아직 UIKit이 필요한 곳: 글자, 조합, 하드웨어 키보드

import SwiftUI
import UIKit

/// A document editor needs UITextView: marked text for Korean composition, TextKit, find, and
/// hardware-keyboard behaviour that SwiftUI's TextEditor does not expose.
struct NoteEditor: UIViewRepresentable {
    @Binding var text: String
    var style: @MainActor (UITextView) -> Void

    func makeUIView(context: Context) -> UITextView {
        let view = UITextView()
        view.delegate = context.coordinator
        view.font = .preferredFont(forTextStyle: .body)
        view.adjustsFontForContentSizeCategory = true
        view.isFindInteractionEnabled = true            // the system find and replace bar
        view.text = text
        return view
    }

    func updateUIView(_ view: UITextView, context: Context) {
        context.coordinator.parent = self
        // A syllable is being composed: replacing the text now would commit or break it.
        guard view.markedTextRange == nil, view.text != text else { return }
        let selection = view.selectedRange
        view.text = text
        view.selectedRange = NSRange(location: min(selection.location, (text as NSString).length), length: 0)
        style(view)
    }

    func makeCoordinator() -> Coordinator { Coordinator(parent: self) }

    @MainActor
    final class Coordinator: NSObject, UITextViewDelegate {
        var parent: NoteEditor
        init(parent: NoteEditor) { self.parent = parent }

        func textViewDidChange(_ view: UITextView) {
            parent.text = view.text                          // the model follows every change
            guard view.markedTextRange == nil else { return } // styling waits for the syllable
            parent.style(view)
        }
    }
}

/// Hardware-keyboard commands that show in the iPad's Command-key overlay.
struct EditorCommands: View {
    let newNote: () -> Void
    let save: () -> Void
    var body: some View {
        HStack {
            Button("New Note", action: newNote).keyboardShortcut("n", modifiers: .command)
            Button("Save", action: save).keyboardShortcut("s", modifiers: .command)
        }
    }
}

// Unreachable: tapping PlaceField moves focus away from the note field, which removes the row
// in the same event that would have delivered the tap.
if writingNote { PlaceField(place: $place) }

// Reachable: gate on content, or on ONE focus value that covers every field in the group.
enum ComposerField: Hashable { case note, place }
@FocusState private var focus: ComposerField?

if focus != nil || !note.isEmpty || !place.isEmpty {
    PlaceField(place: $place).focused($focus, equals: .place)
}