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

163 lines
5.2 KiB
Swift

//
// NotificationTimelineViewModel.swift
// Mastodon
//
// Created by MainasuK on 2022-1-21.
//
import os.log
import UIKit
import Combine
import CoreDataStack
import GameplayKit
import MastodonSDK
import MastodonCore
final class NotificationTimelineViewModel {
let logger = Logger(subsystem: "NotificationTimelineViewModel", category: "ViewModel")
var disposeBag = Set<AnyCancellable>()
// input
let context: AppContext
let authContext: AuthContext
let scope: Scope
let feedFetchedResultsController: FeedFetchedResultsController
let listBatchFetchViewModel = ListBatchFetchViewModel()
@Published var isLoadingLatest = false
@Published var lastAutomaticFetchTimestamp: Date?
// output
var diffableDataSource: UITableViewDiffableDataSource<NotificationSection, NotificationItem>?
var didLoadLatest = PassthroughSubject<Void, Never>()
// 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
}()
init(
context: AppContext,
authContext: AuthContext,
scope: Scope
) {
self.context = context
self.authContext = authContext
self.scope = scope
self.feedFetchedResultsController = FeedFetchedResultsController(managedObjectContext: context.managedObjectContext)
// end init
feedFetchedResultsController.predicate = NotificationTimelineViewModel.feedPredicate(
authenticationBox: authContext.mastodonAuthenticationBox,
scope: scope
)
}
deinit {
os_log(.info, log: .debug, "%{public}s[%{public}ld], %{public}s", ((#file as NSString).lastPathComponent), #line, #function)
}
}
extension NotificationTimelineViewModel {
typealias Scope = APIService.MastodonNotificationScope
static func feedPredicate(
authenticationBox: MastodonAuthenticationBox,
scope: Scope
) -> NSPredicate {
let domain = authenticationBox.domain
let userID = authenticationBox.userID
let acct = Feed.Acct.mastodon(
domain: domain,
userID: userID
)
let predicate: NSPredicate = {
switch scope {
case .everything:
return NSCompoundPredicate(andPredicateWithSubpredicates: [
Feed.hasNotificationPredicate(),
Feed.predicate(
kind: .notificationAll,
acct: acct
)
])
case .mentions:
return NSCompoundPredicate(andPredicateWithSubpredicates: [
Feed.hasNotificationPredicate(),
Feed.predicate(
kind: .notificationMentions,
acct: acct
),
Feed.notificationTypePredicate(types: scope.includeTypes ?? [])
])
}
}()
return predicate
}
}
extension NotificationTimelineViewModel {
// load lastest
func loadLatest() async {
isLoadingLatest = true
defer { isLoadingLatest = false }
do {
_ = try await context.apiService.notifications(
maxID: nil,
scope: scope,
authenticationBox: authContext.mastodonAuthenticationBox
)
} catch {
didLoadLatest.send()
logger.log(level: .debug, "\((#file as NSString).lastPathComponent, privacy: .public)[\(#line, privacy: .public)], \(#function, privacy: .public): \(error.localizedDescription)")
}
}
// load timeline gap
func loadMore(item: NotificationItem) async {
guard case let .feedLoader(record) = item else { return }
let managedObjectContext = context.managedObjectContext
let key = "LoadMore@\(record.objectID)"
// return when already loading state
guard managedObjectContext.cache(froKey: key) == nil else { return }
guard let feed = record.object(in: managedObjectContext) else { return }
guard let maxID = feed.notification?.id else { return }
// keep transient property live
managedObjectContext.cache(feed, key: key)
defer {
managedObjectContext.cache(nil, key: key)
}
// fetch data
do {
_ = try await context.apiService.notifications(
maxID: maxID,
scope: scope,
authenticationBox: authContext.mastodonAuthenticationBox
)
} catch {
logger.log(level: .debug, "\((#file as NSString).lastPathComponent, privacy: .public)[\(#line, privacy: .public)], \(#function, privacy: .public): fetch more failure: \(error.localizedDescription)")
}
}
}