lanework/Kanban/UI/Card/CardBodySurface.swift

import AppKit
import SwiftUI

// MARK: - CardBodySurface

/// The body column's text surface: **one hosted `NSTextView` serving both modes** — the rendered
/// Preview and the raw-Markdown Edit editor.
///
/// ### Why AppKit, and not `Text(…).textSelection(.enabled)`
///
/// Four of Preview's settled rules are things a SwiftUI `Text` cannot do, and each of them is
/// normative rather than nice-to-have:
///
/// - **⌘F is find-in-text here** (05-card-window.md ▸ Preview; 11-command-nexus.md scopes ⌘F to
///   find-in-text in the card window). The standard find bar is `NSTextFinder` over a text view in
///   a scroll view; SwiftUI's text selection offers no find at all, and a hand-rolled search UI
///   would be a second, worse find bar in an app whose whole posture is to use the system's.
/// - **Clicking never edits, but a checkbox does something.** A text view already hit-tests
///   characters, already distinguishes a click from a selection drag, and already reports the one
///   it decided on to its delegate. That machinery is exactly the "selectable everywhere, live in
///   one place" grammar, and re-deriving it from a SwiftUI gesture over a `Text` would mean
///   re-deriving text selection.
/// - **Links open things.** `.link` attributes plus `textView(_:clickedOnLink:at:)` is the whole of
///   "external URLs open in the browser; relative links open the target with its default app".
/// - **Tables.** `NSTextTable`'s automatic layout *is* the browser sizing rule the design names,
///   and it is a TextKit 1 construct — which is why the stack below is built by hand rather than
///   taken from `NSTextView(frame:)`, whose modern default is TextKit 2.
///
/// ### One substrate, two modes
///
/// Preview and Edit differ in three things and nothing else: whether the view is editable, what it
/// is handed (a rendered attributed string, or the raw text under a highlighting pass), and which
/// key means "flip". Everything else — ⌘F, selection, copying, the find bar, the scroll position —
/// belongs to the substrate and is therefore identical in both, without either mode implementing it.
///
/// **One view rather than two representables**, deliberately: `CardBodyPresentation.findInText` holds
/// a closure over *this* text view, and two views swapping across a mode flip would race to own it —
/// ⌘F would work or not depending on the order SwiftUI happened to mount them in. One view has one
/// text view for the window's life, and the flip is a reconfiguration.
///
/// ### What the editor writes, and when
///
/// Nothing here writes to disk. The text view reports every change to `CardBodyEditSession`, which
/// owns the ~700 ms debounce, the three write gates and the flush; this file's whole responsibility
/// is that the buffer and the view agree, and that the view never has text replaced under the user's
/// cursor (the view half of dirty-buffer-wins — the session's half is `adopt(diskBody:)`).
struct CardBodySurface: NSViewRepresentable {

    /// The text to show: `CardBodyEditSession.text`, which is the buffer in Edit and — because a
    /// clean buffer follows disk — the card's body in Preview. One string for both modes is what
    /// makes "the preview never lags the text that produced it" (05 ▸ Mode grammar) fall out rather
    /// than need arranging.
    let body: String
    let mode: CardBodyMode
    /// The card's own folder: what relative images and links resolve against.
    let cardFolder: URL?
    /// The window's body handle — this view fills in its `findInText`.
    let presentation: CardBodyPresentation
    /// The buffer this surface edits. Keystrokes go in through `edited(_:)`; nothing else here
    /// touches it.
    let session: CardBodyEditSession
    /// Whether a checkbox click may write. `false` under the read-only lock, where "the controls
    /// disable in place" (05 ▸ Preview; 02-architecture.md § the lock's scope).
    let isTaskToggleEnabled: Bool
    /// Byte offset and the state the user saw — straight through to `BoardStore.toggleTaskMarker`.
    let onToggleTask: (Int, Bool) -> Void
    /// Whether this surface scrolls on its own — `true`, the default, for every mount and mode
    /// today. `false` is the stacked mount's continuous Preview arrangement
    /// (`CardWindowView.continuousStackedContent`), where this surface's rendered content is one
    /// section of a single shared document scroll rather than its own scrolling region: the hosted
    /// `NSScrollView` loses its scroller and elasticity (the outer `ScrollView` owns wheel/trackpad
    /// scrolling instead) and `sizeThatFits(_:nsView:context:)` below reports the text's own height
    /// for whatever width it is proposed, rather than the view answering nothing and falling back to
    /// a frame nothing constrains.
    var scrolls: Bool = true

