Merge 'ux: Seamless Timeline'

ericholguin (1):
      ux: Seamless Timeline

damus/Util/Extensions/OffsetExtension.swift

@@ -0,0 +1,78 @@
+//
+//  OffsetExtension.swift
+//  damus
+//
+//  Created by eric on 9/6/24.
+//
+
+import SwiftUI
+
+enum SwipeDirection {
+    case up
+    case down
+    case none
+}
+
+extension View {
+    @ViewBuilder
+    func offsetY(completion: @escaping (CGFloat, CGFloat)->())->some View {
+        self
+            .modifier(OffsetHelper(onChange: completion))
+    }
+    
+    func safeArea() -> UIEdgeInsets {
+        guard let scene = this_app.connectedScenes.first as? UIWindowScene else{return .zero}
+        guard let safeArea = scene.windows.first?.safeAreaInsets else{return .zero}
+        return safeArea
+    }
+}
+
+struct OffsetHelper: ViewModifier{
+    var onChange: (CGFloat,CGFloat)->()
+    @State var currentOffset: CGFloat = 0
+    @State var previousOffset: CGFloat = 0
+    
+    func body(content: Content) -> some View {
+        content
+            .overlay {
+                GeometryReader{proxy in
+                    let minY = proxy.frame(in: .named("scroll")).minY
+                    Color.clear
+                        .preference(key: OffsetKey.self, value: minY)
+                        .onPreferenceChange(OffsetKey.self) { value in
+                            previousOffset = currentOffset
+                            currentOffset = value
+                            onChange(previousOffset,currentOffset)
+                        }
+                }
+            }
+    }
+}
+
+struct OffsetKey: PreferenceKey {
+    static var defaultValue: CGFloat = 0
+    
+    static func reduce(value: inout CGFloat, nextValue: () -> CGFloat) {
+        value = nextValue()
+    }
+}
+
+struct HeaderBoundsKey: PreferenceKey{
+    static var defaultValue: Anchor<CGRect>?
+    
+    static func reduce(value: inout Anchor<CGRect>?, nextValue: () -> Anchor<CGRect>?) {
+        value = nextValue()
+    }
+}
+
+func getSafeAreaTop()->CGFloat{
+    guard let scene = this_app.connectedScenes.first as? UIWindowScene else{return .zero}
+    guard let topSafeArea = scene.windows.first?.safeAreaInsets.top else{return .zero}
+    return topSafeArea
+}
+
+func getSafeAreaBottom()->CGFloat{
+    guard let scene = this_app.connectedScenes.first as? UIWindowScene else{return .zero}
+    guard let bottomSafeArea = scene.windows.first?.safeAreaInsets.bottom else{return .zero}
+    return bottomSafeArea
+}