postview: add hashtag suggestions

Closes: #2604
Changelog-Changes: Add hashtag suggestions to post view
Signed-off-by: Swift Coder <scoder1747@gmail.com>

damus/Views/PostView.swift

@@ -401,7 +401,7 @@ struct PostView: View {
         GeometryReader { (deviceSize: GeometryProxy) in
             VStack(alignment: .leading, spacing: 0) {
                 let searching = get_searching_string(focusWordAttributes.0)
-
+                let searchingHashTag = get_searching_hashTag(focusWordAttributes.0)
                 TopBar
                 
                 ScrollViewReader { scroller in
@@ -415,7 +415,7 @@ struct PostView: View {
                                 .padding(.top, 5)
                         }
                     }
-                    .frame(maxHeight: searching == nil ? deviceSize.size.height : 70)
+                    .frame(maxHeight: searching == nil && searchingHashTag == nil ? deviceSize.size.height : 70)
                     .onAppear {
                         scroll_to_event(scroller: scroller, id: "post", delay: 1.0, animate: true, anchor: .top)
                     }
@@ -426,7 +426,17 @@ struct PostView: View {
                     UserSearch(damus_state: damus_state, search: searching, focusWordAttributes: $focusWordAttributes, newCursorIndex: $newCursorIndex, post: $post)
                         .frame(maxHeight: .infinity)
                         .environmentObject(tagModel)
-                } else {
+                // This else observes '#' for hash-tag suggestions and creates SuggestedHashtagsView
+                } else if let searchingHashTag {
+                        SuggestedHashtagsView(damus_state: damus_state,
+                                              events: SearchHomeModel(damus_state: damus_state).events,
+                                              isFromPostView: true,
+                                              queryHashTag: searchingHashTag,
+                                              focusWordAttributes: $focusWordAttributes,
+                                              newCursorIndex: $newCursorIndex,
+                                              post: $post)
+                        .environmentObject(tagModel)
+               } else {
                     Divider()
                     VStack(alignment: .leading) {
                         AttachmentBar
@@ -526,6 +536,17 @@ func get_searching_string(_ word: String?) -> String? {
     return String(word.dropFirst())
 }
 
+fileprivate func get_searching_hashTag(_ word: String?) -> String? {
+    guard let word,
+          word.count >= 2,
+          let first_char = word.first,
+          first_char == "#" else {
+        return nil
+    }
+    
+    return String(word.dropFirst())
+}
+
 struct PostView_Previews: PreviewProvider {
     static var previews: some View {
         PostView(action: .posting(.none), damus_state: test_damus_state)

damus/Views/SuggestedHashtagsView.swift

@@ -39,6 +39,7 @@ struct SuggestedHashtagsView: View {
                 .sorted(by: { a, b in
                     a.count > b.count
                 })
+            SuggestedHashtagsView.lastRefresh_hashtags = all_items // Collecting recent hash-tag data from Search-page
             guard let item_limit else {
                 return all_items
             }
@@ -46,10 +47,55 @@ struct SuggestedHashtagsView: View {
         }
     }
     
