Timeline jump to present

This commit is contained in:
Shadowfacts 2022-11-18 20:49:15 -05:00
parent 8276e99d27
commit 0fddf94292
7 changed files with 145 additions and 85 deletions

View File

@ -11,7 +11,9 @@ import Foundation
public enum RequestRange {
case `default`
case count(Int)
/// Chronologically immediately before the given ID
case before(id: String, count: Int?)
/// Chronologically immediately after the given ID
case after(id: String, count: Int?)
}

View File

@ -97,7 +97,7 @@ class TrendingStatusesViewController: UIViewController {
do {
statuses = try await mastodonController.run(Client.getTrendingStatuses()).0
} catch {
var snapshot = NSDiffableDataSourceSnapshot<Section, Item>()
let snapshot = NSDiffableDataSourceSnapshot<Section, Item>()
await dataSource.apply(snapshot)
let config = ToastConfiguration(from: error, with: "Loading Trending Posts", in: self) { toast in
toast.dismissToast(animated: true)

View File

@ -25,8 +25,8 @@ class ProfileStatusesViewController: UIViewController, TimelineLikeCollectionVie
private var older: RequestRange?
private var cancellables = Set<AnyCancellable>()
var collectionView: UICollectionView {
view as! UICollectionView
var collectionView: UICollectionView! {
view as? UICollectionView
}
private(set) var dataSource: UICollectionViewDiffableDataSource<Section, Item>!
private(set) var headerCell: ProfileHeaderCollectionViewCell?
@ -157,7 +157,7 @@ class ProfileStatusesViewController: UIViewController, TimelineLikeCollectionVie
}
Task {
if case .notLoadedInitial = await controller.state {
if case .notLoadedInitial = controller.state {
await load()
}
}

View File

@ -10,7 +10,7 @@ import UIKit
class TimelineGapCollectionViewCell: UICollectionViewCell {
var fillGap: ((TimelineLikeController<TimelineViewController.TimelineItem>.GapDirection) -> Void)?
var fillGap: ((TimelineGapDirection) -> Void)?
override init(frame: CGRect) {
super.init(frame: frame)

