无法在php中回应响应

Question

我的表单邮件中有两个字段＆amp;密码。

我正在尝试从单一表单进行注册

条件是，如果您已注册，他将登录，否则他将被注册。

无法获得回应响应

   <?php 

include_once('connection.php');
include_once('functions.php');

$username = $_GET['username'];
$password = $_GET['password'];
$response=array();

// Check if that username is already exists.
$find_user = mysqli_query($conDB,"SELECT * FROM `users_info` WHERE `username` = '".$username."'");
if (mysqli_num_rows($find_user) != 0) $error[] = "That username is already  exist.";

if (empty($error)){

$hashed_password = sha1($password);

  // Check if submitted info is correct or not.
 $check = mysqli_query($conDB,"SELECT * FROM `users_info` WHERE `username` = '".$username."' AND `password` = '".$hashed_password."'");

 if (mysqli_num_rows($check) == 1) {

$code="login_success";
array_push($response,array("code"=>$code,"email"=>$username));
echo json_encode($response);

  } else if (empty($error)){

    $result = mysqli_query($conDB," INSERT INTO `users_info` (
    `username`,
    `password`
    ) VALUES (
    '".$username."',
    '".$hashed_password."'
    )");

    if(confirm_query($result)) {
    redirect('login.php?signup=1');
    }



} else {
$error[] = "Incorrect username or password.";
  }

}

?>