feat: add pull to refresh

Mastodon.xcodeproj/project.pbxproj

@@ -16,6 +16,7 @@
 		2D42FF7E25C82218004A627A /* ActionToolBarContainer.swift in Sources */ = {isa = PBXBuildFile; fileRef = 2D42FF7D25C82218004A627A /* ActionToolBarContainer.swift */; };
 		2D42FF8525C8224F004A627A /* HitTestExpandedButton.swift in Sources */ = {isa = PBXBuildFile; fileRef = 2D42FF8425C8224F004A627A /* HitTestExpandedButton.swift */; };
 		2D42FF8F25C8228A004A627A /* UIButton.swift in Sources */ = {isa = PBXBuildFile; fileRef = 2D42FF8E25C8228A004A627A /* UIButton.swift */; };
+		2D45E5BF25C9549700A6D639 /* PublicTimelineViewModel+State.swift in Sources */ = {isa = PBXBuildFile; fileRef = 2D45E5BE25C9549700A6D639 /* PublicTimelineViewModel+State.swift */; };
 		2D46975E25C2A54100CF4AA9 /* NSLayoutConstraint.swift in Sources */ = {isa = PBXBuildFile; fileRef = 2D46975D25C2A54100CF4AA9 /* NSLayoutConstraint.swift */; };
 		2D46976425C2A71500CF4AA9 /* UIIamge.swift in Sources */ = {isa = PBXBuildFile; fileRef = 2D46976325C2A71500CF4AA9 /* UIIamge.swift */; };
 		2D61335825C188A000CAE157 /* APIService+Persist+Timeline.swift in Sources */ = {isa = PBXBuildFile; fileRef = 2D61335725C188A000CAE157 /* APIService+Persist+Timeline.swift */; };
@@ -153,6 +154,7 @@
 		2D42FF7D25C82218004A627A /* ActionToolBarContainer.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ActionToolBarContainer.swift; sourceTree = "<group>"; };
 		2D42FF8425C8224F004A627A /* HitTestExpandedButton.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = HitTestExpandedButton.swift; sourceTree = "<group>"; };
 		2D42FF8E25C8228A004A627A /* UIButton.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = UIButton.swift; sourceTree = "<group>"; };
+		2D45E5BE25C9549700A6D639 /* PublicTimelineViewModel+State.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = "PublicTimelineViewModel+State.swift"; sourceTree = "<group>"; };
 		2D46975D25C2A54100CF4AA9 /* NSLayoutConstraint.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = NSLayoutConstraint.swift; sourceTree = "<group>"; };
 		2D46976325C2A71500CF4AA9 /* UIIamge.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = UIIamge.swift; sourceTree = "<group>"; };
 		2D61335725C188A000CAE157 /* APIService+Persist+Timeline.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "APIService+Persist+Timeline.swift"; sourceTree = "<group>"; };
@@ -357,6 +359,7 @@
 				2D76317C25C14DF400929FB9 /* PublicTimelineViewController+StatusProvider.swift */,
 				2D76316A25C14D4C00929FB9 /* PublicTimelineViewModel.swift */,
 				2D76318225C14E8F00929FB9 /* PublicTimelineViewModel+Diffable.swift */,
+				2D45E5BE25C9549700A6D639 /* PublicTimelineViewModel+State.swift */,
 			);
 			path = PublicTimeline;
 			sourceTree = "<group>";
@@ -1047,6 +1050,7 @@
 				2DF123A725C3B0210020F248 /* ActiveLabel.swift in Sources */,
 				2D76316B25C14D4C00929FB9 /* PublicTimelineViewModel.swift in Sources */,
 				2D46975E25C2A54100CF4AA9 /* NSLayoutConstraint.swift in Sources */,
+				2D45E5BF25C9549700A6D639 /* PublicTimelineViewModel+State.swift in Sources */,
 				2D46976425C2A71500CF4AA9 /* UIIamge.swift in Sources */,
 				DB8AF55D25C138B7002E6C99 /* UIViewController.swift in Sources */,
 				2D42FF7E25C82218004A627A /* ActionToolBarContainer.swift in Sources */,

Mastodon/Scene/PublicTimeline/PublicTimelineViewController.swift

@@ -5,22 +5,22 @@
 //  Created by sxiaojian on 2021/1/27.
 //
 
-import os.log
-import UIKit
 import AVKit
 import Combine
 import CoreDataStack
 import GameplayKit
+import os.log
+import UIKit
 
 final class PublicTimelineViewController: UIViewController, NeedsDependency, TimelinePostTableViewCellDelegate {
-    
     weak var context: AppContext! { willSet { precondition(!isViewLoaded) } }
     weak var coordinator: SceneCoordinator! { willSet { precondition(!isViewLoaded) } }
     
     var disposeBag = Set<AnyCancellable>()
     var viewModel: PublicTimelineViewModel!
     
