mastodon-ios/Mastodon/Scene/HomeTimeline/HomeTimelineViewModel.swift

156 lines
6.3 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 {
var disposeBag = Set<AnyCancellable>()
var observations = Set<NSKeyValueObservation>()
// input
let context: AppContext
let timelinePredicate = CurrentValueSubject<NSPredicate?, Never>(nil)
let fetchedResultsController: NSFetchedResultsController<HomeTimelineIndex>
let isFetchingLatestTimeline = CurrentValueSubject<Bool, Never>(false)
let viewDidAppear = PassthroughSubject<Void, Never>()
let homeTimelineNavigationBarTitleViewModel: HomeTimelineNavigationBarTitleViewModel
weak var contentOffsetAdjustableTimelineViewControllerDelegate: ContentOffsetAdjustableTimelineViewControllerDelegate?
weak var tableView: UITableView?
weak var timelineMiddleLoaderTableViewCellDelegate: TimelineMiddleLoaderTableViewCellDelegate?
let timelineIsEmpty = CurrentValueSubject<Bool, Never>(false)
let homeTimelineNeedRefresh = PassthroughSubject<Void, Never>()
// output
// 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)
// middle loader
let loadMiddleSateMachineList = CurrentValueSubject<[NSManagedObjectID: GKStateMachine], Never>([:]) // TimelineIndex.objectID : middle loading state machine
var diffableDataSource: UITableViewDiffableDataSource<StatusSection, Item>?
var cellFrameCache = NSCache<NSNumber, NSValue>()
init(context: AppContext) {
self.context = context
self.fetchedResultsController = {
let fetchRequest = HomeTimelineIndex.sortedFetchRequest
fetchRequest.fetchBatchSize = 20
fetchRequest.returnsObjectsAsFaults = false
fetchRequest.relationshipKeyPathsForPrefetching = [
#keyPath(HomeTimelineIndex.status),
#keyPath(HomeTimelineIndex.status.author),
#keyPath(HomeTimelineIndex.status.reblog),
#keyPath(HomeTimelineIndex.status.reblog.author),
]
let controller = NSFetchedResultsController(
fetchRequest: fetchRequest,
managedObjectContext: context.managedObjectContext,
sectionNameKeyPath: nil,
cacheName: nil
)
return controller
}()
self.homeTimelineNavigationBarTitleViewModel = HomeTimelineNavigationBarTitleViewModel(context: context)
super.init()
fetchedResultsController.delegate = self
timelinePredicate
.receive(on: DispatchQueue.main)
.compactMap { $0 }
.first() // set once
.sink { [weak self] predicate in
guard let self = self else { return }
self.fetchedResultsController.fetchRequest.predicate = predicate
do {
self.diffableDataSource?.defaultRowAnimation = .fade
try self.fetchedResultsController.performFetch()
DispatchQueue.main.asyncAfter(deadline: .now() + 3) { [weak self] in
guard let self = self else { return }
self.diffableDataSource?.defaultRowAnimation = .automatic
}
} catch {
assertionFailure(error.localizedDescription)
}
}
.store(in: &disposeBag)
context.authenticationService.activeMastodonAuthentication
.sink { [weak self] activeMastodonAuthentication in
guard let self = self else { return }
guard let mastodonAuthentication = activeMastodonAuthentication else { return }
let domain = mastodonAuthentication.domain
let userID = mastodonAuthentication.userID
let predicate = NSCompoundPredicate(andPredicateWithSubpredicates: [
HomeTimelineIndex.predicate(domain: domain, userID: userID),
HomeTimelineIndex.notDeleted()
])
self.timelinePredicate.value = predicate
}
.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: SuggestionAccountViewModelDelegate { }