JourneyGPSTracker/JourneyGPSTracker/ViewController.swift

//
//  ViewController.swift
//  JourneyGPSTracker
//
//  Created by Thomas Chef on 2022-04-16.
//  Copyright © 2022 Thomas Chef. All rights reserved.
//

import UIKit
import CoreLocation
import CoreData

class ViewController: UIViewController {
    
    struct GPS_POS_LOG: Codable {
        var latitude: Double
        var longitude: Double
        var ts: String
        var horizAcc: Int32
    }
   
    
    @IBOutlet weak var horizSpeedLabelUI: UILabel!
    @IBOutlet weak var distSliderUI: UISlider!
    @IBOutlet weak var distUpdateMetersUI: UILabel!
    @IBOutlet weak var GPSAccuracy: UILabel!
    @IBOutlet weak var noOfFailedUpdatesUI: UILabel!
    @IBOutlet weak var latestTSSent: UILabel!
    @IBOutlet weak var noOfRxGPSPos: UILabel!
    @IBOutlet weak var noOfSentGPSToServer: UILabel!
    @IBOutlet weak var pauseSwitch: UISwitch!
    @IBOutlet weak var clickButton: UIButton!
    @IBOutlet weak var trackingActivateSwitch: UISwitch!
    
    var locationManager: CLLocationManager?
    
    var noOfSentPos: Int = 0
    var noOfSentToServer: Int = 0
    var noOfFailedUpdates: Int = 0
    
    var gpsLogData: [NSManagedObject] = []
    
    let appDelegate = UIApplication.shared.delegate as! AppDelegate
    
    var latestDateSuccSent: Date = Date(timeIntervalSinceReferenceDate: -123456789.0)
    
    override func viewDidLoad() {
        super.viewDidLoad()
        locationManager = CLLocationManager()
        locationManager?.delegate = self
        locationManager?.requestWhenInUseAuthorization()
        locationManager?.requestAlwaysAuthorization()
        locationManager?.desiredAccuracy = kCLLocationAccuracyBest //kCLLocationAccuracyNearestTenMeters
        locationManager?.activityType = CLActivityType.otherNavigation
        locationManager?.distanceFilter = CLLocationDistance(distSliderUI.value)
        locationManager?.allowsBackgroundLocationUpdates = true
        pauseSwitch.isEnabled = false
        distUpdateMetersUI.text = String(distSliderUI.value)+" m"
    }
    
    @IBAction func distSlider(_ sender: UISlider) {
        let currentValue = Int(sender.value)
        distUpdateMetersUI.text = String(currentValue)+" m"
        locationManager?.distanceFilter = CLLocationDistance(currentValue)
    }
    
    
    // This timer is used to send data to the back-end server every 60 seconds
    // Data source is the core data DB
    func setupTimer() {
        
        _ = Timer.scheduledTimer(withTimeInterval: 60.0, repeats: true) { [self] timer in
            
            var latestDate: Date = Date(timeIntervalSinceReferenceDate: -123456789.0)
            
            let cnxt = self.appDelegate.persistentContainer.viewContext
            let request: NSFetchRequest<GPS> = GPS.fetchRequest()
            let myPredicate = NSPredicate(format: "ts > %@", latestDateSuccSent as CVarArg)
            
            request.predicate = myPredicate
            
            do {
                let fd = try cnxt.fetch(request)
                print( "Timer: DB Request returned:" + String(fd.count) )
                
                if( fd.count > 0 ) {
                    var positions: [GPS_POS_LOG] = []
                    
                    fd.forEach { row in
                        let ts = convertStartDate(StartDate: row.ts!)
                        let gpsPosLog = GPS_POS_LOG(latitude:row.latitude,longitude: row.longitud,ts: ts, horizAcc: row.horizAcc)
                        positions.append(gpsPosLog)
                        //cnxt.delete(row)          // This row deletes the row in the DB
                        self.noOfSentToServer += 1
                        
                        if( row.ts! > latestDate ) {
                            latestDate = row.ts!;       // Save the latest date
                        }
                    }
                    sendToHttpServer(gpsPosLog: positions, latestDate: latestDate)
                    noOfSentGPSToServer.text = String(noOfSentToServer) // Update GUI
                }
                else {
                    print("Timer: No data to send to back-end");
                }
                
            } catch let error as NSError {
                print("Timer: Could not fetch. \(error), \(error.userInfo)")
            }
            if( self.trackingActivateSwitch.isOn == false ) {
                timer.invalidate()
                print("Timer: Stopping Timer")
            }
            
            latestTSSent.text = convertStartDate(StartDate: latestDate)
        }
    }
    
    enum MyError: Error {
        case DataIsNil
        case BadJSONResponse
    }
    func sendToHttpServer(gpsPosLog: [GPS_POS_LOG], latestDate: Date) {

        let jsonEncoder = JSONEncoder()
        jsonEncoder.outputFormatting = .prettyPrinted
      
        var uploadData:Data?
        do {
            uploadData = try jsonEncoder.encode(gpsPosLog)
        } catch {
            print(error.localizedDescription)
            return
        }
        //print( gpsPosLog )
        
        let url = URL(string: "http://chef.maya.se/gpsapi/registerGPSlocation.php")!
        var request = URLRequest(url: url)
        request.setValue("application/json", forHTTPHeaderField: "Content-Type")
        request.httpMethod = "POST"
        
        let task = URLSession.shared.uploadTask(with: request, from: uploadData) { data, response, error in
            do {
                if let error = error {
                    print ("HTTP: error: ") //\(error)")
                    throw error
                }
                guard let response = response as? HTTPURLResponse,
                    (200...299).contains(response.statusCode) else {
                    print ("HTTP: 200-299 server error")
                    
