Autocomplete wip

Data Sources/AutocompleteDataSource.swift

@@ -0,0 +1,130 @@
+// 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.emoji = $2.applyingDefaultSkinTone(identityContext: parentViewModel.identityContext)
+        }
+
+        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)
+        }
+    }
+}
+
+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)
+        }
+    }
+}

Extensions/PickerEmoji+Extensions.swift

@@ -3,6 +3,17 @@
 import UIKit
 import ViewModels
 
+extension PickerEmoji {
+    func applyingDefaultSkinTone(identityContext: IdentityContext) -> PickerEmoji {
+        if case let .system(systemEmoji, inFrequentlyUsed) = self,
+           let defaultEmojiSkinTone = identityContext.appPreferences.defaultEmojiSkinTone {
+            return .system(systemEmoji.applying(skinTone: defaultEmojiSkinTone), inFrequentlyUsed: inFrequentlyUsed)
+        } else {
+            return self
+        }
+    }
+}
+
 extension Dictionary where Key == PickerEmoji.Category, Value == [PickerEmoji] {
     func snapshot() -> NSDiffableDataSourceSnapshot<PickerEmoji.Category, PickerEmoji> {
         var snapshot = NSDiffableDataSourceSnapshot<PickerEmoji.Category, PickerEmoji>()

Localizations/Localizable.strings

@@ -306,6 +306,7 @@
 "tag.accessibility-recent-uses-%ld" = "%ld recent uses";
 "tag.accessibility-hint.post" = "View posts associated with trend";
 "tag.accessibility-hint.toot" = "View toots associated with trend";
+"tag.per-week-%ld" = "%ld per week";
 "timelines.home" = "Home";
 "timelines.local" = "Local";
 "timelines.federated" = "Federated";

