#if os(macOS)
import AppKit
import SwiftUI

/// Position the field editor's caret as part of gaining focus, before another
/// keyboard event can replace the character that started cell editing.
struct SheetCellEditor: NSViewRepresentable {
    @Binding var text: String
    let enabled: Bool
    let label: String
    let commit: (Bool) -> Void
    let cancel: () -> Void
    func makeCoordinator() -> Coordinator { Coordinator(self) }
    func makeNSView(context: Context) -> CellTextField {
        let field = CellTextField()
        field.isBordered = false; field.drawsBackground = false
        // The cell already draws its selection border around the full cell.
        field.focusRingType = .none
        field.font = .systemFont(ofSize: 13)
        field.delegate = context.coordinator
        field.stringValue = text
        field.setAccessibilityLabel(label)
        return field
    }
    func updateNSView(_ field: CellTextField, context: Context) {
        context.coordinator.parent = self
        let regainedEditing = enabled && !field.isEnabled
        field.isEnabled = enabled
        if field.stringValue != text {
            field.stringValue = text
            if let editor = field.currentEditor() as? NSTextView {
                editor.setSelectedRange(NSRange(location: text.utf16.count, length: 0))
            }
        }
        if regainedEditing { field.window?.makeFirstResponder(field) }
    }
    final class CellTextField: NSTextField {
        override func viewDidMoveToWindow() {
            super.viewDidMoveToWindow()
            guard let window else { return }
            // The representable must be attached before it can become responder.
            DispatchQueue.main.async { [weak self, weak window] in
                guard let self, let window, self.window === window, self.isEnabled else { return }
                window.makeFirstResponder(self)
            }
        }
        override func becomeFirstResponder() -> Bool {
            let accepted = super.becomeFirstResponder()
            if accepted, let editor = currentEditor() as? NSTextView {
                editor.setSelectedRange(NSRange(location: editor.string.utf16.count, length: 0))
            }
            return accepted
        }
    }
    @MainActor final class Coordinator: NSObject, NSTextFieldDelegate {
        var parent: SheetCellEditor
        init(_ parent: SheetCellEditor) { self.parent = parent }
        func controlTextDidChange(_ notification: Notification) {
            guard let field = notification.object as? NSTextField else { return }
            parent.text = field.stringValue
        }
        func control(_ control: NSControl, textView: NSTextView, doCommandBy selector: Selector) -> Bool {
            switch selector {
            case #selector(NSResponder.insertNewline(_:)): parent.commit(false)
            case #selector(NSResponder.insertTab(_:)): parent.commit(true)
            case #selector(NSResponder.cancelOperation(_:)): parent.cancel()
            default: return false
            }
            return true
        }
    }
}
#endif