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<?php
session_start();
class register
{
    private static function db()
    {
        $password = '';
        $mysqli = new mysqli('localhost', 'root', $password, 'test');
        if ($mysqli->connect_error)
        {
            die("MySQL error1: ". htmlspecialchars($mysqli->connect_error , ENT_QUOTES, 'big5'));
        }
        return $mysqli;
    }

    public static function registerUser(): bool
    {
        $success = true;
        if (!self::verifyPassword($_POST['register_pass'], $_POST['register_pass_check']))
        {
            echo "Password does not match";
            $success = false;
        }

        $username = self::db()->escape_string($_POST['register_id']);
        $password_hash = password_hash($_POST['register_pass'], PASSWORD_DEFAULT);

        if (!self::writeUserToDatabase($username, $password_hash)) {
            echo "Account creation failed";
            $success = false;
        }else{
            echo "Account creation success";
        }
        return $success;
    }

    public static function verifyPassword(string $pass, string $pass_verify): bool
    {
        if ($pass !== $pass_verify)
        {
            return false;
        }
        return true;
    }

    public static function writeUserToDatabase(string $username, string $password_hash): bool
    {
        $mysqli = new mysqli('localhost', 'root', '', 'test');
        $sql = "INSERT INTO user (username, password) VALUES(?,?)";
        //$stmt = self::db()->prepare($sql);
        $stmt = $mysqli->prepare($sql);
        $stmt->bind_param("ss", $username, $password_hash);
        $stmt->execute();
        //mysqli_stmt_execute($stmt);
        if (!$stmt->execute())
        {
            die("MySQL error2: ". htmlspecialchars($stmt->error , ENT_QUOTES, 'big5'));
        }
        $stmt->close();
        return true;
    }
}
?>

<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=big5">
    </head>
    <body align="center" valign="center">
        <form action="register.php" method="post">
            <label>Username:</label>
            <input name="register_id" type="text" required/><br/>
            <label>Password:</label>
            <input name="register_pass" type="text" required/><br/>
            <label>Password2:</label>
            <input name="register_pass_check" type="text" required/><br/>
            <button type="submit">Register</button>
        </form>
        <?php
            header('Content-type: text/html; charset=big5');
            if (isset($_POST['register_id']))
            {
                Register::registerUser();
            }
        ?>
    </body>
</html>