/*

    Copyright (C) 2016 Apple Inc. All Rights Reserved.

    See LICENSE.txt for this sample’s licensing information

    Abstract:

    This file contains the StatusViewController class, which controls a view used to start and stop a VPN connection, and display the status of the VPN connection.

*/

import UIKit

import NetworkExtension

import SimpleTunnelServices

// MARK: Extensions

/// Make NEVPNStatus convertible to a string

extension NEVPNStatus: CustomStringConvertible {

    public var description: String {

        switch self {

            case .disconnected: return "Disconnected"

            case .invalid: return "Invalid"

            case .connected: return "Connected"

            case .connecting: return "Connecting"

            case .disconnecting: return "Disconnecting"

            case .reasserting: return "Reconnecting"

        }

    }

}

/// A view controller object for a view that displays VPN status information and allows the user to start and stop the VPN.

class StatusViewController: UITableViewController {

    // MARK: Properties

    /// A switch that toggles the enabled state of the VPN configuration.

    @IBOutlet weak var enabledSwitch: UISwitch!

    /// A switch that starts and stops the VPN.

    @IBOutlet weak var startStopToggle: UISwitch!

    /// A label that contains the current status of the VPN.

    @IBOutlet weak var statusLabel: UILabel!

    /// The target VPN configuration.

    var targetManager = NEVPNManager.shared()

    // MARK: UIViewController

    /// Handle the event where the view is being displayed.

    override func viewWillAppear(_ animated: Bool) {

        super.viewWillAppear(animated)

        // Initialize the UI

        enabledSwitch.isOn = targetManager.isEnabled

        startStopToggle.isOn = (targetManager.connection.status != .disconnected && targetManager.connection.status != .invalid)

        statusLabel.text = targetManager.connection.status.description

        navigationItem.title = targetManager.localizedDescription

        // Register to be notified of changes in the status.

        NotificationCenter.default.addObserver(forName: NSNotification.Name.NEVPNStatusDidChange, object: targetManager.connection, queue: OperationQueue.main, using: { notification in

            self.statusLabel.text = self.targetManager.connection.status.description

            self.startStopToggle.isOn = (self.targetManager.connection.status != .disconnected && self.targetManager.connection.status != .disconnecting && self.targetManager.connection.status != .invalid)

        })

        // Disable the start/stop toggle if the configuration is not enabled.

        startStopToggle.isEnabled = enabledSwitch.isOn

        // Send a simple IPC message to the provider, handle the response.

        if let session = targetManager.connection as? NETunnelProviderSession,

            let message = "Hello Provider".data(using: String.Encoding.utf8)

            , targetManager.connection.status != .invalid

        {

            do {

                try session.sendProviderMessage(message) { response in

                    if response != nil {

                        let responseString = NSString(data: response!, encoding: String.Encoding.utf8.rawValue)

                        simpleTunnelLog("Received response from the provider: \(responseString)")

                    } else {

                        simpleTunnelLog("Got a nil response from the provider")

                    }

                }

            } catch {

                simpleTunnelLog("Failed to send a message to the provider")

            }

        }

    }

    /// Handle the event where the view is being hidden.

    override func viewWillDisappear(_ animated: Bool) {

        super.viewWillDisappear(animated)

        // Stop watching for status change notifications.

        NotificationCenter.default.removeObserver(self, name: NSNotification.Name.NEVPNStatusDidChange, object: targetManager.connection)

    }

    /// Handle the user toggling the "enabled" switch.

    @IBAction func enabledToggled(_ sender: AnyObject) {

        targetManager.isEnabled = enabledSwitch.isOn

        targetManager.saveToPreferences { error in

            guard error == nil else {

                self.enabledSwitch.isOn = self.targetManager.isEnabled

                self.startStopToggle.isEnabled = self.enabledSwitch.isOn

                return

            }

            self.targetManager.loadFromPreferences { error in

                self.enabledSwitch.isOn = self.targetManager.isEnabled

                self.startStopToggle.isEnabled = self.enabledSwitch.isOn

            }

        }

    }

    /// Handle the user toggling the "VPN" switch.

    @IBAction func startStopToggled(_ sender: AnyObject) {

        if targetManager.connection.status == .disconnected || targetManager.connection.status == .invalid {

            do {

                try targetManager.connection.startVPNTunnel()

            }

            catch {

                simpleTunnelLog("Failed to start the VPN: \(error)")

            }

        }

        else {

            targetManager.connection.stopVPNTunnel()

        }

    }

}