deltachat-ios/deltachat-ios/Controller/AccountSetupController.swift

import SafariServices
import UIKit
import UICircularProgressRing

class AccountSetupController: UITableViewController {

    weak var coordinator: AccountSetupCoordinator?

    private var skipOauth = false

    private var backupProgressObserver: Any?
    private var configureProgressObserver: Any?
    private var oauth2Observer: Any?

    lazy var configProgressIndicator: UICircularProgressRing = {
        let progress = UICircularProgressRing()
        progress.style = UICircularRingStyle.inside
        progress.outerRingColor = UIColor.clear
        progress.maxValue = 100
        progress.innerRingColor = DcColors.primary
        progress.innerRingWidth = 2
        progress.startAngle = 270
        progress.fontColor = UIColor.lightGray
        progress.font = UIFont.systemFont(ofSize: 12)
        return progress
    }()

    lazy var configProgressAlert: UIAlertController = {
        let alert = UIAlertController(title: String.localized("configuring_account"), message: "\n\n\n", preferredStyle: .alert)
        // temp workaround: add 3 newlines to let alertbox grow to fit progressview
        let progressView = configProgressIndicator
        progressView.translatesAutoresizingMaskIntoConstraints = false
        alert.view.addSubview(progressView)
        progressView.centerXAnchor.constraint(equalTo: alert.view.centerXAnchor).isActive = true
        progressView.centerYAnchor.constraint(equalTo: alert.view.centerYAnchor, constant: 0).isActive = true
        progressView.heightAnchor.constraint(equalToConstant: 65).isActive = true
        progressView.widthAnchor.constraint(equalToConstant: 65).isActive = true
        alert.addAction(UIAlertAction(title: String.localized("cancel"), style: .cancel, handler: loginCancelled(_:)))
        return alert
    }()

    private lazy var emailCell: TextFieldCell = {
        let cell = TextFieldCell.makeEmailCell(delegate: self)
        cell.textField.tag = 0
        cell.textField.accessibilityIdentifier = "emailTextField" // will be used to eventually show oAuth-Dialogue when pressing return key
        cell.setText(text: DcConfig.addr ?? nil)
        cell.textField.delegate = self
        return cell
    }()

    private lazy var passwordCell: TextFieldCell = {
        let cell = TextFieldCell.makePasswordCell(delegate: self)
        cell.textField.tag = 1
        cell.accessibilityIdentifier = "passwordCell" // will be used to eventually show oAuth-Dialogue when selecting
        cell.setText(text: DcConfig.mailPw ?? nil)
        return cell
    }()

    private lazy var restoreCell: ActionCell = {
        let cell = ActionCell(frame: .zero)
        cell.actionTitle = String.localized("import_backup_title")
        cell.accessibilityIdentifier = "restoreCell"
        return cell
    }()

    lazy var imapServerCell: TextFieldCell = {
        let cell = TextFieldCell(descriptionID: "login_imap_server",
                                 placeholder: DcConfig.mailServer ?? DcConfig.configuredMailServer,
                                 delegate: self)
        cell.accessibilityIdentifier = "IMAPServerCell"
        cell.textField.tag = 2
        cell.textField.autocorrectionType = .no
        cell.textField.spellCheckingType = .no
        cell.textField.autocapitalizationType = .none
        return cell
    }()

    lazy var imapUserCell: TextFieldCell = {
        let cell = TextFieldCell(descriptionID: "login_imap_login", placeholder: DcConfig.mailUser ?? DcConfig.configuredMailUser, delegate: self)
        cell.accessibilityIdentifier = "IMAPUserCell"
        cell.textField.tag = 3
        return cell
    }()

    lazy var imapPortCell: UITableViewCell = {
        let cell = UITableViewCell(style: .value1, reuseIdentifier: nil)
        cell.textLabel?.text = String.localized("login_imap_port")
        cell.accessoryType = .disclosureIndicator
        cell.detailTextLabel?.text = DcConfig.mailPort ?? DcConfig.configuredMailPort
        cell.accessibilityIdentifier = "IMAPPortCell"
        cell.selectionStyle = .none
        return cell
    }()

