From f0b80f3171631dabdc29ecb17c94ada8aa09d1d4 Mon Sep 17 00:00:00 2001
From: dscyrescotti <dscyrescotti@gmail.com>
Date: Mon, 17 Jun 2024 01:33:10 +0700
Subject: [PATCH] feat: implement undo and redo logic

---
 Memola/Canvas/Contexts/GraphicContext.swift     | 17 ++++++++++++++++-
 Memola/Canvas/Core/Canvas.swift                 |  2 +-
 Memola/Canvas/History/History.swift             | 14 ++++++++++++++
 Memola/Canvas/History/HistoryEvent.swift        |  1 +
 .../ViewController/CanvasViewController.swift   |  3 ++-
 5 files changed, 34 insertions(+), 3 deletions(-)

diff --git a/Memola/Canvas/Contexts/GraphicContext.swift b/Memola/Canvas/Contexts/GraphicContext.swift
index 61e811b..fefd095 100644
--- a/Memola/Canvas/Contexts/GraphicContext.swift
+++ b/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
     }
 }
 
diff --git a/Memola/Canvas/Core/Canvas.swift b/Memola/Canvas/Core/Canvas.swift
index 595fa79..4189a32 100644
--- a/Memola/Canvas/Core/Canvas.swift
+++ b/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)
     }
 }
diff --git a/Memola/Canvas/History/History.swift b/Memola/Canvas/History/History.swift
index 6125381..a6d152b 100644
--- a/Memola/Canvas/History/History.swift
+++ b/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()
diff --git a/Memola/Canvas/History/HistoryEvent.swift b/Memola/Canvas/History/HistoryEvent.swift
index 4fb811f..a24d301 100644
--- a/Memola/Canvas/History/HistoryEvent.swift
+++ b/Memola/Canvas/History/HistoryEvent.swift
@@ -9,4 +9,5 @@ import Foundation
 
 enum HistoryEvent {
     case stroke(any Stroke)
+    case photo(Photo)
 }
diff --git a/Memola/Canvas/View/Bridge/ViewController/CanvasViewController.swift b/Memola/Canvas/View/Bridge/ViewController/CanvasViewController.swift
index c995c08..a21f7fb 100644
--- a/Memola/Canvas/View/Bridge/ViewController/CanvasViewController.swift
+++ b/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()
     }
 }