-
+    let refreshControl = UIRefreshControl()
+    
     lazy var tableView: UITableView = {
         let tableView = UITableView()
         tableView.register(TimelinePostTableViewCell.self, forCellReuseIdentifier: String(describing: TimelinePostTableViewCell.self))
@@ -30,16 +30,30 @@ final class PublicTimelineViewController: UIViewController, NeedsDependency, Tim
     }()
     
     deinit {
-        os_log("%{public}s[%{public}ld], %{public}s", ((#file as NSString).lastPathComponent), #line, #function)
+        os_log("%{public}s[%{public}ld], %{public}s", (#file as NSString).lastPathComponent, #line, #function)
     }
-    
 }
 
 extension PublicTimelineViewController {
-    
     override func viewDidLoad() {
         super.viewDidLoad()
         
+        tableView.refreshControl = refreshControl
+        refreshControl.addTarget(self, action: #selector(PublicTimelineViewController.refreshControlValueChanged(_:)), for: .valueChanged)
+        // bind refresh control
+        viewModel.isFetchingLatestTimeline
+            .receive(on: DispatchQueue.main)
+            .sink { [weak self] isFetching in
+                guard let self = self else { return }
+                if !isFetching {
+                    UIView.animate(withDuration: 0.5) { [weak self] in
+                        guard let self = self else { return }
+                        self.refreshControl.endRefreshing()
+                    }
+                }
+            }
+            .store(in: &disposeBag)
+        
         tableView.translatesAutoresizingMaskIntoConstraints = false
         tableView.backgroundColor = Asset.Colors.tootDark.color
         view.addSubview(tableView)
@@ -60,6 +74,7 @@ extension PublicTimelineViewController {
             timelinePostTableViewCellDelegate: self
         )
     }
+
     override func viewWillAppear(_ animated: Bool) {
         super.viewWillAppear(animated)
         viewModel.fetchLatest()
@@ -67,7 +82,7 @@ extension PublicTimelineViewController {
             .sink { completion in
                 switch completion {
                 case .failure(let error):
-                    os_log("%{public}s[%{public}ld], %{public}s: fetch user timeline latest response error: %s", ((#file as NSString).lastPathComponent), #line, #function, error.localizedDescription)
+                    os_log("%{public}s[%{public}ld], %{public}s: fetch user timeline latest response error: %s", (#file as NSString).lastPathComponent, #line, #function, error.localizedDescription)
                 case .finished:
                     break
                 }
@@ -77,12 +92,22 @@ extension PublicTimelineViewController {
             }
             .store(in: &viewModel.disposeBag)
     }
-    
+}
+
+// MARK: - Selector
+
+extension PublicTimelineViewController {
+    @objc private func refreshControlValueChanged(_ sender: UIRefreshControl) {
+        guard viewModel.stateMachine.enter(PublicTimelineViewModel.State.Loading.self) else {
+            sender.endRefreshing()
+            return
+        }
+    }
 }
 
 // MARK: - UITableViewDelegate
+
 extension PublicTimelineViewController: UITableViewDelegate {
-    
     func tableView(_ tableView: UITableView, estimatedHeightForRowAt indexPath: IndexPath) -> CGFloat {
         guard let diffableDataSource = viewModel.diffableDataSource else { return 100 }
         guard let item = diffableDataSource.itemIdentifier(for: indexPath) else { return 100 }
@@ -94,12 +119,9 @@ extension PublicTimelineViewController: UITableViewDelegate {
         return ceil(frame.height)
     }
     
-    func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
+    func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {}
-
-    }
     
     func tableView(_ tableView: UITableView, didEndDisplaying cell: UITableViewCell, forRowAt indexPath: IndexPath) {
-
         guard let diffableDataSource = viewModel.diffableDataSource else { return }
         guard let item = diffableDataSource.itemIdentifier(for: indexPath) else { return }
         

