Fix crash with link previews

Changelog-Fixed: Fixed crash with link previews

damus/Util/LinkView.swift

@@ -12,26 +12,24 @@ class CustomLinkView: LPLinkView {
     override var intrinsicContentSize: CGSize { CGSize(width: 0, height: super.intrinsicContentSize.height) }
 }
 
+enum Metadata {
+    case linkmeta(LPLinkMetadata)
+    case url(URL)
+}
+
 struct LinkViewRepresentable: UIViewRepresentable {
  
     typealias UIViewType = CustomLinkView
     
-    var metadata: LPLinkMetadata?
-    var url: URL?
+    let meta: Metadata
  
     func makeUIView(context: Context) -> CustomLinkView {
-        
-        if let metadata {
-            let linkView = CustomLinkView(metadata: metadata)
-            return linkView
+        switch meta {
+        case .linkmeta(let linkmeta):
+            return CustomLinkView(metadata: linkmeta)
+        case .url(let url):
+            return CustomLinkView(url: url)
         }
-        
-        if let url {
-            let linkView = CustomLinkView(url: url)
-            return linkView
-        }
-        
-        return CustomLinkView()
     }
  
     func updateUIView(_ uiView: CustomLinkView, context: Context) {

damus/Views/NoteContentView.swift

@@ -94,8 +94,10 @@ struct NoteContentView: View {
                 self.preview
             } else {
                 ForEach(artifacts.links, id:\.self) { link in
-                    LinkViewRepresentable(url: link)
-                        .frame(height: 50)
+                    if let url = link {
+                        LinkViewRepresentable(meta: .url(url))
+                            .frame(height: 50)
+                    }
                 }
             }
         }
@@ -136,7 +138,7 @@ struct NoteContentView: View {
                 if show_images, artifacts.links.count == 1 {
                     let meta = await getMetaData(for: artifacts.links.first!)
                     
-                    let view = LinkViewRepresentable(metadata: meta)
+                    let view = meta.map { LinkViewRepresentable(meta: .linkmeta($0)) }
                     previews.store(evid: self.event.id, preview: view)
                     self.preview = view
                 }