mastodon-ios/Mastodon/Scene/Notification/NotificationTimeline/NotificationTimelineViewMod...

128 lines
6.1 KiB
Swift

//
// NotificationTimelineViewModel+Diffable.swift
// Mastodon
//
// Created by MainasuK on 2022-1-21.
//
import os.log
import UIKit
import CoreData
import CoreDataStack
extension NotificationTimelineViewModel {
func setupDiffableDataSource(
tableView: UITableView,
notificationTableViewCellDelegate: NotificationTableViewCellDelegate
) {
diffableDataSource = NotificationSection.diffableDataSource(
tableView: tableView,
context: context,
configuration: NotificationSection.Configuration(
authContext: authContext,
notificationTableViewCellDelegate: notificationTableViewCellDelegate,
filterContext: .notifications,
activeFilters: context.statusFilterService.$activeFilters
)
)
var snapshot = NSDiffableDataSourceSnapshot<NotificationSection, NotificationItem>()
snapshot.appendSections([.main])
diffableDataSource?.apply(snapshot)
feedFetchedResultsController.$records
.receive(on: DispatchQueue.main)
.sink { [weak self] records in
guard let self = self else { return }
guard let diffableDataSource = self.diffableDataSource else { return }
self.logger.log(level: .debug, "\((#file as NSString).lastPathComponent, privacy: .public)[\(#line, privacy: .public)], \(#function, privacy: .public): incoming \(records.count) objects")
Task {
let start = CACurrentMediaTime()
defer {
let end = CACurrentMediaTime()
self.logger.log(level: .debug, "\((#file as NSString).lastPathComponent, privacy: .public)[\(#line, privacy: .public)], \(#function, privacy: .public): cost \(end - start, format: .fixed(precision: 4))s to process \(records.count) feeds")
}
let oldSnapshot = diffableDataSource.snapshot()
var newSnapshot: NSDiffableDataSourceSnapshot<NotificationSection, NotificationItem> = {
let newItems = records.map { record in
NotificationItem.feed(record: record)
}
var snapshot = NSDiffableDataSourceSnapshot<NotificationSection, NotificationItem>()
snapshot.appendSections([.main])
snapshot.appendItems(newItems, toSection: .main)
return snapshot
}()
let parentManagedObjectContext = self.context.managedObjectContext
let managedObjectContext = NSManagedObjectContext(concurrencyType: .privateQueueConcurrencyType)
managedObjectContext.parent = parentManagedObjectContext
try? await managedObjectContext.perform {
let anchors: [Feed] = {
let request = Feed.sortedFetchRequest
request.predicate = NSCompoundPredicate(andPredicateWithSubpredicates: [
Feed.hasMorePredicate(),
self.feedFetchedResultsController.predicate,
])
do {
return try managedObjectContext.fetch(request)
} catch {
assertionFailure(error.localizedDescription)
return []
}
}()
let itemIdentifiers = newSnapshot.itemIdentifiers
for (index, item) in itemIdentifiers.enumerated() {
guard case let .feed(record) = item else { continue }
guard anchors.contains(where: { feed in feed.objectID == record.objectID }) else { continue }
let isLast = index + 1 == itemIdentifiers.count
if isLast {
newSnapshot.insertItems([.bottomLoader], afterItem: item)
} else {
newSnapshot.insertItems([.feedLoader(record: record)], afterItem: item)
}
}
}
let hasChanges = newSnapshot.itemIdentifiers != oldSnapshot.itemIdentifiers
if !hasChanges {
self.logger.log(level: .debug, "\((#file as NSString).lastPathComponent, privacy: .public)[\(#line, privacy: .public)], \(#function, privacy: .public): snapshot not changes")
self.didLoadLatest.send()
return
} else {
self.logger.log(level: .debug, "\((#file as NSString).lastPathComponent, privacy: .public)[\(#line, privacy: .public)], \(#function, privacy: .public): snapshot has changes")
}
await self.updateSnapshotUsingReloadData(snapshot: newSnapshot)
self.didLoadLatest.send()
self.logger.log(level: .debug, "\((#file as NSString).lastPathComponent, privacy: .public)[\(#line, privacy: .public)], \(#function, privacy: .public): applied new snapshot")
} // end Task
}
.store(in: &disposeBag)
} // end func setupDiffableDataSource
}
extension NotificationTimelineViewModel {
@MainActor func updateDataSource(
snapshot: NSDiffableDataSourceSnapshot<NotificationSection, NotificationItem>,
animatingDifferences: Bool
) async {
diffableDataSource?.apply(snapshot, animatingDifferences: animatingDifferences)
}
@MainActor func updateSnapshotUsingReloadData(
snapshot: NSDiffableDataSourceSnapshot<NotificationSection, NotificationItem>
) async {
if #available(iOS 15.0, *) {
await self.diffableDataSource?.applySnapshotUsingReloadData(snapshot)
} else {
diffableDataSource?.applySnapshot(snapshot, animated: false, completion: nil)
}
}
}