Mastodon/Scene/PublicTimeline/PublicTimelineViewModel+Diffable.swift

@@ -5,10 +5,10 @@
 //  Created by sxiaojian on 2021/1/27.
 //
 
-import os.log
-import UIKit
 import CoreData
 import CoreDataStack
+import os.log
+import UIKit
 
 extension PublicTimelineViewModel {
     func setupDiffableDataSource(
@@ -20,26 +20,27 @@ extension PublicTimelineViewModel {
             .autoconnect()
             .share()
             .eraseToAnyPublisher()
-        
+
         diffableDataSource = TimelineSection.tableViewDiffableDataSource(
             for: tableView,
             dependency: dependency,
             managedObjectContext: fetchedResultsController.managedObjectContext,
             timestampUpdatePublisher: timestampUpdatePublisher,
-            timelinePostTableViewCellDelegate: timelinePostTableViewCellDelegate)
+            timelinePostTableViewCellDelegate: timelinePostTableViewCellDelegate
+        )
         items.value = []
     }
 }
 
 // MARK: - NSFetchedResultsControllerDelegate
+
 extension PublicTimelineViewModel: NSFetchedResultsControllerDelegate {
     func controller(_ controller: NSFetchedResultsController<NSFetchRequestResult>, didChangeContentWith snapshot: NSDiffableDataSourceSnapshotReference) {
-        os_log("%{public}s[%{public}ld], %{public}s", ((#file as NSString).lastPathComponent), #line, #function)
+        os_log("%{public}s[%{public}ld], %{public}s", (#file as NSString).lastPathComponent, #line, #function)
-        
+
         let indexes = tootIDs.value
         let toots = fetchedResultsController.fetchedObjects ?? []
-        guard toots.count == indexes.count else { return }
+
-        
         let items: [Item] = toots
             .compactMap { toot -> (Int, Toot)? in
                 guard toot.deletedAt == nil else { return nil }
@@ -49,5 +50,4 @@ extension PublicTimelineViewModel: NSFetchedResultsControllerDelegate {
             .map { Item.toot(objectID: $0.1.objectID) }
         self.items.value = items
     }
-    
 }

Mastodon/Scene/PublicTimeline/PublicTimelineViewModel+State.swift

@@ -0,0 +1,132 @@
+//
+//  PublicTimelineViewModel+State.swift
+//  Mastodon
+//
+//  Created by sxiaojian on 2021/2/2.
+//
+
+import Foundation
+import GameplayKit
+import MastodonSDK
+import os.log
+
+extension PublicTimelineViewModel {
+    class State: GKState {
+        weak var viewModel: PublicTimelineViewModel?
+        
+        init(viewModel: PublicTimelineViewModel) {
+            self.viewModel = viewModel
+        }
+        
+        override func didEnter(from previousState: GKState?) {
+            os_log("%{public}s[%{public}ld], %{public}s: enter %s, previous: %s", (#file as NSString).lastPathComponent, #line, #function, self.debugDescription, previousState.debugDescription)
+        }
+    }
+}
+
+extension PublicTimelineViewModel.State {
+    class Initial: PublicTimelineViewModel.State {
+        override func isValidNextState(_ stateClass: AnyClass) -> Bool {
+            switch stateClass {
+            case is Loading.Type:
+                return true
+            default:
+                return false
+            }
+        }
+    }
+    
+    class Loading: PublicTimelineViewModel.State {
+        override func isValidNextState(_ stateClass: AnyClass) -> Bool {
+            switch stateClass {
+            case is Fail.Type:
+                return true
+            case is Idle.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 }
+
+            viewModel.fetchLatest()
+                .receive(on: DispatchQueue.main)
+                .sink { completion in
+                    switch completion {
+                    case .failure(let error):
+                        os_log("%{public}s[%{public}ld], %{public}s: fetch user timeline latest response error: %s", (#file as NSString).lastPathComponent, #line, #function, error.localizedDescription)
+                        stateMachine.enter(Fail.self)
+                        
+                    case .finished:
+                        break
+                    }
+                } receiveValue: { response in
+                    viewModel.isFetchingLatestTimeline.value = false
+                    let tootsIDs = response.value.map { $0.id }
+                    viewModel.tootIDs.value = tootsIDs
+                    stateMachine.enter(Idle.self)
+                }
+                .store(in: &viewModel.disposeBag)
+        }
+    }
+    
+    class Fail: PublicTimelineViewModel.State {
+        override func isValidNextState(_ stateClass: AnyClass) -> Bool {
+            switch stateClass {
+            case is Loading.Type, is LoadingMore.Type:
+                return true
+            default:
+                return false
+            }
+        }
+    }
+    
+    class Idle: PublicTimelineViewModel.State {
+        override func isValidNextState(_ stateClass: AnyClass) -> Bool {
+            switch stateClass {
+            case is Loading.Type, is LoadingMore.Type:
+                return true
+            default:
+                return false
+            }
+        }
+    }
+    
+    class LoadingMore: PublicTimelineViewModel.State {
+        override func isValidNextState(_ stateClass: AnyClass) -> Bool {
+            switch stateClass {
+            case is Fail.Type:
+                return true
+            case is Idle.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 }
+        
+            viewModel.loadMore()
+                .sink { completion in
+                    switch completion {
+                    case .failure(let error):
+                        stateMachine.enter(Fail.self)
+                        os_log("%{public}s[%{public}ld], %{public}s: load more fail: %s", (#file as NSString).lastPathComponent, #line, #function, error.localizedDescription)
+                    case .finished:
+                        break
+                    }
+                } receiveValue: { response in
+                    viewModel.isFetchingLatestTimeline.value = false
+                    let tootsIDs = response.value.map { $0.id }
+                    viewModel.tootIDs.value = tootsIDs
+                    stateMachine.enter(Idle.self)
+                }
+                .store(in: &viewModel.disposeBag)
+        }
+    }
+}