View File

@ -16,14 +16,10 @@ class TimelineViewController: UIViewController, TimelineLikeCollectionViewContro
private(set) var controller: TimelineLikeController<TimelineItem>!
let confirmLoadMore = PassthroughSubject<Void, Never>()
private var newer: RequestRange?
private var older: RequestRange?
// stored separately because i don't want to query the snapshot every time the user scrolls
private var isShowingTimelineDescription = false
var collectionView: UICollectionView {
view as! UICollectionView
}
private(set) var collectionView: UICollectionView!
private(set) var dataSource: UICollectionViewDiffableDataSource<Section, Item>!
init(for timeline: Timeline, mastodonController: MastodonController!) {
@ -42,7 +38,9 @@ class TimelineViewController: UIViewController, TimelineLikeCollectionViewContro
fatalError("init(coder:) has not been implemented")
}
override func loadView() {
override func viewDidLoad() {
super.viewDidLoad()
var config = UICollectionLayoutListConfiguration(appearance: .plain)
config.leadingSwipeActionsConfigurationProvider = { [unowned self] in
(collectionView.cellForItem(at: $0) as? TimelineStatusCollectionViewCell)?.leadingSwipeActions()
@ -66,9 +64,17 @@ class TimelineViewController: UIViewController, TimelineLikeCollectionViewContro
return config
}
let layout = UICollectionViewCompositionalLayout.list(using: config)
view = UICollectionView(frame: .zero, collectionViewLayout: layout)
collectionView = UICollectionView(frame: .zero, collectionViewLayout: layout)
collectionView.delegate = self
collectionView.dragDelegate = self
collectionView.translatesAutoresizingMaskIntoConstraints = false
view.addSubview(collectionView)
NSLayoutConstraint.activate([
collectionView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
collectionView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
collectionView.topAnchor.constraint(equalTo: view.topAnchor),
collectionView.bottomAnchor.constraint(equalTo: view.bottomAnchor),
])
registerTimelineLikeCells()
collectionView.register(PublicTimelineDescriptionCollectionViewCell.self, forCellWithReuseIdentifier: "publicTimelineDescription")
@ -79,23 +85,31 @@ class TimelineViewController: UIViewController, TimelineLikeCollectionViewContro
collectionView.refreshControl = UIRefreshControl()
collectionView.refreshControl!.addTarget(self, action: #selector(refresh), for: .valueChanged)
#endif
}
override func viewDidLoad() {
super.viewDidLoad()
#if DEBUG
navigationItem.rightBarButtonItem = UIBarButtonItem(image: UIImage(systemName: "square.split.1x2.fill"), primaryAction: UIAction(handler: { [unowned self] _ in
// navigationItem.rightBarButtonItem = UIBarButtonItem(image: UIImage(systemName: "square.split.1x2.fill"), primaryAction: UIAction(handler: { [unowned self] _ in
// var snapshot = self.dataSource.snapshot()
// let statuses = snapshot.itemIdentifiers(inSection: .statuses)
// if statuses.count > 20 {
// let toRemove = Array(Array(statuses.dropFirst(10)).dropLast(10))
// if !toRemove.isEmpty {
// print("REMOVING MIDDLE \(toRemove.count) STATUSES")
// snapshot.insertItems([.gap], beforeItem: toRemove.first!)
// snapshot.deleteItems(toRemove)
// self.dataSource.apply(snapshot)
// }
// }
// }))
navigationItem.rightBarButtonItem = UIBarButtonItem(image: UIImage(systemName: "clock.arrow.circlepath"), primaryAction: UIAction(handler: { [unowned self] _ in
var snapshot = self.dataSource.snapshot()
let statuses = snapshot.itemIdentifiers(inSection: .statuses)
if statuses.count > 20 {
let toRemove = Array(Array(statuses.dropFirst(10)).dropLast(10))
if !toRemove.isEmpty {
print("REMOVING MIDDLE \(toRemove.count) STATUSES")
snapshot.insertItems([.gap], beforeItem: toRemove.first!)
let toRemove = Array(statuses.dropLast(20))
snapshot.deleteItems(toRemove)
self.dataSource.apply(snapshot)
}
// if case .status(id: let id, state: _) = snapshot.itemIdentifiers(inSection: .statuses).first {
// self.controller.dataSource.state.newer = .after(id: id, count: nil)
// }
}
}))
#else
@ -167,7 +181,7 @@ class TimelineViewController: UIViewController, TimelineLikeCollectionViewContro
}
Task {
if case .notLoadedInitial = await controller.state {
if case .notLoadedInitial = controller.state {
await controller.loadInitial()
}
}
@ -224,10 +238,53 @@ class TimelineViewController: UIViewController, TimelineLikeCollectionViewContro
@objc func refresh() {
Task {
if case .notLoadedInitial = await controller.state {
if case .notLoadedInitial = controller.state {
await controller.loadInitial()
} else {
await controller.loadNewer()
// I'm not sure whether this should move into TimelineLikeController/TimelineLikeCollectionViewController
let (_, presentItems) = await (controller.loadNewer(), try? loadInitial())
if let presentItems,
case .status(id: let id, state: _) = dataSource.snapshot().itemIdentifiers(inSection: .statuses).first {
// if there's no overlap between presentItems and the existing items in the data source, prompt the user to scroll to present
if !presentItems.contains(id) {
var snapshot = self.dataSource.snapshot()
let currentItems = snapshot.itemIdentifiers(inSection: .statuses)
guard let item = currentItems.first,
case .status(id: id, state: _) = item else {
return
}
// remove any existing gap if there is one
if let index = currentItems.lastIndex(of: .gap) {
snapshot.deleteItems(Array(currentItems[index...]))
}
snapshot.insertItems([.gap], beforeItem: item)
snapshot.insertItems(presentItems.map { .status(id: $0, state: .unknown) }, beforeItem: .gap)
// use a snapshot of the collection view to hide the flicker as the content offset changes and then changes back
let snapshotView = collectionView.snapshotView(afterScreenUpdates: false)!