-    init(damus_state: DamusState, suggested_hashtags: [String]? = nil, max_items item_limit: Int? = nil, events: EventHolder) {
+    
+    static var lastRefresh_hashtags: [HashtagWithUserCount] = [] // Holds hash-tag data for PostView
+    var isFromPostView: Bool
+    var queryHashTag: String
+    
+    var filteredSuggestedHashtags: [HashtagWithUserCount] {
+        let val = SuggestedHashtagsView.lastRefresh_hashtags.filter {$0.hashtag.hasPrefix(returnFirstWordOnly(hashTag: queryHashTag))}
+        if val.isEmpty {
+            if SuggestedHashtagsView.lastRefresh_hashtags.isEmpty {
+                // This is special case when user goes directly to PostView without opening Search-page previously.
+                var val = hashtags_with_count_to_display // retrieves default hash-tage values
+                // if not-found, put query hash tag at top
+                val.insert(HashtagWithUserCount(hashtag: returnFirstWordOnly(hashTag: queryHashTag), count: 0), at: 0)
+                return val
+            } else {
+                // if not-found, put query hash tag at top
+                var val = SuggestedHashtagsView.lastRefresh_hashtags
+                val.insert(HashtagWithUserCount(hashtag: returnFirstWordOnly(hashTag: queryHashTag), count: 0), at: 0)
+               return val
+            }
+        } else {
+            return val
+        }
+    }
+    
+    @Binding var focusWordAttributes: (String?, NSRange?)
+    @Binding var newCursorIndex: Int?
+    @Binding var post: NSMutableAttributedString
+    @EnvironmentObject var tagModel: TagModel
+    
+    init(damus_state: DamusState,
+         suggested_hashtags: [String]? = nil,
+         max_items item_limit: Int? = nil,
+         events: EventHolder,
+         isFromPostView: Bool = false,
+         queryHashTag: String = "",
+         focusWordAttributes: Binding<(String?, NSRange?)> = .constant((nil, nil)),
+         newCursorIndex: Binding<Int?> = .constant(nil),
+         post: Binding<NSMutableAttributedString> = .constant(NSMutableAttributedString(string: ""))) {
         self.damus_state = damus_state
         self.suggested_hashtags = suggested_hashtags ?? DEFAULT_SUGGESTED_HASHTAGS
         self.item_limit = item_limit
+        
+        self.isFromPostView = isFromPostView
+        self.queryHashTag = queryHashTag
+        self._focusWordAttributes = focusWordAttributes
+        self._newCursorIndex = newCursorIndex
+        self._post = post
+        
         _events = StateObject.init(wrappedValue: events)
     }
     
@@ -59,24 +105,43 @@ struct SuggestedHashtagsView: View {
                 Image(systemName: "sparkles")
                 Text("Suggested hashtags", comment: "A label indicating that the items below it are suggested hashtags")
                 Spacer()
-                Button(action: {
+                // Don't show suggestion expand/contract button when user is in PostView
-                    withAnimation(.easeOut(duration: 0.2)) {
+                if !isFromPostView  {
-                        show_suggested_hashtags.toggle()
+                    Button(action: {
-                    }
+                        withAnimation(.easeOut(duration: 0.2)) {
-                }) {
+                            show_suggested_hashtags.toggle()
-                    if show_suggested_hashtags {
+                        }
-                        Image(systemName: "rectangle.compress.vertical")
+                    }) {
-                            .foregroundStyle(PinkGradient)
+                        if show_suggested_hashtags {
-                    } else {
+                            Image(systemName: "rectangle.compress.vertical")
-                        Image(systemName: "rectangle.expand.vertical")
+                                .foregroundStyle(PinkGradient)
-                            .foregroundStyle(PinkGradient)
+                        } else {
+                            Image(systemName: "rectangle.expand.vertical")
+                                .foregroundStyle(PinkGradient)
+                        }
                     }
                 }
             }
             .foregroundColor(.secondary)
             .padding(.vertical, 10)
             
-            if show_suggested_hashtags {
+            if isFromPostView {
+                ScrollView {
+                    LazyVStack {
+                        ForEach(filteredSuggestedHashtags,
+                                id: \.self) { hashtag_with_count in
+                            SuggestedHashtagView(damus_state: damus_state,
+                                                 hashtag: hashtag_with_count.hashtag,
+                                                 count: hashtag_with_count.count,
+                                                 isFromPostView: true,
+                                                 focusWordAttributes: $focusWordAttributes,
+                                                 newCursorIndex: $newCursorIndex,
+                                                 post: $post)
+                            .environmentObject(tagModel)
+                        }
+                    }
+                }
+            } else if show_suggested_hashtags {
                 ForEach(hashtags_with_count_to_display,
                         id: \.self) { hashtag_with_count in
                     SuggestedHashtagView(damus_state: damus_state, hashtag: hashtag_with_count.hashtag, count: hashtag_with_count.count)
@@ -91,10 +156,26 @@ struct SuggestedHashtagsView: View {
         let hashtag: String
         let count: Int
         
-        init(damus_state: DamusState, hashtag: String, count: Int) {
+        let isFromPostView: Bool
+        @Binding var focusWordAttributes: (String?, NSRange?)
+        @Binding var newCursorIndex: Int?
+        @Binding var post: NSMutableAttributedString
+        @EnvironmentObject var tagModel: TagModel
+        
+        init(damus_state: DamusState,
+             hashtag: String,
+             count: Int,
+             isFromPostView: Bool = false,
+             focusWordAttributes: Binding<(String?, NSRange?)> = .constant((nil, nil)),
+             newCursorIndex: Binding<Int?> = .constant(nil),
+             post: Binding<NSMutableAttributedString> = .constant(NSMutableAttributedString(string: ""))) {
             self.damus_state = damus_state
             self.hashtag = hashtag
             self.count = count
+            self.isFromPostView = isFromPostView
+            self._focusWordAttributes = focusWordAttributes
+            self._newCursorIndex = newCursorIndex
+            self._post = post
         }
         
         var body: some View {
@@ -105,18 +186,48 @@ struct SuggestedHashtagsView: View {
                     Text(verbatim: "#\(hashtag)")
                         .bold()
                     
