Units_SwiftUI

//
//  ContentView.swift
//  Units
//
//  Created by Ishmael Shabazz on 5/16/20.
//  Copyright © 2020 Illuminated Bits LLC. All rights reserved.
//

import SwiftUI

struct ContentView: View {
    @State private var fromAmount = ""
    @State private var toAmount = "2"
    @State private var inputUnit = 0
    @State private var outputUnit = 1
    @State private var selection1 = 0 //Index of first picker
    @State private var selction2 = 1 //Index of second picer
    var units:[UnitTemperature] = [.fahrenheit,
                                   .celsius,
                                   .kelvin]
    var convertedAmount:Double{
        let from =  Double( fromAmount) ?? 0
        let fromMeasurement = Measurement(value: from, unit: units[inputUnit])
        let toMeasurement = fromMeasurement.converted(to: units[outputUnit])
        return toMeasurement.value
    }
    var body: some View {
        
        
        NavigationView{
            
            VStack{
                Form{
                    TextField("Original Amount", text: $fromAmount)
                    Picker("Tip Percentage", selection: $inputUnit) {
                        ForEach (0 ..< units.count) {
                            Text("\(self.units[$0].symbol)")
                        }
                    }.pickerStyle(SegmentedPickerStyle())
                    if Double(fromAmount) != nil{
                        
                        Picker("", selection: $outputUnit) {
                            ForEach (0 ..< units.count) {
                                Text("\(self.units[$0].symbol)")
                            }
                        }.pickerStyle(SegmentedPickerStyle())
                        Text( "\(convertedAmount,specifier: "%.2f")\(units[outputUnit].symbol)")
                    }
                }
                Spacer()
            }
            .navigationBarTitle(Text("Units"))
        }
    }
    
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView().environment(\.colorScheme, .dark)
    }
}