Introduce PGPKeyImporter protocol to reduce code duplications

pass/Controllers/PGPKeyUrlTableViewController.swift

@@ -0,0 +1,70 @@
+//
+//  PGPKeyUrlTableViewController.swift
+//  pass
+//
+//  Created by Mingshen Sun on 21/1/2017.
+//  Copyright © 2017 Bob Sun. All rights reserved.
+//
+
+import UIKit
+import passKit
+
+class PGPKeyUrlTableViewController: AutoCellHeightUITableViewController {
+
+    @IBOutlet weak var pgpPublicKeyURLTextField: UITextField!
+    @IBOutlet weak var pgpPrivateKeyURLTextField: UITextField!
+
+    let passwordStore = PasswordStore.shared
+    let keychain = AppKeychain.shared
+
+    override func viewDidLoad() {
+        super.viewDidLoad()
+        pgpPublicKeyURLTextField.text = Defaults.pgpPublicKeyURL?.absoluteString
+        pgpPrivateKeyURLTextField.text = Defaults.pgpPrivateKeyURL?.absoluteString
+    }
+    
+    @IBAction func save(_ sender: Any) {
+        savePassphraseDialog()
+    }
+}
+
+extension PGPKeyUrlTableViewController: PGPKeyImporter {
+
+    static let keySource = PGPKeySource.url
+    static let label = "DownloadFromUrl".localize()
+
+    func isReadyToUse() -> Bool {
+        return validate(pgpKeyUrl: pgpPublicKeyURLTextField.text)
+            && validate(pgpKeyUrl: pgpPrivateKeyURLTextField.text)
+    }
+    
+    func importKeys() throws {
+        Defaults.pgpKeySource = Self.keySource
+
+        Defaults.pgpPrivateKeyURL = URL(string: pgpPrivateKeyURLTextField.text!.trimmed)
+        Defaults.pgpPublicKeyURL = URL(string: pgpPublicKeyURLTextField.text!.trimmed)
+
+        try KeyFileManager.PublicPgp.importKey(from: Defaults.pgpPublicKeyURL!)
+        try KeyFileManager.PrivatePgp.importKey(from: Defaults.pgpPrivateKeyURL!)
+    }
+
+    func doAfterImport() {
+        Utils.alert(title: "RememberToRemoveKey".localize(), message: "RememberToRemoveKeyFromServer.".localize(), controller: self, completion: nil)
+    }
+
+    func saveImportedKeys() {
+        self.performSegue(withIdentifier: "savePGPKeySegue", sender: self)
+    }
+
+    private func validate(pgpKeyUrl: String?) -> Bool {
+        guard let pgpKeyUrl = pgpKeyUrl, let url = URL(string: pgpKeyUrl), let scheme = url.scheme else {
+            Utils.alert(title: "CannotSavePgpKey".localize(), message: "SetPgpKeyUrlFirst.".localize(), controller: self, completion: nil)
+            return false
+        }
+        guard scheme == "https" else {
+            Utils.alert(title: "CannotSavePgpKey".localize(), message: "UseHttps.".localize(), controller: self, completion: nil)
+            return false
+        }
+        return true
+    }
+}