refactor: clean up

Memola/Canvas/Geometries/Stroke/Core/Stroke.swift

@@ -8,7 +8,8 @@
 import MetalKit
 import Foundation
 
-protocol Stroke: AnyObject, Drawable {
+protocol Stroke: AnyObject, Drawable, Hashable, Equatable {
+    var id: UUID { get set }
     var bounds: [CGFloat] { get set }
     var color: [CGFloat] { get set }
     var style: StrokeStyle { get set }
@@ -30,7 +31,6 @@ protocol Stroke: AnyObject, Drawable {
     func append(to point: CGPoint)
     func finish(at point: CGPoint)
 
-    func loadQuads()
     func addQuad(at point: CGPoint, rotation: CGFloat, shape: QuadShape)
     func removeQuads(from index: Int)
     func saveQuads(to index: Int)
@@ -50,7 +50,9 @@ extension Stroke {
     func isVisible(in bounds: CGRect) -> Bool {
         bounds.contains(strokeBounds) || bounds.intersects(strokeBounds)
     }
+}
 
+extension Stroke {
     func begin(at point: CGPoint) {
         penStyle.generator.begin(at: point, on: self)
     }
@@ -63,7 +65,9 @@ extension Stroke {
         penStyle.generator.finish(at: point, on: self)
         keyPoints.removeAll()
     }
+}
 
+extension Stroke {
     func addQuad(at point: CGPoint, rotation: CGFloat, shape: QuadShape) {
         let quad = Quad(
             origin: point,
@@ -83,7 +87,7 @@ extension Stroke {
 
 extension Stroke {
     func prepare(device: MTLDevice) {
-        guard texture != nil else { return }
+        guard texture == nil else { return }
         texture = penStyle.loadTexture(on: device)
     }
 
@@ -103,3 +107,13 @@ extension Stroke {
         self.indexBuffer = nil
     }
 }
+
+extension Stroke {
+    static func == (lhs: Self, rhs: Self) -> Bool {
+        lhs.id == rhs.id
+    }
+
+    func hash(into hasher: inout Hasher) {
+        hasher.combine(id)
+    }
+}

Memola/Canvas/Geometries/Stroke/Core/StrokeGenerator.swift

@@ -12,7 +12,7 @@ protocol StrokeGenerator {
 
     var configuration: Configuration { get set }
 
-    func begin(at point: CGPoint, on stroke: Stroke)
+    func begin(at point: CGPoint, on stroke: any Stroke)
-    func append(to point: CGPoint, on stroke: Stroke)
+    func append(to point: CGPoint, on stroke: any Stroke)
-    func finish(at point: CGPoint, on stroke: Stroke)
+    func finish(at point: CGPoint, on stroke: any Stroke)
 }

Memola/Canvas/Geometries/Stroke/Generators/SolidPointStrokeGenerator.swift

@@ -10,13 +10,13 @@ import Foundation
 struct SolidPointStrokeGenerator: StrokeGenerator {
     var configuration: Configuration
 
-    func begin(at point: CGPoint, on stroke: Stroke) {
+    func begin(at point: CGPoint, on stroke: any Stroke) {
         let point = stroke.movingAverage.addPoint(point)
         stroke.keyPoints.append(point)
         addPoint(point, on: stroke)
     }
 
-    func append(to point: CGPoint, on stroke: Stroke) {
+    func append(to point: CGPoint, on stroke: any Stroke) {
         guard stroke.keyPoints.endIndex > 0 else {
             return
         }
@@ -29,7 +29,9 @@ struct SolidPointStrokeGenerator: StrokeGenerator {
             let control = CGPoint.middle(p1: start, p2: end)
             addCurve(from: start, to: end, by: control, on: stroke)
         case 3:
-            stroke.removeQuads(from: stroke.quadIndex + 1)
+            let quadIndex = stroke.quadIndex + 1
+            stroke.removeQuads(from: quadIndex)
+            stroke.saveQuads(to: quadIndex)
             let index = stroke.keyPoints.endIndex - 1
             var start = stroke.keyPoints[index - 2]
             var end = CGPoint.middle(p1: stroke.keyPoints[index - 2], p2: stroke.keyPoints[index - 1])
@@ -49,7 +51,7 @@ struct SolidPointStrokeGenerator: StrokeGenerator {
         }
     }
 
