<?php
/**
 * API: Spieler-Fortschritt + Level-System + Wirkungsklammer
 * GET  /api/progress?sim_id=X              → Level/XP für ein Spiel
 * GET  /api/progress?student_id=X          → Alle Fortschritte (Lehrer-Ansicht)
 * POST /api/progress {action}              → Level updaten, Pre/Post-Antworten speichern
 *
 * Bootstrap: idempotent, falls direkt über /php/api/progress.php aufgerufen
 * (Klima 2D + 3D rufen diese URL direkt — bisher ergab das einen Fatal Error,
 *  weil Database/Session/Response erst über index.php geladen werden).
 */
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();

if ($method === 'GET') {
    $simId = $_GET['sim_id'] ?? '';
    $studentId = (int)($_GET['student_id'] ?? 0);

    // Schüler*in: eigener Fortschritt
    if ($simId && !$studentId) {
        $sessionId = Session::requireStudent();
        $session = $db->fetchOne('SELECT class_id, display_name FROM student_sessions WHERE id = ?', [$sessionId]);
        if ($session) {
            $student = $db->fetchOne('SELECT id FROM students WHERE class_id = ? AND display_name = ?', [$session['class_id'], $session['display_name']]);
            if ($student) $studentId = (int)$student['id'];
        }
    }

    if ($studentId && $simId) {
        $progress = $db->fetchOne('SELECT level, xp, plays, best_stars FROM player_progress WHERE student_id = ? AND sim_id = ?', [$studentId, $simId]);
        $answers = $db->fetchAll('SELECT phase, question_id, answer, correct, answered_at FROM assessment_answers WHERE session_id IN (SELECT id FROM student_sessions WHERE class_id = (SELECT class_id FROM students WHERE id = ?)) AND sim_id = ? ORDER BY answered_at DESC', [$studentId, $simId]);
        Response::ok(['progress' => $progress ?: ['level'=>1,'xp'=>0,'plays'=>0,'best_stars'=>0], 'answers' => $answers]);
    }

    // Lehrer*in: alle Fortschritte eines/r bestimmten Schüler*in
    if ($studentId && !$simId) {
        $teacherId = Session::requireTeacher();
        $all = $db->fetchAll('SELECT sim_id, level, xp, plays, best_stars FROM player_progress WHERE student_id = ? ORDER BY sim_id', [$studentId]);
        Response::ok($all);
    }

    // Schüler*in: eigene Fortschritts-Liste (Frontend ruft mit student_id=0 oder ohne)
    if (!$simId) {
        $sessionId = Session::requireStudent();
        $session = $db->fetchOne('SELECT class_id, display_name FROM student_sessions WHERE id = ?', [$sessionId]);
        $student = $session ? $db->fetchOne('SELECT id FROM students WHERE class_id = ? AND display_name = ?', [$session['class_id'], $session['display_name']]) : null;
        if (!$student) { Response::ok([]); }
        $studentId = (int)$student['id'];
        $all = $db->fetchAll(
            'SELECT pp.sim_id, pp.level, pp.xp, pp.plays, pp.best_stars,
                    mi.title, mi.icon,
                    (SELECT MAX(submitted_at) FROM assessments
                       WHERE session_id IN (SELECT id FROM student_sessions
                                             WHERE class_id = ? AND display_name = ?)
                         AND sim_id = pp.sim_id) AS last_played_at
               FROM player_progress pp
               LEFT JOIN module_info mi ON mi.module_id = pp.sim_id
              WHERE pp.student_id = ?
              ORDER BY pp.xp DESC, pp.plays DESC',
            [$session['class_id'], $session['display_name'], $studentId]
        );
        Response::ok($all);
    }

    Response::error('sim_id oder student_id erforderlich');
}

if ($method === 'POST') {
    $body = json_decode(file_get_contents('php://input'), true);
    $action = $body['action'] ?? '';

    // === Spiel-Ergebnis speichern + Level berechnen ===
    if ($action === 'complete') {
        $sessionId = Session::requireStudent();
        $simId = $body['simId'] ?? '';
        $stars = max(0, min(5, (int)($body['stars'] ?? 0)));
        $data = json_encode($body['data'] ?? []);

        if (!$simId) Response::error('simId erforderlich');

        // Student-ID finden
        $session = $db->fetchOne('SELECT class_id, display_name FROM student_sessions WHERE id = ?', [$sessionId]);
        $student = $session ? $db->fetchOne('SELECT id FROM students WHERE class_id = ? AND display_name = ?', [$session['class_id'], $session['display_name']]) : null;
        if (!$student) Response::error('Schüler*in nicht gefunden');
        $studentId = (int)$student['id'];