snapshotView.layer.zPosition = 1000
snapshotView.frame = view.bounds
view.addSubview(snapshotView)
let bottomOffset = collectionView.contentSize.height - collectionView.contentOffset.y
self.dataSource.apply(snapshot, animatingDifferences: false) {
self.collectionView.contentOffset = CGPoint(x: 0, y: self.collectionView.contentSize.height - bottomOffset)
snapshotView.removeFromSuperview()
}
var config = ToastConfiguration(title: "Jump to present")
config.edge = .top
config.systemImageName = "arrow.up"
config.dismissAutomaticallyAfter = 2
config.action = { [unowned self] toast in
toast.dismissToast(animated: true)
self.collectionView.scrollToTop()
}
self.showToast(configuration: config, animated: true)
}
}
}
#if !targetEnvironment(macCatalyst)
collectionView.refreshControl?.endRefreshing()
@ -318,50 +375,48 @@ extension TimelineViewController {
func loadInitial() async throws -> [TimelineItem] {
try await Task.sleep(nanoseconds: 1 * NSEC_PER_SEC)
guard let mastodonController else {
throw Error.noClient
}
let request = Client.getStatuses(timeline: timeline)
let (statuses, _) = try await mastodonController.run(request)
if !statuses.isEmpty {
newer = .after(id: statuses.first!.id, count: nil)
older = .before(id: statuses.last!.id, count: nil)
await withCheckedContinuation { continuation in
mastodonController.persistentContainer.addAll(statuses: statuses) {
continuation.resume()
}
}
return await withCheckedContinuation { continuation in
mastodonController.persistentContainer.addAll(statuses: statuses) {
continuation.resume(returning: statuses.map(\.id))
}
}
return statuses.map(\.id)
}
func loadNewer() async throws -> [TimelineItem] {
guard let newer else {
let statusesSection = dataSource.snapshot().indexOfSection(.statuses)!
guard case .status(id: let id, state: _) = dataSource.itemIdentifier(for: IndexPath(row: 0, section: statusesSection)) else {
throw Error.noNewer
}
let newer = RequestRange.after(id: id, count: nil)
let request = Client.getStatuses(timeline: timeline, range: newer)
let (statuses, _) = try await mastodonController.run(request)
guard !statuses.isEmpty else {
throw Error.allCaughtUp
throw TimelineViewController.Error.allCaughtUp
}
self.newer = .after(id: statuses.first!.id, count: nil)
return await withCheckedContinuation { continuation in
await withCheckedContinuation { continuation in
mastodonController.persistentContainer.addAll(statuses: statuses) {
continuation.resume(returning: statuses.map(\.id))
continuation.resume()
}
}
return statuses.map(\.id)
}
func loadOlder() async throws -> [TimelineItem] {
guard let older else {
throw Error.noOlder
let snapshot = dataSource.snapshot()
let statusesSection = snapshot.indexOfSection(.statuses)!
guard case .status(id: let id, state: _) = dataSource.itemIdentifier(for: IndexPath(row: snapshot.numberOfItems(inSection: .statuses) - 1, section: statusesSection)) else {
throw Error.noNewer
}
let older = RequestRange.before(id: id, count: nil)
let request = Client.getStatuses(timeline: timeline, range: older)
let (statuses, _) = try await mastodonController.run(request)
@ -370,16 +425,16 @@ extension TimelineViewController {
return []
}
self.older = .before(id: statuses.last!.id, count: nil)
return await withCheckedContinuation { continuation in
await withCheckedContinuation { continuation in
mastodonController.persistentContainer.addAll(statuses: statuses) {
continuation.resume(returning: statuses.map(\.id))
}
continuation.resume()
}
}
func loadGap(in direction: TimelineLikeController<TimelineItem>.GapDirection) async throws -> [TimelineItem] {
return statuses.map(\.id)
}
func loadGap(in direction: TimelineGapDirection) async throws -> [TimelineItem] {
guard let gapIndexPath = dataSource.indexPath(for: .gap) else {
throw Error.noGap
}
@ -410,14 +465,16 @@ extension TimelineViewController {
// NOTE: closing the gap (if necessary) happens in handleFillGap
return await withCheckedContinuation { continuation in
await withCheckedContinuation { continuation in
mastodonController.persistentContainer.addAll(statuses: statuses) {
continuation.resume(returning: statuses.map(\.id))
}
continuation.resume()
}
}
func handleLoadGapError(_ error: Swift.Error, direction: TimelineLikeController<String>.GapDirection) async {
return statuses.map(\.id)
}
func handleLoadGapError(_ error: Swift.Error, direction: TimelineGapDirection) async {
// TODO: better title, involving direction?
let config = ToastConfiguration(from: error, with: "Error Loading", in: self) { [weak self] toast in
toast.dismissToast(animated: true)
@ -428,7 +485,7 @@ extension TimelineViewController {
self.showToast(configuration: config, animated: true)
}
func handleFillGap(_ timelineItems: [String], direction: TimelineLikeController<String>.GapDirection) async {
func handleFillGap(_ timelineItems: [String], direction: TimelineGapDirection) async {
var snapshot = dataSource.snapshot()
let addedItems: Bool
@ -496,14 +553,14 @@ extension TimelineViewController {
}
}
// if we didn't add any items, that implies the gap was removed, and we want to animate that to make clear what's happening
// if we didn't add any items, that implies the gap was removed, and we want to to make clear what's happening
if !addedItems {
await apply(snapshot, animatingDifferences: true)
let config = ToastConfiguration(title: "There's nothing in between!")
var config = ToastConfiguration(title: "There's nothing in between!")
config.dismissAutomaticallyAfter = 2
showToast(configuration: config, animated: true)
} else {
await apply(snapshot, animatingDifferences: false)
}
await apply(snapshot, animatingDifferences: true)
}
enum Error: TimelineLikeCollectionViewError {

