Re-add rich-text formatting actions in Compose

Packages/ComposeUI/Sources/ComposeUI/ComposeInput.swift

@@ -10,6 +10,7 @@ import Combine
 import UIKit
 import SwiftUI
 
+@MainActor
 protocol ComposeInput: AnyObject, ObservableObject {
     var toolbarElements: [ToolbarElement] { get }
     var textInputMode: UITextInputMode? { get }

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

@@ -52,6 +52,7 @@ private struct NewMainTextViewRepresentable: UIViewRepresentable {
         }
         view.addInteraction(UIDropInteraction(delegate: context.coordinator))
         view.delegate = context.coordinator
+        context.coordinator.textView = view
         view.adjustsFontForContentSizeCategory = true
         view.textContainer.lineBreakMode = .byWordWrapping
         view.isScrollEnabled = false
@@ -110,9 +111,9 @@ private struct NewMainTextViewRepresentable: UIViewRepresentable {
     
     func makeCoordinator() -> WrappedTextViewCoordinator {
         let coordinator = WrappedTextViewCoordinator(value: $value, handleAttachmentDrop: handleAttachmentDrop)
-//        DispatchQueue.main.async {
+        DispatchQueue.main.async {
-//            inputBox.wrappedValue = coordinator
+            inputBox.wrappedValue = coordinator
-//        }
+        }
         return coordinator
     }
     
@@ -127,7 +128,7 @@ private struct NewMainTextViewRepresentable: UIViewRepresentable {
 // laxer than the CharacterCounter regex, because we want to find mentions that are being typed but aren't yet complete (e.g., "@a@b")
 private let mentionRegex = try! NSRegularExpression(pattern: "(@[a-z0-9_]+)(?:@[a-z0-9\\-\\.]+)?", options: .caseInsensitive)
 
-private final class WrappedTextViewCoordinator: NSObject {
+private final class WrappedTextViewCoordinator: NSObject, ObservableObject {
     private static let attachment: NSTextAttachment = {
         let font = UIFont.systemFont(ofSize: 20)
         let size = /*1.4 * */font.capHeight
@@ -144,6 +145,9 @@ private final class WrappedTextViewCoordinator: NSObject {
     
     var value: Binding<String>
     var handleAttachmentDrop: ([NSItemProvider]) -> Void
+    weak var textView: UITextView?
+    
+    @Published var autocompleteState: AutocompleteState?
 
     init(value: Binding<String>, handleAttachmentDrop: @escaping ([NSItemProvider]) -> Void) {
         self.value = value
@@ -293,9 +297,41 @@ extension WrappedTextViewCoordinator: UITextViewDelegate {
     }
 }
 
-//extension WrappedTextViewCoordinator: ComposeInput {
+extension WrappedTextViewCoordinator: ComposeInput {
-//    
+    var autocompleteStatePublisher: Published<AutocompleteState?>.Publisher { $autocompleteState }
-//}
+    
+    var toolbarElements: [ToolbarElement] {
+        [.emojiPicker, .formattingButtons]
+    }
+    
+    var textInputMode: UITextInputMode? {
+        textView?.textInputMode
+    }
+    
+    func applyFormat(_ format: StatusFormat) {
+        guard let textView,
+              textView.isFirstResponder,
+              let insertionResult = format.insertionResult(for: Preferences.shared.statusContentType) else {
+            return
+        }
+        
+        let currentSelectedRange = textView.selectedRange
+        let utf16 = textView.text.utf16
+        let start = utf16.index(utf16.startIndex, offsetBy: currentSelectedRange.location)
+        let end = utf16.index(start, offsetBy: currentSelectedRange.length)
+        let selectedText = utf16[start..<end]
+        textView.insertText(insertionResult.prefix + String(Substring(selectedText)) + insertionResult.suffix)
+        textView.selectedRange = NSRange(location: currentSelectedRange.location + insertionResult.insertionPoint, length: currentSelectedRange.length)
+    }
+    
+    func beginAutocompletingEmoji() {
+        textView?.insertText(":")
+    }
+    
+    func autocomplete(with string: String) {
+        textView?.autocomplete(with: string, permittedModes: .all, autocompleteState: &autocompleteState)
+    }
+}
 
 // Because of FB11790805, we can't handle drops for the entire screen.
 // The onDrop modifier also doesn't work when applied to the NewMainTextView.
@@ -327,11 +363,11 @@ private final class WrappedTextView: UITextView {
     }
     
     override func toggleBoldface(_ sender: Any?) {
-        // TODO
+        (delegate as! WrappedTextViewCoordinator).applyFormat(.bold)
     }
     
     override func toggleItalics(_ sender: Any?) {
-       // TODO
+        (delegate as! WrappedTextViewCoordinator).applyFormat(.italics)
     }
     
     override func validate(_ command: UICommand) {