Adds ability to delete note

Notes/NotesPageViewController.swift

@@ -12,6 +12,8 @@ class NotesPageViewController : UIPageViewController, UIPageViewControllerDelega
     
     fileprivate var _notes: [Note] = []
     
+    fileprivate var _currentIndex: Int = 0
+    
     override func viewDidLoad() {
         super.viewDidLoad()
         
@@ -19,22 +21,29 @@ class NotesPageViewController : UIPageViewController, UIPageViewControllerDelega
         
         let shareButton = UIBarButtonItem(barButtonSystemItem: .action, target: self, action: #selector(shareHandler))
         let addButton = UIBarButtonItem(barButtonSystemItem: .add, target: self, action: #selector(addHandler))
-        self.navigationItem.rightBarButtonItems = [addButton, shareButton]
+        let deleteButton = UIBarButtonItem(barButtonSystemItem: .trash, target: self, action: #selector(deleteHandler))
+        self.navigationItem.rightBarButtonItems = [addButton, shareButton, deleteButton]
         
         self.dataSource = self
         self.delegate = self
         
+        self._displayLastNote()
+                
+    }
+    
+    fileprivate func _displayLastNote(animated: Bool = false) {
         if let note = self._notes.last {
-            let vc = self.viewController(note: note, index: self._notes.count - 1)
-            self.setViewControllers([vc], direction: .forward, animated: false)
+            let index = self._notes.count - 1
+            let vc = self.viewController(note: note, index: index)
+            self.setViewControllers([vc], direction: .forward, animated: animated)
+            self._currentIndex = index
         }
-                
     }
     
-    fileprivate func _displayNote(note: Note) {
+    fileprivate func _displayNote(note: Note, animated: Bool = false) {
         if let index = self._notes.firstIndex(of: note) {
             let vc = self.viewController(note: note, index: index)
-            self.setViewControllers([vc], direction: .forward, animated: false)
+            self.setViewControllers([vc], direction: .forward, animated: animated)
         } else {
             print("note not found")
         }
@@ -96,11 +105,19 @@ class NotesPageViewController : UIPageViewController, UIPageViewControllerDelega
         return self.viewController(note: note, index: nextIndex)
     }
 
+    func pageViewController(_ pageViewController: UIPageViewController, didFinishAnimating finished: Bool, previousViewControllers: [UIViewController], transitionCompleted completed: Bool) {
+        
+        if completed, let vc = pageViewController.viewControllers?.first as? NoteViewController {
+            self._currentIndex = vc.index
+        }
+        
+    }
+
     // MARK: - Business
     
     @objc func shareHandler() {
         
-        guard let vc = self.presentedViewController as? NoteViewController, let text = vc.note?.content else {
+        guard let text = self._notes[self._currentIndex].content else {
             return
         }
         
@@ -112,6 +129,23 @@ class NotesPageViewController : UIPageViewController, UIPageViewControllerDelega
         self._createNote()
     }
     
+    @objc func deleteHandler() {
+        
+        let note = self._notes[self._currentIndex]
+        guard let content = note.content else {
+            self.showAlert(message: "Sorry!", title: "Note not found")
+            return
+        }
+
+        areYouSure(message: "Do you want to delete this: \(content.prefix(20))...?") {
+            AppDelegate.viewContext.delete(note)
+            AppDelegate.shared.saveContext()
+            self._loadNotes()
+            self._displayLastNote(animated: true)
+        }
+
+    }
+    
     fileprivate func _createNote() {
         let note = Note(context: AppDelegate.viewContext)
         self._loadNotes()

Notes/UIViewController+Extensions.swift

@@ -17,4 +17,19 @@ extension UIViewController {
         self.present(alertController, animated: true, completion: completion)
     }
     
+    func areYouSure(title: String? = nil,
+                    message: String? = NSLocalizedString("Please confirm the action", comment: ""),
+                    executable: @escaping () -> Void) {
+        
+        let alert = UIAlertController(title: title, message: message, preferredStyle: .alert)
+        alert.addAction(UIAlertAction(title: NSLocalizedString("No", comment:""), style: .cancel, handler: { _ in
+            // do nothing
+        }))
+        alert.addAction(UIAlertAction(title: NSLocalizedString("Yes", comment:""), style: .destructive, handler: { action in
+            executable()
+        }))
+        self.present(alert, animated: true, completion: nil)
+        
+    }
+
 }