ListRefresh.swift

import SwiftUI

class Person: Hashable {
	var uuid = UUID().uuidString
	
	var name: String = ""
	var toys: [Toy]
	
	init(name: String, _ toys: Toy...) {
		self.name = name
		self.toys = toys
	}
	
	func copy() -> Person {
		let p = Person(name: name)
		p.toys = toys
		return p
	}
	
	func minToy() -> Toy? {
		return toys.sorted { $0.rating < $1.rating }.first
	}
	
	func maxRating() -> Int {
		return toys.map({ $0.rating }).max() ?? -1
	}
	
	static func == (lhs: Person, rhs: Person) -> Bool {
		return lhs.uuid == rhs.uuid
	}
	
	func hash(into hasher: inout Hasher) {
		hasher.combine(uuid)
	}
}

class Toy: Hashable {
	var uuid = UUID().uuidString
	
	var name: String = ""
	var rating: Int
	
	init(name: String, rating: Int) {
		self.name = name
		self.rating = rating
	}
	
	func copy() -> Toy {
		return Toy(name: name, rating: rating)
	}
	
	static func == (lhs: Toy, rhs: Toy) -> Bool {
		return lhs.uuid == rhs.uuid
	}
	
	func hash(into hasher: inout Hasher) {
		hasher.combine(uuid)
	}
}

struct PersonRow: View {
	var person: Person
	
	var body: some View {
		VStack(alignment: .leading) {
			HStack {
				Text(person.name).bold()
				Spacer()
				Text("toys:\(person.toys.count)")
				Text("max-rating:\(person.maxRating())")
			}
			HStack {
				ForEach(person.toys, id: \.self) { toy in
					Text("\(toy.name)[\(toy.rating)]")
						.font(Font.caption)
				}
			}
		}
	}
}

struct ContentView: View {

	@State var persons: Array<Person>
	@State var idx: Double
	
	func AddToys_A() {
		let n = Int(idx)
		persons[n].toys.append(Toy(name: "Stuff", rating: 0))
	}
	
	func AddToys_B() {
		let n = Int(idx)
		let newPerson = persons[n].copy()
		newPerson.toys.append(Toy(name: "Stuff", rating: 0))
		persons[n] = newPerson
	}
	
	func ToyRating() {
		if let minPerson = persons.sorted(by: { ($0.minToy()?.rating ?? -1) < ($1.minToy()?.rating ?? -1) }).first {
			if let n = persons.firstIndex(of: minPerson) {
				let p = persons[n].copy()
				if let toy = p.toys.sorted(by: { $0.rating < $1.rating }).first {
					toy.rating += 1
				}
				persons[n] = p
			}
		}
	}
	
	func AddPerson() {
		let p = Person(name: "\(Int(Date().timeIntervalSince1970))")
		p.toys.append(Toy(name: "New", rating: 0))
		persons.append(p)
	}
	
	func Reset() {
		persons.removeAll()
		persons.append(Person(name: "Johan", Toy(name: "Docka", rating: 3)))
		persons.append(Person(name: "Elin", Toy(name: "Cykel", rating: 5), Toy(name: "Båll", rating: 4)))
		persons.append(Person(name: "Bengt", Toy(name: "Bil", rating: 1)))
	}
	
	var body: some View {
		NavigationView {
			VStack {
				VStack {
					
					Slider(value: $idx, in: 0...5)
						.frame(height: 40)
					
					HStack {
						Spacer()
						Button(action: AddToys_A) {
							Text("\(Int(idx))+toys (A)")
						}
						Spacer()
						Button(action: AddToys_B) {
							Text("\(Int(idx))+toys (B)")
						}
						Spacer()
					}
					
					HStack {
						Button(action: ToyRating) {
							Text("bump rating")
						}
						Spacer()
						Button(action: AddPerson) {
							Text("new person")
						}
						Spacer()
						Button(action: Reset) {
							Text("reset")
						}
					}
				}
				.padding(EdgeInsets(top: 0, leading: 10, bottom: 0, trailing: 10))
				
				List {
					ForEach(persons, id: \.uuid) { person in
						PersonRow(person: person)
					}
				}
			}
			.navigationBarTitle("Persons and toys")
		}
	}
}

struct ContentView_Previews: PreviewProvider {
	
	static var data: Array<Person> = [
		Person(name: "Johan", Toy(name: "Docka", rating: 3)),
		Person(name: "Elin", Toy(name: "Cykel", rating: 5), Toy(name: "Boll", rating: 4)),
		Person(name: "Bengt", Toy(name: "Bil", rating: 1))
	]
	
	static var previews: some View {
		ContentView(persons: data, idx: 0)
	}
}