Metatext.xcodeproj/project.pbxproj

@@ -165,6 +165,13 @@
 		D0D2AC4D25BCD2A9003D5DF2 /* TagTableViewCell.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0D2AC4C25BCD2A9003D5DF2 /* TagTableViewCell.swift */; };
 		D0D2AC5325BCD2BA003D5DF2 /* TagContentConfiguration.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0D2AC5225BCD2BA003D5DF2 /* TagContentConfiguration.swift */; };
 		D0D2AC6725BD0484003D5DF2 /* LineChartView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0D2AC6625BD0484003D5DF2 /* LineChartView.swift */; };
+		D0D93EBA25D9C70400C622ED /* AutocompleteItemView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0D93EB925D9C70400C622ED /* AutocompleteItemView.swift */; };
+		D0D93EC025D9C71D00C622ED /* AutocompleteItemContentConfiguration.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0D93EBF25D9C71D00C622ED /* AutocompleteItemContentConfiguration.swift */; };
+		D0D93EC525D9C75E00C622ED /* AutocompleteItemContentConfiguration.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0D93EBF25D9C71D00C622ED /* AutocompleteItemContentConfiguration.swift */; };
+		D0D93ECA25D9C76500C622ED /* AutocompleteItemView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0D93EB925D9C70400C622ED /* AutocompleteItemView.swift */; };
+		D0D93ED025D9C9ED00C622ED /* AutocompleteItemCollectionViewCell.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0D93ECF25D9C9ED00C622ED /* AutocompleteItemCollectionViewCell.swift */; };
+		D0D93ED925D9CBE200C622ED /* AutocompleteItemCollectionViewCell.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0D93ECF25D9C9ED00C622ED /* AutocompleteItemCollectionViewCell.swift */; };
+		D0D93EDE25DA014700C622ED /* SeparatorConfiguredCollectionViewListCell.swift in Sources */ = {isa = PBXBuildFile; fileRef = D09D972125C65682007E6394 /* SeparatorConfiguredCollectionViewListCell.swift */; };
 		D0DD50CB256B1F24004A04F7 /* ReportView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0DD50CA256B1F24004A04F7 /* ReportView.swift */; };
 		D0DDA76B25C5F20800FA0F91 /* ExploreDataSource.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0DDA76A25C5F20800FA0F91 /* ExploreDataSource.swift */; };
 		D0DDA77525C5F73F00FA0F91 /* TagCollectionViewCell.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0DDA77425C5F73F00FA0F91 /* TagCollectionViewCell.swift */; };
@@ -173,6 +180,8 @@
 		D0E2C1D124FD97F000854680 /* ViewModels in Frameworks */ = {isa = PBXBuildFile; productRef = D0E2C1D024FD97F000854680 /* ViewModels */; };
 		D0E39AB425D8BF88009C10F8 /* UITextInput+Extensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0E39AB325D8BF88009C10F8 /* UITextInput+Extensions.swift */; };
 		D0E39ABD25D8C046009C10F8 /* UITextInput+Extensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0E39AB325D8BF88009C10F8 /* UITextInput+Extensions.swift */; };
+		D0E39B7E25D9AF23009C10F8 /* AutocompleteDataSource.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0E39B7D25D9AF23009C10F8 /* AutocompleteDataSource.swift */; };
+		D0E39B8725D9B7FD009C10F8 /* AutocompleteDataSource.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0E39B7D25D9AF23009C10F8 /* AutocompleteDataSource.swift */; };
 		D0E5361C24E3EB4D00FB1CE1 /* NotificationService.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0E5361B24E3EB4D00FB1CE1 /* NotificationService.swift */; };
 		D0E5362024E3EB4D00FB1CE1 /* Notification Service Extension.appex in Embed App Extensions */ = {isa = PBXBuildFile; fileRef = D0E5361924E3EB4D00FB1CE1 /* Notification Service Extension.appex */; settings = {ATTRIBUTES = (RemoveHeadersOnCopy, ); }; };
 		D0E569DB2529319100FA1D72 /* LoadMoreView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0E569DA2529319100FA1D72 /* LoadMoreView.swift */; };
@@ -373,6 +382,9 @@
 		D0D2AC5225BCD2BA003D5DF2 /* TagContentConfiguration.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = TagContentConfiguration.swift; sourceTree = "<group>"; };
 		D0D2AC6625BD0484003D5DF2 /* LineChartView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = LineChartView.swift; sourceTree = "<group>"; };
 		D0D7C013250440610039AD6F /* CodableBloomFilter */ = {isa = PBXFileReference; lastKnownFileType = folder; path = CodableBloomFilter; sourceTree = "<group>"; };
+		D0D93EB925D9C70400C622ED /* AutocompleteItemView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AutocompleteItemView.swift; sourceTree = "<group>"; };
+		D0D93EBF25D9C71D00C622ED /* AutocompleteItemContentConfiguration.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AutocompleteItemContentConfiguration.swift; sourceTree = "<group>"; };
+		D0D93ECF25D9C9ED00C622ED /* AutocompleteItemCollectionViewCell.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AutocompleteItemCollectionViewCell.swift; sourceTree = "<group>"; };
 		D0DD50CA256B1F24004A04F7 /* ReportView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ReportView.swift; sourceTree = "<group>"; };
 		D0DDA76A25C5F20800FA0F91 /* ExploreDataSource.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ExploreDataSource.swift; sourceTree = "<group>"; };
 		D0DDA77425C5F73F00FA0F91 /* TagCollectionViewCell.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = TagCollectionViewCell.swift; sourceTree = "<group>"; };
@@ -381,6 +393,7 @@
 		D0E1F582251F13EC00D45315 /* WebfingerIndicatorView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = WebfingerIndicatorView.swift; sourceTree = "<group>"; };
 		D0E2C1CF24FD8BA400854680 /* ViewModels */ = {isa = PBXFileReference; lastKnownFileType = folder; path = ViewModels; sourceTree = "<group>"; };
 		D0E39AB325D8BF88009C10F8 /* UITextInput+Extensions.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "UITextInput+Extensions.swift"; sourceTree = "<group>"; };
+		D0E39B7D25D9AF23009C10F8 /* AutocompleteDataSource.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AutocompleteDataSource.swift; sourceTree = "<group>"; };
