//
//  ViewController.swift
//  BasicTunnel-iOS
//
//  Created by Davide De Rosa on 2/11/17.
//  Copyright (c) 2018 Davide De Rosa. All rights reserved.
//
//  https://github.com/keeshux
//
//  This file is part of TunnelKit.
//
//  TunnelKit is free software: you can redistribute it and/or modify
//  it under the terms of the GNU General Public License as published by
//  the Free Software Foundation, either version 3 of the License, or
//  (at your option) any later version.
//
//  TunnelKit is distributed in the hope that it will be useful,
//  but WITHOUT ANY WARRANTY; without even the implied warranty of
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//  GNU General Public License for more details.
//
//  You should have received a copy of the GNU General Public License
//  along with TunnelKit.  If not, see <http://www.gnu.org/licenses/>.
//
//  This file incorporates work covered by the following copyright and
//  permission notice:
//
//      Copyright (c) 2018-Present Private Internet Access
//
//      Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
//
//      The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
//
//      THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
//

import UIKit
import NetworkExtension
import TunnelKit

private let ca = CryptoContainer(pem: """
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----
""")

extension ViewController {
    private static let appGroup = "group.com.algoritmico.ios.demo.BasicTunnel"
    
    private static let bundleIdentifier = "com.algoritmico.ios.demo.BasicTunnel.BasicTunnelExtension"
    
    private func makeProtocol() -> NETunnelProviderProtocol {
        let server = textServer.text!
        let domain = textDomain.text!
        
        let hostname = ((domain == "") ? server : [server, domain].joined(separator: "."))
        let port = UInt16(textPort.text!)!
        let credentials = SessionProxy.Credentials(textUsername.text!, textPassword.text!)
        
        var sessionBuilder = SessionProxy.ConfigurationBuilder(ca: ca)
        sessionBuilder.cipher = .aes256gcm
        sessionBuilder.digest = .sha1
        sessionBuilder.compressionFraming = .compLZO
        sessionBuilder.renegotiatesAfter = nil
        sessionBuilder.usesPIAPatches = true
        var builder = TunnelKitProvider.ConfigurationBuilder(sessionConfiguration: sessionBuilder.build())
        let socketType: TunnelKitProvider.SocketType = switchTCP.isOn ? .tcp : .udp
        builder.endpointProtocols = [TunnelKitProvider.EndpointProtocol(socketType, port)]
        builder.mtu = 1350
        builder.shouldDebug = true
        builder.debugLogKey = "Log"
        
        let configuration = builder.build()
        return try! configuration.generatedTunnelProtocol(
            withBundleIdentifier: ViewController.bundleIdentifier,
            appGroup: ViewController.appGroup,
            hostname: hostname,
            credentials: credentials
        )
    }
}

class ViewController: UIViewController, URLSessionDataDelegate {
    @IBOutlet var textUsername: UITextField!
    
    @IBOutlet var textPassword: UITextField!
    
    @IBOutlet var textServer: UITextField!
    
    @IBOutlet var textDomain: UITextField!
    
    @IBOutlet var textPort: UITextField!
    
    @IBOutlet var switchTCP: UISwitch!
    
    @IBOutlet var buttonConnection: UIButton!

    @IBOutlet var textLog: UITextView!

    //
    
    var currentManager: NETunnelProviderManager?
    
    var status = NEVPNStatus.invalid
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        textServer.text = "germany"
        textDomain.text = "privateinternetaccess.com"
        textPort.text = "1198"
        switchTCP.isOn = false
        textUsername.text = "myusername"
        textPassword.text = "mypassword"
        
        NotificationCenter.default.addObserver(self,
                                               selector: #selector(VPNStatusDidChange(notification:)),
                                               name: .NEVPNStatusDidChange,
                                               object: nil)
        
        reloadCurrentManager(nil)

        //
        
        testFetchRef()
    }
    
    @IBAction func connectionClicked(_ sender: Any) {
        let block = {
            switch (self.status) {
            case .invalid, .disconnected:
                self.connect()
                
            case .connected, .connecting:
                self.disconnect()
                
            default:
                break
            }
        }
        
        if (status == .invalid) {
            reloadCurrentManager({ (error) in
                block()
            })
        }
        else {
            block()
        }
    }
    