    lazy var imapSecurityCell: UITableViewCell = {
        let text = "\(DcConfig.getImapSecurity())"
        let cell = UITableViewCell(style: .value1, reuseIdentifier: nil)
        cell.textLabel?.text = String.localized("login_imap_security")
        // let cell = TextFieldCell(description: "IMAP Security", placeholder: text, delegate: self)
        cell.accessibilityIdentifier = "IMAPSecurityCell"
        cell.accessoryType = .disclosureIndicator
        cell.detailTextLabel?.text = "\(DcConfig.getImapSecurity())"
        cell.selectionStyle = .none
        return cell
    }()

    lazy var smtpServerCell: TextFieldCell = {
        let cell = TextFieldCell(descriptionID: "login_smtp_server",
                                 placeholder: DcConfig.sendServer ?? DcConfig.configuredSendServer,
                                 delegate: self)
        cell.accessibilityIdentifier = "SMTPServerCell"
        cell.textField.tag = 4
        cell.textField.autocorrectionType = .no
        cell.textField.spellCheckingType = .no
        cell.textField.autocapitalizationType = .none
        return cell
    }()

    lazy var smtpUserCell: TextFieldCell = {
        let cell = TextFieldCell(descriptionID: "login_smtp_login", placeholder: DcConfig.sendUser ?? DcConfig.configuredSendUser, delegate: self)
        cell.accessibilityIdentifier = "SMTPUserCell"
        cell.textField.tag = 5
        return cell
    }()

    lazy var smtpPortCell: UITableViewCell = {
        let cell = UITableViewCell(style: .value1, reuseIdentifier: nil)
        cell.textLabel?.text = String.localized("login_smtp_port")
        cell.accessoryType = .disclosureIndicator
        cell.detailTextLabel?.text = DcConfig.sendPort ?? DcConfig.configuredSendPort
        cell.accessibilityIdentifier = "SMTPPortCell"
        cell.selectionStyle = .none
        return cell
    }()

    lazy var smtpPasswordCell: TextFieldCell = {
        let cell = TextFieldCell(descriptionID: "login_smtp_password", placeholder: "*************", delegate: self)
        cell.textField.textContentType = UITextContentType.password
        cell.textField.isSecureTextEntry = true
        cell.accessibilityIdentifier = "SMTPPasswordCell"
        cell.textField.tag = 6
        return cell
    }()

    lazy var smtpSecurityCell: UITableViewCell = {
        let security = "\(DcConfig.getSmtpSecurity())"
        let cell = UITableViewCell(style: .value1, reuseIdentifier: nil)
        cell.textLabel?.text = String.localized("login_smtp_security")
        cell.detailTextLabel?.text = security
        cell.accessibilityIdentifier = "SMTPSecurityCell"
        cell.accessoryType = .disclosureIndicator
        cell.selectionStyle = .none
        return cell
    }()

    // this loginButton can be enabled and disabled
    private lazy var loginButton: UIBarButtonItem = {
        let button = UIBarButtonItem(title: String.localized("login_title"), style: .done, target: self, action: #selector(loginButtonPressed))
        button.isEnabled = dc_is_configured(mailboxPointer) == 0
        return button
    }()

    private lazy var basicSectionCells: [UITableViewCell] = [emailCell, passwordCell]
    private lazy var restoreCells: [UITableViewCell] = [restoreCell]
    private lazy var advancedSectionCells: [UITableViewCell] = [
        imapServerCell,
        imapUserCell,
        imapPortCell,
        imapSecurityCell,
        smtpServerCell,
        smtpUserCell,
        smtpPortCell,
        smtpPasswordCell,
        smtpSecurityCell
    ]

    private var advancedSectionShowing: Bool = false

    init() {
        super.init(style: .grouped)
        hidesBottomBarWhenPushed = true
    }

    required init?(coder _: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        title = String.localized("login_header")
        // navigationItem.leftBarButtonItem = UIBarButtonItem(title: "Close", style: .plain, target: self, action: #selector(closeButtonPressed))
        navigationItem.rightBarButtonItem = loginButton
    }

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        // needs to be changed if returning from portSettingsController
        smtpPortCell.detailTextLabel?.text = DcConfig.sendPort ?? DcConfig.configuredSendPort
        imapPortCell.detailTextLabel?.text = DcConfig.mailPort ?? DcConfig.configuredMailPort
        smtpSecurityCell.detailTextLabel?.text = SecurityConverter.convertHexToString(type: .SMTPSecurity, hex: DcConfig.getSmtpSecurity())
        imapSecurityCell.detailTextLabel?.text  = SecurityConverter.convertHexToString(type: .IMAPSecurity, hex: DcConfig.getImapSecurity())
    }

