PattysCharmDriverApp_LogIn

ViewController.swift

```

//  ViewController.swift
//  PattysCharmDriver
//  Created by Patty Chen on 5/4
//  Copyright © 2018年 Patty Chen. All rights reserved.


import UIKit
import FirebaseAuth
import Firebase


class ViewController: UIViewController {

    //May 4, to add some log-in outlay features in App.
    
    @IBOutlet weak var emailTextField: UITextField!
    
    @IBOutlet weak var passwordTextField: UITextField!
 
    
    @IBOutlet weak var passengerOrDriverSW: UISwitch!
    
    @IBOutlet weak var passengerLabel: UILabel!
    
    @IBOutlet weak var driverLabel: UILabel!
    
    @IBOutlet weak var topButton: UIButton!
    
    @IBOutlet weak var bottomButton: UIButton!

    
    @IBOutlet weak var passwordLabel: UILabel!
    
    
    @IBOutlet weak var mailAddressLabel: UILabel!
    
    @IBOutlet weak var pattysCharmDriverLabel: UILabel!
    
    
    var signUpStatus = true
   
    
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
    }
    


    //override func didReceiveMemoryWarning() {
       // super.didReceiveMemoryWarning()
      
    //} May 4,delete thid func
    
    

    //May 4, to add some log-in action features & dispaly alert from error occuring in App.
 
    @IBAction func signUP(_ sender: Any) {
        
        if emailTextField.text == "" || passwordTextField.text == "" {
            
            displaySignUpAlert(title: "Missing Info", message: "Plz put in enough info !")
            
        } else {
            
        
            if let mail = emailTextField.text {
                if let password = passwordTextField.text {
                    
                    if signUpStatus {
                        //signUP
                        
                        Auth.auth().createUser(withEmail: mail, password: password,completion: { (user, error) in
                            
                            if error != nil {
                                
                                self.displaySignUpAlert(title: "Error", message: error!.localizedDescription)
                            } else {
                                print("Well done, Sign Up go smoothly!")
                            }
                            
                        }) // May 4, https://firebase.google.com/docs/auth/ios/start validate the email address and password provided by the user, then pass them to the createUser method.
                        
                    } else {
                        //logIn
                        // May 7,
                        
                        Auth.auth().signIn(withEmail: mail, password: password,completion: { (user, error) in
                            
                            if error != nil {
                                self.displaySignUpAlert(title: "Error", message: error!.localizedDescription)
                            } else {
                                print("Well done, Sign Up go smoothly!")
                            }
                            
                            
                        }) //Create a form that allows existing users to sign in using their email address and password. When a user completes the form, call the signIn method.
                        
                        
                    }
                    
                }
            }
            
        }
        
    }
    
    // May 4, addd alert function
    func displaySignUpAlert(title: String, message: String) {
        
        let alertDisplayer = UIAlertController(title: title, message: message, preferredStyle: .alert) // declare an instant of Class, and initiate by below code sentence.
        
        alertDisplayer.addAction(UIAlertAction(title: "Bravo, go ahead!", style: .default, handler: nil))// this is a Enclosure style function in Swift4.
        
        self.present(alertDisplayer, animated: true, completion: nil) // self means the View Controller instance by deafault.
        
    }
    
    
    
    @IBAction func logIN(_ sender: Any ) {
        
        if signUpStatus {
            
            topButton.setTitle("Log In", for: .normal)
            bottomButton.setTitle("Switch to Sign Up", for: .normal)
            passengerLabel.isHidden = true
            driverLabel.isHidden = true
            passengerOrDriverSW.isHidden = true
            signUpStatus = false
            
            
        } else {
            
            topButton.setTitle("Sign Up", for: .normal)
            bottomButton.setTitle("Switch to Log In", for: .normal)
            passengerLabel.isHidden = false
            driverLabel.isHidden = false
            passengerOrDriverSW.isHidden = false
            signUpStatus = true
            
        }
        
        
  }
    
    

}


```