Update: Album art flip

DynamicIsland/managers/MusicManager.swift

@@ -137,7 +137,9 @@ class MusicManager: ObservableObject {
     private var lastArtworkBundleIdentifier: String? = nil
 
     @Published var flipAngle: Double = 0
+    @Published var lastFlipDirection: SkipDirection = .forward
     private let flipAnimationDuration: TimeInterval = 0.45
+    private var flipCooldownActive: Bool = false
 
     @Published var isTransitioning: Bool = false
     private var transitionWorkItem: DispatchWorkItem?
@@ -380,8 +382,22 @@ class MusicManager: ObservableObject {
     }
 
     private func triggerFlipAnimation() {
+        // Debounce: rapid metadata updates (title, artwork, bundle arriving
+        // separately for one track change) should only produce a single flip.
+        guard !flipCooldownActive else { return }
+        flipCooldownActive = true
+
+        // Direction: positive rotation = next (page turn forward),
+        //            negative rotation = previous (page turn backward).
+        let delta: Double = lastFlipDirection == .forward ? 180 : -180
         withAnimation(.easeInOut(duration: flipAnimationDuration)) {
-            flipAngle += 180
+            flipAngle += delta
+        }
+
+        // Reset cooldown after the animation completes so the next
+        // genuine track change can flip again.
+        DispatchQueue.main.asyncAfter(deadline: .now() + flipAnimationDuration + 0.15) { [weak self] in
+            self?.flipCooldownActive = false
         }
     }
 
@@ -624,8 +640,10 @@ class MusicManager: ObservableObject {
         switch behavior {
         case .track:
             if direction == .forward {
+                lastFlipDirection = .forward
                 nextTrack()
             } else {
+                lastFlipDirection = .backward
                 previousTrack()
             }
         case .tenSecond:
@@ -932,24 +950,29 @@ extension MusicManager {
 private struct AlbumArtFlipModifier: ViewModifier {
     let angle: Double
 
-    private var normalizedAngle: Double {
-        var value = angle.truncatingRemainder(dividingBy: 360)
-        if value < 0 { value += 360 }
-        return value
-    }
-
-    private var mirrorScale: CGFloat {
-        (normalizedAngle > 90 && normalizedAngle < 270) ? -1 : 1
-    }
-
     func body(content: Content) -> some View {
         content
             .rotation3DEffect(
                 .degrees(angle),
                 axis: (x: 0, y: 1, z: 0),
-                perspective: 0.65
+                anchor: .center,
+                anchorZ: 0,
+                perspective: 0.5
             )
-            .scaleEffect(x: mirrorScale, y: 1)
+            // Counter-rotate the content so the image never appears mirrored.
+            // At odd multiples of 180° the 3D rotation mirrors along X;
+            // applying an opposite scaleEffect cancels that out.
+            .scaleEffect(x: cosineSign(for: angle), y: 1)
+    }
+
+    /// Returns +1 when the front face is showing, −1 when the back face is showing.
+    private func cosineSign(for degrees: Double) -> CGFloat {
+        let cos = Darwin.cos(degrees * .pi / 180)
+        // Use a small tolerance to avoid flickering exactly at 90°/270°.
+        if cos > 0.001 { return 1 }
+        if cos < -0.001 { return -1 }
+        // At the exact edge, prefer the side we're animating toward.
+        return degrees.truncatingRemainder(dividingBy: 360) >= 0 ? -1 : 1
     }
 }