<?php
declare(strict_types=1);

function app_config(): array
{
    static $config = null;
    if ($config === null) {
        $config = require __DIR__ . '/../config/config.php';
    }
    return $config;
}

function e(string $value): string
{
    return htmlspecialchars($value, ENT_QUOTES, 'UTF-8');
}

function redirect_to(string $url): void
{
    header('Location: ' . $url);
    exit;
}

function set_flash(string $type, string $message): void
{
    $_SESSION['flash'] = [
        'type' => $type,
        'message' => $message,
    ];
}

function get_flash(): ?array
{
    if (!isset($_SESSION['flash']) || !is_array($_SESSION['flash'])) {
        return null;
    }

    $flash = $_SESSION['flash'];
    unset($_SESSION['flash']);
    return $flash;
}

function ensure_dir(string $dir): void
{
    if (!is_dir($dir)) {
        mkdir($dir, 0775, true);
    }
}

function read_json_file(string $path, array $default = []): array
{
    if (!is_file($path)) {
        return $default;
    }

    $content = file_get_contents($path);
    if ($content === false || trim($content) === '') {
        return $default;
    }

    $data = json_decode($content, true);
    return is_array($data) ? $data : $default;
}

function write_json_file(string $path, array $data): bool
{
    ensure_dir(dirname($path));
    $json = json_encode($data, JSON_PRETTY_PRINT | JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES);
    if ($json === false) {
        return false;
    }
    return file_put_contents($path, $json, LOCK_EX) !== false;
}

function append_json_line(string $path, array $data): bool
{
    ensure_dir(dirname($path));
    $json = json_encode($data, JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES);
    if ($json === false) {
        return false;
    }
    return file_put_contents($path, $json . PHP_EOL, FILE_APPEND | LOCK_EX) !== false;
}

function email_key(string $email): string
{
    return sha1(mb_strtolower(trim($email), 'UTF-8'));
}

function slugify(string $text): string
{
    $text = mb_strtolower(trim($text), 'UTF-8');
    $map = [
        'ä' => 'ae', 'ö' => 'oe', 'ü' => 'ue', 'ß' => 'ss',
    ];
    $text = strtr($text, $map);
    $text = preg_replace('/[^a-z0-9]+/u', '-', $text) ?? '';
    $text = trim($text, '-');
    return $text !== '' ? $text : 'test';
}

function current_user(): ?array
{
    if (!isset($_SESSION['participant']) || !is_array($_SESSION['participant'])) {
        return null;
    }
    return $_SESSION['participant'];
}

function require_user(): array
{
    $user = current_user();
    if ($user === null) {
        set_flash('danger', 'Bitte melde dich zuerst mit Name und E-Mail an.');
        redirect_to('index.php');
    }
    return $user;
}

function is_admin(): bool
{
    return !empty($_SESSION['is_admin']);
}

function require_admin(): void
{
    if (!is_admin()) {
        set_flash('danger', 'Bitte erst im Adminbereich anmelden.');
        redirect_to('index.php');
    }
}

function storage_paths(): array
{
    return app_config()['storage'];
}

function register_or_load_user(string $name, string $email): array
{
    $paths = storage_paths();
    $record = [
        'name' => trim($name),
        'email' => trim($email),
        'email_key' => email_key($email),
        'updated_at' => date('Y-m-d H:i:s'),
        'created_at' => date('Y-m-d H:i:s'),
    ];

    append_json_line($paths['users_file'], [
        'action' => 'login',
        'name' => $record['name'],
        'email' => $record['email'],
        'email_key' => $record['email_key'],
        'timestamp' => date('Y-m-d H:i:s'),
        'ip' => $_SERVER['REMOTE_ADDR'] ?? '',
        'user_agent' => $_SERVER['HTTP_USER_AGENT'] ?? '',
    ]);

    return $record;
}

function load_tests(bool $onlyActive = true): array
{
    $paths = storage_paths();
    ensure_dir($paths['tests_dir']);
    $files = glob($paths['tests_dir'] . '/*.json') ?: [];
    $tests = [];

    foreach ($files as $file) {
        $data = read_json_file($file, []);
        if (!$data) {
            continue;
        }
        if ($onlyActive && empty($data['meta']['active'])) {
            continue;
        }
        $tests[] = $data;
    }

    usort($tests, static function (array $a, array $b): int {
        return strcmp((string)($a['meta']['title'] ?? ''), (string)($b['meta']['title'] ?? ''));
    });

    return $tests;
}

function load_test_by_slug(string $slug): ?array
{
    $paths = storage_paths();
    $file = $paths['tests_dir'] . '/' . basename($slug) . '.json';
    if (!is_file($file)) {
        return null;
    }
    $test = read_json_file($file, []);
    return $test ?: null;
}

