Merge pull request #186 from alanpoon/paginate-timeline-by-scroll-#109

Backward Paginate timeline by scroll #109

src/home/room_screen.rs

@@ -1259,6 +1259,8 @@ impl Widget for RoomScreen {
                 }
             }
 
+            // Set visibility of loading message banner based of pagination logic
+            self.send_pagination_request_based_on_scroll_pos(cx, actions);
             // Handle sending any read receipts for the current logged-in user.
             self.send_user_read_receipts_based_on_scroll_pos(cx, actions);
 
@@ -1520,6 +1522,7 @@ impl RoomScreen {
     /// Redraws this RoomScreen view if any updates were applied.
     fn process_timeline_updates(&mut self, cx: &mut Cx) {
         let portal_list = self.portal_list(id!(list));
+        let top_space = self.view(id!(top_space));
         let curr_first_id = portal_list.first_id();
         let Some(tl) = self.tl_state.as_mut() else { return };
 
@@ -1604,14 +1607,14 @@ impl RoomScreen {
                         // log!("Timeline::handle_event(): changed_indices: {changed_indices:?}, items len: {}\ncontent drawn: {:#?}\nprofile drawn: {:#?}", items.len(), tl.content_drawn_since_last_update, tl.profile_drawn_since_last_update);
                     }
                     tl.items = new_items;
+                    done_loading = true;
                 }
                 TimelineUpdate::TimelineStartReached => {
                     log!("Timeline::handle_event(): timeline start reached for room {}", tl.room_id);
                     tl.fully_paginated = true;
-                    done_loading = true;
                 }
                 TimelineUpdate::PaginationIdle => {
-                    done_loading = true;
+                    top_space.set_visible(true);
                 }
                 TimelineUpdate::EventDetailsFetched {event_id, result } => {
                     if let Err(_e) = result {
@@ -1661,8 +1664,7 @@ impl RoomScreen {
         }
 
         if done_loading {
-            log!("TODO: hide topspace loading animation for room {}", tl.room_id);
-            // TODO FIXME: hide TopSpace loading animation, set it to invisible.
+            top_space.set_visible(false);
         }
         if num_updates > 0 {
             // log!("Applied {} timeline updates for room {}, redrawing with {} items...", num_updates, tl.room_id, tl.items.len());
@@ -1904,6 +1906,25 @@ impl RoomScreen {
         self.show_timeline(cx);
         self.label(id!(room_name)).set_text(&self.room_name);
     }
+
+    /// Send Pagination Request when the scroll position is at the top 
+    fn send_pagination_request_based_on_scroll_pos(
+        &mut self,
+        cx: &mut Cx,
+        actions: &ActionsBuf,
+    ) {
+        let portal_list = self.portal_list(id!(list));
+        //stopped scrolling and when scroll position is at top
+        if portal_list.scrolled(actions) {
+            return;
+        }
+
+        let Some(room_id) = self.room_id.as_ref() else { return };
+        if  portal_list.scroll_position() == 0.0 {
+            submit_async_request(MatrixRequest::PaginateRoomTimeline { room_id: room_id.clone(), num_events: 50, forwards: false});
+        }
+
+    }
 }
 
 impl RoomScreenRef {