mastodon-ios/Mastodon/Scene/HomeTimeline/HomeTimelineViewModel+LoadO...

124 lines
4.4 KiB
Swift

//
// HomeTimelineViewModel+LoadOldestState.swift
// Mastodon
//
// Created by sxiaojian on 2021/2/5.
//
import Foundation
import GameplayKit
import MastodonSDK
extension HomeTimelineViewModel {
class LoadOldestState: GKState {
let id = UUID()
weak var viewModel: HomeTimelineViewModel?
init(viewModel: HomeTimelineViewModel) {
self.viewModel = viewModel
}
@MainActor
func enter(state: LoadOldestState.Type) {
stateMachine?.enter(state)
}
}
}
extension HomeTimelineViewModel.LoadOldestState {
class Initial: HomeTimelineViewModel.LoadOldestState {
override func isValidNextState(_ stateClass: AnyClass) -> Bool {
guard let viewModel = viewModel else { return false }
guard !viewModel.fetchedResultsController.records.isEmpty else { return false }
return stateClass == Loading.self
}
}
class Loading: HomeTimelineViewModel.LoadOldestState {
override func isValidNextState(_ stateClass: AnyClass) -> Bool {
return stateClass == Fail.self || stateClass == Idle.self || stateClass == NoMore.self
}
override func didEnter(from previousState: GKState?) {
super.didEnter(from: previousState)
guard let viewModel = viewModel, let stateMachine = stateMachine else { return }
guard let lastFeedRecord = viewModel.fetchedResultsController.records.last else {
stateMachine.enter(Idle.self)
return
}
Task {
let managedObjectContext = viewModel.fetchedResultsController.managedObjectContext
let _maxID: Mastodon.Entity.Status.ID? = try await managedObjectContext.perform {
guard let feed = lastFeedRecord.object(in: managedObjectContext),
let status = feed.status
else { return nil }
return status.id
}
guard let maxID = _maxID else {
await self.enter(state: Fail.self)
return
}
do {
let response = try await viewModel.context.apiService.homeTimeline(
maxID: maxID,
authenticationBox: viewModel.authContext.mastodonAuthenticationBox
)
let statuses = response.value
// enter no more state when no new statuses
if statuses.isEmpty || (statuses.count == 1 && statuses[0].id == maxID) {
await self.enter(state: NoMore.self)
} else {
await self.enter(state: Idle.self)
}
viewModel.homeTimelineNavigationBarTitleViewModel.receiveLoadingStateCompletion(.finished)
} catch {
await self.enter(state: Fail.self)
viewModel.homeTimelineNavigationBarTitleViewModel.receiveLoadingStateCompletion(.failure(error))
}
} // end Task
}
}
class Fail: HomeTimelineViewModel.LoadOldestState {
override func isValidNextState(_ stateClass: AnyClass) -> Bool {
return stateClass == Loading.self || stateClass == Idle.self
}
}
class Idle: HomeTimelineViewModel.LoadOldestState {
override func isValidNextState(_ stateClass: AnyClass) -> Bool {
return stateClass == Loading.self
}
}
class NoMore: HomeTimelineViewModel.LoadOldestState {
override func isValidNextState(_ stateClass: AnyClass) -> Bool {
// reset state if needs
return stateClass == Idle.self
}
override func didEnter(from previousState: GKState?) {
guard let viewModel = viewModel else { return }
guard let diffableDataSource = viewModel.diffableDataSource else {
assertionFailure()
return
}
DispatchQueue.main.async {
var snapshot = diffableDataSource.snapshot()
snapshot.deleteItems([.bottomLoader])
diffableDataSource.apply(snapshot)
}
}
}
}