View File

@ -19,7 +19,7 @@ protocol TimelineLikeCollectionViewController: UIViewController, TimelineLikeCon
var controller: TimelineLikeController<TimelineItem>! { get }
var confirmLoadMore: PassthroughSubject<Void, Never> { get }
var collectionView: UICollectionView { get }
var collectionView: UICollectionView! { get }
var dataSource: UICollectionViewDiffableDataSource<Section, Item>! { get }
}
@ -64,7 +64,7 @@ extension TimelineLikeCollectionViewController {
}
func handleAddLoadingIndicator() async {
if case .loadingInitial(_, _) = await controller.state,
if case .loadingInitial(_, _) = controller.state,
let refreshControl = collectionView.refreshControl,
refreshControl.isRefreshing {
refreshControl.beginRefreshing()
@ -85,7 +85,7 @@ extension TimelineLikeCollectionViewController {
}
func handleRemoveLoadingIndicator() async {
if case .loadingInitial(_, _) = await controller.state,
if case .loadingInitial(_, _) = controller.state,
let refreshControl = collectionView.refreshControl,
refreshControl.isRefreshing {
refreshControl.endRefreshing()
@ -180,14 +180,14 @@ extension TimelineLikeCollectionViewController {
await apply(snapshot, animatingDifferences: false)
}
func loadGap(in direction: TimelineLikeController<TimelineItem>.GapDirection) async throws -> [TimelineItem] {
func loadGap(in direction: TimelineGapDirection) async throws -> [TimelineItem] {
fatalError("not supported by \(String(describing: type(of: self)))")
}
func handleLoadGapError(_ error: Swift.Error, direction: TimelineLikeController<TimelineItem>.GapDirection) async {
func handleLoadGapError(_ error: Swift.Error, direction: TimelineGapDirection) async {
}
func handleFillGap(_ timelineItems: [TimelineItem], direction: TimelineLikeController<TimelineItem>.GapDirection) async {
func handleFillGap(_ timelineItems: [TimelineItem], direction: TimelineGapDirection) async {
fatalError("not supported by \(String(describing: type(of: self)))")
}
}
@ -217,7 +217,7 @@ extension TimelineLikeCollectionViewController {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "confirmLoadMore", for: indexPath) as! ConfirmLoadMoreCollectionViewCell
cell.confirmLoadMore = self.confirmLoadMore
Task {
if case .loadingOlder(_, _) = await controller.state {
if case .loadingOlder(_, _) = controller.state {
cell.isLoading = true
} else {
cell.isLoading = false

