ContentView.swift

//
//  Modal sheets on top of each other in SwiftUI
//  Testing the possibilities
//  
//  ContentView.swift
//  navTest1
//
//  Created by JOSEF RICHTER on 04/03/2020.
//  Copyright © 2020 JOSEF RICHTER. Licence: do whatever you want, aka WTFPL http://www.wtfpl.net
//
//

import SwiftUI

private let dateFormatter: DateFormatter = {
    let dateFormatter = DateFormatter()
    dateFormatter.dateStyle = .medium
    dateFormatter.timeStyle = .medium
    return dateFormatter
}()

struct ContentView: View {
    @State private var dates = [Date]()

    var body: some View {
        NavigationView {
            MasterView(dates: $dates)
                .navigationBarTitle(Text("Master"))
                .navigationBarItems(
                    leading: EditButton(),
                    trailing: Button(
                        action: {
                            withAnimation { self.dates.insert(Date(), at: 0) }
                        }
                    ) {
                        Image(systemName: "plus")
                    }
                )
            DetailView()
        }.navigationViewStyle(DoubleColumnNavigationViewStyle())
    }
}

struct MasterView: View {
    @Binding var dates: [Date]

    var body: some View {
        List {
            ForEach(dates, id: \.self) { date in
                NavigationLink(
                    destination: DetailView(selectedDate: date)
                ) {
                    Text("\(date, formatter: dateFormatter)")
                }
            }.onDelete { indices in
                indices.forEach { self.dates.remove(at: $0) }
            }
        }
    }
}

struct DetailView: View {
    var selectedDate: Date?
    
    @State var isModal: Bool = false
    @State var isSubModal: Bool = false

    var modal: some View {
        Group {
        Text("Modal")
            .padding(20)
        Button("Show SubModal") {
            self.isSubModal = true
        }.sheet(isPresented: $isSubModal, content: {
            self.submodal
        })
        }
    }
    
    var submodal: some View {
        Text("SubModal")
        .padding(20)
    }

    var body: some View {
        Group {
            
            if selectedDate != nil {
                Text("\(selectedDate!, formatter: dateFormatter)")
                    .padding(20)
                NavigationLink(destination: SubView()) {
                    Text("Push one level deeper")
                        .padding(20)
                }
                
                Button("Show Modal") {
                    self.isModal = true
                }.sheet(isPresented: $isModal, content: {
                    self.modal
                })
                
            } else {
                Text("Detail view content goes here")
            }
        }.navigationBarTitle(Text("Detail"))
    }
    
    

    
}

struct SubView: View {

    var body: some View {
        Group {
            
                Text("Subdetail view content goes here")
            
        }.navigationBarTitle(Text("Subdetail"))
    }
}


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