function submission_path(string $slug, string $email): string
{
    $paths = storage_paths();
    return $paths['submissions_dir'] . '/' . basename($slug) . '__' . email_key($email) . '.json';
}

function load_submission(string $slug, string $email): array
{
    return read_json_file(submission_path($slug, $email), []);
}

function save_submission(string $slug, string $email, array $data): bool
{
    return write_json_file(submission_path($slug, $email), $data);
}

function evaluate_test(array $test, array $answers): array
{
    $scores = [];
    foreach ($test['results'] as $result) {
        $scores[(string)$result['key']] = 0;
    }

    foreach ($test['questions'] as $question) {
        $questionId = (string)$question['id'];
        $questionType = (string)$question['type'];
        $selected = $answers[$questionId] ?? [];

        if ($questionType === 'single') {
            $selected = [$selected];
        } elseif (!is_array($selected)) {
            $selected = [];
        }

        foreach ($question['options'] as $option) {
            if (in_array((string)$option['id'], array_map('strval', $selected), true)) {
                $resultKey = (string)($option['result_key'] ?? '');
                $weight = (int)($option['weight'] ?? 1);
                if ($resultKey !== '' && array_key_exists($resultKey, $scores)) {
                    $scores[$resultKey] += $weight;
                }
            }
        }
    }

    arsort($scores);
    $topKey = (string)array_key_first($scores);

    $winner = null;
    foreach ($test['results'] as $result) {
        if ((string)$result['key'] === $topKey) {
            $winner = $result;
            break;
        }
    }

    return [
        'scores' => $scores,
        'winner' => $winner,
    ];
}

function validate_submission(array $test, array $postAnswers): array
{
    $cleanAnswers = [];
    $errors = [];

    foreach ($test['questions'] as $question) {
        $questionId = (string)$question['id'];
        $questionType = (string)$question['type'];
        $allowedIds = array_map(static function (array $opt): string {
            return (string)$opt['id'];
        }, $question['options']);

        if ($questionType === 'single') {
            $value = isset($postAnswers[$questionId]) ? (string)$postAnswers[$questionId] : '';
            if ($value === '' || !in_array($value, $allowedIds, true)) {
                $errors[] = 'Bitte beantworte die Frage: ' . ($question['text'] ?? $questionId);
                continue;
            }
            $cleanAnswers[$questionId] = $value;
            continue;
        }

        $values = $postAnswers[$questionId] ?? [];
        if (!is_array($values) || $values === []) {
            $errors[] = 'Bitte wähle mindestens eine Antwort bei: ' . ($question['text'] ?? $questionId);
            continue;
        }

        $selected = [];
        foreach ($values as $value) {
            $value = (string)$value;
            if (in_array($value, $allowedIds, true)) {
                $selected[] = $value;
            }
        }

        $selected = array_values(array_unique($selected));
        if ($selected === []) {
            $errors[] = 'Ungültige Auswahl bei: ' . ($question['text'] ?? $questionId);
            continue;
        }
        $cleanAnswers[$questionId] = $selected;
    }

    return [
        'errors' => $errors,
        'answers' => $cleanAnswers,
    ];
}

function import_test_from_xml(string $xmlPath): array
{
    if (!is_file($xmlPath)) {
        return ['success' => false, 'message' => 'XML-Datei nicht gefunden.'];
    }

    libxml_use_internal_errors(true);
    $xml = simplexml_load_file($xmlPath);
    if ($xml === false) {
        return ['success' => false, 'message' => 'XML konnte nicht gelesen werden.'];
    }

    $title = trim((string)($xml->meta->title ?? ''));
    $description = trim((string)($xml->meta->description ?? ''));
    $slug = trim((string)($xml->meta->slug ?? ''));
    $active = (string)($xml->meta->active ?? '1') === '1';

    if ($title === '') {
        return ['success' => false, 'message' => 'Im XML fehlt der Titel.'];
    }

    if ($slug === '') {
        $slug = slugify($title);
    } else {
        $slug = slugify($slug);
    }

    $results = [];
    if (isset($xml->results->result)) {
        foreach ($xml->results->result as $result) {
            $key = slugify((string)($result['key'] ?? ''));
            if ($key === '') {
                continue;
            }
            $results[] = [
                'key' => $key,
                'title' => trim((string)($result->title ?? '')),
                'description' => trim((string)($result->description ?? '')),
                'badge_class' => trim((string)($result->badge_class ?? 'primary')),
                'emoji' => trim((string)($result->emoji ?? '✨')),
            ];
        }
    }

    if ($results === []) {
        return ['success' => false, 'message' => 'Im XML wurden keine Ergebnistypen gefunden.'];
    }

