Introduce PGPKeyImporter protocol to reduce code duplications

pass/Controllers/PGPKeyImporter.swift

@@ -0,0 +1,65 @@
+//
+//  PGPKeyImporter.swift
+//  pass
+//
+//  Created by Danny Moesch on 07.02.20.
+//  Copyright © 2020 Bob Sun. All rights reserved.
+//
+
+import passKit
+
+protocol PGPKeyImporter {
+
+    static var keySource: PGPKeySource { get }
+
+    static var label: String { get }
+
+    static var menuLabel: String { get }
+
+    func isReadyToUse() -> Bool
+
+    func importKeys() throws
+
+    func doAfterImport()
+
+    func saveImportedKeys()
+}
+
+extension PGPKeyImporter {
+    
+    static var menuLabel: String {
+        if Defaults.pgpKeySource == Self.keySource {
+            return "✓ \(Self.label)"
+        }
+        return Self.label
+    }
+}
+
+extension PGPKeyImporter where Self: UIViewController {
+
+    func savePassphraseDialog() {
+        let savePassphraseAlert = UIAlertController(title: "Passphrase".localize(), message: "WantToSavePassphrase?".localize(), preferredStyle: UIAlertController.Style.alert)
+        // Do not save the key's passphrase.
+        savePassphraseAlert.addAction(UIAlertAction(title: "No".localize(), style: UIAlertAction.Style.default) { _ in
+            AppKeychain.shared.removeContent(for: Globals.pgpKeyPassphrase)
+            Defaults.isRememberPGPPassphraseOn = false
+            self.saveImportedKeys()
+        })
+        // Save the key's passphrase.
+        savePassphraseAlert.addAction(UIAlertAction(title: "Yes".localize(), style: UIAlertAction.Style.destructive) {_ in
+            // Ask for the passphrase.
+            let alert = UIAlertController(title: "Passphrase".localize(), message: "FillInPgpPassphrase.".localize(), preferredStyle: UIAlertController.Style.alert)
+            alert.addAction(UIAlertAction(title: "Ok".localize(), style: UIAlertAction.Style.default, handler: {_ in
+                AppKeychain.shared.add(string: alert.textFields?.first?.text, for: Globals.pgpKeyPassphrase)
+                Defaults.isRememberPGPPassphraseOn = true
+                self.saveImportedKeys()
+            }))
+            alert.addTextField { textField in
+                textField.text = AppKeychain.shared.get(for: Globals.pgpKeyPassphrase)
+                textField.isSecureTextEntry = true
+            }
+            self.present(alert, animated: true, completion: nil)
+        })
+        self.present(savePassphraseAlert, animated: true, completion: nil)
+    }
+}