Add switch to turn on/off remembering passphrase

If the switch is on, users need  to type passphrase of secret key once. The key will be stored in the Keychain.

If the switch is off, users have to fill in passphrase for each decryption including show password detail and long press to copy.

pass/Controllers/PasswordDetailTableViewController.swift

@@ -17,6 +17,26 @@ class PasswordDetailTableViewController: UITableViewController, UIGestureRecogni
     var passwordCategoryText = ""
     var password: Password?
     var passwordImage: UIImage?
+    
+    let indicatorLable: UILabel = {
+        let label = UILabel(frame: CGRect(x: 0, y: 0, width: UIScreen.main.bounds.width, height: 21))
+        label.center = CGPoint(x: UIScreen.main.bounds.width / 2, y: UIScreen.main.bounds.height * 0.382 + 22)
+        label.backgroundColor = UIColor.clear
+        label.textColor = UIColor.gray
+        label.text = "decrypting password"
+        label.textAlignment = .center
+        label.font = UIFont.preferredFont(forTextStyle: .footnote)
+        return label
+    }()
+    
+    let indicator: UIActivityIndicatorView = {
+        let indicator = UIActivityIndicatorView(activityIndicatorStyle: .gray)
+        indicator.center = CGPoint(x: UIScreen.main.bounds.width / 2, y: UIScreen.main.bounds.height * 0.382)
+        return indicator
+    }()
+    
+    let editUIBarButtonItem = UIBarButtonItem(barButtonSystemItem: .edit, target: self, action: #selector(pressEdit(_:)))
+
 
     struct TableCell {
         var title: String
@@ -54,19 +74,11 @@ class PasswordDetailTableViewController: UITableViewController, UIGestureRecogni
         tableView.contentInset = UIEdgeInsetsMake(-36, 0, 0, 0);
         tableView.rowHeight = UITableViewAutomaticDimension
         tableView.estimatedRowHeight = 52
-        let indicatorLable = UILabel(frame: CGRect(x: 0, y: 0, width: view.frame.width, height: 21))
-        indicatorLable.center = CGPoint(x: view.frame.size.width / 2, y: view.frame.size.height * 0.382 + 22)
-        indicatorLable.backgroundColor = UIColor.clear
-        indicatorLable.textColor = UIColor.gray
-        indicatorLable.text = "decrypting password"
-        indicatorLable.textAlignment = .center
-        indicatorLable.font = UIFont.preferredFont(forTextStyle: .footnote)
-        let indicator = UIActivityIndicatorView(activityIndicatorStyle: .gray)
-        indicator.center = CGPoint(x: view.frame.size.width / 2, y: view.frame.size.height * 0.382)
+ 
+        
         indicator.startAnimating()
         tableView.addSubview(indicator)
         tableView.addSubview(indicatorLable)
-        let editUIBarButtonItem = UIBarButtonItem(barButtonSystemItem: .edit, target: self, action: #selector(pressEdit(_:)))
         editUIBarButtonItem.isEnabled = false
         navigationItem.rightBarButtonItem = editUIBarButtonItem
         
@@ -75,10 +87,33 @@ class PasswordDetailTableViewController: UITableViewController, UIGestureRecogni
             passwordImage = image
         }
         
+        var passphrase = ""
+        if Defaults[.isRememberPassphraseOn] && PasswordStore.shared.pgpKeyPassphrase != nil {
+            passphrase = PasswordStore.shared.pgpKeyPassphrase!
+            self.decryptThenShowPassword(passphrase: passphrase)
+        } else {
+            let alert = UIAlertController(title: "Passphrase", message: "Please fill in the passphrase of your PGP secret key.", preferredStyle: UIAlertControllerStyle.alert)
+            alert.addAction(UIAlertAction(title: "OK", style: UIAlertActionStyle.default, handler: {_ in
+                passphrase = alert.textFields!.first!.text!
+                self.decryptThenShowPassword(passphrase: passphrase)
+            }))
+            alert.addTextField(configurationHandler: {(textField: UITextField!) in
+                textField.text = ""
+                textField.isSecureTextEntry = true
+            })
+            self.present(alert, animated: true, completion: nil)
+        }
         
+        
+    }
+    
+    func decryptThenShowPassword(passphrase: String) {
+        if Defaults[.isRememberPassphraseOn] {
+            PasswordStore.shared.pgpKeyPassphrase = passphrase
+        }
         DispatchQueue.global(qos: .userInitiated).async {
             do {
-                self.password = try self.passwordEntity!.decrypt()!
+                self.password = try self.passwordEntity!.decrypt(passphrase: passphrase)!
             } catch {
                 DispatchQueue.main.async {
                     let alert = UIAlertController(title: "Cannot Show Password", message: error.localizedDescription, preferredStyle: UIAlertControllerStyle.alert)
@@ -89,19 +124,23 @@ class PasswordDetailTableViewController: UITableViewController, UIGestureRecogni
                 }
                 return
             }
-
+            
             let password = self.password!
-            self.setTableData()
             DispatchQueue.main.async { [weak self] in
-                self?.tableView.reloadData()
-                indicator.stopAnimating()
-                indicatorLable.isHidden = true
-                editUIBarButtonItem.isEnabled = true
-                if let url = password.getURL() {
-                    if self?.passwordEntity?.image == nil{
-                        self?.updatePasswordImage(url: url)
-                    }
-                }
+                self?.showPassword(password: password)
+            }
+        }
+    }
+    
+    func showPassword(password: Password) {
+        setTableData()
+        self.tableView.reloadData()
+        indicator.stopAnimating()
+        indicatorLable.isHidden = true
+        editUIBarButtonItem.isEnabled = true
+        if let url = password.getURL() {
+            if self.passwordEntity?.image == nil{
+                self.updatePasswordImage(url: url)
             }
         }
     }