    /// The height a measurement pass lays out into while `scrolls` is `false` — tall enough that no
    /// card body reaches it, finite so the arithmetic stays well-defined. `CommentBodyView`'s own
    /// constant, applied one level down through the hosting scroll view rather than straight to the
    /// represented view.
    private static let embeddedLayoutCeiling: CGFloat = 100_000

    func makeCoordinator() -> Coordinator {
        Coordinator()
    }

    func makeNSView(context: Context) -> NSScrollView {
        // TextKit 1, explicitly: `NSTextView(frame:)` would give a TextKit 2 stack, in which
        // `NSTextTable` does not lay out. Building the stack by hand is the supported way to ask
        // for the older one, and it is the only reason this is not a one-line construction.
        let storage = NSTextStorage()
        let layoutManager = NSLayoutManager()
        storage.addLayoutManager(layoutManager)
        let container = NSTextContainer(size: CGSize(width: 0, height: CGFloat.greatestFiniteMagnitude))
        container.widthTracksTextView = true
        layoutManager.addTextContainer(container)

        let textView = CardBodyTextView(frame: .zero, textContainer: container)
        textView.delegate = context.coordinator
        textView.isEditable = false
        textView.isSelectable = true
        textView.isRichText = true
        textView.drawsBackground = false
        textView.isVerticallyResizable = true
        textView.isHorizontallyResizable = false
        textView.autoresizingMask = NSView.AutoresizingMask.width
        textView.minSize = CGSize(width: 0, height: 0)
        textView.maxSize = CGSize(width: CGFloat.greatestFiniteMagnitude, height: CGFloat.greatestFiniteMagnitude)
        // Nothing about a card body is the app's to rewrite as the user reads it — or as they type
        // it: "the text is the raw Markdown, character for character — no hidden transforms, no
        // smart substitutions" (05 ▸ Edit) is exactly this list, and in Edit it is normative rather
        // than merely tidy. A smart quote substituted into a fenced code block would be the app
        // silently corrupting the user's file.
        textView.isAutomaticLinkDetectionEnabled = false
        textView.isAutomaticQuoteSubstitutionEnabled = false
        textView.isAutomaticDashSubstitutionEnabled = false
        textView.isAutomaticTextReplacementEnabled = false
        textView.isAutomaticSpellingCorrectionEnabled = false
        textView.isAutomaticDataDetectionEnabled = false
        textView.smartInsertDeleteEnabled = false
        // ⌘Z is the editor's own undo (05 ▸ Edit). `allowsUndo` turns it on; the *session* scoping is
        // the coordinator's `undoManager(for:)`, below.
        textView.allowsUndo = true
        // The renderer already coloured links and checkboxes; the only thing the text view should
        // add is the pointer, so the two do not fight over the run's appearance.
        let linkAttributes: [NSAttributedString.Key: Any] = [.cursor: NSCursor.pointingHand]
        textView.linkTextAttributes = linkAttributes
        textView.displaysLinkToolTips = true
        textView.usesFindBar = true
        textView.isIncrementalSearchingEnabled = true

        let gutter = CardWindowMetrics.gutter(bodyPointSize: CardWindowMetrics.bodyPointSize)
        textView.textContainerInset = CGSize(width: gutter, height: gutter)

        // The two fixed keys of the mode grammar, on the surface that owns the keyboard while they
        // are pressed: "Return in Preview also enters Edit … Escape in Edit returns to Preview"
        // (05 ▸ Mode grammar). They are the text view's rather than a SwiftUI `.onKeyPress` because
        // the text view *is* the first responder in both modes — a key handler above it would only
        // see what the editor declined to eat.
        let presentation = presentation
        textView.onReturnInPreview = { presentation.setMode(.edit) }
        textView.onEscapeInEdit = { presentation.setMode(.preview) }

