<?php
/**
 * API: Modulfreigabe (Klasse + individuell pro Schüler)
 * GET  /api/modules?class_id=X              → Modulstatus für Klasse
 * GET  /api/modules?class_id=X&matrix=1     → Matrix: alle Schüler × alle Module
 * POST /api/modules {action}                → Modul freigeben/sperren
 *
 * Bootstrap: idempotent, damit auch direkter /php/api/modules.php-Aufruf funktioniert
 * (live-client.js pollt von der Sim aus diesen Direkt-Pfad).
 */
require_once __DIR__ . '/../config/app.php';
require_once __DIR__ . '/../lib/Database.php';
require_once __DIR__ . '/../lib/Session.php';
require_once __DIR__ . '/../lib/Response.php';

$method = $_SERVER['REQUEST_METHOD'];
$db = Database::get();

// Default-Modus für eine Klasse OHNE expliziten Eintrag: eine neue Klasse startet
// mit NUR Weltküche frei (Einstiegs-Sim), alles andere gesperrt. Die Lehrperson
// gibt weitere Module über die Freigabe-Matrix frei.
function _defaultMode($moduleId) { return $moduleId === 'weltkueche' ? 'free' : 'locked'; }

// Modul-Katalog dynamisch aus module_info (Source of Truth)
// Nur aktive + beta + geplante Module anzeigen (keine archivierten)
$ALL_MODULES = $db->fetchAll(
    "SELECT module_id AS id, title AS name, short_desc AS `desc`, icon,
            card_image, status, play_url, sort_order, available_from
     FROM module_info
     WHERE status IN ('aktiv','beta','geplant')
     ORDER BY sort_order, title"
);

if ($method === 'GET') {
    // Schüler*innen-Ansicht: welche Module sind für mich freigeschaltet?
    if (isset($_GET['student']) && $_GET['student'] === '1') {
        $sessionId = Session::requireStudent();
        $session = $db->fetchOne('SELECT class_id FROM student_sessions WHERE id = ?', [$sessionId]);
        if (!$session || !$session['class_id']) {
            // Kein Klasse = alle Module frei (Autodidakt)
            $result = [];
            foreach ($ALL_MODULES as $mod) {
                $result[] = [
                    'id'             => $mod['id'],
                    'name'           => $mod['name'],
                    'desc'           => $mod['desc'],
                    'icon'           => $mod['icon'],
                    'card_image'     => $mod['card_image'],
                    'status'         => $mod['status'],
                    'play_url'       => $mod['play_url'],
                    'available_from' => $mod['available_from'],
                    'mode'           => $mod['status'] === 'geplant' ? 'coming_soon' : 'free',
                    'licensed'       => true,   // Autodidakt ohne Klasse: nicht lizenzpflichtig
                ];
            }
            Response::ok($result);
        }
        $classId = $session['class_id'];
        $classMap = [];
        $settings = $db->fetchAll(
            'SELECT module_id, mode, current_level, quiz_enabled, audio_info, due_date, started_at, paused
             FROM class_modules WHERE class_id = ?', [$classId]);
        foreach ($settings as $s) $classMap[$s['module_id']] = $s;

        // Pro Sim den letzten Abschluss-Zeitpunkt des Schülers laden (assessments).
        // Wird gegen class_modules.started_at verglichen, um teacher_started-
        // Aufträge als "erledigt" zu markieren, sobald der Schüler nach dem
        // Auftrag-Start einmal abgeschlossen hat.
        $lastDone = [];
        $rows = $db->fetchAll(
            'SELECT sim_id, MAX(submitted_at) AS last_at FROM assessments WHERE session_id = ? GROUP BY sim_id',
            [$sessionId]
        );
        foreach ($rows as $r) $lastDone[$r['sim_id']] = $r['last_at'];

