feat: implement undo and redo logic

Memola/Canvas/Contexts/GraphicContext.swift

@@ -70,6 +70,13 @@ final class GraphicContext: @unchecked Sendable {
                 }
             }
             previousElement = nil
+        case .photo(let photo):
+            tree.remove(photo.element, in: photo.photoBox)
+            withPersistence(\.backgroundContext) { [weak photo] context in
+                photo?.object?.element?.graphicContext = nil
+                try context.saveIfNeeded()
+                context.refreshAllObjects()
+            }
         }
     }
 
@@ -105,6 +112,13 @@ final class GraphicContext: @unchecked Sendable {
                 }
             }
             previousElement = nil
+        case .photo(let photo):
+            tree.insert(photo.element, in: photo.photoBox)
+            withPersistence(\.backgroundContext) { [weak self, weak photo] context in
+                photo?.object?.element?.graphicContext = self?.object
+                try context.saveIfNeeded()
+                context.refreshAllObjects()
+            }
         }
     }
 }
@@ -304,7 +318,7 @@ extension GraphicContext {
 
 // MARK: - Photo
 extension GraphicContext {
-    func insertPhoto(at point: CGPoint, photoItem: PhotoItem) {
+    func insertPhoto(at point: CGPoint, photoItem: PhotoItem) -> Photo {
         let size = photoItem.dimension
         let origin = point
         let bounds = [origin.x - size.width / 2, origin.y - size.height / 2, origin.x + size.width / 2, origin.y + size.height / 2]
@@ -331,6 +345,7 @@ extension GraphicContext {
             try context.saveIfNeeded()
         }
         self.previousElement = .photo(photo)
+        return photo
     }
 }
 

Memola/Canvas/Core/Canvas.swift

@@ -128,7 +128,7 @@ extension Canvas {
 
 // MARK: - Photo
 extension Canvas {
-    func insertPhoto(at point: CGPoint, photoItem: PhotoItem) {
+    func insertPhoto(at point: CGPoint, photoItem: PhotoItem) -> Photo {
         graphicContext.insertPhoto(at: point, photoItem: photoItem)
     }
 }

Memola/Canvas/History/History.swift

@@ -70,6 +70,20 @@ class History: ObservableObject {
                         try context.saveIfNeeded()
                     }
                 }
+            case .photo(let _photo):
+                if let url = _photo.bookmark?.getBookmarkURL() {
+                    do {
+                        try FileManager.default.removeItem(at: url)
+                    } catch {
+                        NSLog("[Memola] - \(error.localizedDescription)")
+                    }
+                }
+                withPersistence(\.backgroundContext) { context in
+                    if let photo = _photo.object {
+                        context.delete(photo)
+                    }
+                    try context.saveIfNeeded()
+                }
             }
         }
         redoStack.removeAll()

Memola/Canvas/History/HistoryEvent.swift

@@ -9,4 +9,5 @@ import Foundation
 
 enum HistoryEvent {
     case stroke(any Stroke)
+    case photo(Photo)
 }

Memola/Canvas/View/Bridge/ViewController/CanvasViewController.swift

@@ -238,7 +238,8 @@ extension CanvasViewController {
             tool.selectedPhotoItem = nil
         }
         let point = gesture.location(in: drawingView)
-        canvas.insertPhoto(at: point.muliply(by: drawingView.ratio), photoItem: photoItem)
+        let photo = canvas.insertPhoto(at: point.muliply(by: drawingView.ratio), photoItem: photoItem)
+        history.addUndo(.photo(photo))
         drawingView.draw()
     }
 }