    $questions = [];
    $questionIndex = 1;
    if (isset($xml->questions->question)) {
        foreach ($xml->questions->question as $question) {
            $questionType = trim((string)($question['type'] ?? 'single'));
            $questionText = trim((string)($question->text ?? ''));

            if ($questionText === '') {
                continue;
            }

            $options = [];
            $optionIndex = 1;
            if (isset($question->options->option)) {
                foreach ($question->options->option as $option) {
                    $resultKey = slugify((string)($option['result_key'] ?? ''));
                    $weight = (int)($option['weight'] ?? 1);
                    $optionText = trim((string)$option);

                    if ($optionText === '' || $resultKey === '') {
                        continue;
                    }

                    $options[] = [
                        'id' => 'o' . $questionIndex . '_' . $optionIndex,
                        'text' => $optionText,
                        'result_key' => $resultKey,
                        'weight' => $weight,
                    ];
                    $optionIndex++;
                }
            }

            if ($options === []) {
                continue;
            }

            $questions[] = [
                'id' => 'q' . $questionIndex,
                'text' => $questionText,
                'type' => $questionType === 'multiple' ? 'multiple' : 'single',
                'options' => $options,
            ];
            $questionIndex++;
        }
    }

    if ($questions === []) {
        return ['success' => false, 'message' => 'Im XML wurden keine Fragen gefunden.'];
    }

    $test = [
        'meta' => [
            'title' => $title,
            'description' => $description,
            'slug' => $slug,
            'active' => $active,
            'created_at' => date('Y-m-d H:i:s'),
            'updated_at' => date('Y-m-d H:i:s'),
        ],
        'results' => $results,
        'questions' => $questions,
    ];

    $paths = storage_paths();
    ensure_dir($paths['tests_dir']);
    $jsonPath = $paths['tests_dir'] . '/' . $slug . '.json';
    $xmlBackupPath = $paths['uploads_dir'] . '/' . date('Ymd_His') . '_' . $slug . '.xml';

    $saved = write_json_file($jsonPath, $test);
    if (!$saved) {
        return ['success' => false, 'message' => 'Die JSON-Testdatei konnte nicht gespeichert werden.'];
    }

    @copy($xmlPath, $xmlBackupPath);

    return [
        'success' => true,
        'message' => 'Test erfolgreich importiert.',
        'test' => $test,
    ];
}

function render_header(string $title): void
{
    $config = app_config();
    $flash = get_flash();
    $user = current_user();
    ?>
<!doctype html>
<html lang="de">
<head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <title><?= e($title) ?> · <?= e($config['app_name']) ?></title>
    <link href="https://cdn.jsdelivr.net/npm/bootstrap@5.3.3/dist/css/bootstrap.min.css" rel="stylesheet">
    <style>
        body { background: #f6f8fb; }
        .navbar-brand { font-weight: 700; }
        .card-soft { border: 0; border-radius: 1rem; box-shadow: 0 .75rem 2rem rgba(0,0,0,.06); }
        .option-label { display:block; padding:1rem; border:1px solid #dee2e6; border-radius:.75rem; cursor:pointer; transition:.15s ease-in-out; }
        .option-label:hover { border-color:#0d6efd; background:#f8fbff; }
        .choice-input:checked + .option-label { border-color:#0d6efd; background:#e7f1ff; }
    </style>
</head>
<body>
<nav class="navbar navbar-expand-lg bg-white border-bottom mb-4">
    <div class="container">
        <a class="navbar-brand" href="index.php"><?= e($config['app_name']) ?></a>
        <div class="ms-auto d-flex gap-2 align-items-center">
            <?php if ($user): ?>
                <span class="text-muted small"><?= e($user['name']) ?> · <?= e($user['email']) ?></span>
                <a class="btn btn-outline-secondary btn-sm" href="dashboard.php">Dashboard</a>
                <a class="btn btn-outline-danger btn-sm" href="logout.php">Logout</a>
            <?php else: ?>
                <a class="btn btn-outline-primary btn-sm" href="index.php">Start</a>
            <?php endif; ?>
            <a class="btn btn-dark btn-sm" href="admin/index.php">Admin</a>
        </div>
    </div>
</nav>
<div class="container pb-5">
    <?php if ($flash): ?>
        <div class="alert alert-<?= e((string)$flash['type']) ?>"><?= e((string)$flash['message']) ?></div>
    <?php endif; ?>
    <?php
}

function render_footer(): void
{
    ?>
</div>
</body>
</html>
    <?php
}