Add unfollow hashtag action to Explore screen

Closes #417

Tusker/API/ToggleFollowHashtagService.swift

@@ -22,7 +22,9 @@ class ToggleFollowHashtagService {
         self.presenter = presenter
     }
     
-    func toggleFollow() async {
+    @discardableResult
+    func toggleFollow() async -> Bool {
+        let success: Bool
         let context = mastodonController.persistentContainer.viewContext
         var config: ToastConfiguration
         if let existing = mastodonController.followedHashtags.first(where: { $0.name == hashtagName }) {
@@ -36,11 +38,14 @@ class ToggleFollowHashtagService {
                 config = ToastConfiguration(title: "Unfollowed Hashtag")
                 config.systemImageName = "checkmark"
                 config.dismissAutomaticallyAfter = 2
+                
+                success = true
             } catch {
                 config = ToastConfiguration(from: error, with: "Error Unfollowing Hashtag", in: presenter) { toast in
                     toast.dismissToast(animated: true)
                     await self.toggleFollow()
                 }
+                success = false
             }
         } else {
             do {
@@ -53,15 +58,19 @@ class ToggleFollowHashtagService {
                 config = ToastConfiguration(title: "Followed Hashtag")
                 config.systemImageName = "checkmark"
                 config.dismissAutomaticallyAfter = 2
+                
+                success = true
             } catch {
                 config = ToastConfiguration(from: error, with: "Error Following Hashtag", in: presenter) { toast in
                     toast.dismissToast(animated: true)
                     await self.toggleFollow()
                 }
+                success = false
             }
         }
         presenter.showToast(configuration: config, animated: true)
         mastodonController.persistentContainer.save(context: context)
+        return success
     }
     
 }

Tusker/Screens/Explore/ExploreViewController.swift

@@ -288,15 +288,6 @@ class ExploreViewController: UIViewController, UICollectionViewDelegate, Collect
         }
     }
     
-    func removeSavedHashtag(_ hashtag: Hashtag) {
-        let context = mastodonController.persistentContainer.viewContext
-        let req = SavedHashtag.fetchRequest(name: hashtag.name, account: mastodonController.accountInfo!)
-        if let hashtag = try? context.fetch(req).first {
-            context.delete(hashtag)
-            try! context.save()
-        }
-    }
-    
     func removeSavedInstance(_ instanceURL: URL) {
         let context = mastodonController.persistentContainer.viewContext
         let req = SavedInstance.fetchRequest(url: instanceURL, account: mastodonController.accountInfo!)
@@ -307,36 +298,45 @@ class ExploreViewController: UIViewController, UICollectionViewDelegate, Collect
     }
     
     private func trailingSwipeActionsForCell(at indexPath: IndexPath) -> UISwipeActionsConfiguration? {
-        let title: String
+        var actions = [UIContextualAction]()
-        let handler: UIContextualAction.Handler
         switch dataSource.itemIdentifier(for: indexPath) {
         case let .list(list):
-            title = NSLocalizedString("Delete", comment: "delete swipe action title")
+            actions.append(UIContextualAction(style: .destructive, title: "Delete", handler: { _, _, completion in
-            handler = { (_, _, completion) in
                 self.deleteList(list, completion: completion)
-            }
+            }))
             
         case let .savedHashtag(hashtag):
-            title = NSLocalizedString("Unsave", comment: "unsave swipe action title")
+            let name = hashtag.name.lowercased()
-            handler = { (_, _, completion) in
+            let context = mastodonController.persistentContainer.viewContext
-                self.removeSavedHashtag(hashtag)
+            let existing = try? context.fetch(SavedHashtag.fetchRequest(name: name, account: mastodonController.accountInfo!)).first
-                completion(true)
+            if let existing {
+                actions.append(UIContextualAction(style: .destructive, title: "Unsave", handler: { _, _, completion in
+                    context.delete(existing)
+                    try! context.save()
+                }))
+            }
+            if mastodonController.instanceFeatures.canFollowHashtags,
+               mastodonController.followedHashtags.contains(where: { $0.name.lowercased() == name }) {
+                actions.append(UIContextualAction(style: .destructive, title: "Unfollow", handler: { _, _, completion in
+                    Task {
+                        let success =
+                            await ToggleFollowHashtagService(hashtagName: hashtag.name, presenter: self)
+                                .toggleFollow()
+                        completion(success)
+                    }
+                }))
             }
             
         case let .savedInstance(url):
-            title = NSLocalizedString("Unsave", comment: "unsave swipe action title")
+            actions.append(UIContextualAction(style: .destructive, title: "Unsave", handler: { _, _, completion in
-            handler = { (_, _, completion) in
                 self.removeSavedInstance(url)
                 completion(true)
-            }
+            }))
         
         default:
             return nil
         }
-        
+        return UISwipeActionsConfiguration(actions: actions)
-        return UISwipeActionsConfiguration(actions: [
-            UIContextualAction(style: .destructive, title: title, handler: handler)
-        ])
     }
     
     // MARK: - Collection View Delegate
@@ -581,3 +581,7 @@ extension ExploreViewController: UICollectionViewDragDelegate {
         return [UIDragItem(itemProvider: provider)]
     }
 }
+
+extension ExploreViewController: TuskerNavigationDelegate {
+    var apiController: MastodonController! { mastodonController }
+}