//
//  PeersViewController.swift
//  YggdrasilNetwork
//
//  Created by Neil Alexander on 07/01/2019.
//

import UIKit
import NetworkExtension
import CoreTelephony

class PeersViewController: UITableViewController {
    var app = UIApplication.shared.delegate as! AppDelegate
    var config: [String: Any]? = nil
    
    @IBOutlet var peerTable: UITableView!
    @IBOutlet weak var addButtonItem: UIBarButtonItem!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        if let proto = self.app.vpnManager.protocolConfiguration as? NETunnelProviderProtocol {
            config = proto.providerConfiguration ?? nil
        }
        
        self.navigationItem.rightBarButtonItems = [
            self.editButtonItem,
            self.addButtonItem
        ]
    }
    
    override func viewWillAppear(_ animated: Bool) {
        NotificationCenter.default.addObserver(self, selector: #selector(self.onYggdrasilPeersUpdated), name: NSNotification.Name.YggdrasilPeersUpdated, object: nil)
    }
    
    override func viewWillDisappear(_ animated: Bool) {
        NotificationCenter.default.removeObserver(self, name: NSNotification.Name.YggdrasilPeersUpdated, object: nil)
    }
    
    @objc func onYggdrasilPeersUpdated(notification: NSNotification) {
        peerTable.reloadData()
    }

    // MARK: - Table view data source

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

    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        switch section {
        case 0: return app.yggdrasilPeers.count
        case 1:
            if let config = self.app.yggdrasilConfig {
                if let peers = config.get("Peers") as? [String] {
                    return peers.count
                }
            }
            return 0
        case 2:
            return 2
        default: return 0
        }
    }

    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        switch indexPath.section {
        case 0:
            let cell = tableView.dequeueReusableCell(withIdentifier: "discoveredPeerPrototype", for: indexPath)
            let peers = app.yggdrasilPeers.sorted { (a, b) -> Bool in
                return (a["Port"] as! Int) < (b["Port"] as! Int)
            }
            
            if indexPath.row < peers.count {
                let value = peers[indexPath.row]
                let proto = value["Protocol"] as? String ?? "tcp"
                let remote = value["Remote"] as? String ?? "unknown"
                let prio = value["Priority"] as? Int ?? 0
                
                cell.textLabel?.text = "\(value["IP"] ?? "(unknown)")"
                cell.detailTextLabel?.text = "\(proto.uppercased()): \(remote)"
            }
            return cell
        case 1:
            let cell = tableView.dequeueReusableCell(withIdentifier: "configuredPeerPrototype", for: indexPath)
            if let config = self.app.yggdrasilConfig {
                if let peers = config.get("Peers") as? [String] {
                    cell.textLabel?.text = peers[indexPath.last!]
                } else {
                    cell.textLabel?.text = "(unknown)"
                }
            }
            return cell
        case 2:
            switch indexPath.last {
            case 0:
                let cell = tableView.dequeueReusableCell(withIdentifier: "togglePrototype", for: indexPath) as! ToggleTableViewCell
                cell.isUserInteractionEnabled = true
                cell.label?.text = "Discoverable over multicast"
                cell.label?.isEnabled = true
                cell.toggle?.addTarget(self, action: #selector(toggledMulticastBeacons), for: .valueChanged)
                cell.toggle?.isEnabled = true
                if let config = self.app.yggdrasilConfig {
                    cell.toggle?.isOn = config.multicastBeacons
                }
                return cell
            case 1:
                let cell = tableView.dequeueReusableCell(withIdentifier: "togglePrototype", for: indexPath) as! ToggleTableViewCell
                cell.isUserInteractionEnabled = true
                cell.label?.text = "Search for multicast peers"
                cell.label?.isEnabled = true
                cell.toggle?.addTarget(self, action: #selector(toggledMulticastListen), for: .valueChanged)
                cell.toggle?.isEnabled = true
                if let config = self.app.yggdrasilConfig {
                    cell.toggle?.isOn = config.multicastListen
                }
                return cell
            default:
                let cell = tableView.dequeueReusableCell(withIdentifier: "menuPrototype", for: indexPath)
                cell.isUserInteractionEnabled = false
                cell.textLabel?.text = "Unknown"
                cell.textLabel?.isEnabled = true
                return cell
            }
        default:
            let cell = tableView.dequeueReusableCell(withIdentifier: "configuredPeerPrototype", for: indexPath)
            cell.textLabel?.text = "(unknown)"
            return cell
        }
    }
    
    func format(bytes: Double) -> String {
        guard bytes > 0 else {
            return "0 bytes"
        }

        // Adapted from http://stackoverflow.com/a/18650828
        let suffixes = ["bytes", "KB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB"]
        let k: Double = 1000
        let i = floor(log(bytes) / log(k))

        // Format number with thousands separator and everything below 1 GB with no decimal places.
        let numberFormatter = NumberFormatter()
        numberFormatter.maximumFractionDigits = i < 3 ? 0 : 1
        numberFormatter.numberStyle = .decimal

        let numberString = numberFormatter.string(from: NSNumber(value: bytes / pow(k, i))) ?? "Unknown"
        let suffix = suffixes[Int(i)]
        return "\(numberString) \(suffix)"
    }
    
