Add complete emoji list to Compose emoji autocomplete

Tusker.xcodeproj/project.pbxproj

@@ -160,6 +160,7 @@
 		D667E5F52135BCD50057A976 /* ConversationTableViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D667E5F42135BCD50057A976 /* ConversationTableViewController.swift */; };
 		D667E5F82135C3040057A976 /* Mastodon+Equatable.swift in Sources */ = {isa = PBXBuildFile; fileRef = D667E5F72135C3040057A976 /* Mastodon+Equatable.swift */; };
 		D66A77BB233838DC0058F1EC /* UIFont+Traits.swift in Sources */ = {isa = PBXBuildFile; fileRef = D66A77BA233838DC0058F1EC /* UIFont+Traits.swift */; };
+		D670F8B62537DC890046588A /* EmojiPickerWrapper.swift in Sources */ = {isa = PBXBuildFile; fileRef = D670F8B52537DC890046588A /* EmojiPickerWrapper.swift */; };
 		D6757A7C2157E01900721E32 /* XCBManager.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6757A7B2157E01900721E32 /* XCBManager.swift */; };
 		D6757A7E2157E02600721E32 /* XCBRequestSpec.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6757A7D2157E02600721E32 /* XCBRequestSpec.swift */; };
 		D6757A822157E8FA00721E32 /* XCBSession.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6757A812157E8FA00721E32 /* XCBSession.swift */; };
@@ -239,6 +240,8 @@
 		D6BC9DDA232D8BE5002CA326 /* SearchResultsViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6BC9DD9232D8BE5002CA326 /* SearchResultsViewController.swift */; };
 		D6BED174212667E900F02DA0 /* TimelineStatusTableViewCell.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6BED173212667E900F02DA0 /* TimelineStatusTableViewCell.swift */; };
 		D6C143DA253510F4007DC240 /* ComposeContentWarningTextField.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6C143D9253510F4007DC240 /* ComposeContentWarningTextField.swift */; };
+		D6C143E025354E34007DC240 /* EmojiPickerCollectionViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6C143DF25354E34007DC240 /* EmojiPickerCollectionViewController.swift */; };
+		D6C143FD25354FD0007DC240 /* EmojiCollectionViewCell.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6C143FB25354FD0007DC240 /* EmojiCollectionViewCell.swift */; };
 		D6C693EF216192C2007D6A6D /* TuskerNavigationDelegate.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6C693EE216192C2007D6A6D /* TuskerNavigationDelegate.swift */; };
 		D6C693FC2162FE6F007D6A6D /* LoadingViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6C693FB2162FE6F007D6A6D /* LoadingViewController.swift */; };
 		D6C693FE2162FEEA007D6A6D /* UIViewController+Children.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6C693FD2162FEEA007D6A6D /* UIViewController+Children.swift */; };
@@ -495,6 +498,7 @@
 		D667E5F42135BCD50057A976 /* ConversationTableViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ConversationTableViewController.swift; sourceTree = "<group>"; };
 		D667E5F72135C3040057A976 /* Mastodon+Equatable.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "Mastodon+Equatable.swift"; sourceTree = "<group>"; };
 		D66A77BA233838DC0058F1EC /* UIFont+Traits.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "UIFont+Traits.swift"; sourceTree = "<group>"; };
+		D670F8B52537DC890046588A /* EmojiPickerWrapper.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = EmojiPickerWrapper.swift; sourceTree = "<group>"; };
 		D6757A7B2157E01900721E32 /* XCBManager.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = XCBManager.swift; sourceTree = "<group>"; };
 		D6757A7D2157E02600721E32 /* XCBRequestSpec.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = XCBRequestSpec.swift; sourceTree = "<group>"; };
