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

require __DIR__ . '/bootstrap.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;
}

/**
 * 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(),
    ]);

    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
    }

    $result = DataService::build($c, $projectId, $nameQid);
    if ($ttl > 0) {
        DataCache::write($key, $result);
    }
    DataCache::releaseLock($lock);

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

// 会话保护：除 auth_check 外，未登录一律拒访
if ($action !== 'auth_check' && !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）
$WRITE_ACTIONS = [
    'config_save', 'roster_save', 'roster_import', 'roster_clear',
    'snapshot_save', 'snapshot_delete', 'unmatched_map',
];
if (in_array($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();
            $c['db_error']      = class_exists('Db') ? Db::lastError() : '';
            ny_ok($c);

        case 'config_save':
            $raw = (string)file_get_contents('php://input');
            $in  = json_decode($raw, true);
            if (!is_array($in)) {
                $in = $_POST;
            }
            $old = cfg();
            $allowed = ['base_url', 'api_prefix', 'username', 'timeout', 'refresh_interval', 'page_size', 'name_keywords', 'history_display', 'export_sort'];
            $new = $old;
            foreach ($allowed as $k) {
                if (array_key_exists($k, $in)) {
                    $new[$k] = is_string($in[$k]) ? trim((string)$in[$k]) : $in[$k];
                }
            }
            // 密码：保留首尾空格的原貌，空 / 占位符 = 不修改
            if (array_key_exists('password', $in)) {
                $pwdIn = (string)$in['password'];
                if ($pwdIn !== '' && $pwdIn !== '******') {
                    $new['password'] = $pwdIn;
                }
            }
            foreach (['verify_ssl', 'include_temp_save', 'dedupe'] as $k) {
                if (array_key_exists($k, $in)) {
                    $new[$k] = filter_var($in[$k], FILTER_VALIDATE_BOOL);
                }
            }
            // 布局配置
            if (array_key_exists('layout', $in)) {
                $new['layout'] = ($in['layout'] === 'side') ? 'side' : 'default';
            }
            // 历史成绩展示方式：click（点击成员弹窗，默认） / inline（明细内全部展开）
            if (array_key_exists('history_display', $in)) {
                $new['history_display'] = ($in['history_display'] === 'inline') ? 'inline' : 'click';
            }
            // 成绩导出排序：time（按提交时间降序，默认）/ sid（按学号）/ score_desc（成绩降序）/ score_asc（成绩升序）
            if (array_key_exists('export_sort', $in)) {
                $v = (string)$in['export_sort'];
                $new['export_sort'] = in_array($v, ['time','sid','score_desc','score_asc'], true) ? $v : 'time';
            }
            // 各试卷独立满分（覆盖整个 full_scores 映射）
            if (array_key_exists('full_scores', $in) && is_array($in['full_scores'])) {
                $new['full_scores'] = $in['full_scores'];
            }
            $new['base_url']   = rtrim((string)$new['base_url'], '/');
            $new['api_prefix'] = '/' . trim((string)$new['api_prefix'], '/');
            $new['timeout']    = (int)$new['timeout'];
            $new['refresh_interval'] = (int)$new['refresh_interval'];
            if ($new['refresh_interval'] < 3) {
                $new['refresh_interval'] = 3;
            }
            // 默认满分
            $fs = (int)($in['full_score'] ?? $new['full_score'] ?? 100);
            if ($fs < 1) {
                $fs = 100;
            }
            $new['full_score'] = $fs;
            // 各试卷独立满分：仅当显式指定 apply_pid 时才写入/清除该卷（修复 bug：之前会误用默认满分覆盖当前卷）
            $applyPid = trim((string)($in['apply_pid'] ?? ''));
            if ($applyPid !== '') {
                $scores = is_array($new['full_scores'] ?? null) ? $new['full_scores'] : [];
                $applyScore = (int)($in['apply_score'] ?? 0);
                if ($applyScore > 0) {
                    $scores[$applyPid] = $applyScore;
                } else {
                    unset($scores[$applyPid]);
                }
                $new['full_scores'] = $scores;
            }
            // 仅当连接信息真的变了才清 token + 重连；保存满分/布局等不应触发登录卷王
            $connKeys = ['base_url', 'api_prefix', 'username', 'password', 'verify_ssl'];
            $connChanged = false;
            foreach ($connKeys as $k) {
                if ((string)($old[$k] ?? '') !== (string)($new[$k] ?? '')) {
                    $connChanged = true;
                    break;
                }
            }
            ny_save_config($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 = (string)file_get_contents('php://input');
            $in  = json_decode($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'];
            $fsMap = is_array($c['full_scores'] ?? null) ? $c['full_scores'] : [];
            $fs = isset($fsMap[$projectId]) ? (int)$fsMap[$projectId] : (int)($c['full_score'] ?? 100);
            if ($fs < 1) {
                $fs = 100;
            }
            $result['config'] = [
                'refresh_interval'  => (int)$c['refresh_interval'],
                'base_url'          => $c['base_url'],
                'full_score'        => $fs,
            ];
            // 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'];
            $fsMap = is_array($c['full_scores'] ?? null) ? $c['full_scores'] : [];
            $fs = isset($fsMap[$projectId]) ? (int)$fsMap[$projectId] : (int)($c['full_score'] ?? 100);
            if ($fs < 1) {
                $fs = 100;
            }

