feat: supports hashtag timeline pull-down-refresh

Mastodon.xcodeproj/project.pbxproj

@@ -12,7 +12,7 @@
 		0F202201261326E6000C64BF /* HashtagTimelineViewModel.swift in Sources */ = {isa = PBXBuildFile; fileRef = 0F202200261326E6000C64BF /* HashtagTimelineViewModel.swift */; };
 		0F20220726134DA4000C64BF /* HashtagTimelineViewModel+Diffable.swift in Sources */ = {isa = PBXBuildFile; fileRef = 0F20220626134DA4000C64BF /* HashtagTimelineViewModel+Diffable.swift */; };
 		0F202213261351F5000C64BF /* APIService+HashtagTimeline.swift in Sources */ = {isa = PBXBuildFile; fileRef = 0F202212261351F5000C64BF /* APIService+HashtagTimeline.swift */; };
-		0F20222D261457EE000C64BF /* HashtagTimelineViewModel+LoadOldestState.swift in Sources */ = {isa = PBXBuildFile; fileRef = 0F20222C261457EE000C64BF /* HashtagTimelineViewModel+LoadOldestState.swift */; };
+		0F20222D261457EE000C64BF /* HashtagTimelineViewModel+State.swift in Sources */ = {isa = PBXBuildFile; fileRef = 0F20222C261457EE000C64BF /* HashtagTimelineViewModel+State.swift */; };
 		0F20223926146553000C64BF /* Array.swift in Sources */ = {isa = PBXBuildFile; fileRef = 0F20223826146553000C64BF /* Array.swift */; };
 		0FAA0FDF25E0B57E0017CCDE /* WelcomeViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = 0FAA0FDE25E0B57E0017CCDE /* WelcomeViewController.swift */; };
 		0FAA101225E105390017CCDE /* PrimaryActionButton.swift in Sources */ = {isa = PBXBuildFile; fileRef = 0FAA101125E105390017CCDE /* PrimaryActionButton.swift */; };
@@ -715,7 +715,7 @@
 		0F202200261326E6000C64BF /* HashtagTimelineViewModel.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = HashtagTimelineViewModel.swift; sourceTree = "<group>"; };
 		0F20220626134DA4000C64BF /* HashtagTimelineViewModel+Diffable.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "HashtagTimelineViewModel+Diffable.swift"; sourceTree = "<group>"; };
 		0F202212261351F5000C64BF /* APIService+HashtagTimeline.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "APIService+HashtagTimeline.swift"; sourceTree = "<group>"; };
-		0F20222C261457EE000C64BF /* HashtagTimelineViewModel+LoadOldestState.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "HashtagTimelineViewModel+LoadOldestState.swift"; sourceTree = "<group>"; };
+		0F20222C261457EE000C64BF /* HashtagTimelineViewModel+State.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "HashtagTimelineViewModel+State.swift"; sourceTree = "<group>"; };
 		0F20223826146553000C64BF /* Array.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Array.swift; sourceTree = "<group>"; };
 		0FAA0FDE25E0B57E0017CCDE /* WelcomeViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = WelcomeViewController.swift; sourceTree = "<group>"; };
 		0FAA101125E105390017CCDE /* PrimaryActionButton.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PrimaryActionButton.swift; sourceTree = "<group>"; };
@@ -1489,7 +1489,7 @@
 				DB0FCB9B27980AB6006C02E2 /* HashtagTimelineViewController+DataSourceProvider.swift */,
 				0F202200261326E6000C64BF /* HashtagTimelineViewModel.swift */,
 				0F20220626134DA4000C64BF /* HashtagTimelineViewModel+Diffable.swift */,
-				0F20222C261457EE000C64BF /* HashtagTimelineViewModel+LoadOldestState.swift */,
+				0F20222C261457EE000C64BF /* HashtagTimelineViewModel+State.swift */,
 			);
 			path = HashtagTimeline;
 			sourceTree = "<group>";
@@ -4109,7 +4109,7 @@
 				DB6B74F4272FBAE700C70B6E /* FollowerListViewModel+Diffable.swift in Sources */,
 				DB6B74F2272FB67600C70B6E /* FollowerListViewModel.swift in Sources */,
 				DB44767B260B3B8C00B66B82 /* CustomEmojiPickerInputView.swift in Sources */,
-				0F20222D261457EE000C64BF /* HashtagTimelineViewModel+LoadOldestState.swift in Sources */,
+				0F20222D261457EE000C64BF /* HashtagTimelineViewModel+State.swift in Sources */,
 				DB0009A626AEE5DC009B9D2D /* Intents.intentdefinition in Sources */,
 				5B90C462262599800002E742 /* SettingsSectionHeader.swift in Sources */,
 				DB44768B260B3F2100B66B82 /* CustomEmojiPickerItem.swift in Sources */,