 		D6757A812157E8FA00721E32 /* XCBSession.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = XCBSession.swift; sourceTree = "<group>"; };
@@ -569,6 +573,8 @@
 		D6BC9DD9232D8BE5002CA326 /* SearchResultsViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SearchResultsViewController.swift; sourceTree = "<group>"; };
 		D6BED173212667E900F02DA0 /* TimelineStatusTableViewCell.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = TimelineStatusTableViewCell.swift; sourceTree = "<group>"; };
 		D6C143D9253510F4007DC240 /* ComposeContentWarningTextField.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ComposeContentWarningTextField.swift; sourceTree = "<group>"; };
+		D6C143DF25354E34007DC240 /* EmojiPickerCollectionViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = EmojiPickerCollectionViewController.swift; sourceTree = "<group>"; };
+		D6C143FB25354FD0007DC240 /* EmojiCollectionViewCell.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = EmojiCollectionViewCell.swift; sourceTree = "<group>"; };
 		D6C693EE216192C2007D6A6D /* TuskerNavigationDelegate.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = TuskerNavigationDelegate.swift; sourceTree = "<group>"; };
 		D6C693FB2162FE6F007D6A6D /* LoadingViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = LoadingViewController.swift; sourceTree = "<group>"; };
 		D6C693FD2162FEEA007D6A6D /* UIViewController+Children.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "UIViewController+Children.swift"; sourceTree = "<group>"; };
@@ -1007,6 +1013,9 @@
 				D62275A724F1CA2800B82A16 /* ComposeReplyContentView.swift */,
 				D6E4267625327FB400C02E1C /* ComposeAutocompleteView.swift */,
 				D6C143D9253510F4007DC240 /* ComposeContentWarningTextField.swift */,
+				D6C143DF25354E34007DC240 /* EmojiPickerCollectionViewController.swift */,
+				D6C143FB25354FD0007DC240 /* EmojiCollectionViewCell.swift */,
+				D670F8B52537DC890046588A /* EmojiPickerWrapper.swift */,
 			);
 			path = Compose;
 			sourceTree = "<group>";
@@ -1815,6 +1824,7 @@
 				D68E525B24A3D77E0054355A /* TuskerRootViewController.swift in Sources */,
 				D62D2422217AA7E1005076CC /* UserActivityManager.swift in Sources */,
 				D6CA6A92249FAD8900AD45C1 /* AudioSessionHelper.swift in Sources */,
+				D6C143FD25354FD0007DC240 /* EmojiCollectionViewCell.swift in Sources */,
 				D60D2B8223844C71001B87A3 /* BaseStatusTableViewCell.swift in Sources */,
 				D60E2F272442372B005F8713 /* StatusMO.swift in Sources */,
 				D60E2F2C24423EAD005F8713 /* LazilyDecoding.swift in Sources */,
@@ -1829,6 +1839,7 @@
 				D667E5F82135C3040057A976 /* Mastodon+Equatable.swift in Sources */,
 				D681E4D5246E2BC30053414F /* UnmuteConversationActivity.swift in Sources */,
 				D6B4A4FF2506B81A000C81C1 /* AccountDisplayNameLabel.swift in Sources */,
+				D6C143E025354E34007DC240 /* EmojiPickerCollectionViewController.swift in Sources */,
 				D6B053A623BD2D0C00A066FA /* AssetCollectionViewController.swift in Sources */,
 				D67B506D250B291200FAECFB /* BlurHashDecode.swift in Sources */,
 				D62275A024F1677200B82A16 /* ComposeHostingController.swift in Sources */,
@@ -1906,6 +1917,7 @@
 				D627FF76217E923E00CC0648 /* DraftsManager.swift in Sources */,
 				D64F80E2215875CC00BEF393 /* XCBActionType.swift in Sources */,
 				04586B4322B301470021BD04 /* AppearancePrefsView.swift in Sources */,
+				D670F8B62537DC890046588A /* EmojiPickerWrapper.swift in Sources */,
 				D67C57AF21E28EAD00C3118B /* Array+Uniques.swift in Sources */,
 				D6945C3223AC4D36005C403C /* HashtagTimelineViewController.swift in Sources */,
 				D647D92824257BEB0005044F /* AttachmentPreviewViewController.swift in Sources */,