-                    let pluralizedString = pluralizedString(key: "users_talking_about_it", count: self.count)
+                    // Don't show user-talking label from PostView when the count is 0
-                    Text(pluralizedString)
+                    if isFromPostView {
-                        .foregroundStyle(.secondary)
+                        if  count != 0 {
+                            let pluralizedString = pluralizedString(key: "users_talking_about_it", count: self.count)
+                            Text(pluralizedString)
+                                .foregroundStyle(.secondary)
+                        }
+                    } else {
+                        let pluralizedString = pluralizedString(key: "users_talking_about_it", count: self.count)
+                        Text(pluralizedString)
+                            .foregroundStyle(.secondary)
+                    }
                 }
                 
                 Spacer()
             }
+            .contentShape(Rectangle()) // make the entire row/rectangle tappable
             .onTapGesture {
-                let search_model = SearchModel(state: damus_state, search: NostrFilter.init(hashtag: [hashtag]))
+                if isFromPostView {
-                damus_state.nav.push(route: Route.Search(search: search_model))
+                    let hashTag = NSMutableAttributedString(string: "#\(returnFirstWordOnly(hashTag: hashtag))",
+                                                            attributes: [
+                                                                NSAttributedString.Key.foregroundColor: UIColor.black,
+                                                                NSAttributedString.Key.link: "#\(hashtag)"
+                                                            ])
+                    appendHashTag(withTag: hashTag)
+                } else {
+                    let search_model = SearchModel(state: damus_state, search: NostrFilter.init(hashtag: [hashtag]))
+                    damus_state.nav.push(route: Route.Search(search: search_model))
+                }
             }
         }
+        
+        // Current working-code similar to UserSearch/appendUserTag
+        private func appendHashTag(withTag tag: NSMutableAttributedString) {
+            guard let wordRange = focusWordAttributes.1 else { return }
+            let appended = append_user_tag(tag: tag, post: post, word_range: wordRange)
+            self.post = appended.post
+            // adjust cursor position appropriately: ('diff' used in TextViewWrapper / updateUIView after below update of 'post')
+            tagModel.diff = appended.tag.length - wordRange.length
+            focusWordAttributes = (nil, nil)
+            newCursorIndex = wordRange.location + appended.tag.length
+        }
     }
     
     func users_talking_about(hashtag: Hashtag) -> Int {
@@ -147,3 +258,6 @@ struct SuggestedHashtagsView_Previews: PreviewProvider {
     }
 }
 
+fileprivate func returnFirstWordOnly(hashTag: String) -> String {
+    return hashTag.components(separatedBy: " ").first?.lowercased() ?? ""
+}

damus/Views/TextViewWrapper.swift

@@ -93,7 +93,7 @@ struct TextViewWrapper: UIViewRepresentable {
         let updateCursorPosition: ((Int) -> Void)
         let initialTextSuffix: String?
         var initialTextSuffixWasAdded: Bool = false
-        static let ESCAPE_SEQUENCES = ["\n", "@", "  ", ", ", ". ", "! ", "? ", "; "]
+        static let ESCAPE_SEQUENCES = ["\n", "@", "  ", ", ", ". ", "! ", "? ", "; ", "#"]
 
         init(attributedText: Binding<NSMutableAttributedString>,
              getFocusWordForMention: ((String?, NSRange?) -> Void)?,

damus/damusApp.swift

@@ -44,6 +44,7 @@ struct MainView: View {
         .onReceive(handle_notify(.logout)) { () in
             try? clear_keypair()
             keypair = nil
+            SuggestedHashtagsView.lastRefresh_hashtags.removeAll()
             // We need to disconnect and reconnect to all relays when the user signs out
             // This is to conform to NIP-42 and ensure we aren't persisting old connections
             notify(.disconnect_relays)