views: allow embeddable views at top of timeline

This allows you to put stuff at the top of a timeline inside the scroll
view. We could also remove the scrollview from the timeline
eventually... but this works for now.

damus/ContentView.swift

@@ -142,7 +142,7 @@ struct ContentView: View {
     func contentTimelineView(filter: (@escaping (NostrEvent) -> Bool)) -> some View {
         ZStack {
             if let damus = self.damus_state {
-                TimelineView(events: home.events, loading: .constant(false), damus: damus, show_friend_icon: false, filter: filter)
+                TimelineView<AnyView>(events: home.events, loading: .constant(false), damus: damus, show_friend_icon: false, filter: filter)
             }
         }
     }

damus/Views/SearchHomeView.swift

@@ -44,7 +44,7 @@ struct SearchHomeView: View {
     }
     
     var GlobalContent: some View {
-        return TimelineView(
+        return TimelineView<AnyView>(
             events: model.events,
             loading: $model.loading,
             damus: damus_state,

damus/Views/SearchView.swift

@@ -13,7 +13,7 @@ struct SearchView: View {
     @Environment(\.dismiss) var dismiss
     
     var body: some View {
-        TimelineView(events: search.events, loading: $search.loading, damus: appstate, show_friend_icon: true, filter: { _ in true })
+        TimelineView<AnyView>(events: search.events, loading: $search.loading, damus: appstate, show_friend_icon: true, filter: { _ in true })
             .navigationBarTitle(describe_search(search.search))
             .onReceive(handle_notify(.switched_timeline)) { obj in
                 dismiss()

damus/Views/TimelineView.swift

@@ -7,14 +7,24 @@
 
 import SwiftUI
 
-struct TimelineView: View {
+struct TimelineView<Content: View>: View {
     @ObservedObject var events: EventHolder
     @Binding var loading: Bool
 
     let damus: DamusState
     let show_friend_icon: Bool
     let filter: (NostrEvent) -> Bool
-    
+    let content: Content?
+
+    init(events: EventHolder, loading: Binding<Bool>, damus: DamusState, show_friend_icon: Bool, filter: @escaping (NostrEvent) -> Bool, content: (() -> Content)? = nil) {
+        self.events = events
+        self._loading = loading
+        self.damus = damus
+        self.show_friend_icon = show_friend_icon
+        self.filter = filter
+        self.content = content?()
+    }
+
     var body: some View {
         MainContent
     }
@@ -22,10 +32,14 @@ struct TimelineView: View {
     var MainContent: some View {
         ScrollViewReader { scroller in
             ScrollView {
+                if let content {
+                    content
+                }
+
                 Color.white.opacity(0)
                     .id("startblock")
                     .frame(height: 1)
-                
+
                 InnerTimelineView(events: events, damus: damus, filter: loading ? { _ in true } : filter)
                     .redacted(reason: loading ? .placeholder : [])
                     .shimmer(loading)
@@ -52,7 +66,7 @@ struct TimelineView: View {
 struct TimelineView_Previews: PreviewProvider {
     @StateObject static var events = test_event_holder
     static var previews: some View {
-        TimelineView(events: events, loading: .constant(true), damus: Constants.EXAMPLE_DEMOS, show_friend_icon: true, filter: { _ in true })
+        TimelineView<AnyView>(events: events, loading: .constant(true), damus: Constants.EXAMPLE_DEMOS, show_friend_icon: true, filter: { _ in true })
     }
 }