Tusker/Caching/ImageCache.swift

@@ -26,6 +26,8 @@ class ImageCache {
     
     private var groups = MultiThreadDictionary<URL, RequestGroup>(name: "ImageCache request groups")
     
+    private var backgroundQueue = DispatchQueue(label: "ImageCache completion queue", qos: .default)
+    
     init(name: String, memoryExpiry expiry: Expiry) {
         let storage = MemoryStorage<Data>(config: MemoryConfig(expiry: expiry))
         self.cache = .memory(storage)
@@ -45,8 +47,14 @@ class ImageCache {
     func get(_ url: URL, completion: ((Data?) -> Void)?) -> Request? {
         let key = url.absoluteString
         if !ImageCache.disableCaching,
+           // todo: calling object(forKey: key) does disk I/O and this method is often called from the main thread
+           // in performance sensitive paths. a nice optimization to DiskStorage would be adding an internal cache
+           // of the state (unknown/exists/does not exist) of whether or not objects exist on disk so that the slow, disk I/O
+           // path can be avoided most of the time
            let data = try? cache.object(forKey: key) {
-            completion?(data)
+            backgroundQueue.async {
+                completion?(data)
+            }
             return nil
         } else {
             if let completion = completion, let group = groups[url] {

Tusker/Screens/Compose/ComposeAutocompleteView.swift

@@ -218,9 +218,40 @@ struct ComposeAutocompleteEmojisView: View {
     @EnvironmentObject private var mastodonController: MastodonController
     @EnvironmentObject private var uiState: ComposeUIState
     
+    @State var expanded = false
     @State private var emojis: [Emoji] = []
     
     var body: some View {
+        // When exapnded, the toggle button should be at the top. When collapsed, it should be centered.
+        HStack(alignment: expanded ? .top : .center, spacing: 0) {
+            if case let .emoji(query) = uiState.autocompleteState {
+                emojiList(query: query)
+                    .animation(.default)
+                    .transition(.move(edge: .bottom))
+            } else {
+                // when the autocomplete view is animating out, the autocomplete state is nil
+                // add a spacer so the expand button remains on the right
+                Spacer()
+            }
+            
+            toggleExpandedButton
+                .padding(.trailing, 8)
+                .padding(.top, expanded ? 8 : 0)
+        }
+    }
+    
+    @ViewBuilder
+    private func emojiList(query: String) -> some View {
+        if expanded {
+            EmojiPickerWrapper(searchQuery: query)
+                .frame(height: 150)
+        } else {
+            horizontalScrollView
+                .onReceive(uiState.$autocompleteState, perform: queryChanged)
+        }
+    }
+    
+    private var horizontalScrollView: some View {
         ScrollView(.horizontal) {
             HStack(spacing: 8) {
                 ForEach(emojis, id: \.shortcode) { (emoji) in
@@ -236,15 +267,25 @@ struct ComposeAutocompleteEmojisView: View {
                     }
                     .frame(height: 30)
                     .padding(.vertical, 8)
-                    .animation(.linear(duration: 0.1))
+                    .animation(.linear(duration: 0.2))
                 }
                 
-                Spacer()
+                Spacer(minLength: 30)
             }
             .padding(.horizontal, 8)
-            .iOS13OnlyPadding()
+            .frame(height: 46)
         }
-        .onReceive(uiState.$autocompleteState.debounce(for: .milliseconds(250), scheduler: DispatchQueue.main), perform: queryChanged)
+    }
+    
+    private var toggleExpandedButton: some View {
+        Button {
+            expanded.toggle()
+        } label: {
+            Image(systemName: expanded ? "chevron.down" : "chevron.up")
+                .resizable()
+                .aspectRatio(contentMode: .fit)
+        }
+        .frame(width: 20, height: 20)
     }
     
     private func queryChanged(_ autocompleteState: ComposeUIState.AutocompleteState?) {
@@ -255,8 +296,6 @@ struct ComposeAutocompleteEmojisView: View {
         }
         
         mastodonController.getCustomEmojis { (emojis) in
-            guard case .emoji(query) = self.uiState.autocompleteState else { return }
-            
             self.emojis =
                 emojis.map { (emoji) -> (Emoji, (matched: Bool, score: Int)) in
                     (emoji, FuzzyMatcher.match(pattern: query, str: emoji.shortcode))

