Re-enable offlineness-hint (IOS-234)

Mastodon/Scene/HomeTimeline/HomeTimelineViewController.swift

@@ -333,6 +333,20 @@ extension HomeTimelineViewController {
             })
             .store(in: &disposeBag)
 
+        viewModel?.isOffline
+            .receive(on: DispatchQueue.main)
+            .sink(receiveValue: { [weak self] isOffline in
+                guard let self else { return }
+
+                if isOffline {
+                    self.timelinePill.update(with: .offline)
+                    self.showTimelinePill()
+                } else {
+                    self.hideTimelinePill()
+                }
+            })
+            .store(in: &disposeBag)
+
         context.publisherService.statusPublishResult.prepend(.failure(AppError.badRequest))
         .receive(on: DispatchQueue.main)
         .sink { [weak self] publishResult in

Mastodon/Scene/HomeTimeline/HomeTimelineViewModel+LoadLatestState.swift

@@ -129,6 +129,7 @@ extension HomeTimelineViewModel.LoadLatestState {
                 }
 
                 await enter(state: Idle.self)
+                viewModel.receiveLoadingStateCompletion(.finished)
 
                 // stop refresher if no new statuses
                 let statuses = response.value
@@ -167,6 +168,7 @@ extension HomeTimelineViewModel.LoadLatestState {
             } catch {
                 await enter(state: Idle.self)
                 viewModel.didLoadLatest.send()
+                viewModel.receiveLoadingStateCompletion(.failure(error))
             }
         }   // end Task
     }

Mastodon/Scene/HomeTimeline/HomeTimelineViewModel+LoadOldestState.swift

@@ -84,8 +84,11 @@ extension HomeTimelineViewModel.LoadOldestState {
                         await self.enter(state: Idle.self)
                     }
 
+                    viewModel.receiveLoadingStateCompletion(.finished)
+
                 } catch {
                     await self.enter(state: Fail.self)
+                    viewModel.receiveLoadingStateCompletion(.failure(error))
                 }
             }   // end Task
         }

Mastodon/Scene/HomeTimeline/HomeTimelineViewModel.swift

@@ -34,6 +34,11 @@ final class HomeTimelineViewModel: NSObject {
     @Published var displaySettingBarButtonItem = true
     @Published var hasPendingStatusEditReload = false
     let hasNewPosts = CurrentValueSubject<Bool, Never>(false)
+
+    /// Becomes `true` if `networkErrorCount` is bigger than 5
+    let isOffline = CurrentValueSubject<Bool, Never>(false)
+    var networkErrorCount = CurrentValueSubject<Int, Never>(0)
+
     var timelineContext: MastodonFeed.Kind.TimelineContext = .home
 
     weak var tableView: UITableView?
@@ -103,8 +108,25 @@ final class HomeTimelineViewModel: NSObject {
             })
             .store(in: &disposeBag)
         
+        networkErrorCount
+            .receive(on: DispatchQueue.main)
+            .map { errorCount in
+                return errorCount >= 5
+            }
+            .assign(to: \.value, on: isOffline)
+            .store(in: &disposeBag)
+
         self.dataController.loadInitial(kind: .home(timeline: timelineContext))
     }
+
+    func receiveLoadingStateCompletion(_ completion: Subscribers.Completion<Error>) {
+        switch completion {
+        case .failure:
+            networkErrorCount.value = networkErrorCount.value + 1
+        case .finished:
+            networkErrorCount.value = 0
+        }
+    }
 }
 
 extension HomeTimelineViewModel {