-    func finish(at point: CGPoint, on stroke: Stroke) {
+    func finish(at point: CGPoint, on stroke: any Stroke) {
         switch stroke.keyPoints.endIndex {
         case 0...1:
             break
@@ -58,8 +60,10 @@ struct SolidPointStrokeGenerator: StrokeGenerator {
         }
     }
 
-    private func smoothOutPath(on stroke: Stroke) {
+    private func smoothOutPath(on stroke: any Stroke) {
-        stroke.removeQuads(from: stroke.quadIndex + 1)
+        let quadIndex = stroke.quadIndex + 1
+        stroke.removeQuads(from: quadIndex)
+        stroke.saveQuads(to: quadIndex)
         adjustKeyPoint(on: stroke)
         switch stroke.keyPoints.endIndex {
         case 4:
@@ -79,7 +83,7 @@ struct SolidPointStrokeGenerator: StrokeGenerator {
         stroke.quadIndex = stroke.quads.endIndex - 1
     }
 
-    private func adjustKeyPoint(on stroke: Stroke) {
+    private func adjustKeyPoint(on stroke: any Stroke) {
         let index = stroke.keyPoints.endIndex - 1
         let prev = stroke.keyPoints[index - 1]
         let current = stroke.keyPoints[index]
@@ -89,7 +93,7 @@ struct SolidPointStrokeGenerator: StrokeGenerator {
         stroke.keyPoints[index] = point
     }
 
-    private func addPoint(_ point: CGPoint, on stroke: Stroke) {
+    private func addPoint(_ point: CGPoint, on stroke: any Stroke) {
         let rotation: CGFloat
         switch configuration.rotation {
         case .fixed:
@@ -100,7 +104,7 @@ struct SolidPointStrokeGenerator: StrokeGenerator {
         stroke.addQuad(at: point, rotation: rotation, shape: .rounded)
     }
 
-    private func addCurve(from start: CGPoint, to end: CGPoint, by control: CGPoint, on stroke: Stroke) {
+    private func addCurve(from start: CGPoint, to end: CGPoint, by control: CGPoint, on stroke: any Stroke) {
         let distance = start.distance(to: end)
         let factor: CGFloat
         switch configuration.granularity {

Memola/Canvas/Geometries/Stroke/Strokes/EraserStroke.swift

@@ -9,5 +9,42 @@ import MetalKit
 import Foundation
 
 final class EraserStroke: Stroke, @unchecked Sendable {
+    var id: UUID = UUID()
+    var bounds: [CGFloat]
+    var color: [CGFloat]
+    var style: StrokeStyle
+    var createdAt: Date
+    var thickness: CGFloat
+    var quads: [Quad]
+    var penStyle: any PenStyle
 
+    var batchIndex: Int = 0
+    var quadIndex: Int = -1
+    var keyPoints: [CGPoint] = []
+    var movingAverage: MovingAverage = MovingAverage(windowSize: 3)
+
+    var texture: (any MTLTexture)?
+    var indexBuffer: (any MTLBuffer)?
+    var vertexBuffer: (any MTLBuffer)?
+
+    init(
+        bounds: [CGFloat],
+        color: [CGFloat],
+        style: StrokeStyle,
+        createdAt: Date,
+        thickness: CGFloat,
+        quads: [Quad] = []
+    ) {
+        self.bounds = bounds
+        self.color = color
+        self.style = style
+        self.createdAt = createdAt
+        self.thickness = thickness
+        self.quads = quads
+        self.penStyle = style.penStyle
+    }
+
+    func saveQuads(to index: Int) {
+        
+    }
 }

Memola/Canvas/Geometries/Stroke/Strokes/PenStroke.swift

@@ -10,6 +10,7 @@ import CoreData
 import Foundation
 
 final class PenStroke: Stroke, @unchecked Sendable {
+    var id: UUID = UUID()
     var bounds: [CGFloat]
     var color: [CGFloat]
     var style: StrokeStyle
@@ -70,12 +71,6 @@ final class PenStroke: Stroke, @unchecked Sendable {
         }
     }
 
-    func removeQuads(from index: Int) {
-        let dropCount = quads.endIndex - max(1, index)
-        quads.removeLast(dropCount)
-        saveQuads(to: index)
-    }
-
     func saveQuads(to index: Int) {
         let quads = Array(quads[batchIndex..<index])
         batchIndex = index