Contacts.swift

import UIKit

class Contact: Codable {
    var name = ""
    var photoURL: String = ""
    var id = ""
    
    init(name: String, photoURL: String, id: String) {
        self.name = name
        self.photoURL = photoURL
        self.id = id
    }
    
    enum CodingKeys: String, CodingKey {
        case name = "name"
        case photoURL = "photoURL"
        case id = "id"
    }
}

class ListContactsViewController: UIViewController, UITableViewDataSource, UITableViewDelegate {
    lazy var tableView: UITableView = {
        let tableView = UITableView(frame: .zero, style: .plain)
        tableView.translatesAutoresizingMaskIntoConstraints = false
        tableView.dataSource = self
        return tableView
    }()
    
    var contacts: [Contact]!
    var viewModel: ListContactsViewModel!
    
    init() {
        super.init(nibName: nil, bundle: nil)
    }
    
    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        viewModel = ListContactsViewModel()
        addComponents()
        navigationController?.navigationController?.title = "Lista de contatos"
    }
    
    override func viewDidAppear(_ animated: Bool) {
        loadData()
    }
    
    func addComponents() {
        view.backgroundColor = .red
        view.addSubview(tableView)
        NSLayoutConstraint.activate([
            tableView.topAnchor.constraint(equalTo: view.topAnchor),
            tableView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
            tableView.bottomAnchor.constraint(equalTo: view.bottomAnchor),
            tableView.leadingAnchor.constraint(equalTo: view.leadingAnchor)
        ])
    }

    func numberOfSections(in tableView: UITableView) -> Int {
        return 0
    }
    
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return contacts.count
    }
    
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let reuseCell = "reuseCellContact"
        let cell = tableView.dequeueReusableCell(withIdentifier: reuseCell, for: indexPath)
        
        let contact = contacts[indexPath.row]
        cell.textLabel?.text = contact.name
        
        let urlPhoto = URL(string: contact.photoURL)!
        
        do {
            let data = try Data(contentsOf: urlPhoto)
            let image = UIImage(data: data)
            cell.imageView?.image = image
        } catch _ {}
        
        return cell
    }
    
    func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        let contato = contacts[indexPath.row - 1]
        
        guard isLegacy(contact: contato) else {
            let alert = UIAlertController(title: "Você tocou em", message: "\(contato.name)", preferredStyle: .alert)
            alert.addAction(UIAlertAction(title: "OK", style: .default, handler: nil))
            self.present(alert, animated: true)
            return
        }
       
        let alert = UIAlertController(title: "Atenção", message:"Você tocou no contato sorteado", preferredStyle: .alert)
        alert.addAction(UIAlertAction(title: "OK", style: .default, handler: nil))
        self.present(alert, animated: true)
    }
    
    func loadData() {
        viewModel.loadContacts { (contacts, error) in
            DispatchQueue.global().async {
                if let error = error {
                    print(error)
                    
                    let alert = UIAlertController(title: "Ops, ocorreu um erro", message: error.localizedDescription, preferredStyle: .alert)
                    alert.addAction(UIAlertAction(title: "OK", style: .default, handler: nil))
                    self.present(alert, animated: true)
                    return
                }
                
                self.contacts = contacts!
                self.tableView.reloadData()
            }
        }
    }
    
    func isLegacy(contact: Contact) -> Bool {
          return UserIdsLegacy.isLegacy(id: contact.id)
    }
}

class UserIdsLegacy {
    static let legacyIds = ["123", "4321", "9900"]
  
    static func isLegacy(id: String) -> Bool {
          return legacyIds.contains(id)
    }
}

class ListContactsViewModel {
    private let service = Service()
    
    private var completion: ([Contact]?, Error?) -> Void
    
    func loadContacts(_ completion: @escaping ([Contact]?, Error?) -> Void) {
        self.completion = completion
        service.fetchContacts { contacts, err in
            //... aplica a regra de negocio
            
            self.handle(contacts, err)
        }
    }
    
    private func handle(_ contacts: [Contact]?, _ error: Error?) {
        completion(contacts, err)
    }
}

class Service {
    func fetchContacts(completion: @escaping ([Contact]?, Error?) -> Void) {
        /// Usa URLSession para acessar a API e retorna 
    }
}