 		D0E5361924E3EB4D00FB1CE1 /* Notification Service Extension.appex */ = {isa = PBXFileReference; explicitFileType = "wrapper.app-extension"; includeInIndex = 0; path = "Notification Service Extension.appex"; sourceTree = BUILT_PRODUCTS_DIR; };
 		D0E5361B24E3EB4D00FB1CE1 /* NotificationService.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = NotificationService.swift; sourceTree = "<group>"; };
 		D0E5361D24E3EB4D00FB1CE1 /* Info.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = Info.plist; sourceTree = "<group>"; };
@@ -537,6 +550,7 @@
 		D021A66F25C3E1F9008A0C0D /* Collection View Cells */ = {
 			isa = PBXGroup;
 			children = (
+				D0D93ECF25D9C9ED00C622ED /* AutocompleteItemCollectionViewCell.swift */,
 				D07EC7DB25B13DBB006DF726 /* EmojiCollectionViewCell.swift */,
 				D09D971725C64682007E6394 /* InstanceCollectionViewCell.swift */,
 				D09D972125C65682007E6394 /* SeparatorConfiguredCollectionViewListCell.swift */,
@@ -549,6 +563,7 @@
 			isa = PBXGroup;
 			children = (
 				D0F0B112251A86A000942152 /* AccountContentConfiguration.swift */,
+				D0D93EBF25D9C71D00C622ED /* AutocompleteItemContentConfiguration.swift */,
 				D00702352555F4C500F38136 /* ConversationContentConfiguration.swift */,
 				D07EC7E225B13DD3006DF726 /* EmojiContentConfiguration.swift */,
 				D07EC7F125B13E57006DF726 /* EmojiView.swift */,
@@ -566,6 +581,7 @@
 			isa = PBXGroup;
 			children = (
 				D0F0B10D251A868200942152 /* AccountView.swift */,
+				D0D93EB925D9C70400C622ED /* AutocompleteItemView.swift */,
 				D00702302555F4AE00F38136 /* ConversationView.swift */,
 				D021A61325C36BFB008A0C0D /* IdentityView.swift */,
 				D09D970725C64522007E6394 /* InstanceView.swift */,
@@ -677,6 +693,7 @@
 		D0A1F4F5252E7D2A004435BF /* Data Sources */ = {
 			isa = PBXGroup;
 			children = (
+				D0E39B7D25D9AF23009C10F8 /* AutocompleteDataSource.swift */,
 				D0DDA76A25C5F20800FA0F91 /* ExploreDataSource.swift */,
 				D021A5FF25C3478F008A0C0D /* IdentitiesDataSource.swift */,
 				D0A1F4F6252E7D4B004435BF /* TableViewDataSource.swift */,
@@ -1031,6 +1048,7 @@
 				D0CE9F87258B076900E3A6B6 /* AttachmentUploadView.swift in Sources */,
 				D0F0B113251A86A000942152 /* AccountContentConfiguration.swift in Sources */,
 				D05E688525B55AE8001FB2C6 /* AVURLAsset+Extensions.swift in Sources */,
+				D0D93EC025D9C71D00C622ED /* AutocompleteItemContentConfiguration.swift in Sources */,
 				D09D970E25C64539007E6394 /* InstanceContentConfiguration.swift in Sources */,
 				D036AA02254B6101009094DF /* NotificationTableViewCell.swift in Sources */,
 				D08B8D42253F92B600B1EBEF /* ImagePageViewController.swift in Sources */,
@@ -1069,6 +1087,7 @@
 				D021A61425C36BFB008A0C0D /* IdentityView.swift in Sources */,
 				D06BC5E625202AD90079541D /* ProfileViewController.swift in Sources */,
 				D0D2AC4D25BCD2A9003D5DF2 /* TagTableViewCell.swift in Sources */,
+				D0D93ED025D9C9ED00C622ED /* AutocompleteItemCollectionViewCell.swift in Sources */,
 				D00CB22A25C92C0F008EF267 /* Attachment+Extensions.swift in Sources */,
 				D0D2AC5325BCD2BA003D5DF2 /* TagContentConfiguration.swift in Sources */,
 				D08B8D72254246E200B1EBEF /* PollView.swift in Sources */,
@@ -1077,6 +1096,7 @@
 				D0F0B10E251A868200942152 /* AccountView.swift in Sources */,
 				D0BEB1FF24F9E5BB001B0F04 /* ListsView.swift in Sources */,
 				D021A60025C3478F008A0C0D /* IdentitiesDataSource.swift in Sources */,
+				D0E39B7E25D9AF23009C10F8 /* AutocompleteDataSource.swift in Sources */,
 				D0C7D49724F7616A001EBDBB /* IdentitiesView.swift in Sources */,
 				D025B14D25C4E482001C69A8 /* ImageCacheConfiguration.swift in Sources */,
 				D01EF22425182B1F00650C6B /* AccountHeaderView.swift in Sources */,
@@ -1107,6 +1127,7 @@
 				D0BE980425D229D50057E161 /* SeparatorConfiguredTableViewCell.swift in Sources */,
 				D0A1F4F7252E7D4B004435BF /* TableViewDataSource.swift in Sources */,
 				D025B17E25C500BC001C69A8 /* CapsuleButton.swift in Sources */,
+				D0D93EBA25D9C70400C622ED /* AutocompleteItemView.swift in Sources */,
 				D0C7D4C424F7616A001EBDBB /* AppDelegate.swift in Sources */,
 				D0C7D49924F7616A001EBDBB /* AddIdentityView.swift in Sources */,
 				D0DDA77F25C6058300FA0F91 /* ExploreSectionHeaderView.swift in Sources */,
@@ -1143,8 +1164,10 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				D0D93EDE25DA014700C622ED /* SeparatorConfiguredCollectionViewListCell.swift in Sources */,
 				D08E52A6257C61C000FA2C5F /* ShareExtensionNavigationViewController.swift in Sources */,
 				D00CB23825C93047008EF267 /* String+Extensions.swift in Sources */,
+				D0D93EC525D9C75E00C622ED /* AutocompleteItemContentConfiguration.swift in Sources */,
 				D059373425AAEA7000754FDF /* CompositionPollView.swift in Sources */,
 				D021A67B25C3E32A008A0C0D /* PlayerView.swift in Sources */,
 				D021A69025C3E4B8008A0C0D /* EmojiContentConfiguration.swift in Sources */,
@@ -1173,10 +1196,13 @@
 				D036EBB3259FE28800EC1CFC /* UIColor+Extensions.swift in Sources */,
 				D0E39ABD25D8C046009C10F8 /* UITextInput+Extensions.swift in Sources */,
 				D088406E25AFBBE200BB749B /* EmojiPickerViewController.swift in Sources */,
+				D0E39B8725D9B7FD009C10F8 /* AutocompleteDataSource.swift in Sources */,
 				D00CB23325C92F2D008EF267 /* Attachment+Extensions.swift in Sources */,
+				D0D93ECA25D9C76500C622ED /* AutocompleteItemView.swift in Sources */,
 				D025B14725C4D26B001C69A8 /* ImageCacheSerializer.swift in Sources */,
 				D036EBB8259FE29800EC1CFC /* Status+Extensions.swift in Sources */,
 				D021A6A625C3E584008A0C0D /* EditAttachmentView.swift in Sources */,
+				D0D93ED925D9CBE200C622ED /* AutocompleteItemCollectionViewCell.swift in Sources */,
 				D0BE97E025D086F80057E161 /* ImagePastableTextView.swift in Sources */,
 				D05936DF25A937EC00754FDF /* EditThumbnailView.swift in Sources */,
 				D021A69525C3E4C1008A0C0D /* EmojiView.swift in Sources */,

