<?php
$password = $password2 = $key = $username = "";
$keyErr = $usernameErr = $passwordErr = $password2Err = "";

if($_SERVER["REQUEST_METHOD"] == "POST"){
	$password = test_input($_POST["password"]);
	$password2 = test_input($_POST["password2"]);
	$username = test_input($_POST["username"]);
	$key = test_input($_POST["key"]);

	//Key registration check
	if(strlen($key) < 4){
		$keyErr = "* Reg.key must be at least 4 characters!";
	}		// check if key contains alphanumeric characters
	elseif(!preg_match("/^[a-zA-Z0-9]*$/",$key))	{
		$keyErr = "* Only alphanumeric characters allowed!";
		}
	else{
			$keyErr = "Continue";
		}

		//Checks if username is shorter than 4 characters
		if(strlen($username) < 4){
			$usernameErr = "* Username must be at least 4 characters!";
		}

		//Password check
		if(strlen($password) < 4){
			$passwordErr = "* Password must be 4 characters or longer!";
		}

		//check if both password inputs are identical
	if($password != $password2)
	 {
	     $password2Err = "Password did not match! Try again. ";
	 }
	  else{
		  	$password2Err = "Hi, it works!";
		}

}
function test_input($data) {
  $data = trim($data);
  $data = stripslashes($data);
  $data = htmlspecialchars($data);
  return $data;
}

?>
<div class="container">
	<div id="registerContainer">

		<h4>Register</h4>
		<form method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>">
			<div class="form-control input-sm">Reg. Key: </div><input type="text" name="key" required>
			 <span class="error"> <?php echo $keyErr;?></span>
			<div class="form-control input-sm">Username: </div><input type="text" name="username" required>
			<span class="error"> <?php echo $usernameErr;?></span>
			<div class="form-control input-sm">Password: </div><input type="password" name="password" required>
			<span class="error"> <?php echo $passwordErr;?></span>
			<div class="form-control input-sm">Re-type password: </div><input type="password" name="password2" required>
			<span class="error"> <?php echo $password2Err;?></span>
			<br><button type="submit" name="submit">Register</button>

		</form>

	</div>
</div>