import SwiftUI
import UIKit

/// A hosting controller that answers to the keyboard.
///
/// The keys belong here rather than on the controller that owns this one: SwiftUI's views take
/// first responder, so the responder chain starts inside this hierarchy, and an override on a
/// parent further up was never consulted at all.
final class KeyHostingController: UIHostingController<AnyView> {
    var onKey: ((String) -> Void)?

    override var canBecomeFirstResponder: Bool { true }

    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)
        becomeFirstResponder()
    }

    override var keyCommands: [UIKeyCommand]? { Keys.commands(#selector(key(_:))) }

    @objc private func key(_ command: UIKeyCommand) {
        guard let input = command.input else { return }
        onKey?(input)
    }
}