mastodon-ios/Mastodon/Scene/Discovery/News/DiscoveryNewsViewController...

208 lines
7.5 KiB
Swift

//
// DiscoveryNewsViewController.swift
// Mastodon
//
// Created by MainasuK on 2022-4-13.
//
import UIKit
import Combine
import MastodonCore
import MastodonUI
final class DiscoveryNewsViewController: UIViewController, NeedsDependency, MediaPreviewableViewController {
weak var context: AppContext! { willSet { precondition(!isViewLoaded) } }
weak var coordinator: SceneCoordinator! { willSet { precondition(!isViewLoaded) } }
var disposeBag = Set<AnyCancellable>()
var viewModel: DiscoveryNewsViewModel!
let mediaPreviewTransitionController = MediaPreviewTransitionController()
lazy var tableView: UITableView = {
let tableView = UITableView()
tableView.rowHeight = UITableView.automaticDimension
tableView.estimatedRowHeight = 100
tableView.separatorStyle = .none
tableView.backgroundColor = .clear
return tableView
}()
let refreshControl = RefreshControl()
}
extension DiscoveryNewsViewController {
override func viewDidLoad() {
super.viewDidLoad()
view.backgroundColor = .secondarySystemBackground
tableView.translatesAutoresizingMaskIntoConstraints = false
view.addSubview(tableView)
tableView.pinToParent()
tableView.delegate = self
viewModel.setupDiffableDataSource(
tableView: tableView
)
tableView.refreshControl = refreshControl
refreshControl.addTarget(self, action: #selector(DiscoveryNewsViewController.refreshControlValueChanged(_:)), for: .valueChanged)
viewModel.didLoadLatest
.receive(on: DispatchQueue.main)
.sink { [weak self] _ in
guard let self = self else { return }
self.refreshControl.endRefreshing()
}
.store(in: &disposeBag)
// setup batch fetch
viewModel.listBatchFetchViewModel.setup(scrollView: tableView)
viewModel.listBatchFetchViewModel.shouldFetch
.receive(on: DispatchQueue.main)
.sink { [weak self] _ in
guard let self = self else { return }
guard self.view.window != nil else { return }
self.viewModel.stateMachine.enter(DiscoveryNewsViewModel.State.Loading.self)
}
.store(in: &disposeBag)
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
refreshControl.endRefreshing()
tableView.deselectRow(with: transitionCoordinator, animated: animated)
}
}
extension DiscoveryNewsViewController {
@objc private func refreshControlValueChanged(_ sender: RefreshControl) {
guard viewModel.stateMachine.enter(DiscoveryNewsViewModel.State.Reloading.self) else {
sender.endRefreshing()
return
}
}
}
// MARK: - UITableViewDelegate
extension DiscoveryNewsViewController: UITableViewDelegate {
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
guard case let .link(link) = viewModel.diffableDataSource?.itemIdentifier(for: indexPath) else { return }
guard let url = URL(string: link.url) else { return }
_ = coordinator.present(
scene: .safari(url: url),
from: self,
transition: .safariPresent(animated: true, completion: nil)
)
}
}
// MARK: ScrollViewContainer
extension DiscoveryNewsViewController: ScrollViewContainer {
var scrollView: UIScrollView { tableView }
}
extension DiscoveryNewsViewController {
override var keyCommands: [UIKeyCommand]? {
return navigationKeyCommands
}
}
extension DiscoveryNewsViewController: TableViewControllerNavigateable {
func navigate(direction: TableViewNavigationDirection) {
if let indexPathForSelectedRow = tableView.indexPathForSelectedRow {
// navigate up/down on the current selected item
navigateToLink(direction: direction, indexPath: indexPathForSelectedRow)
} else {
// set first visible item selected
navigateToFirstVisibleLink()
}
}
private func navigateToLink(direction: TableViewNavigationDirection, indexPath: IndexPath) {
guard let diffableDataSource = viewModel.diffableDataSource else { return }
let items = diffableDataSource.snapshot().itemIdentifiers
guard let selectedItem = diffableDataSource.itemIdentifier(for: indexPath),
let selectedItemIndex = items.firstIndex(of: selectedItem) else {
return
}
let _navigateToItem: DiscoveryItem? = {
var index = selectedItemIndex
while 0..<items.count ~= index {
index = {
switch direction {
case .up: return index - 1
case .down: return index + 1
}
}()
guard 0..<items.count ~= index else { return nil }
let item = items[index]
guard Self.validNavigateableItem(item) else { continue }
return item
}
return nil
}()
guard let item = _navigateToItem, let indexPath = diffableDataSource.indexPath(for: item) else { return }
let scrollPosition: UITableView.ScrollPosition = overrideNavigationScrollPosition ?? Self.navigateScrollPosition(tableView: tableView, indexPath: indexPath)
tableView.selectRow(at: indexPath, animated: true, scrollPosition: scrollPosition)
}
private func navigateToFirstVisibleLink() {
guard let indexPathsForVisibleRows = tableView.indexPathsForVisibleRows else { return }
guard let diffableDataSource = viewModel.diffableDataSource else { return }
var visibleItems: [DiscoveryItem] = indexPathsForVisibleRows.sorted().compactMap { indexPath in
guard let item = diffableDataSource.itemIdentifier(for: indexPath) else { return nil }
guard Self.validNavigateableItem(item) else { return nil }
return item
}
if indexPathsForVisibleRows.first?.row != 0, visibleItems.count > 1 {
// drop first when visible not the first cell of table
visibleItems.removeFirst()
}
guard let item = visibleItems.first, let indexPath = diffableDataSource.indexPath(for: item) else { return }
let scrollPosition: UITableView.ScrollPosition = overrideNavigationScrollPosition ?? Self.navigateScrollPosition(tableView: tableView, indexPath: indexPath)
tableView.selectRow(at: indexPath, animated: true, scrollPosition: scrollPosition)
}
static func validNavigateableItem(_ item: DiscoveryItem) -> Bool {
switch item {
case .link:
return true
default:
return false
}
}
func open() {
guard let indexPathForSelectedRow = tableView.indexPathForSelectedRow else { return }
guard let diffableDataSource = viewModel.diffableDataSource else { return }
guard let item = diffableDataSource.itemIdentifier(for: indexPathForSelectedRow) else { return }
guard case let .link(link) = item else { return }
guard let url = URL(string: link.url) else { return }
_ = coordinator.present(
scene: .safari(url: url),
from: self,
transition: .safariPresent(animated: true, completion: nil)
)
}
func navigateKeyCommandHandlerRelay(_ sender: UIKeyCommand) {
navigateKeyCommandHandler(sender)
}
}