Tusker/Screens/Compose/ComposeContentWarningTextField.swift

@@ -54,7 +54,6 @@ struct ComposeContentWarningTextField: UIViewRepresentable {
         }
         
         func textFieldDidEndEditing(_ textField: UITextField) {
-            uiState.autocompleteHandler = nil
             updateAutocompleteState(textField: textField)
         }
         
@@ -76,8 +75,8 @@ struct ComposeContentWarningTextField: UIViewRepresentable {
             let characterBeforeCursorIndex = text.utf16.index(text.startIndex, offsetBy: selectedRangeStartUTF16)
             
             let insertSpace: Bool
-            if text.distance(from: characterBeforeCursorIndex, to: text.endIndex) > 0 {
+            if distanceToEnd > 0 {
-                let charAfterCursor = text[text.index(after: characterBeforeCursorIndex)]
+                let charAfterCursor = text[characterBeforeCursorIndex]
                 insertSpace = charAfterCursor != " " && charAfterCursor != "\n"
             } else {
                 insertSpace = true
@@ -85,10 +84,13 @@ struct ComposeContentWarningTextField: UIViewRepresentable {
             let string = insertSpace ? string + " " : string
             
             textField.text!.replaceSubrange(lastWordStartIndex..<characterBeforeCursorIndex, with: string)
-            didChange(textField)
+            self.didChange(textField)
+            self.updateAutocompleteState(textField: textField)
             
             // keep the cursor at the same position in the text, immediately after what was inserted
-            let newCursorPosition = textField.position(from: textField.endOfDocument, offset: -distanceToEnd)!
+            // if we inserted a space, move the cursor 1 farther so it's immediately after the pre-existing space
+            let insertSpaceOffset = insertSpace ? 0 : 1
+            let newCursorPosition = textField.position(from: textField.endOfDocument, offset: -distanceToEnd + insertSpaceOffset)!
             textField.selectedTextRange = textField.textRange(from: newCursorPosition, to: newCursorPosition)
         }
         

Tusker/Screens/Compose/ComposeUIState.swift

@@ -53,3 +53,7 @@ extension ComposeUIState {
         case hashtag(String)
     }
 }
+
+protocol ComposeAutocompleteHandler: class {
+    func autocomplete(with string: String)
+}

Tusker/Screens/Compose/ComposeView.swift

@@ -66,9 +66,7 @@ struct ComposeView: View {
             // can't use SwiftUI.ProgressView because there's no UIProgressView.Style.bar equivalent, see FB8587149
             WrappedProgressView(value: postProgress, total: postTotalProgress)
             
-            if let state = uiState.autocompleteState {
+            autocompleteSuggestions
-                autocompleteSuggestions(state: state)
-            }
         }
         .onAppear(perform: self.didAppear)
         .navigationBarTitle("Compose")
@@ -83,19 +81,23 @@ struct ComposeView: View {
     }
     
     @ViewBuilder
-    func autocompleteSuggestions(state: ComposeUIState.AutocompleteState) -> some View {
+    var autocompleteSuggestions: some View {
         // on iOS 13, the transition causes SwiftUI to hang on the main thread when the view appears, so it's disabled
         if #available(iOS 14.0, *) {
             VStack(spacing: 0) {
                 Spacer()
-                ComposeAutocompleteView(autocompleteState: state)
+                if let state = uiState.autocompleteState {
+                    ComposeAutocompleteView(autocompleteState: state)
+                }
             }
             .transition(.move(edge: .bottom))
             .animation(.default)
         } else {
             VStack(spacing: 0) {
                 Spacer()
-                ComposeAutocompleteView(autocompleteState: state)
+                if let state = uiState.autocompleteState {
+                    ComposeAutocompleteView(autocompleteState: state)
+                }
             }
         }
     }