        let scrollView = NSScrollView()
        scrollView.documentView = textView
        scrollView.hasVerticalScroller = true
        scrollView.hasHorizontalScroller = false
        scrollView.autohidesScrollers = true
        scrollView.drawsBackground = false
        scrollView.findBarPosition = .aboveContent
        // **`scrolls == false` switches this scroll view off** — no scroller to grab, no elastic
        // bounce to fight the outer `ScrollView`'s own wheel/trackpad scrolling, which is what
        // "embedded in an outer scroll" (the continuous arrangement) actually means at the AppKit
        // layer. `sizeThatFits` below is the other half: without it this view would still have
        // nothing to report and would collapse to zero height inside an unbounded `ScrollView`
        // proposal.
        if !scrolls {
            scrollView.hasVerticalScroller = false
            scrollView.verticalScrollElasticity = .none
            scrollView.horizontalScrollElasticity = .none
        }

        context.coordinator.textView = textView
        context.coordinator.session = session
        context.coordinator.onToggleTask = onToggleTask
        context.coordinator.isTaskToggleEnabled = isTaskToggleEnabled

        // Deferred one turn: `makeNSView` runs inside SwiftUI's update, and `presentation` is
        // observed by a menu item (Edit ▸ Find), so writing to it here would be a mutation during
        // an update of the very graph that reads it.
        Task { @MainActor [weak textView] in
            presentation.findInText = { [weak textView] in
                guard let textView else { return }
                textView.window?.makeFirstResponder(textView)
                // `performTextFinderAction` takes its verb from the sender's `tag`, which is how
                // the standard Edit ▸ Find menu item drives it; a menu item made for the purpose
                // says the same thing from a closure.
                let sender = NSMenuItem()
                sender.tag = NSTextFinder.Action.showFindInterface.rawValue
                textView.performTextFinderAction(sender)
            }
        }

        return scrollView
    }

    /// **The intrinsic height, while `scrolls` is `false`.** `nil` otherwise — the default
    /// (unimplemented) answer, which lets a scrolling instance keep taking whatever frame its
    /// `.frame(maxHeight: .infinity)` modifier proposes exactly as it always has.
    ///
    /// `CommentBodyView.sizeThatFits`'s own trick, one level down through the hosting scroll view:
    /// the container tracks the text view's own frame width (`widthTracksTextView`), so forcing that
    /// frame to the proposed width *is* how the width is proposed at all, and `ensureLayout` is not
    /// optional — `usedRect` only means something once the glyphs are laid, and an unlaid container
    /// answers a zero-height rect, which would collapse the whole body to nothing.
    func sizeThatFits(_ proposal: ProposedViewSize, nsView scrollView: NSScrollView, context: Context) -> CGSize? {
        guard !scrolls else { return nil }
        guard let textView = scrollView.documentView as? NSTextView,
            let container = textView.textContainer,
            let layoutManager = textView.layoutManager
        else { return nil }
        guard let width = proposal.width, width > 0, width.isFinite else { return nil }

        textView.frame = NSRect(x: 0, y: 0, width: width, height: Self.embeddedLayoutCeiling)
        layoutManager.ensureLayout(for: container)
        let usedHeight = layoutManager.usedRect(for: container).height
        // `usedRect` is the text alone; the gutter inset on both edges is this surface's own, added
        // back in rather than folded into the container width above (`textContainerInset` already
        // does that subtraction for `widthTracksTextView`, so doing it twice here would double it).
        let totalHeight = usedHeight + textView.textContainerInset.height * 2
        return CGSize(width: width, height: totalHeight.rounded(.up))
    }

    func updateNSView(_ scrollView: NSScrollView, context: Context) {
        let coordinator = context.coordinator
        coordinator.onToggleTask = onToggleTask
        coordinator.isTaskToggleEnabled = isTaskToggleEnabled
        coordinator.session = session

        guard let textView = scrollView.documentView as? CardBodyTextView else { return }
        let pointSize = CardWindowMetrics.bodyPointSize

        if coordinator.mode != mode {
            coordinator.enter(mode, in: textView)
        }

        let key = Coordinator.RenderKey(body: body, mode: mode, cardFolder: cardFolder, pointSize: pointSize)
        // **Rebuild only when the inputs changed.** SwiftUI re-runs this on every unrelated state
        // change in the window; re-laying out the whole body each time would throw away the scroll
        // position and the selection — the reader's place in a document they are reading.
        guard coordinator.rendered != key else { return }
        coordinator.rendered = key

        switch mode {
        case .preview:
            let context = BodyMarkupRenderer.Context(pointSize: pointSize, cardFolder: cardFolder)
            textView.textStorage?.setAttributedString(
                BodyMarkupRenderer.attributedString(for: BodyMarkup.parse(body), context: context)
            )

        case .edit:
            coordinator.show(body, in: textView, pointSize: pointSize)
        }
    }

