RefreshableScrollView.swift

import SwiftUI

struct RefreshableScrollView<Content: View>: View {
    @State private var isRefreshing = false
    @State private var initialValue: CGFloat = 50
    private var threshold: CGFloat = 100

    let axes: Axis.Set
    let showsIndicators: Bool
    let onRefresh: () async -> Void
    let content: () -> Content

    init(
        _ axes: Axis.Set = .vertical,
        showsIndicators: Bool = true,
        onRefresh: @escaping () async -> Void,
        @ViewBuilder content: @escaping () -> Content
    ) {
        self.axes = axes
        self.showsIndicators = showsIndicators
        self.content = content
    }

    var body: some View {
        ZStack(alignment: .top) {
            ScrollView(axes, showsIndicators: showsIndicators) {
                GeometryReader { reader -> Color in
                    let offset = reader.frame(in: .global)

                    DispatchQueue.main.async {
                        if offset.minY > (initialValue + threshold) {
                            withAnimation {
                                isRefreshing = true
                            }
                        }
                    }

                    return Color.clear
                }
                .frame(height: 1)
                .offset(y: -10)

                content()
                    .padding(.top, isRefreshing ? 40 : 0)
            }

            ProgressView()
                .hidden(when: !isRefreshing)
                .padding(.vertical, 13)
        }
        .onChange(of: isRefreshing) { newValue in
            guard newValue else { return }

            Task {
                await onRefresh()
                withAnimation {
                    isRefreshing = false
                }
            }
        }
    }
}