View File

@ -16,11 +16,11 @@ protocol TimelineLikeControllerDelegate<TimelineItem>: AnyObject {
func loadNewer() async throws -> [TimelineItem]
func loadOlder() async throws -> [TimelineItem]
func canLoadOlder() async -> Bool
func loadGap(in direction: TimelineLikeController<TimelineItem>.GapDirection) async throws -> [TimelineItem]
func loadOlder() async throws -> [TimelineItem]
func loadGap(in direction: TimelineGapDirection) async throws -> [TimelineItem]
func handleAddLoadingIndicator() async
func handleRemoveLoadingIndicator() async
@ -30,15 +30,16 @@ protocol TimelineLikeControllerDelegate<TimelineItem>: AnyObject {
func handlePrependItems(_ timelineItems: [TimelineItem]) async
func handleLoadOlderError(_ error: Swift.Error) async
func handleAppendItems(_ timelineItems: [TimelineItem]) async
func handleLoadGapError(_ error: Swift.Error, direction: TimelineLikeController<TimelineItem>.GapDirection) async
func handleFillGap(_ timelineItems: [TimelineItem], direction: TimelineLikeController<TimelineItem>.GapDirection) async
func handleLoadGapError(_ error: Swift.Error, direction: TimelineGapDirection) async
func handleFillGap(_ timelineItems: [TimelineItem], direction: TimelineGapDirection) async
}
private let logger = Logger(subsystem: Bundle.main.bundleIdentifier!, category: "TimelineLikeController")
actor TimelineLikeController<Item> {
@MainActor
class TimelineLikeController<Item> {
unowned var delegate: any TimelineLikeControllerDelegate<Item>
private unowned var delegate: any TimelineLikeControllerDelegate<Item>
private(set) var state = State.notLoadedInitial {
willSet {
@ -130,7 +131,7 @@ actor TimelineLikeController<Item> {
}
}
func fillGap(in direction: GapDirection) async {
func fillGap(in direction: TimelineGapDirection) async {
guard state == .idle else {
return
}
@ -190,7 +191,7 @@ actor TimelineLikeController<Item> {
case loadingInitial(LoadAttemptToken, hasAddedLoadingIndicator: Bool)
case loadingNewer(LoadAttemptToken)
case loadingOlder(LoadAttemptToken, hasAddedLoadingIndicator: Bool)
case loadingGap(LoadAttemptToken, GapDirection)
case loadingGap(LoadAttemptToken, TimelineGapDirection)
var debugDescription: String {
switch self {
@ -293,8 +294,8 @@ actor TimelineLikeController<Item> {
case prependItems([Item], LoadAttemptToken)
case loadOlderError(Error, LoadAttemptToken)
case appendItems([Item], LoadAttemptToken)
case loadGapError(Error, GapDirection, LoadAttemptToken)
case fillGap([Item], GapDirection, LoadAttemptToken)
case loadGapError(Error, TimelineGapDirection, LoadAttemptToken)
case fillGap([Item], TimelineGapDirection, LoadAttemptToken)
var debugDescription: String {
switch self {
@ -356,11 +357,11 @@ actor TimelineLikeController<Item> {
}
}
enum GapDirection {
}
enum TimelineGapDirection {
/// Fill in below the gap. I.e., statuses that are immediately newer than the status below the gap.
case below
/// Fill in above the gap. I.e., statuses that are immediately older than the status above the gap.
case above
}
}