macos-stats/Stats/Modules/Network/NetworkReader.swift

//
//  NetworkReader.swift
//  Stats
//
//  Created by Serhiy Mytrovtsiy on 24.06.2019.
//  Copyright © 2019 Serhiy Mytrovtsiy. All rights reserved.
//

import Cocoa

class NetworkReader: Reader {
    public var value: Observable<[Double]>!
    public var available: Bool = true
    public var availableAdditional: Bool = false
    public var updateInterval: Int = 0
    
    private var timer: Repeater?
    private var uploadValue: Int64 = 0
    private var downloadValue: Int64 = 0
    
    
    init() {
        self.value = Observable([])
        
        if self.available {
            self.read()
        }
        
        self.timer = Repeater.init(interval: .seconds(1), observer: { _ in
            self.read()
        })
    }
    
    func start() {
        read()
        if self.timer != nil && self.timer!.state.isRunning == false {
            self.timer!.start()
        }
    }
    
    func stop() {
        self.timer?.pause()
    }
    
    func read() {
        var interfaceAddresses: UnsafeMutablePointer<ifaddrs>? = nil

        var upload: Int64 = 0
        var download: Int64 = 0
        guard getifaddrs(&interfaceAddresses) == 0 else { return }

        var pointer = interfaceAddresses
        while pointer != nil {
            guard let info = getDataUsageInfo(from: pointer!) else {
                pointer = pointer!.pointee.ifa_next
                continue
            }
            pointer = pointer!.pointee.ifa_next
            upload = info[0]
            download = info[1]
        }
        freeifaddrs(interfaceAddresses)
        
        let lastUpload = self.uploadValue
        let lastDownload = self.downloadValue
        if lastUpload != 0 && lastDownload != 0 {
            DispatchQueue.main.async(execute: {
                self.value << [Double(download - lastDownload), Double(upload - lastUpload)]
            })
        }

        self.uploadValue = upload
        self.downloadValue = download
    }
    
    func getDataUsageInfo(from infoPointer: UnsafeMutablePointer<ifaddrs>) -> [Int64]? {
        let pointer = infoPointer

        let name: String! = String(cString: infoPointer.pointee.ifa_name)
        let addr = pointer.pointee.ifa_addr.pointee
        guard addr.sa_family == UInt8(AF_LINK) else { return nil }
        var networkData: UnsafeMutablePointer<if_data>? = nil
        
        if name.hasPrefix("en") {
            networkData = unsafeBitCast(pointer.pointee.ifa_data, to: UnsafeMutablePointer<if_data>.self)
            return [Int64(networkData?.pointee.ifi_obytes ?? 0), Int64(networkData?.pointee.ifi_ibytes ?? 0)] // upload, download
        }
        
        return nil
    }
    
    func setInterval(value: Int) {}
}