Prioritize followed/following accounts in mention suggestions

Tusker/Screens/Compose/ComposeAutocompleteView.swift

@@ -143,12 +143,15 @@ struct ComposeAutocompleteMentionsView: View {
             
             localSearchWorkItem.cancel()
             
+            // dispatch back to the main thread because loadAccounts uses CoreData
+            DispatchQueue.main.async {
                 // if the query has changed, don't bother loading the now-outdated results
                 if case .mention(query) = uiState.autocompleteState {
                     self.loadAccounts(accounts.map { .pachyderm($0) }, query: query)
                 }
             }
         }
+    }
     
     private func loadAccounts(_ accounts: [EitherAccount], query: String) {
         // when sorting account suggestions, ignore the domain component of the acct unless the user is typing it themself
@@ -161,8 +164,20 @@ struct ComposeAutocompleteMentionsView: View {
                 return res
             }
             .filter(\.1.matched)
-            // todo: it would be nice to prioritize followee/follower accounts, but relationships aren't cached
+            .map { (account, res) -> (EitherAccount, Int) in
-            .sorted { $0.1.score > $1.1.score }
+                // give higher weight to accounts that the user follows or is followed by
+                var score = res.score
+                if let relationship = mastodonController.persistentContainer.relationship(forAccount: account.id) {
+                    if relationship.following {
+                        score += 3
+                    }
+                    if relationship.followedBy {
+                        score += 2
+                    }
+                }
+                return (account, score)
+            }
+            .sorted { $0.1 > $1.1 }
             .map(\.0)
     }