DIT Time Date Extension w/ SwiftUI Display

ContentView.swift

//
//  ContentView.swift
//  Decimal Time
//
//  Created by Madeline Cray on 4/16/22.
//

import SwiftUI

let DESECS_IN_FRACTIONAL_MS = 0.864;

struct ContentView: View {
    @State var timer = Timer.publish(every: DESECS_IN_FRACTIONAL_MS, on: .main, in: .common).autoconnect()
    @State var formattedTime: String = ""
    
    var body: some View {
        Text(formattedTime)
            .padding()
            .onReceive(timer) { _ in
                formattedTime = Date.now.currentDitTimeString
            }
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}

DIT.swift

/* LICENCE:
Public Domain
Originally by: s0 2022-03-27
Modified by: Madeline Cray 2022-04-19
*/

import Foundation

let MS_PER_SEC: UInt = 1000
let MS_PER_MIN: UInt = (MS_PER_SEC * 60)
let MS_PER_HOUR: UInt = (MS_PER_MIN * 60)
let S_PER_HOUR: UInt = 60 * 60

let DESECS_PER_DESIM: UInt = 100
let DESIMS_PER_DECA: UInt = 100
let DECAS_PER_DAY: UInt = 10
let DESECS_PER_DECA: UInt = (DESECS_PER_DESIM * DESIMS_PER_DECA)
let DESECS_PER_DAY: UInt = (DESECS_PER_DECA * DECAS_PER_DAY)

// 86400 seconds in a day; 100000 desecs in a day; therefore 864 milliseconds per desec, computed by compiler.
let MS_PER_DESEC: UInt = ((1000 * 86400)/DESECS_PER_DAY)

extension Date {
    var currentDitTimeString: String {
        let currentTime = self.timeIntervalSinceReferenceDate
        
        let currentUTC12Milliseconds = UInt((currentTime - (12*60*60)).truncatingRemainder(dividingBy: 86400) * 1000)
        let currentDitDesecs = currentUTC12Milliseconds / MS_PER_DESEC
        
        let s = String(format: "%.0u.%02u.%02u",
                       (currentDitDesecs / DESECS_PER_DECA) % DECAS_PER_DAY,
                       (currentDitDesecs / DESECS_PER_DESIM) % DESIMS_PER_DECA,
                       currentDitDesecs % DESECS_PER_DESIM
        )
        return s
    }

}