ServiceLayer/Sources/ServiceLayer/Services/ExploreService.swift

@@ -20,10 +20,6 @@ public struct ExploreService {
 }
 
 public extension ExploreService {
-    func searchService() -> SearchService {
-        SearchService(mastodonAPIClient: mastodonAPIClient, contentDatabase: contentDatabase)
-    }
-
     func instanceServicePublisher(uri: String) -> AnyPublisher<InstanceService, Error> {
         contentDatabase.instancePublisher(uri: uri)
             .map { InstanceService(instance: $0, mastodonAPIClient: mastodonAPIClient) }

ServiceLayer/Sources/ServiceLayer/Services/IdentityService.swift

@@ -270,6 +270,10 @@ public extension IdentityService {
         ExploreService(mastodonAPIClient: mastodonAPIClient, contentDatabase: contentDatabase)
     }
 
+    func searchService() -> SearchService {
+        SearchService(mastodonAPIClient: mastodonAPIClient, contentDatabase: contentDatabase)
+    }
+
     func notificationsService(excludeTypes: Set<MastodonNotification.NotificationType>) -> NotificationsService {
         NotificationsService(excludeTypes: excludeTypes,
                              mastodonAPIClient: mastodonAPIClient,

View Controllers/EmojiPickerViewController.swift

@@ -20,7 +20,9 @@ final class EmojiPickerViewController: UICollectionViewController {
     private lazy var dataSource: UICollectionViewDiffableDataSource<PickerEmoji.Category, PickerEmoji> = {
         let cellRegistration = UICollectionView.CellRegistration
         <EmojiCollectionViewCell, PickerEmoji> { [weak self] in
-            $0.emoji = self?.applyingDefaultSkinTone(emoji: $2) ?? $2
+            guard let self = self else { return }
+
+            $0.emoji = $2.applyingDefaultSkinTone(identityContext: self.viewModel.identityContext)
         }
 
         let headerRegistration = UICollectionView.SupplementaryRegistration
@@ -149,9 +151,11 @@ final class EmojiPickerViewController: UICollectionViewController {
     }
 
     override func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
+        collectionView.deselectItem(at: indexPath, animated: true)
+
         guard let item = dataSource.itemIdentifier(for: indexPath) else { return }
 
-        select(emoji: applyingDefaultSkinTone(emoji: item))
+        select(item.applyingDefaultSkinTone(identityContext: viewModel.identityContext))
         viewModel.updateUse(emoji: item)
     }
 
@@ -234,13 +238,4 @@ private extension EmojiPickerViewController {
         snapshot.reloadItems(visibleItems)
         dataSource.apply(snapshot)
     }
-
-    func applyingDefaultSkinTone(emoji: PickerEmoji) -> PickerEmoji {
-        if case let .system(systemEmoji, inFrequentlyUsed) = emoji,
-           let defaultEmojiSkinTone = viewModel.identityContext.appPreferences.defaultEmojiSkinTone {
-            return .system(systemEmoji.applying(skinTone: defaultEmojiSkinTone), inFrequentlyUsed: inFrequentlyUsed)
-        } else {
-            return emoji
-        }
-    }
 }

View Controllers/ProfileViewController.swift

@@ -11,7 +11,7 @@ final class ProfileViewController: TableViewController {
 
     required init(
         viewModel: ProfileViewModel,
-        rootViewModel: RootViewModel,
+        rootViewModel: RootViewModel?,
         identityContext: IdentityContext,
         parentNavigationController: UINavigationController?) {
         self.viewModel = viewModel

View Controllers/TableViewController.swift

@@ -13,7 +13,7 @@ class TableViewController: UITableViewController {
     var transitionViewTag = -1
 
     private let viewModel: CollectionViewModel
-    private let rootViewModel: RootViewModel
+    private let rootViewModel: RootViewModel?
     private let loadingTableFooterView = LoadingTableFooterView()
     private let webfingerIndicatorView = WebfingerIndicatorView()
     @Published private var loading = false
@@ -29,7 +29,7 @@ class TableViewController: UITableViewController {
     }()
 
     init(viewModel: CollectionViewModel,
-         rootViewModel: RootViewModel,
+         rootViewModel: RootViewModel? = nil,
          insetBottom: Bool = true,
          parentNavigationController: UINavigationController? = nil) {
         self.viewModel = viewModel
@@ -540,7 +540,7 @@ private extension TableViewController {
     }
 
     func compose(inReplyToViewModel: StatusViewModel?, redraft: Status?) {
-        rootViewModel.navigationViewModel?.presentedNewStatusViewModel = rootViewModel.newStatusViewModel(
+        rootViewModel?.navigationViewModel?.presentedNewStatusViewModel = rootViewModel?.newStatusViewModel(
             identityContext: viewModel.identityContext,
             inReplyTo: inReplyToViewModel,
             redraft: redraft)

