Autocomplete hashtags

Packages/ComposeUI/Sources/ComposeUI/ComposeInput.swift

@@ -107,3 +107,36 @@ struct FocusedInput: DynamicProperty {
     }
     #endif
 }
+
+@propertyWrapper
+struct FocusedInputAutocompleteState: DynamicProperty {
+    @FocusedInput private var input
+    @StateObject private var updater = Updater()
+    
+    var wrappedValue: AutocompleteState? {
+        input?.autocompleteState
+    }
+    
+    func update() {
+        updater.update(input: input)
+    }
+    
+    @MainActor
+    private class Updater: ObservableObject {
+        private var lastInput: (any ComposeInput)?
+        private var cancellable: AnyCancellable?
+        
+        func update(input: (any ComposeInput)?) {
+            guard lastInput !== input else {
+                return
+            }
+            lastInput = input
+            cancellable = input?.autocompleteStatePublisher.sink { [unowned self] _ in
+                // the autocomplete state sometimes changes during a view update, so defer this
+                DispatchQueue.main.async {
+                    self.objectWillChange.send()
+                }
+            }
+        }
+    }
+}

Packages/ComposeUI/Sources/ComposeUI/Views/Autocomplete/AutocompleteHashtagView.swift

@@ -0,0 +1,95 @@
+//
+//  AutocompleteHashtagView.swift
+//  ComposeUI
+//
+//  Created by Shadowfacts on 2/26/25.
+//
+
+import SwiftUI
+import Pachyderm
+import TuskerComponents
+
+struct AutocompleteHashtagView: View {
+    let query: String
+    let mastodonController: any ComposeMastodonContext
+    @State private var loading = false
+    @State private var hashtags: [Hashtag] = []
+    @FocusedInput private var input
+    
+    var body: some View {
+        ScrollView(.horizontal) {
+            HStack(spacing: 8) {
+                if hashtags.isEmpty && loading {
+                    ProgressView()
+                        .progressViewStyle(.circular)
+                }
+                
+                ForEach(hashtags, id: \.name) { hashtag in
+                    Button {
+                        autocomplete(hashtag: hashtag)
+                    } label: {
+                        Text(verbatim: "#\(hashtag.name)")
+                    }
+                    // total height is 44, ComposeToolbarView.autocompleteHeight
+                    .frame(height: 30)
+                    .padding(.vertical, 7)
+                }
+                
+                Spacer()
+            }
+            .padding(.horizontal, 8)
+            .animation(.snappy, value: hashtags)
+        }
+        .frame(height: ComposeToolbarView.autocompleteHeight)
+        .task(id: query) {
+            await queryChanged()
+        }
+    }
+    
+    private func queryChanged() async {
+        guard !query.isEmpty else {
+            loading = false
+            hashtags = []
+            return
+        }
+        
+        loading = true
+        
+        let localTags = mastodonController.searchCachedHashtags(query: query)
+        
+        async let trendingTags = try? mastodonController.run(Client.getTrendingHashtags()).0
+        async let searchResults = try? mastodonController.run(Client.search(query: "#\(query)", types: [.hashtags])).0.hashtags
+        
+        let trending = await trendingTags ?? []
+        let search = await searchResults ?? []
+        
+        guard !Task.isCancelled else {
+            return
+        }
+        
+        updateHashtags(searchResults: search, trending: trending, local: localTags)
+        
+        loading = false
+    }
+    
+    private func updateHashtags(searchResults: [Hashtag], trending: [Hashtag], local: [Hashtag]) {
+        var seenHashtags = Set<String>()
+        var hashtags = [(Hashtag, Int)]()
+        for group in [searchResults, trending, local] {
+            for tag in group where !seenHashtags.contains(tag.name) {
+                seenHashtags.insert(tag.name)
+                let (matched, score) = FuzzyMatcher.match(pattern: query, str: tag.name)
+                if matched {
+                    hashtags.append((tag, score))
+                }
+            }
+        }
+        self.hashtags = hashtags
+            .sorted { $0.1 > $1.1 }
+            .map(\.0)
+    }
+    
+    private func autocomplete(hashtag: Hashtag) {
+        input?.autocomplete(with: "#\(hashtag.name)")
+    }
+}

Packages/ComposeUI/Sources/ComposeUI/Views/Autocomplete/AutocompleteView.swift

@@ -0,0 +1,32 @@
+//
+//  AutocompleteView.swift
+//  ComposeUI
+//
+//  Created by Shadowfacts on 2/26/25.
+//
+
+import SwiftUI
+
+struct AutocompleteView: View {
+    let mastodonController: any ComposeMastodonContext
+    @FocusedInputAutocompleteState private var state
+    
+    var body: some View {
+        contentView
+            .frame(height: ComposeToolbarView.autocompleteHeight)
+    }
+    
+    @ViewBuilder
+    private var contentView: some View {
+        switch state {
+        case nil:
+            Color.clear
+        case .hashtag(let s):
+            AutocompleteHashtagView(query: s, mastodonController: mastodonController)
+                .composeToolbarBackground()
+        default:
+            Color.red
+                .composeToolbarBackground()
+        }
+    }
+}