    // MARK: - Coordinator

    /// The delegate, the render cache, and the editor's session-scoped undo.
    @MainActor
    final class Coordinator: NSObject, NSTextViewDelegate {

        /// What the text view currently shows, as the inputs that produced it.
        struct RenderKey: Equatable {
            let body: String
            let mode: CardBodyMode
            let cardFolder: URL?
            let pointSize: CGFloat
        }

        weak var textView: NSTextView?
        var rendered: RenderKey?
        var session: CardBodyEditSession?
        var onToggleTask: ((Int, Bool) -> Void)?
        var isTaskToggleEnabled = true

        /// Which mode the view is currently *configured* for — `nil` until the first update, which is
        /// what makes the initial configuration a mode entry like any other (and is why a card that
        /// opens straight into Edit gets the caret without a special case).
        private(set) var mode: CardBodyMode?

        /// **The editor's own undo manager, and the whole of "session-scoped"** (05 ▸ Edit: "⌘Z here
        /// is the text view's own undo — session-scoped, ending when the editor loses focus or the
        /// mode flips").
        ///
        /// Without this the text view would use the *window's* undo manager, whose stack outlives
        /// every mode flip and is shared with anything else in the window that registers an
        /// undoable action — so ⌘Z after leaving Edit could reach back into text the user had
        /// already committed. Owning one here makes the scoping structural: `removeAllActions()` at
        /// the two moments 05 names is then an emptying of a stack nothing else can see.
        private let editorUndoManager = UndoManager()

        /// Set while this coordinator is replacing the view's text, so the resulting change
        /// notification is not mistaken for typing.
        private var isSettingText = false

        // MARK: Mode

        /// Reconfigures the view for a mode — the only place editability, the undo stack and first
        /// responder change.
        func enter(_ newMode: CardBodyMode, in textView: CardBodyTextView) {
            mode = newMode
            // The session's undo stack ends with the mode, per 05. Emptied on the way *in* as well
            // as out, so an Edit session never opens on top of the previous one's actions.
            editorUndoManager.removeAllActions()

            switch newMode {
            case .preview:
                textView.isEditable = false

            case .edit:
                textView.isEditable = true
                textView.typingAttributes = MarkdownHighlighter.baseAttributes(
                    pointSize: CardWindowMetrics.bodyPointSize
                )
                // "**Empty body opens in Edit** with the cursor ready" (05 ▸ Mode grammar) — and the
                // same courtesy for a deliberate ⌘E, which is a request to type. Deferred a turn:
                // this runs inside a SwiftUI update, and making a view first responder re-enters
                // AppKit's responder machinery.
                Task { @MainActor [weak textView] in
                    guard let textView, textView.isEditable else { return }
                    textView.window?.makeFirstResponder(textView)
                }
            }
        }

        /// Puts `text` in the editor and highlights it — **never replacing what the user is looking
        /// at unless it actually differs**.
        ///
        /// The equality guard is load-bearing rather than an optimization: this runs on every
        /// keystroke (the buffer changed, so SwiftUI re-ran the update), and replacing the storage
        /// with the string it already holds would collapse the selection, scroll the view, and throw
        /// away the undo stack — on every character typed.
        func show(_ text: String, in textView: CardBodyTextView, pointSize: CGFloat) {
            guard let storage = textView.textStorage else { return }

            if storage.string != text {
                // A foreign edit arriving under a *clean* buffer, or the first fill of the editor.
                // The selection is preserved where it still fits; a caret past the new end clamps
                // rather than disappearing.
                let selected = textView.selectedRange()
                // The undo stack described text that no longer exists — an agent or a hand edit
                // replaced it — and ⌘Z restoring a run of it would be this app inventing a merge.
                editorUndoManager.removeAllActions()
                isSettingText = true
                storage.setAttributedString(NSAttributedString(
                    string: text,
                    attributes: MarkdownHighlighter.baseAttributes(pointSize: pointSize)
                ))
                isSettingText = false
                let length = (text as NSString).length
                textView.setSelectedRange(NSRange(
                    location: min(selected.location, length),
                    length: min(selected.length, max(0, length - min(selected.location, length)))
                ))
            }

            MarkdownHighlighter.highlight(storage, pointSize: pointSize)
            textView.typingAttributes = MarkdownHighlighter.baseAttributes(pointSize: pointSize)
        }

