Update OTP token generation and support HOTP

- Update logic: Only fields otp_secret and otp_type are required for TOTP. Only fields otp_secret, otp_type and otp_counter are required for HOTP. Other fields (i.e., otp_algorithm, otp_digits, otp_period) are optional.
- Support HOTP: (1) passwords are initially concealed; (2) "tap->next" generates a new password and commits the updated password file automatically

pass/Controllers/PasswordDetailTableViewController.swift

@@ -117,7 +117,7 @@ class PasswordDetailTableViewController: UITableViewController, UIGestureRecogni
             self.present(alert, animated: true, completion: nil)
         }
         
-        self.setupUdateOneTimePassword()
+        self.setupUpdateOneTimePassword()
 
     }
     
@@ -159,7 +159,7 @@ class PasswordDetailTableViewController: UITableViewController, UIGestureRecogni
         }
     }
     
-    func setupUdateOneTimePassword() {
+    func setupUpdateOneTimePassword() {
         Timer.scheduledTimer(withTimeInterval: 1, repeats: true) {
             [weak self] timer in
             // bail out of the timer code if the object has been freed
@@ -236,7 +236,12 @@ class PasswordDetailTableViewController: UITableViewController, UIGestureRecogni
             switch token.generator.factor {
             case .counter(_):
                 // counter-based one time password
-                break
+                self.tableData.append(TableSection(title: "One time password", item: []))
+                tableDataIndex += 1
+                oneTimePasswordIndexPath = IndexPath(row: 0, section: tableDataIndex)
+                if let crtPassword = password.otpToken?.currentPassword {
+                    self.tableData[tableDataIndex].item.append(TableCell(title: "HMAC-based", content: crtPassword))
+                }
             case .timer(let period):
                 // time-based one time password
                 self.tableData.append(TableSection(title: "One time password", item: []))
@@ -306,8 +311,9 @@ class PasswordDetailTableViewController: UITableViewController, UIGestureRecogni
                     let menuController = UIMenuController.shared
                     let revealItem = UIMenuItem(title: "Reveal", action: #selector(LabelTableViewCell.revealPassword(_:)))
                     let concealItem = UIMenuItem(title: "Conceal", action: #selector(LabelTableViewCell.concealPassword(_:)))
+                    let nextPasswordItem = UIMenuItem(title: "Next Password", action: #selector(LabelTableViewCell.nextPassword(_:)))
                     let openURLItem = UIMenuItem(title: "Copy Password & Open Link", action: #selector(LabelTableViewCell.openLink(_:)))
-                    menuController.menuItems = [revealItem, concealItem, openURLItem]
+                    menuController.menuItems = [revealItem, concealItem, nextPasswordItem, openURLItem]
                     menuController.setTargetRect(tappedCell.contentLabel.frame, in: tappedCell.contentLabel.superview!)
                     menuController.setMenuVisible(true, animated: true)
                 }
@@ -342,9 +348,10 @@ class PasswordDetailTableViewController: UITableViewController, UIGestureRecogni
             let cell = tableView.dequeueReusableCell(withIdentifier: "labelCell", for: indexPath) as! LabelTableViewCell
             let titleData = tableData[sectionIndex].item[rowIndex].title
             let contentData = tableData[sectionIndex].item[rowIndex].content
-            cell.password = password
+            cell.passwordTableView = self
             cell.isPasswordCell = (titleData.lowercased() == "password" ? true : false)
             cell.isURLCell = (titleData.lowercased() == "url" ? true : false)
+            cell.isHOTPCell = (titleData == "HMAC-based" ? true : false)
             cell.cellData = LabelTableViewCellData(title: titleData, content: contentData)
             return cell
         }

pass/Models/Password.swift

@@ -143,15 +143,15 @@ class Password {
      Example of TOTP fields
      otp_secret: secretsecretsecretsecretsecretsecret
      otp_type: totp
-     otp_algorithm: sha1
+     otp_algorithm: sha1 (default: sha1, optional)
-     otp_period: 30
+     otp_period: 30 (default: 30, optional)
-     otp_digits: 6
+     otp_digits: 6 (default: 6, optional)
      
