SwiftUI: Update struct View when calling mutating func - swift

Question

New to Switch. I need to implement an Analog Clock with auto-updating every second to the current time (like a typical analog clock).
Drawing the Views etc is no problem. But I'm having troubles auto-updating the time.
View
struct ClockView: View {
var viewModel: ClockViewModel
var clock:ClockViewModel.TransformedClock
var size: CGFloat
#State var timer = Timer.publish(every: 1, on: .main, in: .common).autoconnect()
var body: some View {
Circle()
.fill(.white)
.frame(width: size, height: size)
.overlay{
GeometryReader{ geometry in
let radius = geometry.size.width/2
let midX = geometry.safeAreaInsets.top + radius
let midY = geometry.safeAreaInsets.leading + radius
ClockFace(size: size, radius: radius, x: midX, y: midY)
ClockHand(type: .second, angle: clock.secondAngle, x: midX, y: midY, length: radius-size*0.04, size: size)
.onReceive(timer){ _ in updateAngleHere}
}
}
}
}
struct ClockHand:View{
let type: ClockHandType
#State var angle: Double
var x: CGFloat
var y: CGFloat
var length: CGFloat
var size: CGFloat
var body: some View {
RoundedRectangle(cornerRadius: 5)
.fill(type.getColor())
.frame(width: size*type.getWidth(), height: length )
.position(x: x, y: y)
.offset(y: -length/2)
.rotationEffect(Angle.degrees(angle))
}
mutating func update(angle: Double) {
print("calling \(self.angle)")
self.angle = angle
}
}
ViewModel
class ClockViewModel: ObservableObject {
#Published private var model: ClockModel
init(){
model = ClockViewModel.initClocks()
}
static func initClock()->ClockModel {
let places = [
"Europe/Bern",
]
return ClockModel(number: places.count){ index in
places[index]
}
}
var activeClock: TransformedClock{
TransformedClock(clock: model.activeWorldClock!)
}
struct TransformedClock:Identifiable{
var id:Int
var secondAngle:Double
var clock:ClockModel.WorldClock
init(clock:ClockModel.WorldClock){
let second = clock.calendar.component(.second, from: Date())
self.clock = clock
self.id = clock.id
self.secondAngle = Double(second)/60.0*360
}
}
}
Model
struct ClockModel{
var worldClocks: [WorldClock]
init(number: Int, timeFactory: (Int)->String){
worldClocks = [WorldClock]()
for index in 0..<number{
let place = timeFactory(index)
var calendar = Calendar.current
worldClocks.append(
WorldClock(
id: index,
calendar: calendar,
place: formatPlaceString(place)
)
)
}
}
struct WorldClock:Identifiable {
var calendar: Calendar
var place: String
}
}
Find my code above. First of all, I just would like to move the ClockHand for seconds to different positions. For this, I've been told to use a timer and make use of onReceive. My first idea was to call a mutating func of that struct in the closure - but since I can't seem to specifically call it on that struct, I guess it's the wrong option.
So, I need to find a way to teach my second-ClockFace struct to update / redraw itself, whenever I call the mutating func.
Examples I've found only shown functions outside a struct...
Any inut would be much appreciated.