<?php
declare(strict_types=1);

ini_set('display_errors', '1');
error_reporting(E_ALL);
session_start();

$config = require __DIR__ . '/../config/database.php';

$dsn = sprintf(
    'mysql:host=%s;dbname=%s;charset=%s',
    $config['host'],
    $config['dbname'],
    $config['charset'] ?? 'utf8mb4'
);

$pdo = new PDO(
    $dsn,
    $config['user'],
    $config['pass'],
    [
        PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
        PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
    ]
);

$errors = [];
$successMessage = '';

const DEFAULT_LOCATION_NAME = 'Sternwarte Sonneberg';
const DEFAULT_LOCATION_LATITUDE = 50.377;
const DEFAULT_LOCATION_LONGITUDE = 11.189;
const DEFAULT_LOCATION_ELEVATION = 640.0;
const DEFAULT_LOCATION_TIMEZONE = 'Europe/Berlin';
const DEFAULT_SATELLITE_ID = 61;

function sendRegistrationNotification(string $username, string $email, ?string $displayName): void
{
    $to = 'tm@astronomiemuseum.de';
    $subject = 'Neue Registrierung bei SkyView';
    $safeDisplayName = $displayName !== null && $displayName !== '' ? $displayName : '-';

    $messageLines = [
        'Ein neuer Benutzer hat sich registriert.',
        '',
        'Benutzername: ' . $username,
        'E-Mail: ' . $email,
        'Anzeigename: ' . $safeDisplayName,
        'Zeitpunkt: ' . date('Y-m-d H:i:s'),
    ];

    $headers = [
        'MIME-Version: 1.0',
        'Content-Type: text/plain; charset=UTF-8',
        'From: noreply@astronomiemuseum.de',
        'Reply-To: ' . $email,
    ];

    try {
        mail(
            $to,
            $subject,
            implode(PHP_EOL, $messageLines),
            implode("\r\n", $headers)
        );
    } catch (Throwable $e) {
        error_log('Registration notification mail failed: ' . $e->getMessage());
    }
}

if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    $username       = trim($_POST['username'] ?? '');
    $email          = trim($_POST['email'] ?? '');
    $displayName    = trim($_POST['display_name'] ?? '');
    $password       = $_POST['password'] ?? '';
    $passwordRepeat = $_POST['password_repeat'] ?? '';

    if ($username === '') {
        $errors[] = 'Bitte einen Benutzernamen eingeben.';
    } elseif (mb_strlen($username) < 3) {
        $errors[] = 'Der Benutzername muss mindestens 3 Zeichen lang sein.';
    } elseif (mb_strlen($username) > 50) {
        $errors[] = 'Der Benutzername darf maximal 50 Zeichen lang sein.';
    }

    if ($email === '' || !filter_var($email, FILTER_VALIDATE_EMAIL)) {
        $errors[] = 'Bitte eine gültige E-Mail-Adresse eingeben.';
    }

    if ($password === '') {
        $errors[] = 'Bitte ein Passwort eingeben.';
    } elseif (strlen($password) < 8) {
        $errors[] = 'Das Passwort muss mindestens 8 Zeichen lang sein.';
    }

    if ($passwordRepeat === '') {
        $errors[] = 'Bitte das Passwort wiederholen.';
    } elseif ($password !== $passwordRepeat) {
        $errors[] = 'Die Passwörter stimmen nicht überein.';
    }

    if ($displayName !== '' && mb_strlen($displayName) > 100) {
        $errors[] = 'Der Anzeigename darf maximal 100 Zeichen lang sein.';
    }

    if (empty($errors)) {
        $stmtCheck = $pdo->prepare("
            SELECT `id`
            FROM `app_users`
            WHERE `username` = :username OR `email` = :email
            LIMIT 1
        ");
        $stmtCheck->execute([
            ':username' => $username,
            ':email'    => $email,
        ]);

        if ($stmtCheck->fetch()) {
            $errors[] = 'Benutzername oder E-Mail-Adresse ist bereits vergeben.';
        }
    }

    if (empty($errors)) {
        $passwordHash = password_hash($password, PASSWORD_DEFAULT);
        $pdo->beginTransaction();

        try {
            $stmtInsert = $pdo->prepare("
                INSERT INTO `app_users` (
                    `username`,
                    `email`,
                    `password_hash`,
                    `display_name`,
                    `role`,
                    `is_active`,
                    `created_at`,
                    `updated_at`
                ) VALUES (
                    :username,
                    :email,
                    :password_hash,
                    :display_name,
                    'user',
                    0,
                    NOW(),
                    NOW()
                )
            ");