        // Individuelle Overrides für diesen Schüler
        $studentRow = $db->fetchOne(
            'SELECT student_id AS id FROM student_sessions WHERE id = ?',
            [$sessionId]
        );
        $overrides = [];
        if ($studentRow) {
            $rows = $db->fetchAll('SELECT module_id, mode FROM student_modules WHERE student_id = ?', [$studentRow['id']]);
            foreach ($rows as $r) $overrides[$r['module_id']] = $r['mode'];
        }

        // Lizenz-Status des Schülers (fürs Cockpit-Gate). Gültig = zugewiesen,
        // nicht storniert, nicht abgelaufen (valid_until >= heute; NULL = Alt-Code).
        $licensed = false;
        if ($studentRow && !empty($studentRow['id'])) {
            $lic = $db->fetchOne(
                "SELECT 1 AS ok FROM licenses WHERE student_id = ? AND canceled_at IS NULL
                 AND (valid_until IS NULL OR valid_until >= CURDATE()) LIMIT 1",
                [$studentRow['id']]);
            $licensed = (bool)$lic;
        }

        // Einzelner Modul-Filter
        $filterId = $_GET['module_id'] ?? null;

        $result = [];
        foreach ($ALL_MODULES as $mod) {
            if ($filterId && $mod['id'] !== $filterId) continue;
            $cm = $classMap[$mod['id']] ?? null;
            $mode = $overrides[$mod['id']] ?? ($cm['mode'] ?? _defaultMode($mod['id']));
            // 'geplant' überschreibt jeden mode-Eintrag — Modul ist nicht spielbar.
            if ($mod['status'] === 'geplant') $mode = 'coming_soon';

            // Lehrer-Auftrag erledigt? (assessment-submit nach class_modules.started_at)
            $assignmentCompleted = false;
            if ($mode === 'teacher_started' && $cm && !empty($cm['started_at'])) {
                $done = $lastDone[$mod['id']] ?? null;
                if ($done && $done > $cm['started_at']) $assignmentCompleted = true;
            }

            $result[] = [
                'id'                  => $mod['id'],
                'name'                => $mod['name'],
                'desc'                => $mod['desc'],
                'icon'                => $mod['icon'],
                'card_image'          => $mod['card_image'],
                'status'              => $mod['status'],
                'play_url'            => $mod['play_url'],
                'available_from'      => $mod['available_from'],
                'mode'                => $mode,
                'forcedLevel'         => ($mode === 'teacher_started' && $cm) ? (int)($cm['current_level'] ?? 1) : null,
                'quizEnabled'         => (bool)($cm['quiz_enabled'] ?? 0),
                'audioInfo'           => (bool)($cm['audio_info'] ?? 1),
                'dueDate'             => $cm['due_date'] ?? null,
                'paused'              => (bool)($cm['paused'] ?? 0),
                'assignmentCompleted' => $assignmentCompleted,
                'licensed'            => $licensed,
            ];
        }
        // Wenn einzelnes Modul, liefere Objekt statt Array
        if ($filterId) {
            Response::ok($result[0] ?? ['id' => $filterId, 'mode' => 'locked', 'error' => 'not_found']);
        }
        Response::ok($result);
    }

    $teacherId = Session::requireTeacher();
    $classId = (int)($_GET['class_id'] ?? 0);
    if (!$classId) Response::error('class_id erforderlich');

    $class = $db->fetchOne('SELECT id FROM classes WHERE id = ? AND teacher_id = ?', [$classId, $teacherId]);
    if (!$class) Response::error('Klasse nicht gefunden', 404);

    // Klassen-Defaults laden (inkl. Level + Pause-Status für die Lehrer-UI)
    $settings = $db->fetchAll(
        'SELECT module_id, mode, current_level, paused, audio_info, due_date, started_at FROM class_modules WHERE class_id = ?',
        [$classId]
    );
    $classMap = [];
    $classMeta = [];
    foreach ($settings as $s) {
        $classMap[$s['module_id']] = $s['mode'];
        $classMeta[$s['module_id']] = $s;
    }