    @IBAction func tcpClicked(_ sender: Any) {
        if switchTCP.isOn {
            textPort.text = "502"
        } else {
            textPort.text = "1198"
        }
    }
    
    func connect() {
        configureVPN({ (manager) in
            return self.makeProtocol()
        }, completionHandler: { (error) in
            if let error = error {
                print("configure error: \(error)")
                return
            }
            let session = self.currentManager?.connection as! NETunnelProviderSession
            do {
                try session.startTunnel()
            } catch let e {
                print("error starting tunnel: \(e)")
            }
        })
    }
    
    func disconnect() {
        configureVPN({ (manager) in
            return nil
        }, completionHandler: { (error) in
            self.currentManager?.connection.stopVPNTunnel()
        })
    }

    @IBAction func displayLog() {
        guard let vpn = currentManager?.connection as? NETunnelProviderSession else {
            return
        }
        try? vpn.sendProviderMessage(TunnelKitProvider.Message.requestLog.data) { (data) in
            guard let log = String(data: data!, encoding: .utf8) else {
                return
            }
            self.textLog.text = log
        }
    }

    func configureVPN(_ configure: @escaping (NETunnelProviderManager) -> NETunnelProviderProtocol?, completionHandler: @escaping (Error?) -> Void) {
        reloadCurrentManager { (error) in
            if let error = error {
                print("error reloading preferences: \(error)")
                completionHandler(error)
                return
            }
            
            let manager = self.currentManager!
            if let protocolConfiguration = configure(manager) {
                manager.protocolConfiguration = protocolConfiguration
            }
            manager.isEnabled = true
            
            manager.saveToPreferences { (error) in
                if let error = error {
                    print("error saving preferences: \(error)")
                    completionHandler(error)
                    return
                }
                print("saved preferences")
                self.reloadCurrentManager(completionHandler)
            }
        }
    }
    
    func reloadCurrentManager(_ completionHandler: ((Error?) -> Void)?) {
        NETunnelProviderManager.loadAllFromPreferences { (managers, error) in
            if let error = error {
                completionHandler?(error)
                return
            }
            
            var manager: NETunnelProviderManager?
            
            for m in managers! {
                if let p = m.protocolConfiguration as? NETunnelProviderProtocol {
                    if (p.providerBundleIdentifier == ViewController.bundleIdentifier) {
                        manager = m
                        break
                    }
                }
            }
            
            if (manager == nil) {
                manager = NETunnelProviderManager()
            }
            
            self.currentManager = manager
            self.status = manager!.connection.status
            self.updateButton()
            completionHandler?(nil)
        }
    }
    
    func updateButton() {
        switch status {
        case .connected, .connecting:
            buttonConnection.setTitle("Disconnect", for: .normal)
            
        case .disconnected:
            buttonConnection.setTitle("Connect", for: .normal)
            
        case .disconnecting:
            buttonConnection.setTitle("Disconnecting", for: .normal)
            
        default:
            break
        }
    }
    
    @objc private func VPNStatusDidChange(notification: NSNotification) {
        guard let status = currentManager?.connection.status else {
            print("VPNStatusDidChange")
            return
        }
        print("VPNStatusDidChange: \(status.rawValue)")
        self.status = status
        updateButton()
    }
    
    private func testFetchRef() {
//        let keychain = Keychain(group: ViewController.APP_GROUP)
//        let username = "foo"
//        let password = "bar"
//        
//        guard let _ = try? keychain.set(password: password, for: username) else {
//            print("Couldn't set password")
//            return
//        }
//        guard let passwordReference = try? keychain.passwordReference(for: username) else {
//            print("Couldn't get password reference")
//            return
//        }
//        guard let fetchedPassword = try? Keychain.password(for: username, reference: passwordReference) else {
//            print("Couldn't fetch password")
//            return
//        }
//
//        print("\(username) -> \(password)")
//        print("\(username) -> \(fetchedPassword)")
    }
}