//
//  LocationService.swift
//
//
//  Created by Anak Mirasing on 5/18/2558 BE.
//
//

import Foundation
import CoreLocation

protocol LocationServiceDelegate {
    func tracingLocation(currentLocation: CLLocation)
    func tracingLocationDidFailWithError(error: NSError)
}

class LocationService: NSObject, CLLocationManagerDelegate {

//     class var sharedInstance: LocationService {
//         struct Static {
//             static var onceToken: dispatch_once_t = 0

//             static var instance: LocationService? = nil
//         }
//         dispatch_once(&Static.onceToken) {
//             Static.instance = LocationService()
//         }
//         return Static.instance!
//     }

    static let sharedInstance = LocationService() //Simple, Short & Sweet :)

    var locationManager: CLLocationManager?
    var lastLocation: CLLocation?
    var delegate: LocationServiceDelegate?

    override init() {
        super.init()

        self.locationManager = CLLocationManager()
        guard let locationManager = self.locationManager else {
            return
        }

        if CLLocationManager.authorizationStatus() == .NotDetermined {
            // you have 2 choice
            // 1. requestAlwaysAuthorization
            // 2. requestWhenInUseAuthorization
            locationManager.requestAlwaysAuthorization()
        }

        locationManager.desiredAccuracy = kCLLocationAccuracyBest // The accuracy of the location data
        locationManager.distanceFilter = 200 // The minimum distance (measured in meters) a device must move horizontally before an update event is generated.
        locationManager.delegate = self
    }

    func startUpdatingLocation() {
        print("Starting Location Updates")
        self.locationManager?.startUpdatingLocation()
    }

    func stopUpdatingLocation() {
        print("Stop Location Updates")
        self.locationManager?.stopUpdatingLocation()
    }

    // CLLocationManagerDelegate
    func locationManager(manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {

        guard let location = locations.last else {
            return
        }

        // singleton for get last location
        self.lastLocation = location

        // use for real time update location
        updateLocation(location)
    }

    func locationManager(manager: CLLocationManager, didFailWithError error: NSError) {

        // do on error
        updateLocationDidFailWithError(error)
    }

    // Private function
    private func updateLocation(currentLocation: CLLocation){

        guard let delegate = self.delegate else {
            return
        }

        delegate.tracingLocation(currentLocation)
    }

    private func updateLocationDidFailWithError(error: NSError) {

        guard let delegate = self.delegate else {
            return
        }

        delegate.tracingLocationDidFailWithError(error)
    }
}