[AltStore] Revises authentication flow with better UI

AltStore/Authentication/AuthenticationViewController.swift

@@ -0,0 +1,151 @@
+//
+//  AuthenticationViewController.swift
+//  AltStore
+//
+//  Created by Riley Testut on 6/5/19.
+//  Copyright © 2019 Riley Testut. All rights reserved.
+//
+
+import UIKit
+
+import AltSign
+import Roxas
+
+class AuthenticationViewController: UITableViewController
+{
+    var authenticationHandler: (((ALTAccount, String)?) -> Void)?
+    
+    private var _didLayoutSubviews = false
+    
+    @IBOutlet private var emailAddressTextField: UITextField!
+    @IBOutlet private var passwordTextField: UITextField!
+    
+    override func viewDidLoad()
+    {
+        super.viewDidLoad()
+        
+        self.update()
+    }
+    
+    override func viewDidLayoutSubviews()
+    {
+        super.viewDidLayoutSubviews()
+        
+        if !_didLayoutSubviews
+        {
+            self.emailAddressTextField.becomeFirstResponder()
+        }
+        
+        _didLayoutSubviews = true
+    }
+    
+    override func viewDidDisappear(_ animated: Bool)
+    {
+        super.viewDidDisappear(animated)
+        
+        self.navigationItem.rightBarButtonItem?.isIndicatingActivity = false
+    }
+}
+
+private extension AuthenticationViewController
+{
+    func update()
+    {
+        if let _ = self.validate()
+        {
+            self.navigationItem.rightBarButtonItem?.isEnabled = true
+        }
+        else
+        {
+            self.navigationItem.rightBarButtonItem?.isEnabled = false
+        }
+    }
+    
+    func validate() -> (String, String)?
+    {
+        guard
+            let emailAddress = self.emailAddressTextField.text?.trimmingCharacters(in: .whitespacesAndNewlines), !emailAddress.isEmpty,
+            let password = self.passwordTextField.text?.trimmingCharacters(in: .whitespacesAndNewlines), !password.isEmpty
+        else { return nil }
+        
+        return (emailAddress, password)
+    }
+    
+    func authenticate(emailAddress: String, password: String, completionHandler: @escaping (Result<(ALTAccount, [ALTTeam]), Error>) -> Void)
+    {
+        ALTAppleAPI.shared.authenticate(appleID: emailAddress, password: password) { (account, error) in
+            switch Result(account, error)
+            {
+            case .failure(let error): completionHandler(.failure(error))
+            case .success(let account):
+                
+                ALTAppleAPI.shared.fetchTeams(for: account) { (teams, error) in
+                    let result = Result(teams, error).map { (account, $0) }
+                    completionHandler(result)
+                }
+            }
+        }
+    }
+}
+
+private extension AuthenticationViewController
+{
+    @IBAction func authenticate()
+    {
+        guard let (emailAddress, password) = self.validate() else { return }
+        
+        self.emailAddressTextField.resignFirstResponder()
+        self.passwordTextField.resignFirstResponder()
+        
+        self.navigationItem.rightBarButtonItem?.isIndicatingActivity = true
+        
+        ALTAppleAPI.shared.authenticate(appleID: emailAddress, password: password) { (account, error) in
+            do
+            {
+                let account = try Result(account, error).get()
+                self.authenticationHandler?((account, password))
+            }
+            catch
+            {
+                DispatchQueue.main.async {
+                    let toastView = RSTToastView(text: NSLocalizedString("Failed to Log In", comment: ""), detailText: error.localizedDescription)
+                    toastView.tintColor = .altPurple
+                    toastView.show(in: self.navigationController?.view ?? self.view, duration: 2.0)
+                    
+                    self.navigationItem.rightBarButtonItem?.isIndicatingActivity = false
+                }
+            }
+        }
+    }
+    
+    @IBAction func cancel()
+    {
+        self.authenticationHandler?(nil)
+    }
+}
+
+extension AuthenticationViewController: UITextFieldDelegate
+{
+    func textFieldShouldReturn(_ textField: UITextField) -> Bool
+    {
+        switch textField
+        {
+        case self.emailAddressTextField: self.passwordTextField.becomeFirstResponder()
+        case self.passwordTextField: self.authenticate()
+        default: break
+        }
+        
+        self.update()
+        
+        return false
+    }
+    
+    func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool
+    {
+        DispatchQueue.main.async {
+            self.update()
+        }
+        
+        return true
+    }
+}