import Foundation

struct ToDo: Identifiable {
    let id: UUID
    var title: String

    init(title: String) {
        self.id = UUID()
        self.title = title
    }
}

import SwiftUI

struct AddToDoView: View {
    @Binding var todos: [ToDo]
    @State private var newToDoTitle = ""
    // injects presentationmode environment value (property wrapper)
    @Environment(\.presentationMode) var presentationMode

    var body: some View {
        VStack {
            TextField("Enter todo", text: $newToDoTitle)
                .padding()

            Button("Done") {
                if(!newToDoTitle.isEmpty) {
                    let newToDo = ToDo(title: newToDoTitle)
                    todos.append(newToDo)
                }
                // dismiss after new item is added to the array -> returns to the main view
                // this value has state of presentationMode
                // dismiss: take off the view from the screen. close the current view
                presentationMode.wrappedValue.dismiss()
            }
            .padding()
        }
    }
}

import SwiftUI

struct ContentView: View {
    // create an array of todos
    @State private var todos = [
        ToDo(title: "Buy groceries"),
        ToDo(title: "Email John"),
    ]

    // based on this value -> we will either show or don't show the list
    @State private var showingAddToDoView = false

    var body: some View {
        ZStack(alignment: .bottom) { // .bottom -> push button on the bottom
            List {
                ForEach(todos) { todo in
                    Text(todo.title)
                }.onDelete(perform: delete) // takes a delete function
            }

            Button(action: {
                self.showingAddToDoView.toggle() // toggle the boolean (true -> false)
            }) {
                Image(systemName: "plus")
                    .resizable()
                    .frame(width: 20, height: 20)
                    .foregroundColor(.white)
                    .padding()
                    .background(Color.blue)
                    .clipShape(Circle())
            }
            .buttonStyle(.plain) // remove the gray area surrounding the button
            .sheet(isPresented: $showingAddToDoView) { // when it's true -> present AddToDoView()
                AddToDoView(todos: self.$todos)
            }
        }
    }

    // implement delete function
    private func delete(at offsets: IndexSet) {
        todos.remove(atOffsets: offsets)
    }
}