Facebook login and App Invites for iOS in Swift - ios

Question

I am stuck after coding the Facebook login.....!
After the login procedure I just end up with a logout button.
I would like to make use of the App Invites for iOS but I cant figure out how to integrate it...
The documentations on "Facebook.developer" is hard to understand.
This is my code so far in the view controller:
import UIKit
import FacebookLogin
import FBSDKLoginKit
class ViewController: UIViewController, FBSDKLoginButtonDelegate {
var dict : [String : AnyObject]!
override func viewDidLoad() {
super.viewDidLoad()
//creating button
let loginButton = LoginButton(readPermissions: [ .publicProfile, .userFriends, .email ])
loginButton.center = view.center
//adding it to view
view.addSubview(loginButton)
//if the user is already logged in
if let accessToken = FBSDKAccessToken.current(){
getFBUserData()
}
}
//when login button clicked
#objc func loginButtonClicked() {
let loginManager = LoginManager()
loginManager.logIn([ .publicProfile, .userFriends, .email ], viewController: self) { loginResult in
switch loginResult {
case .failed(let error):
print(error)
case .cancelled:
print("User cancelled login.")
case .success(let grantedPermissions, let declinedPermissions, let accessToken):
self.getFBUserData()
}
}
}
//function is fetching the user data
func getFBUserData(){
if((FBSDKAccessToken.current()) != nil){
FBSDKGraphRequest(graphPath: "me", parameters: ["fields": "id, name, picture.type(large), email"]).start(completionHandler: { (connection, result, error) -> Void in
if (error == nil){
self.dict = result as! [String : AnyObject]
print(result!)
print(self.dict)
}
})
}
}
func loginButton(_ loginButton: FBSDKLoginButton!, didCompleteWith result: FBSDKLoginManagerLoginResult!, error: Error!) {
/*
Check for successful login and act accordingly.
Perform your segue to another UIViewController here.
*/
let viewController = self.storyboard?.instantiateInitialViewController("StoryBoardID") as? UITableViewController
self.presentViewController(viewController, animated: true, completion: nil)
}
func loginButtonDidLogOut(_ loginButton: FBSDKLoginButton!) {
// Actions for when the user logged out goes here
}
}
Any help?