['name' => '每次考试', 'rows' => [['暂无数据']], 'widths' => [12], 'header_rows' => 1];
            }

            /* 附缺考名单：与单考试导出同一口径——「名单里有、答卷里没有」即为缺考。
               多考试场景取「所选考试全都没交」才算缺考（某场没交但在别场交过的人
               已在块表里以「未考」体现，再列进缺考名单属于重复噪音）。 */
            $noAbsent = !empty($_GET['noAbsent']) || !empty($_GET['no_absent']);
            if (!$noAbsent) {
                $roster = Roster::all();
                // 逐场收集「已提交学号」，取并集：某场没交但在别场交过的人
                // 已在块表里以「未考」体现，不再重复列进缺考名单
                $submittedAny = [];
                foreach ($exams as $ex) {
                    foreach ((array)($ex['rows'] ?? []) as $r) {
                        $sidR = trim((string)($r['sid'] ?? ''));
                        if ($sidR !== '') {
                            $submittedAny[$sidR] = true;
                        }
                    }
                }
                $absentRows = [];
                foreach ($roster as $s) {
                    $sidR = trim((string)($s['sid'] ?? ''));
                    if ($sidR === '' || isset($submittedAny[$sidR])) {
                        continue;
                    }
                    if (!$hit($s)) {
                        continue;   // 跟随班级 / 组别筛选
                    }
                    $absentRows[] = $s;
                }
                if ($absentRows !== []) {
                    $sheets[] = [
                        'name'   => '缺考名单',
                        'rows'   => ny_absent_sheet_rows($absentRows),
                        'widths' => [16, 14, 16, 10],
                    ];
                }
            }

            $safe     = static fn(string $s): string => preg_replace('/[\\\\\\/:*?"<>|]/u', '_', $s) ?? '';
            $stamp    = date('Ymd_His');
            // 文件名带上筛选范围，便于分辨"这次导的是哪个班"
            $scopeTag = ($clsPick !== [] ? '_' . $safe(implode('+', array_slice($clsPick, 0, 3)) . (count($clsPick) > 3 ? '等' : '')) : '')
                . ($grpPick !== [] ? '_' . $safe(implode('+', array_slice($grpPick, 0, 3)) . (count($grpPick) > 3 ? '等' : '')) : '');
            if ($mode === 'block') {
                $filename = '每次考试_' . count($ids) . '场' . $scopeTag . '_' . $stamp . '.xlsx';
            } elseif ($mode === 'both') {
                $filename = '每次考试与成绩对比_' . count($ids) . '场' . $scopeTag . '_' . $stamp . '.xlsx';
            } else {
                $filename = '多考试成绩对比_' . count($ids) . '场' . $scopeTag . '_'
                    . ($scoreMode === 'highest' ? '最高分' : '最新成绩') . '_' . $stamp . '.xlsx';
            }

            // format=json：把同一套装配结果原样交给前端——「多考试打印」用它渲染 HTML，
            // 保证打印版式与导出的 Excel 完全一致（同一份逻辑，不在前端重写排版规则）
            if ((string)($_GET['format'] ?? '') === 'json') {
                $examNames = [];
                foreach ($exams as $pid => $ex) {
                    $examNames[] = (string)($ex['name'] ?? $pid);
                }
                ny_ok([
                    'sheets'   => $sheets,
                    'filename' => $filename,
                    'meta'     => [
                        'mode'      => $mode,
                        'wide'      => ($wantWide && count($ids) === 1),
                        'examCount' => count($ids),
                        'examNames' => $examNames,
                        'cls'       => $clsPick,
                        'grp'       => $grpPick,
                        'scoreMode' => $scoreMode,
                        'with_cls'  => $colFlags['with_cls'],
                        'with_grp'  => $colFlags['with_grp'],
                        'students'  => ($block !== null ? $block['students'] : null),
                        'rows'      => ($block !== null ? $block['total_rows'] : null),
                        // 合格口径：前端据此在打印说明里写清楚"合格线几分、几次算通过"
                        'pass_row'   => ($block !== null ? !empty($block['pass_row']) : false),
                        'pass_times' => $passTimes,
                        'pass_lines' => $passLineOf,
                    ],
                ]);
            }

            $bin = XlsxWriter::renderMulti($sheets);

            header('Content-Type: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet');
            header('Content-Disposition: attachment; filename="export.xlsx"; filename*=UTF-8\'\'' . rawurlencode($filename));
            header('Content-Length: ' . strlen($bin));
            header('Cache-Control: no-store');
            echo $bin;
            exit;

        // ---------------- 随机抽取：导出白名单（xlsx，列：姓名 / 登陆账号） ----------------
        case 'draw_export':
            $raw = ny_request_body();
            $in  = json_decode($raw, true);
            if (!is_array($in)) {
                $in = $_POST + $_GET;
            }
            // type=import → 白名单导入模板.xlsx；type=list → 白名单列表.xlsx
            $type    = (($in['type'] ?? '') === 'import') ? 'import' : 'list';
            $members = [];
            foreach ((array)($in['members'] ?? []) as $m) {
                if (!is_array($m)) {
                    continue;
                }
                $name  = trim((string)($m['name'] ?? ''));
                // 登陆账号优先（名单导入的"登陆账号"列），没有则回退学号
                $acct  = trim((string)($m['login'] ?? ''));
                $sid   = trim((string)($m['sid'] ?? ''));
                if ($name === '' && $acct === '' && $sid === '') {
                    continue;
                }
                $members[] = [$name, $acct !== '' ? $acct : $sid];
            }
            $bin = XlsxWriter::render(
                array_merge([['姓名', '登陆账号']], $members),
                ['widths' => [16, 24], 'title' => '白名单']
            );
            $filename = $type === 'import' ? '白名单导入模板.xlsx' : '白名单列表.xlsx';
            header('Content-Type: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet');
            header('Content-Disposition: attachment; filename="whitelist.xlsx"; filename*=UTF-8\'\'' . rawurlencode($filename));
            header('Content-Length: ' . strlen($bin));
            header('Cache-Control: no-store');
            echo $bin;
            exit;

        default:
            ny_fail('未知操作：' . $action);
    }
} catch (Throwable $e) {
    $msg = $e->getMessage();
    // 鉴权类错误（账号未配置 / 登录卷王失败）打标，前端据此跳登录页自愈
    $isAuth = str_contains($msg, '未配置卷王登录账号')
        || str_contains($msg, '登录卷王失败')
        || str_contains($msg, '登录失败');
    // 鉴权失败时回传落盘诊断（账号到底有没有存住、data 目录可不可写），
    // 否则前端只能给出"账号未配置"这一句空话，用户无法自查，也容易陷入反复跳登录页。
    ny_fail($msg, [
        'auth'  => $isAuth,
        'diag'  => $isAuth ? ny_config_diag() : null,
        'trace' => defined('NY_DEBUG') && NY_DEBUG ? $e->getTraceAsString() : null,
    ]);
}