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

            $byCls = [];
            foreach ($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
            $statOf = static function (array $stu, array $rs, int $fs): 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'] >= 0.6 * $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']);
            });

            ny_ok([
                'project'    => $result['project'],
                'full_score' => $fs,
                'overall'    => $result['stats'],
                'classes'    => $classes,
                'updated_at' => $result['updated_at'],
            ]);

        // ---------------- 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'];
            $ext  = strtolower(pathinfo((string)$f['name'], PATHINFO_EXTENSION));
            $dest = NY_DATA . '/uploads/roster_' . date('Ymd_His') . '.' . ($ext !== '' ? $ext : 'dat');
            if (!@move_uploaded_file($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());
            }
            $mode = (string)($_POST['mode'] ?? 'replace');
            if ($mode === 'append') {
                $merged = array_merge(Roster::all(), $res['students']);
                Roster::save($merged);
            } else {
                Roster::save($res['students']);
            }
            ny_ok([
                'students'   => Roster::all(),
                'meta'       => Roster::meta(),
                'imported'   => $res['count'],
                'skipped'    => $res['skipped'] ?? 0,
                'duplicates' => $res['duplicates'] ?? 0,
            ]);

        case 'roster_save':
            $raw = (string)file_get_contents('php://input');
            $in  = json_decode($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'] ?? '')),
                ];
            }
            Roster::save($students);
            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 = (string)file_get_contents('php://input');
            $in  = json_decode($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' => $login];
            }
            Roster::save($roster);
            ny_ok(['students' => Roster::all(), 'meta' => Roster::meta(), 'mapped' => $name]);

        // ---------------- 成绩快照 / 趋势 ----------------
        case 'snapshot_save':
            $projectId = (string)($_GET['projectId'] ?? $_POST['projectId'] ?? '');
            if ($projectId === '') {
                ny_fail('请先选择问卷/考试');
            }
            $raw = (string)file_get_contents('php://input');
            $in  = json_decode($raw, true);
            if (!is_array($in)) {
                $in = $_POST;
            }
            $label = trim((string)($in['label'] ?? ''));
            // 复用缓存构建（不强制，快照本就是"当前看到的成绩"）
            $c      = cfg();
            $nameQid = (string)($_GET['nameQid'] ?? '');
            $built  = ny_build_data($c, $projectId, $nameQid);
            $snap   = Snapshot::summarize($built['result'], $label);
            $file   = Snapshot::save($projectId, $snap);
            ny_ok(['file' => $file, 'label' => $snap['label'], 'at_txt' => $snap['at_txt'], 'count' => count($snap['students'])]);

        case 'snapshot_list':
            $projectId = (string)($_GET['projectId'] ?? '');
            if ($projectId === '') {
                ny_fail('请先选择问卷/考试');
            }
            ny_ok(['snapshots' => Snapshot::list($projectId)]);

        case 'snapshot_delete':
            $projectId = (string)($_GET['projectId'] ?? $_POST['projectId'] ?? '');
            $raw = (string)file_get_contents('php://input');
            $in  = json_decode($raw, true);
            if (!is_array($in)) {
                $in = $_POST;
            }
            $file = (string)($in['file'] ?? '');
            if ($projectId === '' || $file === '') {
                ny_fail('参数错误');
            }
            ny_ok(['deleted' => Snapshot::delete($projectId, $file)]);