Mastodon.xcodeproj/xcuserdata/mainasuk.xcuserdatad/xcschemes/xcschememanagement.plist

@@ -114,7 +114,7 @@
 		<key>MastodonIntent.xcscheme_^#shared#^_</key>
 		<dict>
 			<key>orderHint</key>
-			<integer>22</integer>
+			<integer>20</integer>
 		</dict>
 		<key>MastodonIntents.xcscheme_^#shared#^_</key>
 		<dict>
@@ -129,12 +129,12 @@
 		<key>NotificationService.xcscheme_^#shared#^_</key>
 		<dict>
 			<key>orderHint</key>
-			<integer>20</integer>
+			<integer>21</integer>
 		</dict>
 		<key>ShareActionExtension.xcscheme_^#shared#^_</key>
 		<dict>
 			<key>orderHint</key>
-			<integer>21</integer>
+			<integer>22</integer>
 		</dict>
 	</dict>
 	<key>SuppressBuildableAutocreation</key>

Mastodon/Scene/HashtagTimeline/HashtagTimelineViewController.swift

@@ -46,6 +46,8 @@ final class HashtagTimelineViewController: UIViewController, NeedsDependency, Me
         return tableView
     }()
     
+    let refreshControl = UIRefreshControl()
+    
     deinit {
         os_log(.info, log: .debug, "%{public}s[%{public}ld], %{public}s:", ((#file as NSString).lastPathComponent), #line, #function)
     }
@@ -89,13 +91,23 @@ extension HashtagTimelineViewController {
             statusTableViewCellDelegate: self
         )
         
+        tableView.refreshControl = refreshControl
+        refreshControl.addTarget(self, action: #selector(HashtagTimelineViewController.refreshControlValueChanged(_:)), for: .valueChanged)
+        viewModel.didLoadLatest
+            .receive(on: DispatchQueue.main)
+            .sink { [weak self] _ in
+                guard let self = self else { return }
+                self.refreshControl.endRefreshing()
+            }
+            .store(in: &disposeBag)
+        
         // setup batch fetch
         viewModel.listBatchFetchViewModel.setup(scrollView: tableView)
         viewModel.listBatchFetchViewModel.shouldFetch
             .receive(on: DispatchQueue.main)
             .sink { [weak self] _ in
                 guard let self = self else { return }
-                self.viewModel.loadOldestStateMachine.enter(HashtagTimelineViewModel.LoadOldestState.Loading.self)
+                self.viewModel.stateMachine.enter(HashtagTimelineViewModel.State.Loading.self)
             }
             .store(in: &disposeBag)
         
@@ -144,6 +156,13 @@ extension HashtagTimelineViewController {
 
 extension HashtagTimelineViewController {
     
+    @objc private func refreshControlValueChanged(_ sender: UIRefreshControl) {
+        guard viewModel.stateMachine.enter(HashtagTimelineViewModel.State.Reloading.self) else {
+            sender.endRefreshing()
+            return
+        }
+    }
+    
     @objc private func composeBarButtonItemPressed(_ sender: UIBarButtonItem) {
         os_log(.info, log: .debug, "%{public}s[%{public}ld], %{public}s", ((#file as NSString).lastPathComponent), #line, #function)
         guard let authenticationBox = context.authenticationService.activeMastodonAuthenticationBox.value else { return }

Mastodon/Scene/HashtagTimeline/HashtagTimelineViewModel+Diffable.swift

@@ -27,6 +27,8 @@ extension HashtagTimelineViewModel {
             )
         )
 
+        stateMachine.enter(State.Reloading.self)
+        
         var snapshot = NSDiffableDataSourceSnapshot<StatusSection, StatusItem>()
         snapshot.appendSections([.main])
         diffableDataSource?.apply(snapshot)
@@ -43,14 +45,17 @@ extension HashtagTimelineViewModel {
                 let items = records.map { StatusItem.status(record: $0) }
                 snapshot.appendItems(items, toSection: .main)
                 
-                if let currentState = self.loadOldestStateMachine.currentState {
+                if let currentState = self.stateMachine.currentState {
                     switch currentState {
-                    case is LoadOldestState.Initial,
+                    case is State.Initial,
-                        is LoadOldestState.Loading,
+                        is State.Reloading,
-                        is LoadOldestState.Idle,
+                        is State.Loading,
-                        is LoadOldestState.Fail:
+                        is State.Idle,
-                        snapshot.appendItems([.bottomLoader], toSection: .main)
+                        is State.Fail:
-                    case is LoadOldestState.NoMore:
+                        if !items.isEmpty {
+                            snapshot.appendItems([.bottomLoader], toSection: .main)
+                        }
+                    case is State.NoMore:
                         break
                     default:
                         assertionFailure()