Tusker/Screens/Compose/EmojiCollectionViewCell.swift

@@ -0,0 +1,64 @@
+//
+//  EmojiCollectionViewCell.swift
+//  Tusker
+//
+//  Created by Shadowfacts on 10/12/20.
+//  Copyright © 2020 Shadowfacts. All rights reserved.
+//
+
+import UIKit
+import Pachyderm
+
+class EmojiCollectionViewCell: UICollectionViewCell {
+
+    private var emojiImageView: UIImageView!
+    private var emojiNameLabel: UILabel!
+    
+    private var currentEmojiShortcode: String?
+    private var imageRequest: ImageCache.Request?
+    
+    override init(frame: CGRect) {
+        super.init(frame: frame)
+        
+        commonInit()
+    }
+    
+    required init?(coder: NSCoder) {
+        super.init(coder: coder)
+        
+        commonInit()
+    }
+    
+    private func commonInit() {
+        emojiImageView = UIImageView()
+        emojiImageView.translatesAutoresizingMaskIntoConstraints = false
+        emojiImageView.contentMode = .scaleAspectFit
+        addSubview(emojiImageView)
+        NSLayoutConstraint.activate([
+            emojiImageView.leadingAnchor.constraint(equalTo: leadingAnchor),
+            emojiImageView.trailingAnchor.constraint(equalTo: trailingAnchor),
+            emojiImageView.topAnchor.constraint(equalTo: topAnchor),
+            emojiImageView.bottomAnchor.constraint(equalTo: bottomAnchor),
+        ])
+    }
+    
+    func updateUI(emoji: Emoji) {
+        currentEmojiShortcode = emoji.shortcode
+        
+        imageRequest = ImageCache.emojis.get(emoji.url) { [weak self] (data) in
+            if let data = data, let image = UIImage(data: data) {
+                DispatchQueue.main.async { [weak self] in
+                    guard let self = self, self.currentEmojiShortcode == emoji.shortcode else { return }
+                    self.emojiImageView.image = image
+                }
+            }
+        }
+    }
+    
+    override func prepareForReuse() {
+        super.prepareForReuse()
+        
+        imageRequest?.cancel()
+    }
+
+}