      Example of HOTP fields
      otp_secret: secretsecretsecretsecretsecretsecret
      otp_type: hotp
      otp_counter: 1
-     otp_digits: 6
+     otp_digits: 6 (default: 6, optional)
      
      */
     func updateOtpToken() {
@@ -170,12 +170,10 @@ class Password {
                 return
         }
         
-        // get algorithm
+        // get algorithm (optional)
         var algorithm = Generator.Algorithm.sha1
         if let algoString = getAdditionValue(withKey: "otp_algorithm") {
             switch algoString.lowercased() {
-                case "sha1":
-                    algorithm = Generator.Algorithm.sha1
                 case "sha256":
                     algorithm = Generator.Algorithm.sha256
                 case "sha512":
@@ -187,20 +185,58 @@ class Password {
     
         // construct the token
         if type == "totp" {
-            if let digits = Int(getAdditionValue(withKey: "otp_digits") ?? ""),
+            // HOTP
-                let period = Double(getAdditionValue(withKey: "otp_period") ?? "") {
+            // default: 6 digits, 30 seconds
+            guard let digits = Int(getAdditionValue(withKey: "otp_digits") ?? "6"),
+                let period = Double(getAdditionValue(withKey: "otp_period") ?? "30.0") else {
+                    let alertMessage = "Invalid otp_digits or otp_period."
+                    print(alertMessage)
+                    return
+            }
             guard let generator = Generator(
                 factor: .timer(period: period),
                 secret: secretData,
                 algorithm: algorithm,
                 digits: digits) else {
-                        print("Invalid generator parameters \(self.plainText)")
+                    let alertMessage = "Invalid OTP generator parameters."
+                    print(alertMessage)
+                    return
+            }
+            self.otpToken = Token(name: self.name, issuer: "", generator: generator)
+        } else {
+            // HOTP
+            // default: 6 digits
+            guard let digits = Int(getAdditionValue(withKey: "otp_digits") ?? "6"),
+                let counter = UInt64(getAdditionValue(withKey: "otp_counter") ?? "") else {
+                    let alertMessage = "Invalid otp_digits or otp_counter."
+                    print(alertMessage)
+                    return
+            }
+            guard let generator = Generator(
+                factor: .counter(counter),
+                secret: secretData,
+                algorithm: algorithm,
+                digits: digits) else {
+                    let alertMessage = "Invalid OTP generator parameters."
+                    print(alertMessage)
                     return
             }
             self.otpToken = Token(name: self.name, issuer: "", generator: generator)
         }
-        } else {
-            print("We do not support HOTP currently.")
     }
+    
+    // it is guaranteed that it is a HOTP password when we call this
+    func increaseHotpCounter() {
+        var lines : [String] = []
+        self.plainText.enumerateLines() { line, _ in
+            let (key, value) = Password.getKeyValuePair(from: line)
+            if key == "otp_counter", let newValue = UInt64(value)?.advanced(by: 1) {
+                let newLine = "\(key!): \(newValue)"
+                lines.append(newLine)
+            } else {
+                lines.append(line)
+            }
+        }
+        self.updatePassword(name: self.name, plainText: lines.joined(separator: "\n"))
     }
 }

pass/Views/LabelTableViewCell.swift

@@ -7,6 +7,7 @@
 //
 
 import UIKit
+import SVProgressHUD
 
 
 struct LabelTableViewCellData {
@@ -22,15 +23,27 @@ class LabelTableViewCell: UITableViewCell {
     var isPasswordCell = false
     var isURLCell = false
     var isReveal = false
-    var password: Password?
+    var isHOTPCell = false
     let passwordDots = "••••••••••••"
     
