Fix taps on mentions in note drafts to not redirect to other Nostr clients

Changelog-Fixed: Fix taps on mentions in note drafts to not redirect to other Nostr clients

damus/Views/PostView.swift

@@ -79,13 +79,27 @@ struct PostView: View {
 
         post.enumerateAttributes(in: NSRange(location: 0, length: post.length), options: []) { attributes, range, stop in
             if let link = attributes[.link] as? String {
-                post.replaceCharacters(in: range, with: link)
+                let normalized_link: String
+                if link.hasPrefix("damus:nostr:") {
+                    // Replace damus:nostr: URI prefix with nostr: since the former is for internal navigation and not meant to be posted.
+                    normalized_link = String(link.dropFirst(6))
+                } else {
+                    normalized_link = link
+                }
+
+                // Add zero-width space in case text preceding the mention is not a whitespace.
+                // In the case where the character preceding the mention is a whitespace, the added zero-width space will be stripped out.
+                post.replaceCharacters(in: range, with: "\u{200B}\(normalized_link)\u{200B}")
             }
         }
 
         var content = self.post.string
+            // If two zero-width spaces are next to each other, normalize it to just one zero-width space.
+            .replacingOccurrences(of: "\u{200B}\u{200B}", with: "\u{200B}")
+            // If zero-width space is next to an actual whitespace, remove the zero-width space.
+            .replacingOccurrences(of: " \u{200B}", with: " ")
+            .replacingOccurrences(of: "\u{200B} ", with: " ")
             .trimmingCharacters(in: CharacterSet.whitespacesAndNewlines)
-            .replacingOccurrences(of: "\u{200B}", with: "") // these characters are added when adding mentions.
 
         let imagesString = uploadedMedias.map { $0.uploadedURL.absoluteString }.joined(separator: " ")
         

damus/Views/Posting/UserSearch.swift

@@ -63,7 +63,8 @@ struct UserSearch: View {
 
         let tagAttributedString = NSMutableAttributedString(string: tagString,
                                    attributes: [NSAttributedString.Key.font: UIFont.systemFont(ofSize: 18.0),
-                                                NSAttributedString.Key.link: "nostr:\(pk)"])
+                                                // Add damus: URI so that taps within the post creation view redirect internally within Damus instead of redirecting to a different Nostr client. The damus: prefix will be stripped out prior to sending the note to relays.
+                                                NSAttributedString.Key.link: "damus:nostr:\(pk)"])
         tagAttributedString.removeAttribute(.link, range: NSRange(location: tagAttributedString.length - 2, length: 2))
         tagAttributedString.addAttributes([NSAttributedString.Key.foregroundColor: UIColor.label], range: NSRange(location: tagAttributedString.length - 2, length: 2))