    // Matrix-Modus: alle Schüler × alle Module
    if (isset($_GET['matrix']) && $_GET['matrix'] === '1') {
        $students = $db->fetchAll(
            'SELECT id, username, display_name, emoji_avatar FROM students WHERE class_id = ? ORDER BY username',
            [$classId]
        );

        // Individuelle Overrides laden
        $studentIds = array_column($students, 'id');
        $overrides = [];
        if (!empty($studentIds)) {
            $placeholders = implode(',', array_fill(0, count($studentIds), '?'));
            $rows = $db->fetchAll(
                "SELECT student_id, module_id, mode FROM student_modules WHERE student_id IN ($placeholders)",
                $studentIds
            );
            foreach ($rows as $r) {
                $overrides[$r['student_id']][$r['module_id']] = $r['mode'];
            }
        }

        // Matrix aufbauen
        $matrix = [];
        foreach ($students as $s) {
            $row = [
                'id' => (int)$s['id'],
                'username' => $s['username'],
                'displayName' => $s['display_name'] ?: $s['username'],
                'emoji' => $s['emoji_avatar'] ?: '🧑‍🎓',
                'modules' => [],
            ];
            foreach ($ALL_MODULES as $mod) {
                $row['modules'][$mod['id']] = $overrides[$s['id']][$mod['id']] ?? $classMap[$mod['id']] ?? _defaultMode($mod['id']);
            }
            $matrix[] = $row;
        }

        // Modul-Infos mit Klassen-Defaults
        $modulesInfo = [];
        foreach ($ALL_MODULES as $mod) {
            $meta = $classMeta[$mod['id']] ?? null;
            $modulesInfo[] = [
                'id' => $mod['id'],
                'name' => $mod['name'],
                'desc' => $mod['desc'],
                'icon' => $mod['icon'],
                'card_image' => $mod['card_image'],
                'status' => $mod['status'],
                'available_from' => $mod['available_from'],
                'classMode'    => $classMap[$mod['id']] ?? _defaultMode($mod['id']),
                'currentLevel' => $meta ? (int)($meta['current_level'] ?? 1) : 1,
                'paused'       => $meta ? (bool)($meta['paused'] ?? 0) : false,
                'audioInfo'    => $meta ? (bool)($meta['audio_info'] ?? 1) : true,
                'dueDate'      => $meta['due_date'] ?? null,
                'startedAt'    => $meta['started_at'] ?? null,
            ];
        }

        Response::ok(['modules' => $modulesInfo, 'students' => $matrix]);
    }

    // Standard: nur Klassen-Defaults
    $result = [];
    foreach ($ALL_MODULES as $mod) {
        $result[] = [
            'id' => $mod['id'],
            'name' => $mod['name'],
            'desc' => $mod['desc'],
            'icon' => $mod['icon'],
            'status' => $mod['status'],
            'mode' => $classMap[$mod['id']] ?? _defaultMode($mod['id']),
        ];
    }
    Response::ok($result);
}

if ($method === 'POST') {
    $teacherId = Session::requireTeacher();
    $body = json_decode(file_get_contents('php://input'), true);
    $action = $body['action'] ?? '';
    $classId = (int)($body['classId'] ?? 0);
    $moduleId = $body['moduleId'] ?? '';

    if (!$classId || !$moduleId) Response::error('classId und moduleId erforderlich');

    $class = $db->fetchOne('SELECT id FROM classes WHERE id = ? AND teacher_id = ?', [$classId, $teacherId]);
    if (!$class) Response::error('Klasse nicht gefunden', 404);

    // Schutz: 'geplant'-Module dürfen NICHT freigeschaltet werden — sie sind
    // im Lehrer-UI auch nur als 'In Vorbereitung' sichtbar.
    $modStatus = $db->fetchOne('SELECT status FROM module_info WHERE module_id = ?', [$moduleId]);
    if (!$modStatus || $modStatus['status'] === 'geplant' || $modStatus['status'] === 'archiv') {
        Response::error('Modul ist noch in Vorbereitung und kann nicht freigeschaltet werden.');
    }

