nip48: initial support

This patch adds a new ProxyView which is added to the Event Shell
whenever an event has the proxy tag. It includes images of the protocol
logos that are listed in the NIP docs.

Reviewed-by: William Casarin <jb55@jb55>.com
Link: 20240205032400.7069-1-ericholguin@apache.org
Signed-off-by: William Casarin <jb55@jb55.com>

damus/Views/Events/Components/ProxyView.swift

@@ -0,0 +1,100 @@
+//
+//  ProxyView.swift
+//  damus
+//
+//  Created by eric on 2/3/24.
+//
+
+import SwiftUI
+
+struct ProxyTag {
+    let id: String
+    let protocolName: String
+    
+    init(id: String, protocolName: String) {
+        self.id = id
+        self.protocolName = protocolName
+    }
+}
+
+struct ProxyView: View {
+    let event: NostrEvent
+    
+    @Environment(\.openURL) var openURL
+    
+    var body: some View {
+        Group {
+            if let proxy = event_proxy(ev: event) {
+                VStack(alignment: .leading) {
+                    Button(
+                        action: {
+                            if let url = URL(string: proxy.id) {
+                                openURL(url)
+                            }
+                        },
+                        label: {
+                            HStack {
+                                let protocolLogo = get_protocol_image(protocolName: proxy.protocolName)
+                                if protocolLogo.isEmpty {
+                                    Text("\(proxy.protocolName)")
+                                        .font(.caption)
+                                } else {
+                                    Image(protocolLogo)
+                                        .resizable()
+                                        .scaledToFit()
+                                        .frame(width: proxy.protocolName == "activitypub" ? 75 : 20, height: proxy.protocolName == "activitypub" ? 20 : 25)
+                                }
+                            }
+                        }
+                    )
+                    .buttonStyle(NeutralButtonStyle(padding: EdgeInsets(top: 2, leading: 5, bottom: 2, trailing: 5), cornerRadius: 20))
+                }
+            } else {
+                EmptyView()
+            }
+        }
+    }
+}
+
+func get_protocol_image(protocolName: String) -> String {
+    switch protocolName {
+    case "activitypub": return "activityPub"
+    case "rss": return "rss"
+    case "atproto": return "atproto"
+    case "web": return "globe"
+    default:
+        return ""
+    }
+}
+
+func event_proxy(ev: NostrEvent) -> ProxyTag? {
+    var proxyParts = [String]()
+    for tag in ev.tags {
+        if tag.count == 3 && tag[0].matches_str("proxy") {
+            proxyParts = tag.strings()
+            guard proxyParts.count == 3 else {
+                return nil
+            }
+            return ProxyTag(id: proxyParts[1], protocolName: proxyParts[2])
+        }
+    }
+    return nil
+}
+
+
+struct ProxyView_Previews: PreviewProvider {
+    static var previews: some View {
+        let activityPubEv = NostrEvent(content: "", keypair: test_keypair, kind: 1, tags: [["proxy", "", "activitypub"]])!
+        let atProtoEv = NostrEvent(content: "", keypair: test_keypair, kind: 1, tags: [["proxy", "", "atproto"]])!
+        let rssEv = NostrEvent(content: "", keypair: test_keypair, kind: 1, tags: [["proxy", "", "rss"]])!
+        let webEv = NostrEvent(content: "", keypair: test_keypair, kind: 1, tags: [["proxy", "", "web"]])!
+        let unsupportedEv = NostrEvent(content: "", keypair: test_keypair, kind: 1, tags: [["proxy", "", "unsupported"]])!
+        VStack(alignment: .center, spacing: 10) {
+            ProxyView(event: activityPubEv)
+            ProxyView(event: rssEv)
+            ProxyView(event: atProtoEv)
+            ProxyView(event: webEv)
+            ProxyView(event: unsupportedEv)
+        }
+    }
+}

damus/Views/Events/EventShell.swift

@@ -96,6 +96,7 @@ struct EventShell<Content: View>: View {
                     EventTop(state: state, event: event, pubkey: pubkey, is_anon: is_anon)
                     UserStatusView(status: state.profiles.profile_data(pubkey).status, show_general: state.settings.show_general_statuses, show_music: state.settings.show_music_statuses)
                     ReplyPart(events: state.events, event: event, keypair: state.keypair, ndb: state.ndb)
+                    ProxyView(event: event)
                 }
             }
             .padding(.horizontal)