import MapKit
import SwiftUI

struct AttachmentLocationPickerView: View {
    @StateObject var locationManager = LocationManager()
    @State private var region = MKCoordinateRegion()
    @State private var userInteraction = false

    var body: some View {
        ZStack {
            // MapView
            MapView(
                region: $region,
                userInteraction: $userInteraction
            )

            // Track button
            let img = userInteraction ? "location.circle" : "location.circle.fill"
            VStack {
                Spacer()
                HStack {
                    Spacer()
                    Image(systemName: img)
                        .resizable()
                        .frame(width: 30, height: 30)
                        .foregroundColor(.Material.Elements.active)
                        .background(Color.Material.Shape.white)
                        .clipShape(Circle())
                        .padding(16)
                        .shadow(color: .white, radius: 2)
                        .tappablePadding(.symmetric(10)) {
                            userInteraction = false
                        }
                }
            }
        }
        .onAppear {
            locationManager.start()
        }
        .onChange(of: locationManager.region) { region in
            if !userInteraction {
                self.region = region
            }
        }
    }
}

struct MapView: UIViewRepresentable {
    @Binding var region: MKCoordinateRegion
    @Binding var userInteraction: Bool

    func makeUIView(context: Context) -> MKMapView {
        let mapView = MKMapView()
        mapView.delegate = context.coordinator
        mapView.showsUserLocation = false
        mapView.userTrackingMode = .none

        return mapView
    }

    func updateUIView(_ uiView: MKMapView, context _: Context) {
        if uiView.region != region, !userInteraction {
            uiView.setRegion(region, animated: true)
        }
    }

    func makeCoordinator() -> Coordinator {
        Coordinator(self)
    }

    class Coordinator: NSObject, MKMapViewDelegate {
        var parent: MapView

        init(_ parent: MapView) {
            self.parent = parent
        }
    }
}

class LocationManager: NSObject, ObservableObject, CLLocationManagerDelegate {
    private let locationManager = CLLocationManager()
    @Published var region: MKCoordinateRegion

    override init() {
        region = MKCoordinateRegion()
        super.init()
        locationManager.delegate = self
        locationManager.desiredAccuracy = kCLLocationAccuracyBest
    }

    func start() {
        locationManager.requestWhenInUseAuthorization()
        locationManager.startUpdatingLocation()
    }

    func stop() {
        locationManager.stopUpdatingLocation()
    }

    func locationManager(_: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
        if let loc = locations.first {
            region = MKCoordinateRegion(
                center: loc.coordinate,
                span: MKCoordinateSpan(latitudeDelta: 0.002, longitudeDelta: 0.002)
            )
        }
    }
}

extension MKCoordinateRegion: Equatable {
    public static func == (lhs: MKCoordinateRegion, rhs: MKCoordinateRegion) -> Bool {
        lhs.center.latitude == rhs.center.latitude &&
            lhs.center.longitude == rhs.center.longitude &&
            lhs.span.latitudeDelta == rhs.span.latitudeDelta &&
            lhs.span.longitudeDelta == rhs.span.longitudeDelta
    }
}