    // Klassen-Default setzen
    if ($action === 'set_mode') {
        $mode = $body['mode'] ?? 'locked';
        if (!in_array($mode, ['locked', 'free', 'teacher_started'])) Response::error('Ungültiger Modus');
        $level   = isset($body['currentLevel']) ? max(1, min(3, (int)$body['currentLevel'])) : 1;
        $dueDate = !empty($body['dueDate']) ? $body['dueDate'] : null;
        $paused  = !empty($body['paused']) ? 1 : 0;

        $db->execute(
            'INSERT INTO class_modules (class_id, module_id, enabled, mode, current_level, due_date, paused)
             VALUES (?, ?, 1, ?, ?, ?, ?)
             ON DUPLICATE KEY UPDATE mode = VALUES(mode), enabled = 1,
               current_level = VALUES(current_level), due_date = VALUES(due_date), paused = VALUES(paused)',
            [$classId, $moduleId, $mode, $level, $dueDate, $paused]
        );
        // Bei "teacher_started" started_at frisch setzen — markiert Auftragsstart
        // und macht alte assessments unter dieser started_at zu "vorher".
        if ($mode === 'teacher_started') {
            $db->execute(
                'UPDATE class_modules SET started_at = NOW() WHERE class_id = ? AND module_id = ?',
                [$classId, $moduleId]
            );
        } else {
            $db->execute(
                'UPDATE class_modules SET started_at = NULL, paused = 0 WHERE class_id = ? AND module_id = ?',
                [$classId, $moduleId]
            );
        }
        Response::ok();
    }

    // Vorlese-Modus (Audio-Info) für die Klasse erlauben/sperren
    if ($action === 'set_audio_info') {
        $on = !empty($body['enabled']) ? 1 : 0;
        $db->execute(
            'INSERT INTO class_modules (class_id, module_id, enabled, audio_info)
             VALUES (?, ?, 1, ?)
             ON DUPLICATE KEY UPDATE audio_info = VALUES(audio_info)',
            [$classId, $moduleId, $on]
        );
        Response::ok();
    }

    // Auftrag pausieren / fortsetzen
    if ($action === 'pause' || $action === 'resume') {
        $paused = $action === 'pause' ? 1 : 0;
        $db->execute(
            'UPDATE class_modules SET paused = ? WHERE class_id = ? AND module_id = ?',
            [$paused, $classId, $moduleId]
        );
        Response::ok();
    }

    // Individuell pro Schüler setzen
    if ($action === 'set_student_mode') {
        $studentId = (int)($body['studentId'] ?? 0);
        $mode = $body['mode'] ?? 'locked';
        if (!$studentId) Response::error('studentId erforderlich');
        if (!in_array($mode, ['locked', 'free', 'teacher_started'])) Response::error('Ungültiger Modus');

        // Prüfen dass Schüler zur Klasse gehört
        $student = $db->fetchOne('SELECT id FROM students WHERE id = ? AND class_id = ?', [$studentId, $classId]);
        if (!$student) Response::error('Schüler nicht in dieser Klasse');

        $db->execute(
            'INSERT INTO student_modules (student_id, module_id, mode)
             VALUES (?, ?, ?)
             ON DUPLICATE KEY UPDATE mode = VALUES(mode)',
            [$studentId, $moduleId, $mode]
        );
        Response::ok();
    }

    // Klassen-Default für ALLE Schüler übernehmen (reset overrides)
    if ($action === 'reset_overrides') {
        $db->execute(
            'DELETE sm FROM student_modules sm JOIN students s ON s.id = sm.student_id WHERE s.class_id = ? AND sm.module_id = ?',
            [$classId, $moduleId]
        );
        Response::ok();
    }

    Response::error('Unbekannte Aktion');
}

Response::error('Methode nicht erlaubt', 405);