Mastodon/Scene/HashtagTimeline/HashtagTimelineViewModel+State.swift

@@ -1,5 +1,5 @@
 //
-//  HashtagTimelineViewModel+LoadOldestState.swift
+//  HashtagTimelineViewModel+State.swift
 //  Mastodon
 //
 //  Created by BradGao on 2021/3/31.
@@ -11,7 +11,7 @@ import GameplayKit
 import CoreDataStack
 
 extension HashtagTimelineViewModel {
-    class LoadOldestState: GKState, NamingState {
+    class State: GKState, NamingState {
         
         let logger = Logger(subsystem: "HashtagTimelineViewModel.LoadOldestState", category: "StateMachine")
         
@@ -28,14 +28,14 @@ extension HashtagTimelineViewModel {
         }
         
         override func didEnter(from previousState: GKState?) {
-            let previousState = previousState as? HashtagTimelineViewModel.LoadOldestState
+            let previousState = previousState as? HashtagTimelineViewModel.State
             logger.log(level: .debug, "\((#file as NSString).lastPathComponent, privacy: .public)[\(#line, privacy: .public)], \(#function, privacy: .public): [\(self.id.uuidString)] enter \(self.name), previous: \(previousState?.name  ?? "<nil>")")
 
             viewModel?.loadOldestStateMachinePublisher.send(self)
         }
         
         @MainActor
-        func enter(state: LoadOldestState.Type) {
+        func enter(state: State.Type) {
             stateMachine?.enter(state)
         }
         
@@ -45,24 +45,96 @@ extension HashtagTimelineViewModel {
     }
 }
 
-extension HashtagTimelineViewModel.LoadOldestState {
+extension HashtagTimelineViewModel.State {
-    class Initial: HashtagTimelineViewModel.LoadOldestState {
+    class Initial: HashtagTimelineViewModel.State {
         override func isValidNextState(_ stateClass: AnyClass) -> Bool {
-            return stateClass == Loading.self
+            switch stateClass {
+            case is Reloading.Type:
+                return true
+            default:
+                return false
+            }
         }
     }
     
-    class Loading: HashtagTimelineViewModel.LoadOldestState {
+    class Reloading: HashtagTimelineViewModel.State {
-        var maxID: Status.ID?
-        
         override func isValidNextState(_ stateClass: AnyClass) -> Bool {
-            return stateClass == Fail.self || stateClass == Idle.self || stateClass == NoMore.self
+            switch stateClass {
+            case is Loading.Type:
+                return true
+            default:
+                return false
+            }
         }
         
         override func didEnter(from previousState: GKState?) {
             super.didEnter(from: previousState)
-            
             guard let viewModel = viewModel, let stateMachine = stateMachine else { return }
+
+            stateMachine.enter(Loading.self)
+        }
+    }
+    
+    class Fail: HashtagTimelineViewModel.State {
+        override func isValidNextState(_ stateClass: AnyClass) -> Bool {
+            switch stateClass {
+            case is Loading.Type:
+                return true
+            default:
+                return false
+            }
+        }
+        
+        override func didEnter(from previousState: GKState?) {
+            super.didEnter(from: previousState)
+            guard let _ = viewModel, let stateMachine = stateMachine else { return }
+            
+            os_log(.info, log: .debug, "%{public}s[%{public}ld], %{public}s: retry loading 3s later…", ((#file as NSString).lastPathComponent), #line, #function)
+            DispatchQueue.main.asyncAfter(deadline: .now() + 3) {
+                os_log(.info, log: .debug, "%{public}s[%{public}ld], %{public}s: retry loading", ((#file as NSString).lastPathComponent), #line, #function)
+                stateMachine.enter(Loading.self)
+            }
+        }
+    }
+    
+    class Idle: HashtagTimelineViewModel.State {
+        override func isValidNextState(_ stateClass: AnyClass) -> Bool {
+            switch stateClass {
+            case is Reloading.Type, is Loading.Type:
+                return true
+            default:
+                return false
+            }
+        }
+    }
+    
+    class Loading: HashtagTimelineViewModel.State {
+        var maxID: Status.ID?
+        
+        override func isValidNextState(_ stateClass: AnyClass) -> Bool {
+            switch stateClass {
+            case is Fail.Type:
+                return true
+            case is Idle.Type:
+                return true
+            case is NoMore.Type:
+                return true
+            default:
+                return false
+            }
+        }
+        
+        override func didEnter(from previousState: GKState?) {
+            super.didEnter(from: previousState)
+            guard let viewModel = viewModel, let stateMachine = stateMachine else { return }
+            
+            switch previousState {
+            case is Reloading:
+                maxID = nil
+            default:
+                break
+            }
+            
             guard let authenticationBox = viewModel.context.authenticationService.activeMastodonAuthenticationBox.value else {
                 assertionFailure()
                 stateMachine.enter(Fail.self)
@@ -71,6 +143,8 @@ extension HashtagTimelineViewModel.LoadOldestState {
             
