100DaysOfSwitfUI - Day 19.swift

//
//  ContentView.swift
//  Conversion
//
//  Created by nmbr73 on 07.09.22.
//

import SwiftUI

struct ContentView: View {
    
    let units = ["secs","mins","hrs","days"]
    let factors = [ 1.0, 60.0, 60.0 * 60.0, 60.0 * 60.0 * 24.0]

    func factor(for unit: String) -> Double {
        let unitIndex = units.firstIndex(of: unit) ?? 0
        return factors[unitIndex]
    }
    
    @State private var fromValue = 0
    @State private var fromUnit = "secs"
    @State private var toUnit = "secs"
    
    var toValue: Double {
        let fromSeconds = Double(fromValue) * factor(for: fromUnit)
        return fromSeconds / factor(for: toUnit)
    }
    

    var body: some View {
        NavigationView {
            Form {
                Section {
                    
                    TextField("Input Value", value: $fromValue, format: .number)
                        .keyboardType(.numberPad)
                    
                    Picker("Unit", selection: $fromUnit) {
                        ForEach(units, id: \.self) {
                            Text($0)
                        }
                    }
                    .pickerStyle(.segmented)
                                        
                }
                footer: { Text("Enter a value and select its unit.") }
                
                Section {
                    
                    Text(String(toValue))

                    Picker("Unit", selection: $toUnit) {
                        ForEach(units, id: \.self) {
                            Text($0)
                        }
                    }
                    .pickerStyle(.segmented)

                }
                footer: { Text("Select the unit used for the conversion.") }

            }
            .navigationTitle("Converter")
        }
    }
}


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