                    throw MyError.DataIsNil
                }
                if let mimeType = response.mimeType,
                    mimeType == "text/html",
                    let data = data,
                    let dataString = String(data: data, encoding: .utf8) {
                    print ("HTTP: got data: \(dataString)")
                    print ("HTTP: Latest date sent: " + self.convertStartDate(StartDate: latestDate))
                    //self.latestTSSent.text = self.convertStartDate(StartDate: latestDate)
                    self.latestDateSuccSent = latestDate
                }
                else {
                    print("HTTP: KALLE:" + String(response.mimeType!))
                    throw MyError.DataIsNil
                    //self.noOfFailedUpdates += 1
                }
            } catch  {
                self.noOfFailedUpdates += 1
                //self.noOfFailedUpdatesUI.text = String(self.noOfFailedUpdates)
                print("CATCH ERROR !!!")
            }
        }
        task.resume()
        print("Resume.....")
        self.noOfFailedUpdatesUI.text = String(noOfFailedUpdates)

    }
   
    @IBAction func tackingPauseChanged(_ sender: UISwitch) {
        print("Pause-Switch Changed !")
        switch sender.isOn {
        case true:
            print("Pause ON")
            locationManager?.stopUpdatingLocation()
        default:
            print("Pause OFF")
            locationManager?.startUpdatingLocation()
        }
    }
    
    @IBAction func trackingEnabledChanged(_ sender: UISwitch) {
        print("Switch Changed !")
        switch sender.isOn {
        case true:
            let managedContext = appDelegate.persistentContainer.viewContext
            let fetchRequest = NSFetchRequest<NSFetchRequestResult>(entityName: "GPS")
            let batchDeleteRequest = NSBatchDeleteRequest(fetchRequest: fetchRequest)
            do {
                try managedContext.execute(batchDeleteRequest)
            } catch {
                // Error Handling
            }
            latestDateSuccSent = Date(timeIntervalSinceReferenceDate: -123456789.0)
            print("ON")
            locationManager?.startUpdatingLocation()
            pauseSwitch.isEnabled = true
            noOfSentPos = 0
            noOfSentToServer = 0
            noOfFailedUpdates = 0
            noOfFailedUpdatesUI.text = String(noOfFailedUpdates)
            noOfRxGPSPos.text = String(noOfSentPos)
            noOfSentGPSToServer.text = String(noOfSentToServer)
            latestTSSent.text = "-"
            setupTimer()
        default:
            print("OFF")
            locationManager?.stopUpdatingLocation()
            pauseSwitch.isEnabled = false
            pauseSwitch.isOn = false
        }
    }
    
   
}

extension ViewController: CLLocationManagerDelegate {

    
    // Step 7: Handle the location information
    // This function is called when there is a new location available
    // The data is put into the core data DB
    func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
        
        print("Got a new position: numberOfLocations received: \(locations.count)")
        let dateFormatter = DateFormatter()
        dateFormatter.dateFormat = "yyyy-MM-dd HH:mm:ss"
        
        
        
        noOfSentPos += 1
        noOfRxGPSPos.text = String(noOfSentPos)
        
        let managedContext = appDelegate.persistentContainer.viewContext
        let entity = NSEntityDescription.entity(forEntityName: "GPS", in: managedContext)!

        // Loop through all GPS Positions and send them to the Database
        locations.forEach { (location) in
            //print("LocationManager horizontalAccuracy: \(location.horizontalAccuracy)")
            
            GPSAccuracy.text = String(location.horizontalAccuracy)+" m"
            horizSpeedLabelUI.text = String(format: "%.1f", location.speed * 3.6 ) + " km/h"
            
            let pos = NSManagedObject(entity: entity,insertInto: managedContext)
            pos.setValue(location.horizontalAccuracy, forKey: "horizAcc")
            pos.setValue(location.coordinate.longitude, forKey: "longitud")
            pos.setValue(location.coordinate.latitude, forKey: "latitude")
            pos.setValue(location.timestamp, forKey: "ts")
            do {
                try managedContext.save()
            } catch let error as NSError {
                print("Could not save. \(error), \(error.userInfo)")
            }
        }
    }
    
    func locationManager(_ manager: CLLocationManager, didFailWithError error: Error) {
      print("LocationManager didFailWithError \(error.localizedDescription)")
      if let error = error as? CLError, error.code == .denied {
         // Location updates are not authorized.
        // To prevent forever looping of `didFailWithError` callback
         locationManager?.stopMonitoringSignificantLocationChanges()
         return
      }
    }
    
    func locationManager(_ manager: CLLocationManager, didChangeAuthorization status: CLAuthorizationStatus) {
        print("location manager authorization status changed")
        
        switch status {
        case .authorizedAlways:
            print("user allow app to get location data when app is active or in background")
        case .authorizedWhenInUse:
            print("user allow app to get location data only when app is active")
        case .denied:
            print("user tap 'disallow' on the permission dialog, cant get location data")
        case .restricted:
            print("parental control setting disallow location data")
        case .notDetermined:
            print("the location permission dialog haven't shown before, user haven't tap allow/disallow")
        }
    }
    
    func convertStartDate(StartDate: Date) -> String {

        let dateFormatter = DateFormatter()
        dateFormatter.timeZone = TimeZone.current
        dateFormatter.dateFormat = "yyy-MM-dd' 'HH:mm:ss"
        let dateString = dateFormatter.string(from: StartDate)
        //dateFormatter.dateFormat = "yyy-MM-dd HH:mm:ss +0000"
        //let date = dateFormatter.date(from: dateString)
        return dateString
    }


}