Tusker/Screens/Compose/EmojiPickerCollectionViewController.swift

@@ -0,0 +1,128 @@
+//
+//  EmojiPickerCollectionViewController.swift
+//  Tusker
+//
+//  Created by Shadowfacts on 10/12/20.
+//  Copyright © 2020 Shadowfacts. All rights reserved.
+//
+
+import UIKit
+import Pachyderm
+
+private let reuseIdentifier = "EmojiCell"
+
+protocol EmojiPickerCollectionViewControllerDelegate: class {
+    func selectedEmoji(_ emoji: Emoji)
+}
+
+// It would be nice to replace this with a LazyVGrid when the deployment target is bumped to 14.0
+class EmojiPickerCollectionViewController: UICollectionViewController {
+
+    weak var delegate: EmojiPickerCollectionViewControllerDelegate?
+    
+    private weak var mastodonController: MastodonController!
+
+    private var dataSource: UICollectionViewDiffableDataSource<Section, Item>!
+    
+    var searchQuery: String = "" {
+        didSet {
+            guard let emojis = mastodonController.customEmojis else { return }
+            let snapshot = createFilteredSnapshot(emojis: emojis)
+            DispatchQueue.main.async {
+                self.dataSource.apply(snapshot)
+            }
+        }
+    }
+    
+    init(mastodonController: MastodonController) {
+        self.mastodonController = mastodonController
+        
+        let itemWidth = NSCollectionLayoutDimension.fractionalWidth(1.0 / 10)
+        let itemSize = NSCollectionLayoutSize(widthDimension: itemWidth, heightDimension: itemWidth)
+        let item = NSCollectionLayoutItem(layoutSize: itemSize)
+        
+        let groupSize = NSCollectionLayoutSize(widthDimension: .fractionalWidth(1.0), heightDimension: itemWidth)
+        let group = NSCollectionLayoutGroup.horizontal(layoutSize: groupSize, subitems: [item])
+        group.interItemSpacing = .fixed(4)
+        
+        let section = NSCollectionLayoutSection(group: group)
+        section.interGroupSpacing = 4
+        
+        let layout = UICollectionViewCompositionalLayout(section: section)
+        
+        super.init(collectionViewLayout: layout)
+    }
+    
+    required init?(coder: NSCoder) {
+        fatalError("init(coder:) has not been implemented")
+    }
+    
+    override func viewDidLoad() {
+        super.viewDidLoad()
+        
+        additionalSafeAreaInsets = UIEdgeInsets(top: 0, left: 8, bottom: 0, right: 8)
+        // use negative indicator insets to bring the indicators back to the edge of the containing view
+        // using collectionView.contentInset doesn't work the compositional layout ignores the inset when calculating fractional widths
+        collectionView.scrollIndicatorInsets = UIEdgeInsets(top: 0, left: -8, bottom: 0, right: -8)
+        collectionView.contentInset = UIEdgeInsets(top: 8, left: 0, bottom: 8, right: 0)
+        
+        collectionView.backgroundColor = .clear
+        collectionView.register(EmojiCollectionViewCell.self, forCellWithReuseIdentifier: reuseIdentifier)
+        
+        dataSource = UICollectionViewDiffableDataSource(collectionView: collectionView) { (collectionView, indexPath, item) -> UICollectionViewCell? in
+            let cell = collectionView.dequeueReusableCell(withReuseIdentifier: reuseIdentifier, for: indexPath) as! EmojiCollectionViewCell
+            cell.updateUI(emoji: item.emoji)
+            return cell
+        }
+        
+        mastodonController.getCustomEmojis { (emojis) in
+            DispatchQueue.main.async {
+                self.dataSource.apply(self.createFilteredSnapshot(emojis: emojis))
+            }
+        }
+    }
+    
+    private func createFilteredSnapshot(emojis: [Emoji]) -> NSDiffableDataSourceSnapshot<Section, Item> {
+        let items: [Item]
+        if searchQuery.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty {
+            items = emojis.map { Item(emoji: $0) }
+        } else {
+            items = emojis
+                .map { ($0, FuzzyMatcher.match(pattern: searchQuery, str: $0.shortcode)) }
+                .filter(\.1.matched)
+                .sorted { $0.1.score > $1.1.score }
+                .map { Item(emoji: $0.0) }
+        }
+        
+        var snapshot = NSDiffableDataSourceSnapshot<Section, Item>()
+        snapshot.appendSections([.emojis])
+        snapshot.appendItems(items)
+        return snapshot
+    }
+
+    // MARK: UICollectionViewDelegate
+    
+    override func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
+        guard let item = dataSource.itemIdentifier(for: indexPath) else { return }
+        delegate?.selectedEmoji(item.emoji)
+    }
+
+}
+
+extension EmojiPickerCollectionViewController {
+    enum Section {
+        case emojis
+    }
+    
+    struct Item: Hashable, Equatable {
+        let emoji: Emoji
+        
+        func hash(into hasher: inout Hasher) {
+            hasher.combine(emoji.shortcode)
+        }
+        
+        static func ==(lhs: Item, rhs: Item) -> Bool {
+            lhs.emoji.shortcode == rhs.emoji.shortcode
+        }
+    }
+}

