MBNavigationService.swift

import MapboxDirections
import Turf
import ARKit

public class NavigationService {
    
    public init() { }
    
    public static func navigate(from startingLocation: CLLocation, to destinationLocation: CLLocation, completion: @escaping ([Waypoint]?, [Route]?, Error?) -> Void) {
        let waypoints = [
            Waypoint(coordinate: CLLocationCoordinate2D(latitude: startingLocation.coordinate.latitude, longitude: startingLocation.coordinate.longitude), name: "start"),
            Waypoint(coordinate: CLLocationCoordinate2D(latitude: destinationLocation.coordinate.latitude, longitude: destinationLocation.coordinate.longitude), name: "destination"),
            ]
        let options = RouteOptions(waypoints: waypoints, profileIdentifier: .walking)
        options.includesSteps = true
        Directions.shared.calculate(options) { waypoints, routes, error in
            if let error = error {
                completion(nil, nil, error)
            } else if let waypoints = waypoints, let routes = routes {
                completion(waypoints, routes, nil)
            }
        }
    }
    
    
    public static func coordinatesForDistance(leg: RouteLeg) -> [CLLocation] {
        var coordinates: [CLLocation] = []
        var polyline = [CLLocationCoordinate2D]()
        for step in leg.steps {
            let coordinate = step.coordinates!.first!
            polyline.append(coordinate)
        }
        let metersPerNode: CLLocationDistance = 5
        let turfPolyline = Polyline(polyline)
        for i in stride(from: metersPerNode, to: turfPolyline.distance() - metersPerNode, by: metersPerNode) {
            if let nextCoordinate = turfPolyline.coordinateFromStart(distance: i) {
                let interpolatedStepLocation = CLLocation(latitude: nextCoordinate.latitude, longitude: nextCoordinate.longitude)
                coordinates.append(interpolatedStepLocation)
            }
        }
        return coordinates
    }
}