        // MARK: NSTextViewDelegate

        /// The editor's undo manager — see `editorUndoManager`.
        func undoManager(for view: NSTextView) -> UndoManager? {
            editorUndoManager
        }

        /// Every keystroke, straight into the buffer. The session decides what that costs: a
        /// restarted debounce, or a cancelled one when the change happened to restore the file's own
        /// text.
        func textDidChange(_ notification: Notification) {
            guard !isSettingText, mode == .edit, let textView = notification.object as? NSTextView else { return }
            session?.edited(textView.string)
        }

        /// Focus leaving the editor ends the undo session (05 ▸ Edit), and is *not* a save: the
        /// debounce is still running and will land on its own, which is what keeps clicking into the
        /// sidebar from being a commit point the design never named.
        func textDidEndEditing(_ notification: Notification) {
            editorUndoManager.removeAllActions()
        }

        /// The click grammar, in one method: a checkbox writes, anything else opens, and the return
        /// value is always `true` so the text view never falls back to its own link handling.
        func textView(_ textView: NSTextView, clickedOnLink link: Any, at charIndex: Int) -> Bool {
            guard let url = Self.url(from: link) else { return false }

            if let task = CardBodyLink.parseTask(url) {
                // Disabled in place under the read-only lock: the click is swallowed rather than
                // attempted, because a write that would be refused should not post a banner the
                // standing lock row already explains.
                guard isTaskToggleEnabled else { return true }
                onToggleTask?(task.offset, task.isChecked)
                return true
            }

            // External URLs go to the browser and relative ones — already resolved to file URLs by
            // the renderer — go to their default app. `NSWorkspace.open` is both of those sentences
            // (05 ▸ Preview ▸ Links).
            NSWorkspace.shared.open(url)
            return true
        }

        private static func url(from link: Any) -> URL? {
            switch link {
            case let url as URL: url
            case let string as String: URL(string: string)
            default: nil
            }
        }
    }
}

// MARK: - CardBodyTextView

/// The body surface's text view, subclassed for exactly two keys.
///
/// Return in Preview and Escape in Edit are **fixed grammar, not menu items** (05-card-window.md ▸
/// Mode grammar: "Return in Preview also enters Edit — the board's edit key applied to the body;
/// fixed grammar like the board's Return, not a menu item"), so they have to be intercepted where
/// the keyboard actually is. Both are guarded by editability, which is the mode: a Return in Edit is
/// a newline like any other, and an Escape in Preview means nothing here.
final class CardBodyTextView: NSTextView {

    var onReturnInPreview: (() -> Void)?
    var onEscapeInEdit: (() -> Void)?

    /// Preview is not editable, so AppKit would send this nowhere — the mode's own key handling has
    /// to come before `super`, which for a read-only text view merely beeps.
    override func keyDown(with event: NSEvent) {
        let isPlainReturn = event.keyCode == 36 || event.keyCode == 76
        let modifiers = event.modifierFlags.intersection(.deviceIndependentFlagsMask)
            .subtracting([.function, .numericPad, .capsLock])
        if !isEditable, isPlainReturn, modifiers.isEmpty {
            onReturnInPreview?()
            return
        }
        super.keyDown(with: event)
    }

    /// Escape. Intercepted before `NSTextView`'s own meaning for it (text completion), and only
    /// while editing — with the find bar up the bar is first responder and never reaches this.
    override func cancelOperation(_ sender: Any?) {
        guard isEditable, let onEscapeInEdit else {
            super.cancelOperation(sender)
            return
        }
        onEscapeInEdit()
    }

    /// **A file drop is never the editor's** (05-card-window.md ▸ Attachments, settled: "file drops
    /// import as attachments anywhere in the window — Edit mode included, the text editor never
    /// intercepts a file drop; dragged *text* lands in the Edit editor at the caret").
    ///
    /// An editable, rich `NSTextView` would otherwise happily take a dragged file and turn it into a
    /// path or an attachment cell inside the user's Markdown. Dropping the *file* types from what
    /// this view accepts lets that drag fall through to the window, which is where the attachment
    /// import belongs. Every text type — a plain-text drag, a URL dragged out of a browser — is left
    /// exactly as AppKit offers it, so the other half of the rule is the default behaviour rather
    /// than a re-implementation of it.
    ///
    // m6-card-attachments: the window-level drop surface that catches what this declines.
    override var acceptableDragTypes: [NSPasteboard.PasteboardType] {
        let fileTypes: Set<NSPasteboard.PasteboardType> = [
            .fileURL,
            // The Carbon-era name AppKit still puts on a Finder drag alongside the modern one.
            NSPasteboard.PasteboardType("NSFilenamesPboardType")
        ]
        return super.acceptableDragTypes.filter { !fileTypes.contains($0) }
    }