    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)
        addProgressHudEventListener()
        // loginButton.isEnabled = false
    }

    override func viewWillDisappear(_ animated: Bool) {
        resignFirstResponderOnAllCells()
    }

    override func viewDidDisappear(_: Bool) {

        let nc = NotificationCenter.default
        if let backupProgressObserver = self.backupProgressObserver {
            nc.removeObserver(backupProgressObserver)
        }
        if let configureProgressObserver = self.configureProgressObserver {
            nc.removeObserver(configureProgressObserver)
        }
        if let oauth2Observer = self.oauth2Observer {
            nc.removeObserver(oauth2Observer)
        }
    }

    // MARK: - Table view data source

    override func numberOfSections(in _: UITableView) -> Int {
        return 3
    }

    override func tableView(_: UITableView, numberOfRowsInSection section: Int) -> Int {
        if section == 0 {
            return basicSectionCells.count
        } else if section == 1 {
            return restoreCells.count
        } else {
            return advancedSectionShowing ? advancedSectionCells.count : 0
        }
    }

    override func tableView(_: UITableView, titleForHeaderInSection section: Int) -> String? {
        if section == 2 {
            return String.localized("menu_advanced")
        } else {
            return nil
        }
    }

    override func tableView(_: UITableView, viewForHeaderInSection section: Int) -> UIView? {
        if section == 2 {
            // Advanced Header
            let advancedView = AdvancedSectionHeader()
            advancedView.handleTap = toggleAdvancedSection
            // set tapHandler
            return advancedView

        } else {
            return nil
        }
    }

    override func tableView(_: UITableView, heightForHeaderInSection _: Int) -> CGFloat {
        return 36.0
    }

    override func tableView(_: UITableView, titleForFooterInSection section: Int) -> String? {
        if section == 0 {
            return String.localized("login_no_servers_hint")
        } else if section == 2 {
            if advancedSectionShowing {
                return String.localized("login_subheader")
            } else {
                return nil
            }
        } else {
            return nil
        }
    }

    override func tableView(_: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let section = indexPath.section
        let row = indexPath.row

        if section == 0 {
            // basicSection
            return basicSectionCells[row]
        } else if section == 1 {
            return restoreCells[row]
        } else {
            // advancedSection
            return advancedSectionCells[row]
        }
    }

    // FIXME: replace if-else-if with switch-case
    override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        guard let tappedCell = tableView.cellForRow(at: indexPath) else { return }
        // handle tap on password -> show oAuthDialogue
        if let textFieldCell = tappedCell as? TextFieldCell {
            if textFieldCell.accessibilityIdentifier == "passwordCell" {
                if let emailAdress = textFieldCell.getText() {
                    _ = showOAuthAlertIfNeeded(emailAddress: emailAdress, handleCancel: nil)
                }
            }
        }

        if tappedCell.accessibilityIdentifier == "restoreCell" {
            restoreBackup()
        } else if tappedCell.accessibilityIdentifier == "IMAPPortCell" {
            coordinator?.showImapPortOptions()
        } else if tappedCell.accessibilityIdentifier == "SMTPPortCell" {
            coordinator?.showSmtpPortsOptions()
        } else if tappedCell.accessibilityIdentifier == "IMAPSecurityCell" {
            coordinator?.showImapSecurityOptions()
        } else if tappedCell.accessibilityIdentifier == "SMTPSecurityCell" {
            coordinator?.showSmptpSecurityOptions()
        }
    }

    private func toggleAdvancedSection(button: UILabel) {
        let willShow = !advancedSectionShowing

        // extract indexPaths from advancedCells
        let advancedIndexPaths: [IndexPath] = advancedSectionCells.indices.map { IndexPath(row: $0, section: 2) }

        // advancedSectionCells.indices.map({indexPaths.append(IndexPath(row: $0, section: 1))}