        case 'snapshot_trend':
            $projectId = (string)($_GET['projectId'] ?? '');
            if ($projectId === '') {
                ny_fail('请先选择问卷/考试');
            }
            // 支持跨项目对比：projectId 可用逗号分隔多个项目，取各自快照混合趋势
            $pids = array_values(array_filter(array_map('trim', explode(',', $projectId))));
            $snaps = [];
            foreach ($pids as $pid) {
                foreach (Snapshot::list($pid) as $s) {
                    $full = Snapshot::get($pid, $s['file']);
                    if ($full !== null) {
                        $snaps[] = $full;
                    }
                }
            }
            ny_ok(Snapshot::trend($snaps));

        // ---------------- 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');
            $filename = ($action === 'export_absent' ? '缺考名单' : '成绩明细')
                . '_' . $safe((string)$result['project']['name'])
                . $tag
                . ($isLatest ? '_最新成绩' : '')
                . '_' . 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 ? '最新成绩' : '成绩',
                'best_score'   => '最高分',
                'attempts'     => '考试次数',
                'idx'          => '第几次',
                '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', 'attempts', 'idx', '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：成绩取「最近一次提交」的分数（不受 dedupe 影响），并附最高分与考试次数
                $all = [];
                foreach ($rows as $r) {
                    $list = array_values((array)($r['attempts_list'] ?? []));
                    $last = $list !== [] ? $list[count($list) - 1] : null;
                    $all[] = [
                        'sid'          => (string)($r['sid'] ?? ''),
                        'name'         => (string)($r['name'] ?? ''),
                        'cls'          => (string)($r['cls'] ?? ''),
                        'grp'          => (string)($r['grp'] ?? ''),
                        'score'        => $last !== null ? ($last['score'] ?? null) : ($r['score'] ?? null),
                        'best_score'   => $r['best_score'] ?? null,
                        'attempts'     => (int)($r['attempts'] ?? 1),
                        'idx'          => (int)($r['attempts'] ?? 1),
                        'submit_ts'    => (int)($r['last_submit_ts'] ?? 0),
                        'submit_at'    => (string)($r['last_submit_at'] ?? ($last['submit_at'] ?? ($r['submit_at'] ?? '-'))),
                        'duration_txt' => (string)($last['duration_txt'] ?? ($r['duration_txt'] ?? '-')),
                        'duration'     => $last['duration'] ?? ($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 ($sortMode === 'score_desc' || $sortMode === 'score_asc') {
                    $all = ny_sort_by_score($all, $sortMode === 'score_desc');
                } else {
                    $all = DataService::sortForExport($all, ($sortMode === 'sid') ? 'sid' : 'time');
                }
            }

            // ---------------- 组装工作表 ----------------
            $toRows = static function (array $list) use ($cols, $colLabels): array {
                $head = [];
                foreach ($cols as $c) {
                    $head[] = $colLabels[$c];
                }
                $out = [$head];
                foreach ($list as $r) {
                    $line = [];
                    foreach ($cols as $c) {
                        $v = $r[$c] ?? null;
                        $line[] = ($v === null || $v === '') ? '' : (string)$v;
                    }
                    $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];
                    }
                } else {
                    $sheets[] = ['name' => $isLatest ? '成绩明细(最新)' : '成绩明细', 'rows' => $toRows($all), 'widths' => $widths];
                }
                // 附加：缺考名单 / 未匹配答卷（仅非空时输出）
                if ($absent !== []) {
                    $sheets[] = ['name' => '缺考名单', 'rows' => ny_absent_sheet_rows($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]];
                }
            }

            // 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;

        // ---------------- 随机抽取：导出白名单（xlsx，列：姓名 / 登陆账号） ----------------
        case 'draw_export':
            $raw = (string)file_get_contents('php://input');
            $in  = json_decode($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');
    ny_fail($msg, [
        'auth'  => $isAuth,
        'trace' => defined('NY_DEBUG') && NY_DEBUG ? $e->getTraceAsString() : null,
    ]);
}