functions.php

function ituk_listing_register_user(){
	
	if (isset($_POST['ap_form_submit_button'], $_POST['ap_form_nonce'])) { //this is returning false -> WHY?
		
		//create new user from author email
		if ( in_array('author_email', $_POST[ 'form_included_fields' ]) && $_POST[ 'ap_form_author_email' ] != '' ) {
			
			$user_email = sanitize_email($_POST[ 'ap_form_author_email' ]);
			$user_id = username_exists( $username );
			//if no user is registered with this email
			if ( !$user_id and email_exists($user_email) == false ) {
				//create new user
				$random_password = wp_generate_password( $length=12, $include_standard_special_chars=false );
				$user_id = wp_create_user( $username, $random_password, $user_email );
				$user = new WP_User($user_id);
				$user->set_role('listing_author');
							
				//add author name to user
				if ( in_array('author_name', $_POST[ 'form_included_fields' ]) && $_POST[ 'ap_form_author_name' ] != '' ) {
					$user_first_name = sanitize_text_field($_POST[ 'ap_form_author_name' ]);
					update_user_meta( $user_id, 'user_firstname', $user_first_name );
				}
				//add author url to user
				if ( in_array('author_url', $_POST[ 'form_included_fields' ]) && $_POST[ 'ap_form_author_url' ] != '' ) {
					$user_url = sanitize_text_field($_POST[ 'ap_form_author_url' ]);
					update_user_meta( $user_id, 'user_url', $user_url );
				}
				//add author phone to user
				if ( in_array('listing_phone', $_POST[ 'form_included_fields' ]) && $_POST[ 'listing_phone' ] != '' ) {
					$user_phone = sanitize_text_field($_POST[ 'listing_phone' ]);
					update_user_meta( $user_id, 'user_phone', $user_phone );
				}				
				//add author phone to user
				if ( in_array('listing_city', $_POST[ 'form_included_fields' ]) && $_POST[ 'listing_city' ] != '' ) {
					$user_city = sanitize_text_field($_POST[ 'listing_city' ]);
					update_user_meta( $user_id, 'user_city', $user_city );
				}
				
			// if user already exists
			} else {
				//redirect to login page and back to form
				auth_redirect();
			}
		
		// if no author email
		} else {
			echo "no email";
		}
	
	// if user is not logged in
	}else{
		echo "no \$_POST";
	}
}
add_action('template_redirect', 'ituk_listing_register_user');