ViewModels/Sources/ViewModels/View Models/EmojiPickerViewModel.swift

@@ -20,7 +20,7 @@ final public class EmojiPickerViewModel: ObservableObject {
     private var cancellables = Set<AnyCancellable>()
 
     // swiftlint:disable:next function_body_length
-    public init(identityContext: IdentityContext) {
+    public init(identityContext: IdentityContext, queryOnly: Bool = false) {
         self.identityContext = identityContext
         emojiPickerService = identityContext.service.emojiPickerService()
 
@@ -67,13 +67,17 @@ final public class EmojiPickerViewModel: ObservableObject {
                             }
                         }
                     }
+                } else if queryOnly {
+                    return [:]
                 }
 
+                if !queryOnly {
                     emojis[.frequentlyUsed] = emojiUses.compactMap { use in
                         emojis.values.reduce([], +)
                             .first { use.system == $0.system && use.emoji == $0.name }
                             .map(\.inFrequentlyUsed)
                     }
+                }
 
                 return emojis.filter { !$0.value.isEmpty }
             }

ViewModels/Sources/ViewModels/View Models/ExploreViewModel.swift

@@ -21,9 +21,7 @@ public final class ExploreViewModel: ObservableObject {
     init(service: ExploreService, identityContext: IdentityContext) {
         exploreService = service
         self.identityContext = identityContext
-        searchViewModel = SearchViewModel(
+        searchViewModel = SearchViewModel(identityContext: identityContext)
-            searchService: exploreService.searchService(),
-            identityContext: identityContext)
         events = eventsSubject.eraseToAnyPublisher()
 
         identityContext.$identity

ViewModels/Sources/ViewModels/View Models/SearchViewModel.swift

@@ -11,8 +11,8 @@ public final class SearchViewModel: CollectionItemsViewModel {
     private let searchService: SearchService
     private var cancellables = Set<AnyCancellable>()
 
-    public init(searchService: SearchService, identityContext: IdentityContext) {
+    public init(identityContext: IdentityContext) {
-        self.searchService = searchService
+        self.searchService = identityContext.service.searchService()
 
         super.init(collectionService: searchService, identityContext: identityContext)
 
@@ -40,7 +40,7 @@ public final class SearchViewModel: CollectionItemsViewModel {
 }
 
 private extension SearchViewModel {
-    static let debounceInterval: TimeInterval = 0.5
+    static let debounceInterval: TimeInterval = 0.2
 }
 
 private extension SearchScope {

Views/UIKit/Collection View Cells/AutocompleteItemCollectionViewCell.swift

@@ -0,0 +1,23 @@
+// Copyright © 2021 Metabolist. All rights reserved.
+
+import UIKit
+import ViewModels
+
+final class AutocompleteItemCollectionViewCell: SeparatorConfiguredCollectionViewListCell {
+    var item: AutocompleteItem?
+    var identityContext: IdentityContext?
+
+    override func updateConfiguration(using state: UICellConfigurationState) {
+        guard let item = item, let identityContext = identityContext else { return }
+
+        contentConfiguration = AutocompleteItemContentConfiguration(item: item, identityContext: identityContext)
+
+        var backgroundConfiguration = UIBackgroundConfiguration.listPlainCell()
+
+        backgroundConfiguration.backgroundColor = state.isHighlighted || state.isSelected ? nil : .clear
+
+        self.backgroundConfiguration = backgroundConfiguration
+
+        accessibilityElements = [contentView]
+    }
+}

Views/UIKit/Collection View Cells/EmojiCollectionViewCell.swift

@@ -10,5 +10,12 @@ final class EmojiCollectionViewCell: UICollectionViewCell {
         guard let emoji = emoji else { return }
 
         contentConfiguration = EmojiContentConfiguration(emoji: emoji)
+
+        var backgroundConfiguration = UIBackgroundConfiguration.listPlainCell()
+
+        backgroundConfiguration.backgroundColor = state.isHighlighted || state.isSelected ? nil : .clear
+        backgroundConfiguration.cornerRadius = .defaultCornerRadius
+
+        self.backgroundConfiguration = backgroundConfiguration
     }
 }