        // set flag before delete/insert operation, because cellForRowAt will be triggered and uses this flag
        advancedSectionShowing = willShow

        button.text = String.localized(willShow ? "hide" : "pref_notifications_show")

        if willShow {
            tableView.insertRows(at: advancedIndexPaths, with: .fade)
        } else {
            tableView.deleteRows(at: advancedIndexPaths, with: .fade)
        }
        tableView.reloadData() // to re-organize footer view (without that sometimes advanced section footer is still visible)
    }

    @objc private func loginButtonPressed() {
        guard let emailAddress = emailCell.getText() else {
            return // handle case when either email or pw fields are empty
        }

        let oAuthStarted = showOAuthAlertIfNeeded(emailAddress: emailAddress, handleCancel: loginButtonPressed)
        // if canceled we will run this method again but this time oAuthStarted will be false

        if oAuthStarted {
            // the loginFlow will be handled by oAuth2
            return
        }

        let password = passwordCell.getText() ?? "" // empty passwords are ok -> for oauth there is no password needed

        login(emailAddress: emailAddress, password: password)
    }

    private func login(emailAddress: String, password: String, skipAdvanceSetup: Bool = false) {
        resignFirstResponderOnAllCells()	// this will resign focus from all textFieldCells so the keyboard wont pop up anymore
        DcConfig.addr = emailAddress
        DcConfig.mailPw = password

        if !skipAdvanceSetup {
            evaluateAdvancedSetup() // this will set MRConfig related to advanced fields
        }

        print("oAuth-Flag when loggin in: \(DcConfig.getAuthFlags())")
        dc_configure(mailboxPointer)
        showProgressHud()
    }

    @objc func closeButtonPressed() {
        dismiss(animated: true, completion: nil)
    }

    // returns true if needed
    private func showOAuthAlertIfNeeded(emailAddress: String, handleCancel: (() -> Void)?) -> Bool {
        return false

        // disable oauth2 for now as not yet supported by deltachat-rust.
        /*
         if skipOauth {
         	// user has previously denied oAuth2-setup
         	return false
         }

         guard let oAuth2UrlPointer = dc_get_oauth2_url(mailboxPointer, emailAddress, "chat.delta:/auth") else {
         	//MRConfig.setAuthFlags(flags: Int(DC_LP_AUTH_NORMAL)) -- do not reset, there may be different values
         	return false
         }

         let oAuth2Url = String(cString: oAuth2UrlPointer)

         if let url = URL(string: oAuth2Url) {
         	let title = "Continue with simplified setup"
         	// swiftlint:disable all
         	let message = "The entered e-mail address supports a simplified setup (oAuth2).\n\nIn the next step, please allow Delta Chat to act as your Chat with E-Mail app.\n\nThere are no Delta Chat servers, your data stays on your device."

         	let oAuthAlertController = UIAlertController(title: title, message: message, preferredStyle: .alert)
         	let confirm = UIAlertAction(title: "Confirm", style: .default, handler: {
         		[unowned self] _ in
         		let nc = NotificationCenter.default
         		self.oauth2Observer = nc.addObserver(self, selector: #selector(self.oauthLoginApproved), name: NSNotification.Name("oauthLoginApproved"), object: nil)
         		self.launchOAuthBrowserWindow(url: url)
         	})
         	let cancel = UIAlertAction(title: "Cancel", style: .cancel, handler: {
         		_ in
         		MRConfig.setAuthFlags(flags: Int(DC_LP_AUTH_NORMAL))
         		self.skipOauth = true
         		handleCancel?()

         	})
         	oAuthAlertController.addAction(confirm)
         	oAuthAlertController.addAction(cancel)

         	present(oAuthAlertController, animated: true, completion: nil)
         	return true
         } else {
         	return false
         }
         */
    }

    @objc func oauthLoginApproved(notification: Notification) {
        guard let userInfo = notification.userInfo, let token = userInfo["token"] as? String, let emailAddress = emailCell.getText() else {
            return
        }
        passwordCell.setText(text: token)
        DcConfig.setAuthFlags(flags: Int(DC_LP_AUTH_OAUTH2))
        login(emailAddress: emailAddress, password: token, skipAdvanceSetup: true)
    }

    private func launchOAuthBrowserWindow(url: URL) {
        UIApplication.shared.open(url) // this opens safari as seperate app
    }

