Index out of range, SwiftUI

Hello

import SwiftUI


enum When: String {
    case Today
    case Week
    case Month
    case Year
}


struct ChartView: View {
    
    var when: When
    @EnvironmentObject var millilitriInseritiModel: MillilitriInseritiModel
    var valoriAsseX: [String]{
        if when == When.Week{
            return   ["M", "T", "W", "T", "F", "S", "S"]
        } else if when == When.Month{
            return   ["7", "14", "21", "28"]
        } else if when == When.Year{
            return  ["J", "F", "M", "A", "M", "J", "J", "A", "S", "O", "N", "D"]
        }
        
        return []
    }
    
    var valoriAsseY: [Double]{
        return []
    }
    
    var dates: [Date] = [Date(), Date().addingTimeInterval(86400), Date().addingTimeInterval(86400 * 2)]
    @State var valori: [Double] = [1000, 2000, 3000, 1000, 2000, 1000, 2000, 3000, 1000, 2000, 3000]
    
    var altezzaRettangolo: [Double]?{
        var altezze: [Double] = []
        for i in 0..<valori.count{
            altezze.append(valori[i])
        }
        
        return altezze
    }
    
    @State var animation: Bool = false
    
    var body: some View{
        HStack(alignment: .bottom, spacing: 8, content: {
            ForEach(valoriAsseX.indices){ i in
                VStack{
                    RoundedRectangle(cornerRadius: 3)
                        .fill(LinearGradient(gradient: Gradient(colors: [Color.red, Color.blue]), startPoint: .top, endPoint: .bottom))
                        .frame(width: 40, height: animation ? CGFloat(altezzaRettangolo?[i] ?? 0) / 7 : 0)
                        .animation(.easeInOut)
                    
                    Text(valoriAsseX[i])
                        .fontWeight(.semibold)
                        .multilineTextAlignment(.leading)
                        .onTapGesture {
                            withAnimation{
                                valori[i] += 100
                            }
                        }
                }
            }
        })
        .padding()
        .onAppear {
            animation = true
        }
        .onDisappear {
            animation = false
        }
    }
}

struct ChartView_Previews: PreviewProvider {
    static var previews: some View {
        ChartView(when: When.Year)
    }
}

As you might notice, in the previews I set when to When.Year, that is crashing the app because the array valoriAsseX is bigger than the array altezzaRettangolo, so when I iterate it in the ForEach loop it crashes, I can't find any way to solve this, I tried an if let but it is crashing anyway, any ideas?

Thank you