    @objc func toggledMulticastBeacons(_ sender: UISwitch) {
        if let config = self.app.yggdrasilConfig {
            config.multicastBeacons = sender.isOn
            try? config.save(to: &app.vpnManager)
        }
    }
    
    @objc func toggledMulticastListen(_ sender: UISwitch) {
        if let config = self.app.yggdrasilConfig {
            config.multicastListen = sender.isOn
            try? config.save(to: &app.vpnManager)
        }
    }
    
    override func tableView(_ tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
        switch section {
        case 0:
            if self.app.yggdrasilPeers.count > 0 {
              return "Connected Peers"
            }
            return "No peers currently connected"
        case 1:
            if let config = self.app.yggdrasilConfig {
                if let peers = config.get("Peers") as? [String] {
                    if peers.count > 0 {
                        return "Configured Peers"
                    }
                }
            }
            return "No peers currently configured"
        case 2:
            return "Peer Connectivity"
        default: return "(Unknown)"
        }
    }
    
    override func tableView(_ tableView: UITableView, titleForFooterInSection section: Int) -> String? {
        switch section {
        case 1:
            return "Yggdrasil will automatically attempt to connect to configured peers when started. If you configure more than one peer, your device may carry traffic on behalf of other network nodes. Avoid this by configuring only a single peer."
        case 2:
            var str = "Multicast peers will be discovered on the same Wi-Fi network or via USB."
            if UIDevice.current.hasCellularCapabilites {
                str += " Data charges may apply when using mobile data. You can prevent mobile data usage in the device settings."
            }
            return str
        default: return nil
        }
    }
    
    override func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool {
        return indexPath.first == 1
    }
    
    override func tableView(_ tableView: UITableView, editActionsForRowAt indexPath: IndexPath) -> [UITableViewRowAction]? {
        switch indexPath.first {
        case 0:
            return [UITableViewRowAction(style: UITableViewRowAction.Style.default, title: "Disconnect", handler: { (action, index) in
                
            })]
        case 1:
            return [UITableViewRowAction(style: UITableViewRowAction.Style.normal, title: "Remove", handler: { (action, index) in
                print(action, index)
                if let config = self.app.yggdrasilConfig {
                    config.remove(index: index.last!, from: "Peers")
                    do {
                        try config.save(to: &self.app.vpnManager)
                        tableView.reloadSections(IndexSet(integer: 1), with: UITableView.RowAnimation.automatic)
                    } catch {
                        let alert = UIAlertController(title: "Error", message: error.localizedDescription, preferredStyle: .alert)
                        alert.addAction(UIAlertAction(title: "OK", style: .cancel, handler: nil))
                        self.parent?.present(alert, animated: true, completion: nil)
                        print("Error removing: \(error)")
                    }
                }
            })]
        default:
            return []
        }
    }
    
    override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        switch indexPath.first {
        case 2:
            if let last = indexPath.last, last == 2 {
                UIApplication.shared.open(NSURL(string:UIApplication.openSettingsURLString)! as URL, options: [:]) { (result) in
                    NSLog("Result " + result.description)
                }
            }
        default:
            break
        }
        tableView.deselectRow(at: indexPath, animated: true)
    }
    
    @IBAction func addNewPeerButtonPressed(_ sender: UIBarButtonItem) {
        let alert = UIAlertController(title: "Add Configured Peer", message: """
            Enter the full URI of the peer to add. Yggdrasil will automatically connect to this peer when started.
        """, preferredStyle: UIAlertController.Style.alert)
        let action = UIAlertAction(title: "Add", style: .default) { (alertAction) in
            let textField = alert.textFields![0] as UITextField
            if let text = textField.text?.trimmingCharacters(in: .whitespacesAndNewlines) {
                if let config = self.app.yggdrasilConfig {
                    if let peers = config.get("Peers") as? [String], !peers.contains(text) {
                        config.add(text, in: "Peers")
                        do {
                            try config.save(to: &self.app.vpnManager)
                            if let index = config.get("Peers") as? [String] {
                                self.peerTable.insertRows(at: [IndexPath(indexes: [1, index.count-1])], with: .automatic)
                                self.peerTable.reloadSections(IndexSet(integer: 1), with: UITableView.RowAnimation.automatic)
                            }
                        } catch {
                            let alert = UIAlertController(title: "Error", message: error.localizedDescription, preferredStyle: .alert)
                            alert.addAction(UIAlertAction(title: "OK", style: .cancel, handler: nil))
                            self.parent?.present(alert, animated: true, completion: nil)
                            print("Add error: \(error)")
                        }
                    } else {
                        let alert = UIAlertController(title: "Error", message: "Peer already exists", preferredStyle: .alert)
                        alert.addAction(UIAlertAction(title: "OK", style: .cancel, handler: nil))
                        self.parent?.present(alert, animated: true, completion: nil)
                    }
                }
            }
        }
        let cancel = UIAlertAction(title: "Cancel", style: .cancel)
        alert.addTextField { (textField) in
            textField.placeholder = "tcp://hostname:port"
        }
        alert.addAction(action)
        alert.addAction(cancel)
        self.present(alert, animated: true, completion: nil)
    }
    
}