             // TODO: only set large count when using Wi-Fi
             let maxID = self.maxID
+            let isReloading = maxID == nil
+
             Task {
                 do {
                     let response = try await viewModel.context.apiService.hashtagTimeline(
@@ -79,24 +153,35 @@ extension HashtagTimelineViewModel.LoadOldestState {
                         hashtag: viewModel.hashtag,
                         authenticationBox: authenticationBox
                     )
+                                        
+                    let newMaxID: String? = {
+                        guard let maxID = response.link?.maxID else { return nil }
+                        return maxID
+                    }()
                     
-                    var hasMore = false
+                    let hasMore: Bool = {
+                        guard let newMaxID = newMaxID else { return false }
+                        return newMaxID != maxID
+                    }()
                     
-                    if let _maxID = response.link?.maxID,
+                    self.maxID = newMaxID
-                        _maxID != maxID
+                    
-                    {
+                    var hasNewStatusesAppend = false
-                        self.maxID = _maxID
+                    var statusIDs = isReloading ? [] : viewModel.fetchedResultsController.statusIDs.value
-                        hasMore = true
+                    for status in response.value {
+                        guard !statusIDs.contains(status.id) else { continue }
+                        statusIDs.append(status.id)
+                        hasNewStatusesAppend = true
                     }
-                    if hasMore {
+
+                    if hasNewStatusesAppend, hasMore {
                         await enter(state: Idle.self)
                     } else {
                         await enter(state: NoMore.self)
                     }
                     
-                    let statusIDs = response.value.map { $0.id }
                     viewModel.fetchedResultsController.append(statusIDs: statusIDs)
-                    
+                    viewModel.didLoadLatest.send()
                 } catch {
                     logger.log(level: .debug, "\((#file as NSString).lastPathComponent, privacy: .public)[\(#line, privacy: .public)], \(#function, privacy: .public): fetch statues failed: \(error.localizedDescription)")
                     await enter(state: Fail.self)
@@ -104,22 +189,15 @@ extension HashtagTimelineViewModel.LoadOldestState {
             }   // end Task
         }
     }
-    
-    class Fail: HashtagTimelineViewModel.LoadOldestState {
-        override func isValidNextState(_ stateClass: AnyClass) -> Bool {
-            return stateClass == Loading.self || stateClass == Idle.self
-        }
-    }
-    
-    class Idle: HashtagTimelineViewModel.LoadOldestState {
-        override func isValidNextState(_ stateClass: AnyClass) -> Bool {
-            return stateClass == Loading.self
-        }
-    }
 
-    class NoMore: HashtagTimelineViewModel.LoadOldestState {
+    class NoMore: HashtagTimelineViewModel.State {
         override func isValidNextState(_ stateClass: AnyClass) -> Bool {
-            return false
+            switch stateClass {
+            case is Reloading.Type:
+                return true
+            default:
+                return false
+            }
         }
         
         override func didEnter(from previousState: GKState?) {

Mastodon/Scene/HashtagTimeline/HashtagTimelineViewModel.swift

@@ -36,19 +36,20 @@ final class HashtagTimelineViewModel {
     let didLoadLatest = PassthroughSubject<Void, Never>()
 
     // bottom loader
-    private(set) lazy var loadOldestStateMachine: GKStateMachine = {
+    private(set) lazy var stateMachine: GKStateMachine = {
         // exclude timeline middle fetcher state
         let stateMachine = GKStateMachine(states: [
-            LoadOldestState.Initial(viewModel: self),
+            State.Initial(viewModel: self),
-            LoadOldestState.Loading(viewModel: self),
+            State.Reloading(viewModel: self),
-            LoadOldestState.Fail(viewModel: self),
+            State.Fail(viewModel: self),
-            LoadOldestState.Idle(viewModel: self),
+            State.Idle(viewModel: self),
-            LoadOldestState.NoMore(viewModel: self),
+            State.Loading(viewModel: self),
+            State.NoMore(viewModel: self),
         ])
-        stateMachine.enter(LoadOldestState.Initial.self)
+        stateMachine.enter(State.Initial.self)
         return stateMachine
     }()
-    lazy var loadOldestStateMachinePublisher = CurrentValueSubject<LoadOldestState?, Never>(nil)
+    lazy var loadOldestStateMachinePublisher = CurrentValueSubject<State?, Never>(nil)
     
     init(context: AppContext, hashtag: String) {
         self.context  = context