+    weak var passwordTableView : PasswordDetailTableViewController?
+    
     var cellData: LabelTableViewCellData? {
         didSet {
-            titleLabel.text = cellData?.title
+            titleLabel.text = cellData?.title ?? ""
             if isPasswordCell {
+                if isReveal {
+                    contentLabel.attributedText = Utils.attributedPassword(plainPassword: cellData?.content ?? "")
+                } else {
                     contentLabel.text = passwordDots
+                }
                 contentLabel.font = UIFont(name: "Menlo", size: contentLabel.font.pointSize)
+            } else if isHOTPCell {
+                if isReveal {
+                    contentLabel.text = cellData?.content ?? ""
+                } else {
+                    contentLabel.text = passwordDots
+                }
             } else {
                 contentLabel.text = cellData?.content
             }
@@ -62,6 +75,13 @@ class LabelTableViewCell: UITableViewCell {
         if isURLCell {
             return action == #selector(copy(_:)) || action == #selector(LabelTableViewCell.openLink(_:))
         }
+        if isHOTPCell {
+            if isReveal {
+                return action == #selector(copy(_:)) || action == #selector(LabelTableViewCell.concealPassword(_:)) || action == #selector(LabelTableViewCell.nextPassword(_:))
+            } else {
+                return action == #selector(copy(_:)) || action == #selector(LabelTableViewCell.revealPassword(_:)) || action == #selector(LabelTableViewCell.nextPassword(_:))
+            }
+        }
         return action == #selector(copy(_:))
     }
     
@@ -71,7 +91,11 @@ class LabelTableViewCell: UITableViewCell {
         
     func revealPassword(_ sender: Any?) {
         if let plainPassword = cellData?.content {
+            if isHOTPCell {
+                contentLabel.text = plainPassword
+            } else {
                 contentLabel.attributedText = Utils.attributedPassword(plainPassword: plainPassword)
+            }
         } else {
             contentLabel.text = ""
         }
@@ -83,8 +107,45 @@ class LabelTableViewCell: UITableViewCell {
         isReveal = false
     }
     
+    func nextPassword(_ sender: Any?) {
+        guard let password = passwordTableView?.password,
+            let passwordEntity = passwordTableView?.passwordEntity else {
+                print("Cannot find password/passwordEntity of a cell")
+                return;
+        }
+        
+        // increase HOTP counter
+        password.increaseHotpCounter()
+        
+        // only the HOTP password needs update
+        if let plainPassword = password.otpToken?.currentPassword {
+            cellData?.content = plainPassword
+            // contentLabel will be updated automatically
+        }
+        
+        // commit
+        if password.changed {
+            DispatchQueue.global(qos: .userInitiated).async {
+                PasswordStore.shared.update(passwordEntity: passwordEntity, password: password, progressBlock: {_ in })
+                DispatchQueue.main.async {
+                    passwordEntity.synced = false
+                    PasswordStore.shared.saveUpdated(passwordEntity: passwordEntity)
+                    NotificationCenter.default.post(Notification(name: Notification.Name("passwordUpdated")))
+                    // reload so that the "unsynced" symbol could be added
+                    self.passwordTableView?.tableView.reloadRows(at: [IndexPath(row: 0, section: 0)], with: UITableViewRowAnimation.automatic)
+                    SVProgressHUD.showSuccess(withStatus: "Password Copied\nCounter Updated")
+                    SVProgressHUD.dismiss(withDelay: 1)
+                }
+            }
+        }
+    }
+    
     func openLink(_ sender: Any?) {
-        Utils.copyToPasteboard(textToCopy: password?.password)
+        guard let password = passwordTableView?.password else {
+            print("Cannot find password of a cell")
+            return;
+        }
+        Utils.copyToPasteboard(textToCopy: password.password)
         UIApplication.shared.open(URL(string: cellData!.content)!, options: [:], completionHandler: nil)
     }
 }