/*

    Copyright (C) 2018 Apple Inc. All Rights Reserved.

    See LICENSE.txt for this sample’s licensing information

    Abstract:

    Runs the UI to add a new SSID.

 */

import UIKit

/// This simple view controller lets the user enter the details of a network to

/// add.

///

/// It’s expecting to be presented modally, and calls delegate methods to

/// indicate that it’s done.

///

/// To simplify things this holds the ‘truth‘ (like the current SSID) in views

/// rather than in a model object or its own properties.  The goal here is to

/// keep things simple, not to show ideal app architecture.

///

/// Also see the comments about user defaults wrangling below.

class AddViewController : UITableViewController {

    /// An alias to bring this type into our namespace.

    typealias Delegate = AddViewControllerDelegate

    /// When the view controller is done it calls methods on this delegate.

    weak var delegate: Delegate?

    override func viewDidLoad() {

        super.viewDidLoad()

        self.readDefaults()

        self.updateViews()

    }

    @IBOutlet private var addBarButton: UIBarButtonItem!

    @IBOutlet private var ssidField: UITextField!

    @IBOutlet private var passwordField: UITextField!

    @IBOutlet private var isWEPSwitch: UISwitch!

    @IBOutlet private var joinOnceSwitch: UISwitch!

    /// The current SSID value.

    private var ssid: String {

        return self.ssidField.text ?? ""

    }

    /// The current password value.

    private var password: String? {

        return self.passwordField.text.flatMap({ $0.isEmpty ? nil : $0 })

    }

    /// Enables the *Add* button based on the current state of other views.

    private func updateViews() {

        self.addBarButton.isEnabled = !self.ssid.isEmpty

    }

    /// An alias to bring this type into our namespace.

    typealias Network = HotspotManager.Network

    /// Called when the user taps the *Add* button.

    @IBAction

    private func addAction(_ sender: Any) {

        let ssid = self.ssid

        guard !ssid.isEmpty else {

            // The Add button should have been disabled in this case, so we

            // assert if it happens.

            assert(false)

            return

        }

        let network = Network(

            ssid: ssid, 

            password: self.password,

            isWEP: self.isWEPSwitch.isOn,

            joinOnce: self.joinOnceSwitch.isOn

        )

        self.delegate?.add(network: network, addViewController: self)

        self.saveDefaults()

    }

    /// Called when the user taps the *Cancel* button.

    @IBAction

    private func cancelAction(_ sender: Any) {

        self.delegate?.cancel(addViewController: self)

        self.saveDefaults()

    }

    /// Called when the changes the text in a text field.

    @IBAction

    private func textFieldDidChange(_ sender: Any) {

        self.updateViews()

    }

}

// MARK: - User defaults wrangling

// Note that our approach to user defaults is kinda weird.  For example:

//

// * We save to user defaults even if the user taps *Cancel*.

//

// * We store a password in the user defaults, whereas passwords belong in the

//   keychain.

//

// This all makes sense in the context of a sample app like this one, but in a

// real app you should store security sensitive data in the keychain.

extension AddViewController {

    /// Set up the views from user default.

    private func readDefaults() {

        let defaults = UserDefaults.standard

        self.ssidField.text = defaults.string(forKey: "addSSID")

        self.passwordField.text = defaults.string(forKey: "addPassword")

        self.isWEPSwitch.isOn = defaults.bool(forKey: "addIsWEP")

        self.joinOnceSwitch.isOn = defaults.bool(forKey: "addJoinOnce")

    }

    /// Saves the views to user default.

    private func saveDefaults() {

        let defaults = UserDefaults.standard

        func save(string value: String?, key: String) {

            if let v = value, !v.isEmpty {

                defaults.set(v, forKey: key)

            } else {

                defaults.removeObject(forKey: key)

            }

        }

        save(string: self.ssidField.text, key: "addSSID")

        save(string: self.passwordField.text, key: "addPassword")

        defaults.set(self.isWEPSwitch.isOn, forKey: "addIsWEP")

        defaults.set(self.joinOnceSwitch.isOn, forKey: "addJoinOnce")

    }

}

protocol AddViewControllerDelegate : AnyObject {

    /// This delegate callback is called when the user successfully enters the 

    /// details of a network to add.

    ///

    /// - Parameters:

    ///   - network: Details of the network to add.

    ///   - addViewController: A reference to the view controller itself.

    func add(network: AddViewController.Network, addViewController: AddViewController)

    /// This delegate callback is called when the user hits cancel.

    ///

    ///   - addViewController: A reference to the view controller itself.

    func cancel(addViewController: AddViewController)

}