        // XP berechnen: 10 pro Stern + 5 Bonus für 5 Sterne
        $xpGain = $stars * 10 + ($stars >= 5 ? 5 : 0);

        // Upsert progress
        $db->execute(
            'INSERT INTO player_progress (student_id, sim_id, level, xp, plays, best_stars)
             VALUES (?, ?, 1, ?, 1, ?)
             ON DUPLICATE KEY UPDATE xp = xp + VALUES(xp), plays = plays + 1, best_stars = GREATEST(best_stars, VALUES(best_stars))',
            [$studentId, $simId, $xpGain, $stars]
        );

        // Level berechnen: 0-49 XP = Level 1, 50-149 = Level 2, 150-299 = Level 3, 300+ = Level 4
        $progress = $db->fetchOne('SELECT xp FROM player_progress WHERE student_id = ? AND sim_id = ?', [$studentId, $simId]);
        $xp = (int)$progress['xp'];
        $newLevel = $xp < 50 ? 1 : ($xp < 150 ? 2 : ($xp < 300 ? 3 : 4));
        $db->execute('UPDATE player_progress SET level = ? WHERE student_id = ? AND sim_id = ?', [$newLevel, $studentId, $simId]);

        // Assessment speichern
        $db->execute(
            'INSERT INTO assessments (session_id, sim_id, class_id, results, duration_ms, submitted_at) VALUES (?, ?, ?, ?, ?, NOW())',
            [$sessionId, $simId, $session['class_id'], $data, (int)($body['durationMs'] ?? 0)]
        );

        Response::ok(['xpGained' => $xpGain, 'totalXp' => $xp + $xpGain, 'level' => $newLevel, 'stars' => $stars]);
    }

    // === Pre/Post-Antworten speichern ===
    if ($action === 'answer') {
        $sessionId = Session::requireStudent();
        $simId = $body['simId'] ?? '';
        $phase = $body['phase'] ?? ''; // 'pre' oder 'post'
        $questionId = (int)($body['questionId'] ?? 0);
        $answer = substr(trim($body['answer'] ?? ''), 0, 1);
        $correct = (bool)($body['correct'] ?? false);

        if (!$simId || !$phase || !$questionId || !$answer) Response::error('Felder unvollständig');

        $db->execute(
            'INSERT INTO assessment_answers (session_id, sim_id, phase, question_id, answer, correct) VALUES (?, ?, ?, ?, ?, ?)',
            [$sessionId, $simId, $phase, $questionId, $answer, $correct ? 1 : 0]
        );
        Response::ok();
    }

    // === Sim-Abschluss speichern (Klima-Format mit nested data) ===
    // Klima 2D + 3D senden action: 'submit_assessment' mit Body
    // {sim_id, data: {level, stars, score, duration_ms, completed, results, action_log, badges_earned}}.
    // 'complete' (oben) erwartet ein anderes Format; daher hier ein eigener Handler.
    if ($action === 'submit_assessment') {
        $sessionId = Session::requireStudent();
        $simId = $body['sim_id'] ?? $body['simId'] ?? '';
        if (!$simId) Response::error('sim_id erforderlich');

        $payload = is_array($body['data'] ?? null) ? $body['data'] : [];
        $stars   = max(0, min(5, (int)($payload['stars'] ?? 0)));
        $durationMs = (int)($payload['duration_ms'] ?? $body['durationMs'] ?? 0);
        $resultsJson = json_encode($payload, JSON_UNESCAPED_UNICODE);

        $session = $db->fetchOne('SELECT class_id, display_name FROM student_sessions WHERE id = ?', [$sessionId]);
        $student = $session ? $db->fetchOne('SELECT id FROM students WHERE class_id = ? AND display_name = ?', [$session['class_id'], $session['display_name']]) : null;
        if (!$student) Response::error('Schüler*in nicht gefunden');
        $studentId = (int)$student['id'];

        // XP + player_progress upserten (gleiche Logik wie 'complete')
        $xpGain = $stars * 10 + ($stars >= 5 ? 5 : 0);
        $db->execute(
            'INSERT INTO player_progress (student_id, sim_id, level, xp, plays, best_stars)
             VALUES (?, ?, 1, ?, 1, ?)
             ON DUPLICATE KEY UPDATE xp = xp + VALUES(xp), plays = plays + 1, best_stars = GREATEST(best_stars, VALUES(best_stars))',
            [$studentId, $simId, $xpGain, $stars]
        );
        $progress = $db->fetchOne('SELECT xp FROM player_progress WHERE student_id = ? AND sim_id = ?', [$studentId, $simId]);
        $xp = (int)$progress['xp'];
        $newLevel = $xp < 50 ? 1 : ($xp < 150 ? 2 : ($xp < 300 ? 3 : 4));
        $db->execute('UPDATE player_progress SET level = ? WHERE student_id = ? AND sim_id = ?', [$newLevel, $studentId, $simId]);

