Allow refreshing bookmarks list

Tusker/Screens/Bookmarks/BookmarksViewController.swift

@@ -10,7 +10,7 @@ import UIKit
 import Pachyderm
 import CoreData
 
-class BookmarksViewController: UIViewController, CollectionViewController {
+class BookmarksViewController: UIViewController, CollectionViewController, RefreshableViewController {
     
     private static let pageSize = 40
 
@@ -95,6 +95,13 @@ class BookmarksViewController: UIViewController, CollectionViewController {
     override func viewDidLoad() {
         super.viewDidLoad()
         
+        #if !targetEnvironment(macCatalyst)
+        collectionView.refreshControl = UIRefreshControl()
+        collectionView.refreshControl!.addTarget(self, action: #selector(refresh), for: .valueChanged)
+        #endif
+        
+        addKeyCommand(MenuController.refreshCommand(discoverabilityTitle: "Refresh Bookmarks"))
+        
         NotificationCenter.default.addObserver(self, selector: #selector(handleStatusDeleted), name: .statusDeleted, object: nil)
         NotificationCenter.default.addObserver(self, selector: #selector(managedObjectsDidChange), name: .NSManagedObjectContextObjectsDidChange, object: mastodonController.persistentContainer.viewContext)
     }
@@ -176,8 +183,6 @@ class BookmarksViewController: UIViewController, CollectionViewController {
             snapshot.deleteItems([.loadingIndicator])
             snapshot.appendItems(statuses.map { .status(id: $0.id, state: .unknown, addedLocally: false) })
             await apply(snapshot: snapshot, animatingDifferences: true)
-            
-            state = .loaded
         } catch {
             let config = ToastConfiguration(from: error, with: "Error Loading Older Bookmarks", in: self) { [weak self] toast in
                 toast.dismissToast(animated: true)
@@ -187,9 +192,9 @@ class BookmarksViewController: UIViewController, CollectionViewController {
             
             snapshot.deleteItems([.loadingIndicator])
             await apply(snapshot: snapshot, animatingDifferences: false)
-            
-            state = .loaded
         }
+        
+        state = .loaded
     }
     
     @objc private func handleStatusDeleted(_ notification: Foundation.Notification) {
@@ -249,6 +254,67 @@ class BookmarksViewController: UIViewController, CollectionViewController {
         }
     }
     
+    // MARK: Interaction
+    
+    @objc func refresh() {
+        guard case .loaded = state,
+              let newer else {
+            #if !targetEnvironment(macCatalyst)
+            collectionView.refreshControl!.endRefreshing()
+            #endif
+            return
+        }
+        state = .loadingNewer
+        
+        Task {
+            
+            do {
+                let req = Client.getBookmarks(range: newer.withCount(BookmarksViewController.pageSize))
+                let (statuses, pagination) = try await mastodonController.run(req)
+                self.newer = pagination?.newer
+                
+                await mastodonController.persistentContainer.addAll(statuses: statuses)
+                
+                var snapshot = dataSource.snapshot()
+                let localItems: [String: CollapseState] = Dictionary(uniqueKeysWithValues: snapshot.itemIdentifiers.compactMap({
+                    if case .status(id: let id, state: let state, addedLocally: true) = $0 {
+                        return (id, state)
+                    } else {
+                        return nil
+                    }
+                }))
+                var newItems: [Item] = []
+                for status in statuses {
+                    let state: CollapseState
+                    if let existing = localItems[status.id] {
+                        state = existing
+                        snapshot.deleteItems([.status(id: status.id, state: existing, addedLocally: true)])
+                    } else {
+                        state = .unknown
+                    }
+                    newItems.append(.status(id: status.id, state: state, addedLocally: false))
+                }
+                if let first = snapshot.itemIdentifiers.first {
+                    snapshot.insertItems(newItems, beforeItem: first)
+                } else {
+                    snapshot.appendItems(newItems)
+                }
+                await apply(snapshot: snapshot, animatingDifferences: true)
+            } catch {
+                let config = ToastConfiguration(from: error, with: "Error Refreshing Bookmarks", in: self) { [weak self] toast in
+                    toast.dismissToast(animated: true)
+                    self?.refresh()
+                }
+                showToast(configuration: config, animated: true)
+            }
+            
+            #if !targetEnvironment(macCatalyst)
+            collectionView.refreshControl!.endRefreshing()
+            #endif
+            state = .loaded
+        }
+    }
+
 }
 
 extension BookmarksViewController {
@@ -297,6 +363,7 @@ extension BookmarksViewController {
         case loadingInitial
         case loaded
         case loadingOlder
+        case loadingNewer
     }
 }