Packages/ComposeUI/Sources/ComposeUI/Views/ComposeToolbarView.swift

@@ -12,8 +12,23 @@ import Pachyderm
 import TuskerPreferences
 
 struct ComposeToolbarView: View {
-    static let height: CGFloat = 44
+    static let toolbarHeight: CGFloat = 44
+    static let autocompleteHeight: CGFloat = 44
+
+    @ObservedObject var draft: Draft
+    let mastodonController: any ComposeMastodonContext
+    @FocusState.Binding var focusedField: FocusableField?
     
+    var body: some View {
+        VStack(spacing: 0) {
+            AutocompleteView(mastodonController: mastodonController)
+            
+            ToolbarContentView(draft: draft, mastodonController: mastodonController, focusedField: $focusedField)
+        }
+    }
+}
+
+private struct ToolbarContentView: View {
     @ObservedObject var draft: Draft
     let mastodonController: any ComposeMastodonContext
     @FocusState.Binding var focusedField: FocusableField?
@@ -26,12 +41,8 @@ struct ComposeToolbarView: View {
             buttons
                 .padding(.horizontal, 16)
         }
-        .frame(height: Self.height)
-        .background(.regularMaterial, ignoresSafeAreaEdges: [.bottom, .leading, .trailing])
-        .overlay(alignment: .top) {
-            Divider()
-                .ignoresSafeArea(edges: [.leading, .trailing])
-        }
+        .frame(height: ComposeToolbarView.toolbarHeight)
+        .composeToolbarBackground()
         #endif
     }
     
@@ -52,6 +63,17 @@ struct ComposeToolbarView: View {
     }
 }
 
+extension View {
+    func composeToolbarBackground() -> some View {
+        self
+            .background(.regularMaterial, ignoresSafeAreaEdges: [.bottom, .leading, .trailing])
+            .overlay(alignment: .top) {
+                Divider()
+                    .ignoresSafeArea(edges: [.leading, .trailing])
+            }
+    }
+}
+
 #if !os(visionOS)
 private struct ToolbarScrollView<Content: View>: View {
     @ViewBuilder let content: Content

Packages/ComposeUI/Sources/ComposeUI/Views/ComposeView.swift

@@ -298,16 +298,28 @@ enum FocusableField: Hashable {
 #if !os(visionOS) && !targetEnvironment(macCatalyst)
 private struct ToolbarSafeAreaInsetModifier: ViewModifier {
     @StateObject private var keyboardReader = KeyboardReader()
+    @FocusedInputAutocompleteState private var autocompleteState
+    
+    private var inset: CGFloat {
+        var height: CGFloat = 0
+        if keyboardReader.isVisible {
+            height += ComposeToolbarView.toolbarHeight
+        }
+        if autocompleteState != nil {
+            height += ComposeToolbarView.autocompleteHeight
+        }
+        return height
+    }
     
     func body(content: Content) -> some View {
         if #available(iOS 17.0, *) {
             content
-                .safeAreaPadding(.bottom, keyboardReader.isVisible ? 0 : ComposeToolbarView.height)
+                .safeAreaPadding(.bottom, inset)
         } else {
             content
                 .safeAreaInset(edge: .bottom) {
                     if !keyboardReader.isVisible {
-                        Color.clear.frame(height: ComposeToolbarView.height)
+                        Color.clear.frame(height: inset)
                     }
                 }
         }

Packages/ComposeUI/Sources/ComposeUI/Views/NewMainTextView.swift

@@ -266,7 +266,16 @@ extension WrappedTextViewCoordinator: UITextViewDelegate {
         }
     }
     
+    func textViewDidBeginEditing(_ textView: UITextView) {
+        autocompleteState = textView.updateAutocompleteState(permittedModes: .all)
+    }
+    
+    func textViewDidEndEditing(_ textView: UITextView) {
+        autocompleteState = textView.updateAutocompleteState(permittedModes: .all)
+    }
+    
     func textViewDidChangeSelection(_ textView: UITextView) {
+        autocompleteState = textView.updateAutocompleteState(permittedModes: .all)
     }
     
     func textView(_ textView: UITextView, editMenuForTextIn range: NSRange, suggestedActions: [UIMenuElement]) -> UIMenu? {