facebookLogin.logInWithReadPermissions with Firebase issues - swift

Question

I am able to successfully authenticate login with facebook using basic SDK procedures, but am having some confusion when I am trying to authenticate with Firebase. I have read through the documentation and copied and pasted the code but I am still getting a warning that reads
'logInWithReadPermissions(_:handler:)' is deprecated: use logInWithReadPermissions:fromViewController:handler: instead facebookLogin.logInWithReadPermissions(["email"], handler: instead.
1) What does this warning mean and how do I fix it?
2) With emails and password sign in you see the registered users created, but how do I know and see if users were registered with facebook authentication in the Firebase DB?
Thanks for any help or direction!
import UIKit
import Firebase
import FBSDKCoreKit
import FBSDKLoginKit
class ViewController: UIViewController, FBSDKLoginButtonDelegate {
let loginButton: FBSDKLoginButton = {
let button = FBSDKLoginButton()
button.readPermissions = ["email"]
return button
}()
override func viewDidLoad() {
super.viewDidLoad()
view.addSubview(loginButton)
loginButton.center = view.center
loginButton.delegate = self
let ref = Firebase(url: "https://my-app.firebaseio.com")
let facebookLogin = FBSDKLoginManager()
facebookLogin.logInWithReadPermissions(["email"], handler: {
(facebookResult, facebookError) -> Void in
if facebookError != nil {
print("Facebook login failed. Error \(facebookError)")
} else if facebookResult.isCancelled {
print("Facebook login was cancelled.")
} else {
let accessToken = FBSDKAccessToken.currentAccessToken().tokenString
ref.authWithOAuthProvider("facebook", token: accessToken,
withCompletionBlock: { error, authData in
if error != nil {
print("Login failed. \(error)")
} else {
print("Logged in! \(authData)")
}
})
}
})
}
func loginButton(loginButton: FBSDKLoginButton!, didCompleteWithResult result: FBSDKLoginManagerLoginResult!, error: NSError!) {
if error == nil {
print("completed login")
self.performSegueWithIdentifier("showNew", sender: self)
}
else {
print(error.localizedDescription)
}
}
func loginButtonDidLogOut(loginButton: FBSDKLoginButton!) {
print("user logged out")
}
func loginButtonWillLogin(loginButton: FBSDKLoginButton!) -> Bool {
return true
}
}

Answer 1

Try something like (compiles without warnings to me):
let currentToken = FBSDKAccessToken.currentAccessToken()
// Show login only if we had not logged in before
if (currentToken == nil || !currentToken.hasGranted("email")) {
let ref = Firebase(url: "https://my-app.firebaseio.com")
let facebookLogin = FBSDKLoginManager()
facebookLogin.logInWithReadPermissions(["email"], fromViewController: self, handler: {
(facebookResult, facebookError) -> Void in
if facebookError != nil {
log.error("Facebook login failed. Error \(facebookError)")
.
.
.