Views/UIKit/CompositionInputAccessoryView.swift

@@ -6,12 +6,17 @@ import Mastodon
 import UIKit
 import ViewModels
 
-final class CompositionInputAccessoryView: UIToolbar {
+final class CompositionInputAccessoryView: UIView {
     let tagForInputView = UUID().hashValue
 
     private let viewModel: CompositionViewModel
     private let parentViewModel: NewStatusViewModel
-    private let autocompleteQueryPublisher: AnyPublisher<String?, Never>
+    private let toolbar = UIToolbar()
+    private let autocompleteCollectionView = UICollectionView(
+        frame: .zero,
+        collectionViewLayout: CompositionInputAccessoryView.autocompleteLayout())
+    private let autocompleteDataSource: AutocompleteDataSource
+    private let autocompleteCollectionViewHeightConstraint: NSLayoutConstraint
     private var cancellables = Set<AnyCancellable>()
 
     init(viewModel: CompositionViewModel,
@@ -19,7 +24,12 @@ final class CompositionInputAccessoryView: UIToolbar {
          autocompleteQueryPublisher: AnyPublisher<String?, Never>) {
         self.viewModel = viewModel
         self.parentViewModel = parentViewModel
-        self.autocompleteQueryPublisher = autocompleteQueryPublisher
+        autocompleteDataSource = AutocompleteDataSource(
+            collectionView: autocompleteCollectionView,
+            queryPublisher: autocompleteQueryPublisher,
+            parentViewModel: parentViewModel)
+        autocompleteCollectionViewHeightConstraint =
+            autocompleteCollectionView.heightAnchor.constraint(equalToConstant: .minimumButtonDimension)
 
         super.init(
             frame: .init(
@@ -36,11 +46,42 @@ final class CompositionInputAccessoryView: UIToolbar {
 }
 
 private extension CompositionInputAccessoryView {
+    static let autocompleteCollectionViewMaxHeight: CGFloat = 150
+
+    var heightConstraint: NSLayoutConstraint? {
+        superview?.constraints.first(where: { $0.identifier == "accessoryHeight" })
+    }
+
     // swiftlint:disable:next function_body_length
     func initialSetup() {
         autoresizingMask = .flexibleHeight
 
-        heightAnchor.constraint(equalToConstant: .minimumButtonDimension).isActive = true
+        addSubview(autocompleteCollectionView)
+        autocompleteCollectionView.translatesAutoresizingMaskIntoConstraints = false
+        autocompleteCollectionView.alwaysBounceVertical = false
+        autocompleteCollectionView.backgroundColor = .clear
+        autocompleteCollectionView.layer.cornerRadius = .defaultCornerRadius
+        autocompleteCollectionView.layer.maskedCorners = [.layerMaxXMinYCorner, .layerMinXMinYCorner]
+
+        let autocompleteBackgroundView = UIVisualEffectView(effect: UIBlurEffect(style: .systemChromeMaterial))
+
+        autocompleteCollectionView.backgroundView = autocompleteBackgroundView
+
+        addSubview(toolbar)
+        toolbar.translatesAutoresizingMaskIntoConstraints = false
+        toolbar.setContentCompressionResistancePriority(.required, for: .vertical)
+
+        NSLayoutConstraint.activate([
+            autocompleteCollectionView.leadingAnchor.constraint(equalTo: leadingAnchor),
+            autocompleteCollectionView.topAnchor.constraint(equalTo: topAnchor),
+            autocompleteCollectionView.trailingAnchor.constraint(equalTo: trailingAnchor),
+            autocompleteCollectionView.bottomAnchor.constraint(equalTo: toolbar.topAnchor),
+            toolbar.leadingAnchor.constraint(equalTo: leadingAnchor),
+            toolbar.trailingAnchor.constraint(equalTo: trailingAnchor),
+            toolbar.bottomAnchor.constraint(equalTo: bottomAnchor),
+            toolbar.heightAnchor.constraint(equalToConstant: .minimumButtonDimension),
+            autocompleteCollectionViewHeightConstraint
+        ])
 
         var attachmentActions = [
             UIAction(
@@ -129,15 +170,11 @@ private extension CompositionInputAccessoryView {
                 NSLocalizedString("compose.add-button-accessibility-label.post", comment: "")
         }
 
-        let charactersLabel = UILabel()
+        let charactersBarItem = UIBarButtonItem()
 
-        charactersLabel.font = .preferredFont(forTextStyle: .callout)
+        charactersBarItem.isEnabled = false
-        charactersLabel.adjustsFontForContentSizeCategory = true
-        charactersLabel.adjustsFontSizeToFitWidth = true
 
-        let charactersBarItem = UIBarButtonItem(customView: charactersLabel)
+        toolbar.items = [
-
-        items = [
             attachmentButton,
             UIBarButtonItem.fixedSpace(.defaultSpacing),
             pollButton,
@@ -162,9 +199,11 @@ private extension CompositionInputAccessoryView {
             .store(in: &cancellables)
 
         viewModel.$remainingCharacters.sink {
-            charactersLabel.text = String($0)
+            charactersBarItem.title = String($0)
-            charactersLabel.textColor = $0 < 0 ? .systemRed : .label
+            charactersBarItem.setTitleTextAttributes(
-            charactersLabel.accessibilityLabel = String.localizedStringWithFormat(
+                [.foregroundColor: $0 < 0 ? UIColor.systemRed : UIColor.label],
+                for: .disabled)
+            charactersBarItem.accessibilityHint = String.localizedStringWithFormat(
                 NSLocalizedString("compose.characters-remaining-accessibility-label-%ld", comment: ""),
                 $0)
         }
@@ -174,9 +213,15 @@ private extension CompositionInputAccessoryView {
             .sink { addButton.isEnabled = $0 }
             .store(in: &cancellables)
 