            $stmtInsert->execute([
                ':username'      => $username,
                ':email'         => $email,
                ':password_hash' => $passwordHash,
                ':display_name'  => $displayName !== '' ? $displayName : null,
            ]);

            $userId = (int)$pdo->lastInsertId();

            $stmtInsertLocation = $pdo->prepare("
                INSERT INTO `app_user_locations` (
                    `user_id`,
                    `name`,
                    `latitude`,
                    `longitude`,
                    `elevation`,
                    `timezone`,
                    `is_default`,
                    `created_at`,
                    `updated_at`
                ) VALUES (
                    :user_id,
                    :name,
                    :latitude,
                    :longitude,
                    :elevation,
                    :timezone,
                    1,
                    NOW(),
                    NOW()
                )
            ");
            $stmtInsertLocation->execute([
                ':user_id' => $userId,
                ':name' => DEFAULT_LOCATION_NAME,
                ':latitude' => DEFAULT_LOCATION_LATITUDE,
                ':longitude' => DEFAULT_LOCATION_LONGITUDE,
                ':elevation' => DEFAULT_LOCATION_ELEVATION,
                ':timezone' => DEFAULT_LOCATION_TIMEZONE,
            ]);

            $stmtInsertSatellite = $pdo->prepare("
                INSERT INTO `app_user_satellites` (
                    `user_id`,
                    `satellite_id`,
                    `is_favorite`,
                    `created_at`
                ) VALUES (
                    :user_id,
                    :satellite_id,
                    1,
                    NOW()
                )
            ");
            $stmtInsertSatellite->execute([
                ':user_id' => $userId,
                ':satellite_id' => DEFAULT_SATELLITE_ID,
            ]);

            $pdo->commit();
        } catch (Throwable $e) {
            if ($pdo->inTransaction()) {
                $pdo->rollBack();
            }

            throw $e;
        }

        sendRegistrationNotification(
            $username,
            $email,
            $displayName !== '' ? $displayName : null
        );

        $successMessage = 'Die Registrierung war erfolgreich. Das Konto wurde angelegt und muss noch freigeschaltet werden.';

        $_POST = [];
    }
}
$loggedIn = false;
?>
<?php require __DIR__ . '/header.php'; ?>

<div class="auth-wrap">
    <div class="card auth-card">
        <h2>Registrieren</h2>

        <p class="hint mb-lg">Nach der Registrierung wird das Konto zunächst deaktiviert und später freigeschaltet.</p>

        <?php if ($successMessage !== ''): ?>
            <p class="msg-success"><?= htmlspecialchars($successMessage, ENT_QUOTES, 'UTF-8') ?></p>
        <?php endif; ?>

        <?php if (!empty($errors)): ?>
            <ul class="msg-error">
                <?php foreach ($errors as $error): ?>
                    <li><?= htmlspecialchars($error, ENT_QUOTES, 'UTF-8') ?></li>
                <?php endforeach; ?>
            </ul>
        <?php endif; ?>

        <form method="post" action="" class="form-stack">
            <div class="form-group">
                <label for="username">Benutzername</label>
                <input
                    type="text"
                    id="username"
                    name="username"
                    required
                    maxlength="50"
                    value="<?= htmlspecialchars($_POST['username'] ?? '', ENT_QUOTES, 'UTF-8') ?>"
                >
            </div>

            <div class="form-group">
                <label for="display_name">Anzeigename <span class="form-optional">(optional)</span></label>
                <input
                    type="text"
                    id="display_name"
                    name="display_name"
                    maxlength="100"
                    value="<?= htmlspecialchars($_POST['display_name'] ?? '', ENT_QUOTES, 'UTF-8') ?>"
                >
            </div>

            <div class="form-group">
                <label for="email">E-Mail-Adresse</label>
                <input
                    type="email"
                    id="email"
                    name="email"
                    required
                    maxlength="190"
                    value="<?= htmlspecialchars($_POST['email'] ?? '', ENT_QUOTES, 'UTF-8') ?>"
                >
            </div>

            <div class="form-group">
                <label for="password">Passwort</label>
                <input
                    type="password"
                    id="password"
                    name="password"
                    required
                >
            </div>

            <div class="form-group">
                <label for="password_repeat">Passwort wiederholen</label>
                <input
                    type="password"
                    id="password_repeat"
                    name="password_repeat"
                    required
                >
            </div>

            <button type="submit" class="btn btn-primary btn-full">Konto anlegen</button>
        </form>

        <p class="form-footer">Bereits registriert? <a href="login.php">Anmelden</a></p>
    </div>
</div>

<?php require __DIR__ . '/footer.php'; ?>