<?php
/**
 * GET /api/teacher/live-status?classId=42&sinceId=0
 *
 * Polling-Variante des Live-Dashboards. Liefert pro Schüler*in den
 * neuesten Telemetry-Stand der letzten 5 Min plus alle Events
 * mit id > sinceId.
 *
 * Lehrer-Cockpit pollt alle 3s. Robuster als SSE auf XAMPP-Apache.
 */
declare(strict_types=1);
require_once __DIR__ . '/../../bootstrap.php';

v2_validate_method('GET');
$auth = v2_auth_require('teacher');
$teacherId = (int) ($auth['sub'] ?? 0);
$classId = (int) ($_GET['classId'] ?? 0);
$sinceId = (int) ($_GET['sinceId'] ?? 0);

if (!$classId) v2_response_error(400, 'missing_classId', 'classId fehlt.');

$own = v2_db_one('SELECT id FROM classes WHERE id = :c AND teacher_id = :t',
    [':c' => $classId, ':t' => $teacherId]);
if (!$own) v2_response_error(403, 'forbidden', 'Klasse nicht deine.');

// Pro Schüler*in das jüngste Event (für Status-Cards)
$status = v2_db_all("
    SELECT t.student_id, t.module_slug, t.event_type, t.phase, t.phase_label,
           t.step, t.current_score, t.score_max, t.idle_s, t.ts,
           s.display_name, s.username, s.avatar_slug, s.nachteilsausgleich
    FROM telemetry_events_v2 t
    JOIN (
        SELECT student_id, MAX(id) AS max_id
        FROM telemetry_events_v2
        WHERE class_id = :cid AND ts > NOW() - INTERVAL 5 MINUTE
        GROUP BY student_id
    ) latest ON latest.max_id = t.id
    JOIN students s ON s.id = t.student_id
    ORDER BY s.display_name, s.username
", [':cid' => $classId]);

// Neue Events seit sinceId (für Event-Feed)
$newEvents = v2_db_all("
    SELECT id, student_id, module_slug, event_type, phase, phase_label,
           milestone_id, milestone_label, idle_s, ts
    FROM telemetry_events_v2
    WHERE class_id = :cid AND id > :since
    ORDER BY id ASC
    LIMIT 100
", [':cid' => $classId, ':since' => $sinceId]);

$maxId = $sinceId;
foreach ($newEvents as $e) {
    if ((int) $e['id'] > $maxId) $maxId = (int) $e['id'];
}

v2_response_ok([
    'studentStatus' => array_map(fn($r) => [
        'studentId' => (int) $r['student_id'],
        'displayName' => $r['display_name'] ?? $r['username'],
        'avatarSlug' => $r['avatar_slug'],
        'nachteilsausgleich' => (bool) $r['nachteilsausgleich'],
        'moduleSlug' => $r['module_slug'],
        'eventType' => $r['event_type'],
        'phase' => $r['phase'],
        'phaseLabel' => $r['phase_label'],
        'step' => $r['step'],
        'currentScore' => $r['current_score'] !== null ? (int) $r['current_score'] : null,
        'scoreMax' => $r['score_max'] !== null ? (int) $r['score_max'] : null,
        'idleS' => $r['idle_s'] !== null ? (int) $r['idle_s'] : null,
        'lastTs' => $r['ts'],
        'isStuck' => $r['event_type'] === 'stuck',
    ], $status),
    'newEvents' => $newEvents,
    'maxId' => $maxId,
]);