Kurdtvs-Live-Kurdish-TV-Kur.../Mastodon/Scene/HomeTimeline/HomeTimelineViewModel.swift

203 lines
7.2 KiB
Swift

//
// HomeTimelineViewModel.swift
// Mastodon
//
// Created by sxiaojian on 2021/2/5.
//
import os.log
import func AVFoundation.AVMakeRect
import UIKit
import AVKit
import Combine
import CoreData
import CoreDataStack
import GameplayKit
import AlamofireImage
import DateToolsSwift
final class HomeTimelineViewModel: NSObject {
let logger = Logger(subsystem: "HomeTimelineViewModel", category: "ViewModel")
var disposeBag = Set<AnyCancellable>()
var observations = Set<NSKeyValueObservation>()
// input
let context: AppContext
let fetchedResultsController: FeedFetchedResultsController
let homeTimelineNavigationBarTitleViewModel: HomeTimelineNavigationBarTitleViewModel
let listBatchFetchViewModel = ListBatchFetchViewModel()
let viewDidAppear = PassthroughSubject<Void, Never>()
@Published var lastAutomaticFetchTimestamp: Date? = nil
@Published var scrollPositionRecord: ScrollPositionRecord? = nil
@Published var displaySettingBarButtonItem = true
@Published var displayComposeBarButtonItem = true
weak var tableView: UITableView?
weak var timelineMiddleLoaderTableViewCellDelegate: TimelineMiddleLoaderTableViewCellDelegate?
let timelineIsEmpty = CurrentValueSubject<Bool, Never>(false)
let homeTimelineNeedRefresh = PassthroughSubject<Void, Never>()
// output
var diffableDataSource: UITableViewDiffableDataSource<StatusSection, StatusItem>?
let didLoadLatest = PassthroughSubject<Void, Never>()
// top loader
private(set) lazy var loadLatestStateMachine: GKStateMachine = {
// exclude timeline middle fetcher state
let stateMachine = GKStateMachine(states: [
LoadLatestState.Initial(viewModel: self),
LoadLatestState.Loading(viewModel: self),
LoadLatestState.Fail(viewModel: self),
LoadLatestState.Idle(viewModel: self),
])
stateMachine.enter(LoadLatestState.Initial.self)
return stateMachine
}()
lazy var loadLatestStateMachinePublisher = CurrentValueSubject<LoadLatestState?, Never>(nil)
// bottom loader
private(set) lazy var loadOldestStateMachine: GKStateMachine = {
// exclude timeline middle fetcher state
let stateMachine = GKStateMachine(states: [
LoadOldestState.Initial(viewModel: self),
LoadOldestState.Loading(viewModel: self),
LoadOldestState.Fail(viewModel: self),
LoadOldestState.Idle(viewModel: self),
LoadOldestState.NoMore(viewModel: self),
])
stateMachine.enter(LoadOldestState.Initial.self)
return stateMachine
}()
lazy var loadOldestStateMachinePublisher = CurrentValueSubject<LoadOldestState?, Never>(nil)
var cellFrameCache = NSCache<NSNumber, NSValue>()
init(context: AppContext) {
self.context = context
self.fetchedResultsController = FeedFetchedResultsController(managedObjectContext: context.managedObjectContext)
self.homeTimelineNavigationBarTitleViewModel = HomeTimelineNavigationBarTitleViewModel(context: context)
super.init()
context.authenticationService.activeMastodonAuthenticationBox
.sink { [weak self] authenticationBox in
guard let self = self else { return }
guard let authenticationBox = authenticationBox else {
self.fetchedResultsController.predicate = Feed.predicate(kind: .none, acct: .none)
return
}
self.fetchedResultsController.predicate = Feed.predicate(
kind: .home,
acct: .mastodon(domain: authenticationBox.domain, userID: authenticationBox.userID)
)
}
.store(in: &disposeBag)
homeTimelineNeedRefresh
.sink { [weak self] _ in
self?.loadLatestStateMachine.enter(LoadLatestState.Loading.self)
}
.store(in: &disposeBag)
// refresh after publish post
homeTimelineNavigationBarTitleViewModel.isPublished
.delay(for: 2, scheduler: DispatchQueue.main)
.sink { [weak self] isPublished in
guard let self = self else { return }
self.homeTimelineNeedRefresh.send()
}
.store(in: &disposeBag)
}
deinit {
os_log(.info, log: .debug, "%{public}s[%{public}ld], %{public}s:", ((#file as NSString).lastPathComponent), #line, #function)
}
}
extension HomeTimelineViewModel {
struct ScrollPositionRecord {
let item: StatusItem
let offset: CGFloat
let timestamp: Date
}
}
extension HomeTimelineViewModel {
// load timeline gap
func loadMore(item: StatusItem) async {
guard case let .feedLoader(record) = item else { return }
guard let authenticationBox = context.authenticationService.activeMastodonAuthenticationBox.value else { return }
guard let diffableDataSource = diffableDataSource else { return }
var snapshot = diffableDataSource.snapshot()
let managedObjectContext = context.managedObjectContext
let key = "LoadMore@\(record.objectID)"
guard let feed = record.object(in: managedObjectContext) else { return }
guard let status = feed.status else { return }
// keep transient property live
managedObjectContext.cache(feed, key: key)
defer {
managedObjectContext.cache(nil, key: key)
}
do {
// update state
try await managedObjectContext.performChanges {
feed.update(isLoadingMore: true)
}
} catch {
assertionFailure(error.localizedDescription)
}
// reconfigure item
if #available(iOS 15.0, *) {
snapshot.reconfigureItems([item])
} else {
// Fallback on earlier versions
snapshot.reloadItems([item])
}
await updateSnapshotUsingReloadData(snapshot: snapshot)
// fetch data
do {
let maxID = status.id
_ = try await context.apiService.homeTimeline(
maxID: maxID,
authenticationBox: authenticationBox
)
} catch {
do {
// restore state
try await managedObjectContext.performChanges {
feed.update(isLoadingMore: false)
}
} catch {
assertionFailure(error.localizedDescription)
}
logger.log(level: .debug, "\((#file as NSString).lastPathComponent, privacy: .public)[\(#line, privacy: .public)], \(#function, privacy: .public): fetch more failure: \(error.localizedDescription)")
}
// reconfigure item again
if #available(iOS 15.0, *) {
snapshot.reconfigureItems([item])
} else {
// Fallback on earlier versions
snapshot.reloadItems([item])
}
await updateSnapshotUsingReloadData(snapshot: snapshot)
}
}
// MARK: - SuggestionAccountViewModelDelegate
extension HomeTimelineViewModel: SuggestionAccountViewModelDelegate {
}