-        autocompleteQueryPublisher
+        self.autocompleteCollectionView.publisher(for: \.contentSize)
-            .print()
+            .map(\.height)
-            .sink { _ in /* TODO */ }
+            .removeDuplicates()
+            .throttle(for: .seconds(TimeInterval.shortAnimationDuration), scheduler: DispatchQueue.main, latest: true)
+            .sink { [weak self] height in
+                UIView.animate(withDuration: .zeroIfReduceMotion(.shortAnimationDuration)) {
+                    self?.setAutocompleteCollectionViewHeight(height)
+                }
+            }
             .store(in: &cancellables)
 
         parentViewModel.$visibility
@@ -192,6 +237,41 @@ private extension CompositionInputAccessoryView {
 }
 
 private extension CompositionInputAccessoryView {
+    static func autocompleteLayout() -> UICollectionViewLayout {
+        var listConfig = UICollectionLayoutListConfiguration(appearance: .plain)
+
+        listConfig.backgroundColor = .clear
+
+        return UICollectionViewCompositionalLayout { index, environment -> NSCollectionLayoutSection? in
+            guard let autocompleteSection = AutocompleteSection(rawValue: index) else { return nil }
+
+            switch autocompleteSection {
+            case .search:
+                return .list(using: listConfig, layoutEnvironment: environment)
+            case .emoji:
+                let itemSize = NSCollectionLayoutSize(
+                    widthDimension: .fractionalWidth(1.0),
+                    heightDimension: .fractionalHeight(1.0))
+                let item = NSCollectionLayoutItem(layoutSize: itemSize)
+                let groupSize = NSCollectionLayoutSize(
+                    widthDimension: .absolute(.minimumButtonDimension),
+                    heightDimension: .absolute(.minimumButtonDimension))
+                let group = NSCollectionLayoutGroup.horizontal(layoutSize: groupSize, subitems: [item])
+                let section = NSCollectionLayoutSection(group: group)
+
+                section.interGroupSpacing = .defaultSpacing
+                section.orthogonalScrollingBehavior = .continuous
+                section.contentInsets = NSDirectionalEdgeInsets(
+                    top: .compactSpacing,
+                    leading: .compactSpacing,
+                    bottom: .compactSpacing,
+                    trailing: .compactSpacing)
+
+                return section
+            }
+        }
+    }
+
     func visibilityMenu(selectedVisibility: Status.Visibility) -> UIMenu {
         UIMenu(children: Status.Visibility.allCasesExceptUnknown.reversed().map { visibility in
             UIAction(
@@ -203,4 +283,15 @@ private extension CompositionInputAccessoryView {
             }
         })
     }
+
+    func setAutocompleteCollectionViewHeight(_ height: CGFloat) {
+        let autocompleteCollectionViewHeight = min(max(height, .hairline), Self.autocompleteCollectionViewMaxHeight)
+
+        autocompleteCollectionViewHeightConstraint.constant = autocompleteCollectionViewHeight
+        autocompleteCollectionView.alpha = autocompleteCollectionViewHeightConstraint.constant == .hairline ? 0 : 1
+
+        heightConstraint?.constant = .minimumButtonDimension + autocompleteCollectionViewHeight
+        updateConstraints()
+        superview?.superview?.layoutIfNeeded()
+    }
 }

Views/UIKit/Content Configurations/AutocompleteItemContentConfiguration.swift

@@ -0,0 +1,19 @@
+// Copyright © 2020 Metabolist. All rights reserved.
+
+import UIKit
+import ViewModels
+
+struct AutocompleteItemContentConfiguration {
+    let item: AutocompleteItem
+    let identityContext: IdentityContext
+}
+
+extension AutocompleteItemContentConfiguration: UIContentConfiguration {
+    func makeContentView() -> UIView & UIContentView {
+        AutocompleteItemView(configuration: self)
+    }
+
+    func updated(for state: UIConfigurationState) -> AutocompleteItemContentConfiguration {
+        self
+    }
+}

Views/UIKit/Content Configurations/EmojiView.swift

@@ -4,7 +4,7 @@ import Kingfisher
 import UIKit
 
 final class EmojiView: UIView {
-    private let imageView = UIImageView()
+    private let imageView = AnimatedImageView()
     private let emojiLabel = UILabel()
     private var emojiConfiguration: EmojiContentConfiguration
 

