mastodon-ios/Mastodon/Scene/PublicTimeline/PublicTimelineViewModel+Dif...

73 lines
2.9 KiB
Swift

//
// PublicTimelineViewModel+Diffable.swift
// Mastodon
//
// Created by sxiaojian on 2021/1/27.
//
import CoreData
import CoreDataStack
import os.log
import UIKit
extension PublicTimelineViewModel {
func setupDiffableDataSource(
for tableView: UITableView,
dependency: NeedsDependency,
statusTableViewCellDelegate: StatusTableViewCellDelegate,
timelineMiddleLoaderTableViewCellDelegate: TimelineMiddleLoaderTableViewCellDelegate
) {
let timestampUpdatePublisher = Timer.publish(every: 1.0, on: .main, in: .common)
.autoconnect()
.share()
.eraseToAnyPublisher()
diffableDataSource = StatusSection.tableViewDiffableDataSource(
for: tableView,
timelineContext: .public,
dependency: dependency,
managedObjectContext: fetchedResultsController.managedObjectContext,
timestampUpdatePublisher: timestampUpdatePublisher,
statusTableViewCellDelegate: statusTableViewCellDelegate,
timelineMiddleLoaderTableViewCellDelegate: timelineMiddleLoaderTableViewCellDelegate,
threadReplyLoaderTableViewCellDelegate: nil
)
items.value = []
stateMachine.enter(PublicTimelineViewModel.State.Loading.self)
}
}
// 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)
let indexes = statusIDs.value
let statuses = fetchedResultsController.fetchedObjects ?? []
guard statuses.count == indexes.count else { return }
let indexStatusTuples: [(Int, Status)] = statuses
.compactMap { status -> (Int, Status)? in
guard status.deletedAt == nil else { return nil }
return indexes.firstIndex(of: status.id).map { index in (index, status) }
}
.sorted { $0.0 < $1.0 }
var oldSnapshotAttributeDict: [NSManagedObjectID: Item.StatusAttribute] = [:]
for item in self.items.value {
guard case let .status(objectID, attribute) = item else { continue }
oldSnapshotAttributeDict[objectID] = attribute
}
var items = [Item]()
for (_, status) in indexStatusTuples {
let attribute = oldSnapshotAttributeDict[status.objectID] ?? Item.StatusAttribute()
items.append(Item.status(objectID: status.objectID, attribute: attribute))
if statusIDsWhichHasGap.contains(status.id) {
items.append(Item.publicMiddleLoader(statusID: status.id))
}
}
self.items.value = items
}
}