MapKit marker following a route animation

MapKitView.swift

import SwiftUI
import MapKit

struct MapKitView: View {
    @State private var selectedResult: MKMapItem?
    @State private var route: MKRoute?
    @State private var markerCoordinate: CLLocationCoordinate2D
    @State private var timer: Timer?
    @State private var pathCoordinates: [CLLocationCoordinate2D] = []
    @State private var currentIndex: Int = 0

    private let startingPoint = CLLocationCoordinate2D(
        latitude: 40.83657722488077,
        longitude: 14.306896671048852
    )

    private let destinationCoordinates = CLLocationCoordinate2D(
        latitude: 40.849761,
        longitude: 14.263364
    )

    init() {
        markerCoordinate = startingPoint
    }
    var body: some View {
        Map(selection: $selectedResult) {
            // Adding the marker for the current position
            Marker("Moving", coordinate: markerCoordinate)
            
            // Show the route if it is available
            if let route {
                MapPolyline(route)
                    .stroke(.blue, lineWidth: 5)
            }
        }
        .onChange(of: selectedResult) {
            getDirections()
        }
        .onAppear {
            self.markerCoordinate = startingPoint
            self.selectedResult = MKMapItem(placemark: MKPlacemark(coordinate: self.destinationCoordinates))
        }
    }

    func getDirections() {
        self.route = nil

        // Check if there is a selected result
        guard let selectedResult else { return }

        // Create and configure the request
        let request = MKDirections.Request()
        request.source = MKMapItem(placemark: MKPlacemark(coordinate: self.startingPoint))
        request.destination = self.selectedResult

        // Get the directions based on the request
        Task {
            let directions = MKDirections(request: request)
            let response = try? await directions.calculate()
            route = response?.routes.first
            if let polyline = route?.polyline {
                extractCoordinates(from: polyline)
                animateMarker()
            }
        }
    }

    func extractCoordinates(from polyline: MKPolyline) {
        pathCoordinates = []
        for i in 0..<polyline.pointCount {
            let point = polyline.points()[i]
            pathCoordinates.append(CLLocationCoordinate2D(latitude: point.coordinate.latitude, longitude: point.coordinate.longitude))
        }
    }

    func animateMarker() {
        timer?.invalidate()
        currentIndex = 0

        timer = Timer.scheduledTimer(withTimeInterval: 0.05, repeats: true) { _ in
            guard currentIndex < pathCoordinates.count else {
                timer?.invalidate()
                return
            }
            markerCoordinate = pathCoordinates[currentIndex]
            currentIndex += 1
        }
    }
}