Erreur

<?php require 'inc/header.php'; ?>
  

<?php 
 if(!empty($_POST)){


  $errors = array();

  require 'inc/db.php';

  if(empty($_POST['username']) || !preg_match('/^[a-z -Z0-9_]+s/', $_POST['username'])){

   $errors['username'] = "Votre pseudo n'est pas valide (alphanumerique)";
  }else{
   $req = $pdo->prepare('SELECT id FROM users WHERE username = ?');
   $req->execute(array($_POST['username']));
   $user = $req->fetch();
   if($user){
    $errors['username'] = 'ce pseudo est deja pris';
   }
  }


  if(empty($_POST['email']) || !filter_var($_POST['email'], FILTER_VALIDATE_EMAIL)){
   $errors['email'] = "votre email n'est pas valide";
  } else{
   $req = $pdo->prepare('SELECT id FROM users WHERE email = ?');
   $req->execute(array($_POST['email']));
   $user = $req->fetch();
   if($user){
    $errors['email'] = 'ce email est deja utilisé pour un autre compte';
   }

  if(empty($_POST['password']) || $_POST['password'] != $_POST['password_confirm']){
   $errors['password'] = "vous devez rentrer un mot de passe valide";
  } 

  if(empty($errors)){
    require 'db.php';
   $req = $pdo->prepare("INSERT INTO users(username, password, email,confirmation_token) VALUES(?, ?,?,?)");
   //$password = password_hash($_POST['password'], PASSWORD_BCRIPT);
   $token = str_random(60);
   $req->execute(array($_POST['username'], $_POST['password'], $_POST['email']));
     die ('Notre compte a bien été crée'); 
  }
  
 }

?>
   
         <h3>S'incrire</h3>

   <form action="" method="POST">

  <div class="form-group">
   <label for="">Pseudo</label>
   <input type="text" name="username" class="form-control" required/>
  </div>

  <div class="form-group">
   <label for="">Email</label>
   <input type="email" name="email" class="form-control" required/>
  </div>

  <div class="form-group">
   <label for="">Mot de passe</label>
   <input type="password" name="password" class="form-control" required/>
  </div>

  <div class="form-group">
   <label for="">Confirmez votre mot de passe</label>
   <input type="password" name="password_confirm" class="form-control" required/>
  </div> 

 <input type="submit" name="submit" value="M'inscrire" class="btn btn-primary">

 </form>
 <?php require 'inc/footer.php'; ?>

<?php
//Affichage des erreurs PHP
error_reporting(E_ALL);

//connexion à la BDD
require_once 'inc/db.php';

//initialisation des variables
$errors = array();
$username = !empty($_POST['username']) ? $_POST['username'] : NULL;
$email = !empty($_POST['email']) ? $_POST['email'] : NULL;
$password = !empty($_POST['password']) ? $_POST['password'] : NULL;
$password_confirm = !empty($_POST['password_confirm']) ? $_POST['password_confirm'] : NULL;

//traitement du submit
 if(!empty($_POST)){
  if(!$username || !preg_match('/^[a-z -Z0-9_]+s/', $username)){
    $errors['username'] = "Votre pseudo n'est pas valide (alphanumerique)";
  }else{
   $req = $pdo->prepare('SELECT id FROM users WHERE username = ?');
   $req->execute(array($username));
   $user = $req->fetch();
   if($user){
    $errors['username'] = 'ce pseudo est deja pris';
   }
  }

  if(!$email || !filter_var($email, FILTER_VALIDATE_EMAIL)){
    $errors['email'] = "votre email n'est pas valide";
  }else{
    $req = $pdo->prepare('SELECT id FROM users WHERE email = ?');
    $req->execute(array($email));
    $user = $req->fetch();
    if($user){
      $errors['email'] = 'ce email est deja utilisé pour un autre compte';
    }
    if(!$password || $password != $password_confirm ){
      $errors['password'] = "vous devez rentrer un mot de passe valide";
    } 
    if(empty($errors)){
      $req = $pdo->prepare("INSERT INTO users(username, password, email,confirmation_token) VALUES(?, ?,?,?)");
      //$password = password_hash($password, PASSWORD_BCRIPT);
      $token = str_random(60);
      $req->execute(array($username, $password, $email));
      die ('Notre compte a bien été crée'); 
    }
  }

?>

<?php require 'inc/header.php'; ?>
 <h3>S'incrire</h3>
 <form action="" method="POST">
    <div class="form-group">
     <label for="">Pseudo</label>
     <input type="text" name="username" class="form-control" required/>
    </div>
    <div class="form-group">
     <label for="">Email</label>
     <input type="email" name="email" class="form-control" required/>
    </div>
    <div class="form-group">
     <label for="">Mot de passe</label>
     <input type="password" name="password" class="form-control" required/>
    </div>
    <div class="form-group">
     <label for="">Confirmez votre mot de passe</label>
     <input type="password" name="password_confirm" class="form-control" required/>
    </div> 
    <input type="submit" name="submit" value="M'inscrire" class="btn btn-primary">
 </form>
 <?php require 'inc/footer.php'; ?>