        // Assessment speichern (zentrale Tabelle für Lehrer-Auswertung)
        $db->execute(
            'INSERT INTO assessments (session_id, sim_id, class_id, results, duration_ms, submitted_at) VALUES (?, ?, ?, ?, ?, NOW())',
            [$sessionId, $simId, $session['class_id'], $resultsJson, $durationMs]
        );

        // Spiegel in student_results (V2)
        $score = isset($payload['score']) ? (float)$payload['score'] : null;
        $db->execute(
            'INSERT INTO student_results (student_id, class_id, module_id, score, duration_sec, detail_json, completed_at)
             VALUES (?, ?, ?, ?, ?, ?, NOW())',
            [$studentId, $session['class_id'], $simId, $score, (int)round($durationMs/1000), $resultsJson]
        );

        Response::ok(['xpGained' => $xpGain, 'totalXp' => $xp + $xpGain, 'level' => $newLevel, 'stars' => $stars]);
    }

    // === Endscreen-Reflexion speichern (Multiple-Choice-Antwort am Spielende) ===
    // Sims senden {action:'reflection', data:{level, question, answer}}.
    // Speichert die Antwort an den letzten assessment-Eintrag des Schülers für
    // diese Sim — damit Lehrkräfte später nachvollziehen können, was die
    // Bearbeiter:in als wirksamste/schwierigste Entscheidung empfunden hat.
    if ($action === 'reflection') {
        $sessionId = Session::requireStudent();
        $simId = $body['sim_id'] ?? $body['simId'] ?? '';
        $data  = is_array($body['data'] ?? null) ? $body['data'] : [];
        if (!$simId) Response::error('sim_id erforderlich');

        // Letzten assessment-Eintrag dieser Schüler:in × Sim suchen.
        $row = $db->fetchOne(
            'SELECT id, reflections FROM assessments
              WHERE session_id = ? AND sim_id = ? ORDER BY submitted_at DESC LIMIT 1',
            [$sessionId, $simId]
        );
        $entry = [
            'level'      => $data['level']    ?? null,
            'question'   => $data['question'] ?? null,
            'answer'     => $data['answer']   ?? null,
            'recorded_at'=> date('Y-m-d H:i:s'),
        ];

        if ($row) {
            $existing = $row['reflections'] ? json_decode($row['reflections'], true) : [];
            if (!is_array($existing)) $existing = [];
            $existing[] = $entry;
            $db->execute(
                'UPDATE assessments SET reflections = ? WHERE id = ?',
                [json_encode($existing, JSON_UNESCAPED_UNICODE), $row['id']]
            );
        } else {
            // Kein Assessment-Eintrag (z. B. Reflexion vor submit_assessment) →
            // schreibe einen Stub mit nur Reflexion. Wird bei späterem Submit
            // nicht überschrieben (verschiedene IDs).
            $session = $db->fetchOne('SELECT class_id FROM student_sessions WHERE id = ?', [$sessionId]);
            $db->execute(
                'INSERT INTO assessments (session_id, sim_id, class_id, reflections) VALUES (?, ?, ?, ?)',
                [$sessionId, $simId, $session['class_id'] ?? null, json_encode([$entry], JSON_UNESCAPED_UNICODE)]
            );
        }
        Response::ok();
    }

    // === Wirkungsklammer-Ergebnis abrufen ===
    if ($action === 'wirkung') {
        $sessionId = $body['sessionId'] ?? Session::studentId();
        $simId = $body['simId'] ?? '';
        if (!$simId) Response::error('simId erforderlich');

        $pre = $db->fetchAll('SELECT question_id, correct FROM assessment_answers WHERE session_id = ? AND sim_id = ? AND phase = "pre"', [$sessionId, $simId]);
        $post = $db->fetchAll('SELECT question_id, correct FROM assessment_answers WHERE session_id = ? AND sim_id = ? AND phase = "post"', [$sessionId, $simId]);

        $preCorrect = count(array_filter($pre, function($a){return $a['correct'];}));
        $postCorrect = count(array_filter($post, function($a){return $a['correct'];}));

        Response::ok([
            'pre' => ['total' => count($pre), 'correct' => $preCorrect],
            'post' => ['total' => count($post), 'correct' => $postCorrect],
            'improvement' => $postCorrect - $preCorrect,
        ]);
    }

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

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