Tusker/Screens/Compose/EmojiPickerWrapper.swift

@@ -0,0 +1,46 @@
+//
+//  EmojiPickerWrapper.swift
+//  Tusker
+//
+//  Created by Shadowfacts on 10/14/20.
+//  Copyright © 2020 Shadowfacts. All rights reserved.
+//
+
+import SwiftUI
+import Pachyderm
+
+struct EmojiPickerWrapper: UIViewControllerRepresentable {
+    typealias UIViewControllerType = EmojiPickerCollectionViewController
+    
+    let searchQuery: String
+    
+    @EnvironmentObject private var mastodonController: MastodonController
+    @EnvironmentObject private var uiState: ComposeUIState
+    
+    func makeUIViewController(context: Context) -> EmojiPickerCollectionViewController {
+        let vc = EmojiPickerCollectionViewController(mastodonController: mastodonController)
+        vc.delegate = context.coordinator
+        return vc
+    }
+    
+    func updateUIViewController(_ uiViewController: EmojiPickerCollectionViewController, context: Context) {
+        uiViewController.searchQuery = searchQuery
+    }
+    
+    func makeCoordinator() -> Coordinator {
+        return Coordinator(uiState: uiState)
+    }
+    
+    class Coordinator: EmojiPickerCollectionViewControllerDelegate {
+        let uiState: ComposeUIState
+        
+        init(uiState: ComposeUIState) {
+            self.uiState = uiState
+        }
+        
+        func selectedEmoji(_ emoji: Emoji) {
+            uiState.autocompleteHandler?.autocomplete(with: ":\(emoji.shortcode):")
+            uiState.autocompleteState = nil
+        }
+    }
+}

Tusker/Screens/Compose/MainComposeTextView.swift

@@ -184,8 +184,6 @@ struct MainComposeWrappedTextView: UIViewRepresentable {
         func textViewDidChange(_ textView: UITextView) {
             text.wrappedValue = textView.text
             didChange(textView)
-            
-            updateAutocompleteState()
         }
         
         @objc func formatButtonPressed(_ sender: UIBarButtonItem) {
@@ -224,7 +222,6 @@ struct MainComposeWrappedTextView: UIViewRepresentable {
         }
         
         func textViewDidEndEditing(_ textView: UITextView) {
-            uiState.autocompleteHandler = nil
             updateAutocompleteState()
         }
         
@@ -244,8 +241,8 @@ struct MainComposeWrappedTextView: UIViewRepresentable {
             let characterBeforeCursorIndex = text.utf16.index(text.startIndex, offsetBy: textView.selectedRange.upperBound)
             
             let insertSpace: Bool
-            if text.distance(from: characterBeforeCursorIndex, to: text.endIndex) > 0 {
+            if distanceToEnd > 0 {
-                let charAfterCursor = text[text.index(after: characterBeforeCursorIndex)]
+                let charAfterCursor = text[characterBeforeCursorIndex]
                 insertSpace = charAfterCursor != " " && charAfterCursor != "\n"
             } else {
                 insertSpace = true
@@ -254,9 +251,12 @@ struct MainComposeWrappedTextView: UIViewRepresentable {
             
             textView.text.replaceSubrange(lastWordStartIndex..<characterBeforeCursorIndex, with: string)
             self.textViewDidChange(textView)
+            self.updateAutocompleteState()
             
             // keep the cursor at the same position in the text, immediately after what was inserted
-            textView.selectedRange = NSRange(location: textView.text.utf16.count - distanceToEnd, length: 0)
+            // if we inserted a space, move the cursor 1 farther so it's immediately after the pre-existing space
+            let insertSpaceOffset = insertSpace ? 0 : 1
+            textView.selectedRange = NSRange(location: textView.text.utf16.count - distanceToEnd + insertSpaceOffset, length: 0)
         }
         
         private func updateAutocompleteState() {
@@ -358,7 +358,3 @@ struct MainComposeWrappedTextView: UIViewRepresentable {
         }
     }
 }
-
-protocol ComposeAutocompleteHandler: class {
-    func autocomplete(with string: String)
-}