conform homeVM and favoritesVM to coredata delegate protocol

Author: lauramarson

AnimalsApp/AnimalsApp/Services/CoreData.swift

@@ -9,6 +9,7 @@ import UIKit
 import CoreData
 
 protocol CoreDataContract: AnyObject {
+    var delegate: [UpdateDelegateProtocol] { get set }
     var favoriteAnimals: [FavoriteAnimal] { get set }
     func loadFavoriteAnimals(completion: @escaping () -> ())
     func isFavorite(id: String) -> Bool
@@ -26,10 +27,10 @@ class CoreData: CoreDataContract {
 
     private var managedContext: NSManagedObjectContext?
 
-    var delegate: [UpdateDelegateProtocol]?
+    var delegate = [UpdateDelegateProtocol]()
     var favoriteAnimals = [FavoriteAnimal]() {
         didSet {
-            delegate?.forEach { delegate in
+            delegate.forEach { delegate in
                 delegate.updateFavoriteAnimals()
             }
         }

AnimalsApp/AnimalsApp/View Models/FavoritesViewModel.swift

@@ -8,19 +8,24 @@
 import Foundation
 
 class FavoritesViewModel {
-    var favoriteAnimals = [Animal]()
     let coreData: CoreDataContract
 
+    var favoriteAnimals = [Animal]()
+    private var newCoreDataChanges = true
+    
     init(coreData: CoreDataContract = CoreData.shared) {
         self.coreData = coreData
+        coreData.delegate.append(self)
     }
 
     func getFavoriteAnimals(completion: @escaping () -> Void) {
-
+        guard newCoreDataChanges else { return }
+        
         favoriteAnimals = coreData.favoriteAnimals.map { favoriteAnimal in
             Animal(id: favoriteAnimal.id, name: favoriteAnimal.name, description: favoriteAnimal.descript, age: Int(favoriteAnimal.age), species: favoriteAnimal.species, isFavorite: true, imageData: favoriteAnimal.image)
         }
 
+        newCoreDataChanges = false
         completion()
     }
 
@@ -31,4 +36,18 @@ class FavoritesViewModel {
     func modelAt(_ index: Int) -> Animal {
         return favoriteAnimals[index]
     }
+    
+    func removeFavorite(at index: Int, completion: @escaping () -> Void) {
+        guard let id = favoriteAnimals[index].id else { return }
+        favoriteAnimals.remove(at: index)
+        coreData.removeFavorite(id: id)
+        completion()
+    }
+}
+
+extension FavoritesViewModel: UpdateDelegateProtocol {
+    func updateFavoriteAnimals() {
+        newCoreDataChanges = true
+    }
+    
 }

AnimalsApp/AnimalsApp/View Models/HomeViewModel.swift

@@ -15,6 +15,7 @@ class HomeViewModel {
     init(webServices: WebServicesContract = WebServices(), coreData: CoreDataContract = CoreData.shared) {
         self.webServices = webServices
         self.coreData = coreData
+        coreData.delegate.append(self)
     }
 
     func numberOfRows() -> Int {
@@ -78,3 +79,9 @@ class HomeViewModel {
         coreData.saveChanges()
     }
 }
+
+extension HomeViewModel: UpdateDelegateProtocol {
+    func updateFavoriteAnimals() {
+//        setFavorite()
+    }
+}

AnimalsApp/AnimalsApp/Views/Components/AnimalTableViewCell.swift

@@ -67,8 +67,10 @@ class AnimalTableViewCell: UITableViewCell {
             self.animal?.isFavorite = true
         }
 
-        if let index = index, let image = SDImageCache.shared.imageFromDiskCache(forKey: animal.imageURL.absoluteString) {
-            let imageData = image.jpegData(compressionQuality: 0.9)
+        let image = SDImageCache.shared.imageFromDiskCache(forKey: animal.imageURL.absoluteString)
+        
+        if let index = index {
+            let imageData = image?.jpegData(compressionQuality: 0.9)
             delegate?.favoriteButtonTapped(at: index, with: imageData ?? Data())
         }
     }

AnimalsApp/AnimalsApp/Views/FavoritesViewController/FavoritesViewController.swift

@@ -9,24 +9,27 @@ import UIKit
 
 class FavoritesViewController: UIViewController {
 
-    var favoritesVM = FavoritesViewModel()
+    var favoritesVM: FavoritesViewModel?
 
     @IBOutlet weak var tableView: UITableView!
 
     override func viewDidLoad() {
         super.viewDidLoad()
+        favoritesVM = FavoritesViewModel()
 
         tableView.dataSource = self
         tableView.delegate = self
 
         tableView.register(UINib(nibName: "AnimalTableViewCell", bundle: nil), forCellReuseIdentifier: "Animal")
 
         setNavigationItems()
+        favoritesVM?.getFavoriteAnimals { [weak self] in            self?.tableView.reloadData()
+        }
     }
 
     override func viewWillAppear(_ animated: Bool) {
         super.viewWillAppear(animated)
-        favoritesVM.getFavoriteAnimals() { [weak self] in            self?.tableView.reloadData()
+        favoritesVM?.getFavoriteAnimals { [weak self] in            self?.tableView.reloadData()
         }
     }
 
@@ -47,7 +50,7 @@ class FavoritesViewController: UIViewController {
 // MARK: TableView Data Source
 extension FavoritesViewController: UITableViewDataSource {
     func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
-        return favoritesVM.numberOfRows()
+        return favoritesVM?.numberOfRows() ?? 0
     }
 
     func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
@@ -56,7 +59,7 @@ extension FavoritesViewController: UITableViewDataSource {
             return UITableViewCell()
         }
 
-        cell.animal = favoritesVM.modelAt(indexPath.row)
+        cell.animal = favoritesVM?.modelAt(indexPath.row)
         cell.index = indexPath.row
         cell.delegate = self
         cell.configure()
@@ -84,7 +87,9 @@ extension FavoritesViewController: UITableViewDelegate {
 // MARK: Action Delegate Protocol
 extension FavoritesViewController: ActionDelegateProtocol {
     func favoriteButtonTapped(at index: Int, with image: Data) {
-//        homeVM.addOrRemoveFavorite(at: index, with: image)
+        favoritesVM?.removeFavorite(at: index) { [weak self] in
+            self?.tableView.reloadData()
+        }
     }
 }