    // MARK: The paste yield

    /// **A pasteboard this editor cannot read is never the editor's either** — the drop rule above,
    /// arrived at the keyboard (04-interactions.md ▸ Clipboard, the image-data and file-URL branches;
    /// 05 ▸ Attachments makes the *window* answer ⌘V with an attachment import).
    ///
    /// The focused-editor rule says a focused text surface wins ⌘V, and it still does: any pasteboard
    /// carrying something this view can take — text, foremost — pastes into the text exactly as
    /// before, image flavors riding beside it or not. But this view holds the keyboard from the
    /// moment the window opens, and a *screenshot* pasteboard (image data, no text) is one it cannot
    /// read at all: `NSTextView`'s own answer is a disabled menu row, which here means the window's
    /// image branch sits one responder below the keyboard and can never be reached by it. "Wins"
    /// must not mean "blocks what it cannot take" — so a paste this editor has no reading of is
    /// passed to the responder behind it, and the standard validation walks the same path.
    ///
    /// The yield is by *capability*, not by content kind, for the image branch — `readablePasteboardTypes`
    /// is AppKit's own statement of what this view would accept, so the expression cannot drift from
    /// the paste it guards. In Preview the view is not editable and takes no paste, so there the
    /// window's branch simply owns ⌘V outright.
    ///
    /// **The file-URL branch needs one content check, and here is why.** `acceptableDragTypes` above
    /// excludes `.fileURL` outright, but `readablePasteboardTypes`' own answer already omits it too —
    /// `importsGraphics` is `false` on this view, so AppKit does not offer it. The leak is one level
    /// up: `public.file-url` *conforms to* `public.url`, which this view legitimately does read (so a
    /// dragged or pasted web link still lands as text), and `NSPasteboard.availableType(from:)`
    /// matches by conformance, not exact type — so a Finder copy that also declares a generic URL
    /// representation beside its file URL would still read as "text this editor takes" through sheer
    /// ancestry, and the paste would never reach the window at all. `PastedImage.carriesFileURL` is
    /// the one predicate this whole feature already classifies file-URL pasteboards with
    /// (`ClipboardStore.fileURLPayload`); reusing it here rather than a second UTI walk is what keeps
    /// this check in step with that one.

    /// The pasteboard the yield reads — the general one in the app; tests hand in their own so the
    /// suite never touches the machine's (`FakePasteboard`'s reason, one seam over).
    var yieldPasteboard: NSPasteboard = .general

    /// Whether this editor itself would take the current pasteboard.
    private var takesPasteboardAsText: Bool {
        guard isEditable else { return false }
        // A file URL is never this editor's, whatever generic ancestor type rides beside it on the
        // pasteboard (the doc block above) — the file-URL branch owns this paste instead.
        guard !PastedImage.carriesFileURL((yieldPasteboard.types ?? []).map(\.rawValue)) else { return false }
        return yieldPasteboard.availableType(from: readablePasteboardTypes) != nil
    }

    /// The responder behind this view that answers `paste:` — the card window's file or image branch
    /// when either is armed (`cardWindowPaste`; SwiftUI's bridge responds only while the handler is
    /// attached), and `nil` when nothing behind would take the paste either.
    private var pasteYieldTarget: NSResponder? {
        var responder = nextResponder
        while let current = responder {
            if current.responds(to: #selector(NSText.paste(_:))) { return current }
            responder = current.nextResponder
        }
        return nil
    }

    override func validateUserInterfaceItem(_ item: any NSValidatedUserInterfaceItem) -> Bool {
        if item.action == #selector(NSText.paste(_:)), !takesPasteboardAsText {
            return pasteYieldTarget != nil
        }
        return super.validateUserInterfaceItem(item)
    }

    override func paste(_ sender: Any?) {
        guard !takesPasteboardAsText, let target = pasteYieldTarget else {
            super.paste(sender)
            return
        }
        target.tryToPerform(#selector(NSText.paste(_:)), with: sender)
    }
}