    private func addProgressHudEventListener() {
        let nc = NotificationCenter.default
        backupProgressObserver = nc.addObserver(
            forName: dcNotificationBackupProgress,
            object: nil,
            queue: nil
        ) {
            notification in
            if let ui = notification.userInfo {
                if ui["error"] as! Bool {
                    self.updateProgressHud(error: ui["errorMessage"] as? String)
                } else if ui["done"] as! Bool {
                    self.updateProgressHudSuccess(callback: self.handleLoginSuccess)
                } else {
                    self.updateProgressHudValue(value: ui["progress"] as? Int)
                }
            }
        }
        configureProgressObserver = nc.addObserver(
            forName: dcNotificationConfigureProgress,
            object: nil,
            queue: nil
        ) {
            notification in
            if let ui = notification.userInfo {
                if ui["error"] as! Bool {
                    self.updateProgressHud(error: ui["errorMessage"] as? String)
                } else if ui["done"] as! Bool {
                    self.updateProgressHudSuccess(callback: self.handleLoginSuccess)
                } else {
                    self.updateProgressHudValue(value: ui["progress"] as? Int)
                }
            }
        }
    }

    private func evaluateAdvancedSetup() {
        for cell in advancedSectionCells {
            if let textFieldCell = cell as? TextFieldCell {
                switch cell.accessibilityIdentifier {
                case "IMAPServerCell":
                    DcConfig.mailServer = textFieldCell.getText() ?? nil
                case "IMAPUserCell":
                    DcConfig.mailUser = textFieldCell.getText() ?? nil
                case "IMAPPortCell":
                    DcConfig.mailPort = textFieldCell.getText() ?? nil
                case "IMAPSecurityCell":
                    let flag = 0
                    DcConfig.setImapSecurity(imapFlags: flag)
                case "SMTPServerCell":
                    DcConfig.sendServer = textFieldCell.getText() ?? nil
                case "SMTPUserCell":
                    DcConfig.sendUser = textFieldCell.getText() ?? nil
                case "SMTPPortCell":
                    DcConfig.sendPort = textFieldCell.getText() ?? nil
                case "SMTPPasswordCell":
                    DcConfig.sendPw = textFieldCell.getText() ?? nil
                case "SMTPSecurityCell":
                    let flag = 0
                    DcConfig.setSmtpSecurity(smptpFlags: flag)
                default:
                    logger.info("unknown identifier", cell.accessibilityIdentifier ?? "")
                }
            }
        }
    }

    private func restoreBackup() {
        logger.info("restoring backup")
        if DcConfig.configured {
            return
        }
        let documents = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)
        if !documents.isEmpty {
            logger.info("looking for backup in: \(documents[0])")

            if let file = dc_imex_has_backup(mailboxPointer, documents[0]) {
                logger.info("restoring backup: \(String(cString: file))")

                // hudHandler.showBackupHud("Restoring Backup")
                dc_imex(mailboxPointer, DC_IMEX_IMPORT_BACKUP, file, nil)

                return
            }

            let alert = UIAlertController(title: String.localized("import_backup_title"), message: String.localizedStringWithFormat(String.localized("import_backup_no_backup_found"), "DUMMYPATH TBD"), preferredStyle: .alert)
            alert.addAction(UIAlertAction(title: String.localized("ok"), style: .cancel, handler: { _ in

            }))
            present(alert, animated: true, completion: nil)
            return
        }

        logger.error("no documents directory found")
    }

    private func handleLoginSuccess() {
        // used when login hud successfully went trough
        dismiss(animated: true, completion: nil)
        let appDelegate = UIApplication.shared.delegate as! AppDelegate
        appDelegate.registerForPushNotifications()
    }

    private func resignFirstResponderOnAllCells() {
        let _ = basicSectionCells.map({
            resignCell(cell: $0)
        })

        let _ = advancedSectionCells.map({
            resignCell(cell: $0)
        }
        )
    }

    func resignCell(cell: UITableViewCell) {
        if let c = cell as? TextFieldCell {
            c.textField.resignFirstResponder()
        }
    }
}

extension AccountSetupController: UITextFieldDelegate {
    func textFieldShouldReturn(_ textField: UITextField) -> Bool {
        let currentTag = textField.tag
        if let nextField = tableView.viewWithTag(currentTag + 1) as? UITextField {
            if nextField.tag > 1, !advancedSectionShowing {
                // gets here when trying to activate a collapsed cell
                return false
            }
            nextField.becomeFirstResponder()
        }
        return false
    }