Views/UIKit/Content Views/AutocompleteItemView.swift

@@ -0,0 +1,126 @@
+// Copyright © 2021 Metabolist. All rights reserved.
+
+import Kingfisher
+import UIKit
+
+final class AutocompleteItemView: UIView {
+    private let imageView = AnimatedImageView()
+    private let primaryLabel = UILabel()
+    private let secondaryLabel = UILabel()
+    private let stackView = UIStackView()
+    private var autocompleteItemConfiguration: AutocompleteItemContentConfiguration
+
+    init(configuration: AutocompleteItemContentConfiguration) {
+        self.autocompleteItemConfiguration = configuration
+
+        super.init(frame: .zero)
+
+        initialSetup()
+        applyAutocompleteItemConfiguration()
+    }
+
+    @available(*, unavailable)
+    required init?(coder: NSCoder) {
+        fatalError("init(coder:) has not been implemented")
+    }
+}
+
+extension AutocompleteItemView: UIContentView {
+    var configuration: UIContentConfiguration {
+        get { autocompleteItemConfiguration }
+        set {
+            guard let autocompleteItemConfiguration = newValue as? AutocompleteItemContentConfiguration else { return }
+
+            self.autocompleteItemConfiguration = autocompleteItemConfiguration
+
+            applyAutocompleteItemConfiguration()
+        }
+    }
+}
+
+private extension AutocompleteItemView {
+    func initialSetup() {
+        addSubview(stackView)
+        stackView.translatesAutoresizingMaskIntoConstraints = false
+        stackView.spacing = .defaultSpacing
+
+        stackView.addArrangedSubview(imageView)
+        imageView.layer.cornerRadius = .barButtonItemDimension / 2
+        imageView.clipsToBounds = true
+        imageView.contentMode = .scaleAspectFill
+
+        stackView.addArrangedSubview(primaryLabel)
+        primaryLabel.adjustsFontForContentSizeCategory = true
+        primaryLabel.font = .preferredFont(forTextStyle: .headline)
+        primaryLabel.setContentHuggingPriority(.required, for: .horizontal)
+
+        stackView.addArrangedSubview(secondaryLabel)
+        secondaryLabel.adjustsFontForContentSizeCategory = true
+        secondaryLabel.font = .preferredFont(forTextStyle: .subheadline)
+        secondaryLabel.textColor = .secondaryLabel
+
+        NSLayoutConstraint.activate([
+            imageView.widthAnchor.constraint(equalToConstant: .barButtonItemDimension),
+            imageView.heightAnchor.constraint(equalToConstant: .barButtonItemDimension),
+            stackView.leadingAnchor.constraint(equalTo: layoutMarginsGuide.leadingAnchor),
+            stackView.topAnchor.constraint(equalTo: layoutMarginsGuide.topAnchor),
+            stackView.trailingAnchor.constraint(equalTo: layoutMarginsGuide.trailingAnchor),
+            stackView.bottomAnchor.constraint(equalTo: layoutMarginsGuide.bottomAnchor)
+        ])
+    }
+
+    func applyAutocompleteItemConfiguration() {
+        switch autocompleteItemConfiguration.item {
+        case let .account(account):
+            let appPreferences = autocompleteItemConfiguration.identityContext.appPreferences
+            let avatarURL = appPreferences.animateAvatars == .everywhere
+                && !appPreferences.shouldReduceMotion
+                ? account.avatar
+                : account.avatarStatic
+
+            imageView.kf.setImage(with: avatarURL)
+            imageView.isHidden = false
+
+            let mutableDisplayName = NSMutableAttributedString(string: account.displayName)
+
+            mutableDisplayName.insert(emojis: account.emojis, view: primaryLabel)
+            mutableDisplayName.resizeAttachments(toLineHeight: primaryLabel.font.lineHeight)
+            primaryLabel.attributedText = mutableDisplayName
+            primaryLabel.isHidden = account.displayName.isEmpty
+            secondaryLabel.text = "@".appending(account.acct)
+            primaryLabel.setContentCompressionResistancePriority(.defaultLow, for: .horizontal)
+            secondaryLabel.setContentCompressionResistancePriority(.required, for: .horizontal)
+        case let .tag(tag):
+            imageView.isHidden = true
+            imageView.image = nil
+            primaryLabel.text = "#".appending(tag.name)
+            primaryLabel.isHidden = false
+
+            if let uses = tag.history?.compactMap({ Int($0.uses) }).reduce(0, +), uses > 0 {
+                secondaryLabel.text =
+                    String.localizedStringWithFormat(NSLocalizedString("tag.per-week-%ld", comment: ""), uses)
+            } else {
+                secondaryLabel.text = nil
+            }
+
+            primaryLabel.setContentCompressionResistancePriority(.required, for: .horizontal)
+            secondaryLabel.setContentCompressionResistancePriority(.defaultLow, for: .horizontal)
+        default:
+            break
+        }
+
+        let accessibilityAttributedLabel = NSMutableAttributedString(string: "")
+
+        if !primaryLabel.isHidden, let primaryLabelAttributedText = primaryLabel.attributedText {
+            accessibilityAttributedLabel.append(primaryLabelAttributedText)
+        }
+
+        if let secondaryLabelText = secondaryLabel.text, !secondaryLabelText.isEmpty {
+            accessibilityAttributedLabel.appendWithSeparator(secondaryLabelText)
+        }
+
+        self.accessibilityAttributedLabel = accessibilityAttributedLabel
+
+        isAccessibilityElement = true
+    }
+}