Mastodon/Scene/PublicTimeline/PublicTimelineViewModel.swift

@@ -5,28 +5,39 @@
 //  Created by sxiaojian on 2021/1/27.
 //
 
-import os.log
+import AlamofireImage
-import UIKit
-import GameplayKit
 import Combine
 import CoreData
 import CoreDataStack
+import GameplayKit
 import MastodonSDK
-import AlamofireImage
+import os.log
-
+import UIKit
 
 class PublicTimelineViewModel: NSObject {
-    
     var disposeBag = Set<AnyCancellable>()
     
     // input
     let context: AppContext
     let fetchedResultsController: NSFetchedResultsController<Toot>
+    let isFetchingLatestTimeline = CurrentValueSubject<Bool, Never>(false)
     weak var tableView: UITableView?
     
     // output
     var diffableDataSource: UITableViewDiffableDataSource<TimelineSection, Item>?
 
+    lazy var stateMachine: GKStateMachine = {
+        let stateMachine = GKStateMachine(states: [
+            State.Initial(viewModel: self),
+            State.Loading(viewModel: self),
+            State.Fail(viewModel: self),
+            State.Idle(viewModel: self),
+            State.LoadingMore(viewModel: self),
+        ])
+        stateMachine.enter(State.Initial.self)
+        return stateMachine
+    }()
+    
     let tootIDs = CurrentValueSubject<[String], Never>([])
     let items = CurrentValueSubject<[Item], Never>([])
     var cellFrameCache = NSCache<NSNumber, NSValue>()
@@ -49,7 +60,7 @@ class PublicTimelineViewModel: NSObject {
         }()
         super.init()
         
-        self.fetchedResultsController.delegate = self
+        fetchedResultsController.delegate = self
         
         items
             .receive(on: DispatchQueue.main)
@@ -57,7 +68,7 @@ class PublicTimelineViewModel: NSObject {
             .sink { [weak self] items in
                 guard let self = self else { return }
                 guard let diffableDataSource = self.diffableDataSource else { return }
-                os_log("%{public}s[%{public}ld], %{public}s: items did change", ((#file as NSString).lastPathComponent), #line, #function)
+                os_log("%{public}s[%{public}ld], %{public}s: items did change", (#file as NSString).lastPathComponent, #line, #function)
 
                 var snapshot = NSDiffableDataSourceSnapshot<TimelineSection, Item>()
                 snapshot.appendSections([.main])
@@ -82,14 +93,16 @@ class PublicTimelineViewModel: NSObject {
     }
     
     deinit {
-        os_log("%{public}s[%{public}ld], %{public}s", ((#file as NSString).lastPathComponent), #line, #function)
+        os_log("%{public}s[%{public}ld], %{public}s", (#file as NSString).lastPathComponent, #line, #function)
     }
-    
 }
 
 extension PublicTimelineViewModel {
-    
     func fetchLatest() -> AnyPublisher<Mastodon.Response.Content<[Mastodon.Entity.Toot]>, Error> {
         return context.apiService.publicTimeline(count: 20, domain: "mstdn.jp")
     }
+    
+    func loadMore() -> AnyPublisher<Mastodon.Response.Content<[Mastodon.Entity.Toot]>, Error> {
+        return context.apiService.publicTimeline(count: 20, domain: "mstdn.jp")
+    }
 }