metatext/Data Sources/AutocompleteDataSource.swift

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2021-02-15 08:47:30 +00:00
// Copyright © 2021 Metabolist. All rights reserved.
import Combine
import Mastodon
import UIKit
import ViewModels
enum AutocompleteSection: Int, Hashable {
case search
case emoji
}
enum AutocompleteItem: Hashable {
case account(Account)
case tag(Tag)
case emoji(PickerEmoji)
}
final class AutocompleteDataSource: UICollectionViewDiffableDataSource<AutocompleteSection, AutocompleteItem> {
@Published private var searchViewModel: SearchViewModel
@Published private var emojiPickerViewModel: EmojiPickerViewModel
private let updateQueue =
DispatchQueue(label: "com.metabolist.metatext.autocomplete-data-source.update-queue")
private var cancellables = Set<AnyCancellable>()
init(collectionView: UICollectionView,
queryPublisher: AnyPublisher<String?, Never>,
parentViewModel: NewStatusViewModel) {
searchViewModel = SearchViewModel(identityContext: parentViewModel.identityContext)
emojiPickerViewModel = EmojiPickerViewModel(identityContext: parentViewModel.identityContext, queryOnly: true)
let registration = UICollectionView.CellRegistration<AutocompleteItemCollectionViewCell, AutocompleteItem> {
$0.item = $2
$0.identityContext = parentViewModel.identityContext
}
let emojiRegistration = UICollectionView.CellRegistration<EmojiCollectionViewCell, PickerEmoji> {
$0.viewModel = EmojiViewModel(emoji: $2, identityContext: parentViewModel.identityContext)
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}
super.init(collectionView: collectionView) {
if case let .emoji(emoji) = $2 {
return $0.dequeueConfiguredReusableCell(using: emojiRegistration, for: $1, item: emoji)
} else {
return $0.dequeueConfiguredReusableCell(using: registration, for: $1, item: $2)
}
}
queryPublisher
.replaceNil(with: "")
.removeDuplicates()
.combineLatest($searchViewModel, $emojiPickerViewModel)
.sink(receiveValue: Self.combine(query:searchViewModel:emojiPickerViewModel:))
.store(in: &cancellables)
$searchViewModel.map(\.updates)
.switchToLatest()
.combineLatest($emojiPickerViewModel.map(\.$emoji).switchToLatest())
.receive(on: DispatchQueue.main)
.sink { [weak self] in self?.apply(searchViewModelUpdate: $0, emojiSections: $1) }
.store(in: &cancellables)
parentViewModel.$identityContext
.dropFirst()
.sink { [weak self] in
guard let self = self else { return }
self.searchViewModel = SearchViewModel(identityContext: $0)
self.emojiPickerViewModel = EmojiPickerViewModel(identityContext: $0, queryOnly: true)
}
.store(in: &cancellables)
}
override func apply(_ snapshot: NSDiffableDataSourceSnapshot<AutocompleteSection, AutocompleteItem>,
animatingDifferences: Bool = true,
completion: (() -> Void)? = nil) {
updateQueue.async {
super.apply(snapshot, animatingDifferences: animatingDifferences, completion: completion)
}
}
}
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extension AutocompleteDataSource {
func updateUse(emoji: PickerEmoji) {
emojiPickerViewModel.updateUse(emoji: emoji)
}
}
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private extension AutocompleteDataSource {
static func combine(query: String, searchViewModel: SearchViewModel, emojiPickerViewModel: EmojiPickerViewModel) {
if query.starts(with: ":") {
searchViewModel.query = ""
emojiPickerViewModel.query = String(query.dropFirst())
} else {
if query.starts(with: "@") {
searchViewModel.scope = .accounts
} else if query.starts(with: "#") {
searchViewModel.scope = .tags
}
searchViewModel.query = String(query.dropFirst())
emojiPickerViewModel.query = ""
}
}
func apply(searchViewModelUpdate: CollectionUpdate, emojiSections: [PickerEmoji.Category: [PickerEmoji]]) {
var newSnapshot = NSDiffableDataSourceSnapshot<AutocompleteSection, AutocompleteItem>()
let items: [AutocompleteItem] = searchViewModelUpdate.sections.map(\.items).reduce([], +).compactMap {
switch $0 {
case let .account(account, _, _):
return .account(account)
case let .tag(tag):
return .tag(tag)
default:
return nil
}
}
let emojis = emojiSections.sorted { $0.0 < $1.0 }.map(\.value).reduce([], +).map(AutocompleteItem.emoji)
newSnapshot.appendSections([.search])
if !items.isEmpty {
newSnapshot.appendItems(items, toSection: .search)
} else if !emojis.isEmpty {
newSnapshot.appendSections([.emoji])
newSnapshot.appendItems(emojis, toSection: .emoji)
}
apply(newSnapshot, animatingDifferences: !UIAccessibility.isReduceMotionEnabled) {
// animation causes issue with custom emoji images requiring reload
newSnapshot.reloadItems(newSnapshot.itemIdentifiers)
self.apply(newSnapshot, animatingDifferences: false)
}
}
}