    func textFieldDidBeginEditing(_ textField: UITextField) {
        if textField.accessibilityIdentifier == "emailTextField" {
            loginButton.isEnabled = true
            // this will re-enable possible oAuth2-login
            skipOauth = false
        }
    }

    func textFieldDidEndEditing(_ textField: UITextField) {
        if textField.accessibilityIdentifier == "emailTextField" {
            let _ = showOAuthAlertIfNeeded(emailAddress: textField.text ?? "", handleCancel: {
                self.passwordCell.textField.becomeFirstResponder()
            })
        }
    }
}

class AdvancedSectionHeader: UIView {
    var handleTap: ((UILabel) -> Void)?

    private var label: UILabel = {
        let label = UILabel()
        label.text = String.localized("menu_advanced").uppercased()
        label.font = UIFont.systemFont(ofSize: 15)
        label.textColor = UIColor.darkGray
        return label
    }()

    /*
     why UILabel, why no UIButton? For unknown reasons UIButton's target function was not triggered when one of the textfields in the tableview was active -> used label as workaround
     */
    private lazy var toggleButton: UILabel = {
        let label = UILabel()
        label.text = String.localized("pref_notifications_show")
        label.font = UIFont.systemFont(ofSize: 15, weight: .medium)
        label.textColor = UIColor.systemBlue
        return label
    }()

    init() {
        super.init(frame: .zero) // will be constraint from tableViewDelegate
        setupSubviews()
        let tap = UITapGestureRecognizer(target: self, action: #selector(viewTapped)) // use this if the whole header is supposed to be clickable
        addGestureRecognizer(tap)
    }

    required init?(coder _: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    func setupSubviews() {
        addSubview(label)
        label.translatesAutoresizingMaskIntoConstraints = false
        label.leadingAnchor.constraint(equalTo: leadingAnchor, constant: 15).isActive = true
        label.centerYAnchor.constraint(equalTo: centerYAnchor, constant: 0).isActive = true
        addSubview(toggleButton)
        toggleButton.translatesAutoresizingMaskIntoConstraints = false
        toggleButton.leadingAnchor.constraint(equalTo: trailingAnchor, constant: -60).isActive = true // since button will change title it should be left aligned
        toggleButton.centerYAnchor.constraint(equalTo: label.centerYAnchor, constant: 0).isActive = true
    }

    @objc func buttonTapped(_: UIButton) {
        // handleTap?(button)
    }

    @objc func viewTapped() {
        handleTap?(toggleButton)
    }
}

extension AccountSetupController {

    func showProgressHud() {
        configProgressAlert.actions[0].isEnabled = true
        configProgressAlert.title = String.localized("configuring_account")
        configProgressAlert.message = "\n\n\n"	// workaround to create space for progress indicator
        configProgressIndicator.alpha = 1
        configProgressIndicator.value = 0
        present(configProgressAlert, animated: true, completion: nil)

    }

    func updateProgressHud(error message: String?) {
        configProgressAlert.title = String.localized("login_error_title")
        configProgressAlert.message = message
        configProgressIndicator.alpha = 0
    }

    func updateProgressHudSuccess(callback: (()->())?) {
        configProgressAlert.actions[0].isEnabled = false
        configProgressIndicator.alpha = 0
        configProgressAlert.title = String.localized("login_successful_title")
        configProgressAlert.message = String.localized("login_successful_message")
        loginButton.isEnabled = dc_is_configured(mailboxPointer) == 0
        DispatchQueue.main.asyncAfter(deadline: .now() + 2, execute: {
            self.configProgressAlert.dismiss(animated: true) {
                self.handleLoginSuccess()
            }
        })
    }

    private func updateProgressHudValue(value: Int?) {
        if let value = value {
            print("progress hud: \(value)")
            configProgressIndicator.value = CGFloat(value / 10)
        }
    }

    func loginCancelled(_ action: UIAlertAction) {
        DcConfig.addr = nil
        DcConfig.mailPw = nil
        DispatchQueue.global(qos: .background).async {
            dc_stop_ongoing_process(mailboxPointer)		// this function freezes UI so execute in background thread
        }
    }
}