SwiftUI keyboard events based on keyawareview and keyboardshortcuts

onKeyPress.swift

//
//  KeyAwareView.swift
//
//  Created by Stef Kors on 04/09/2023.
//
//  source: https://onmyway133.com/posts/how-to-handle-keydown-in-swiftui-for-macos/
//  source: https://github.com/sindresorhus/KeyboardShortcuts/blob/main/Sources/KeyboardShortcuts/Key.swift

import SwiftUI
import Carbon.HIToolbox


struct KeyAwareViewModifier: ViewModifier {
    let key: KeyboardKey
    let callback: (KeyAwareView.Event) -> Void

    init(_ key: KeyboardKey, callback: @escaping (KeyAwareView.Event) -> Void) {
        self.key = key
        self.callback = callback
    }

    func body(content: Content) -> some View {
        content
            .background(KeyAwareView(key: key, onEvent: callback))
    }
}

extension View {
    func onKeyPress(_ key: KeyboardKey, callback: @escaping (KeyAwareView.Event) -> Void) -> some View {
        modifier(KeyAwareViewModifier(key, callback: callback))
    }
}

struct KeyAwareView: NSViewRepresentable {
    let key: KeyboardKey
    let onEvent: (Event) -> Void

    func makeNSView(context: Context) -> NSView {
        let view = KeyView()
        view.key = key
        view.onEvent = onEvent
        DispatchQueue.main.async {
            view.window?.makeFirstResponder(view)
        }
        return view
    }

    func updateNSView(_ nsView: NSView, context: Context) {}
}

extension KeyAwareView {
    enum Event {
        case upArrow
        case downArrow
        case leftArrow
        case rightArrow
        case space
        case delete
        case cmdC
    }
}

private class KeyView: NSView {
    var key: KeyboardKey? = nil
    var onEvent: (KeyAwareView.Event) -> Void = { _ in }

    override var acceptsFirstResponder: Bool { true }
    override func keyDown(with event: NSEvent) {
        switch Int(event.keyCode) {
        case KeyboardKey.space.rawValue:
            onEvent(.space)
        default:
            super.keyDown(with: event)
        }
    }
}

/**
 Represents a key on the keyboard.
 */
public struct KeyboardKey: Hashable, RawRepresentable {
    // MARK: Letters

    public static let a = Self(kVK_ANSI_A)
    public static let b = Self(kVK_ANSI_B)
    public static let c = Self(kVK_ANSI_C)
    public static let d = Self(kVK_ANSI_D)
    public static let e = Self(kVK_ANSI_E)
    public static let f = Self(kVK_ANSI_F)
    public static let g = Self(kVK_ANSI_G)
    public static let h = Self(kVK_ANSI_H)
    public static let i = Self(kVK_ANSI_I)
    public static let j = Self(kVK_ANSI_J)
    public static let k = Self(kVK_ANSI_K)
    public static let l = Self(kVK_ANSI_L)
    public static let m = Self(kVK_ANSI_M)
    public static let n = Self(kVK_ANSI_N)
    public static let o = Self(kVK_ANSI_O)
    public static let p = Self(kVK_ANSI_P)
    public static let q = Self(kVK_ANSI_Q)
    public static let r = Self(kVK_ANSI_R)
    public static let s = Self(kVK_ANSI_S)
    public static let t = Self(kVK_ANSI_T)
    public static let u = Self(kVK_ANSI_U)
    public static let v = Self(kVK_ANSI_V)
    public static let w = Self(kVK_ANSI_W)
    public static let x = Self(kVK_ANSI_X)
    public static let y = Self(kVK_ANSI_Y)
    public static let z = Self(kVK_ANSI_Z)
    // swiftlint:enable identifier_name

    // MARK: Numbers

    public static let zero = Self(kVK_ANSI_0)
    public static let one = Self(kVK_ANSI_1)
    public static let two = Self(kVK_ANSI_2)
    public static let three = Self(kVK_ANSI_3)
    public static let four = Self(kVK_ANSI_4)
    public static let five = Self(kVK_ANSI_5)
    public static let six = Self(kVK_ANSI_6)
    public static let seven = Self(kVK_ANSI_7)
    public static let eight = Self(kVK_ANSI_8)
    public static let nine = Self(kVK_ANSI_9)

    // MARK: Modifiers

    public static let capsLock = Self(kVK_CapsLock)
    public static let shift = Self(kVK_Shift)
    public static let function = Self(kVK_Function)
    public static let control = Self(kVK_Control)
    public static let option = Self(kVK_Option)
    public static let command = Self(kVK_Command)
    public static let rightCommand = Self(kVK_RightCommand)
    public static let rightOption = Self(kVK_RightOption)
    public static let rightControl = Self(kVK_RightControl)
    public static let rightShift = Self(kVK_RightShift)

    // MARK: Miscellaneous

    public static let `return` = Self(kVK_Return)
    public static let backslash = Self(kVK_ANSI_Backslash)
    public static let backtick = Self(kVK_ANSI_Grave)
    public static let comma = Self(kVK_ANSI_Comma)
    public static let equal = Self(kVK_ANSI_Equal)
    public static let minus = Self(kVK_ANSI_Minus)
    public static let period = Self(kVK_ANSI_Period)
    public static let quote = Self(kVK_ANSI_Quote)
    public static let semicolon = Self(kVK_ANSI_Semicolon)
    public static let slash = Self(kVK_ANSI_Slash)
    public static let space = Self(kVK_Space)
    public static let tab = Self(kVK_Tab)
    public static let leftBracket = Self(kVK_ANSI_LeftBracket)
    public static let rightBracket = Self(kVK_ANSI_RightBracket)
    public static let pageUp = Self(kVK_PageUp)
    public static let pageDown = Self(kVK_PageDown)
    public static let home = Self(kVK_Home)
    public static let end = Self(kVK_End)
    public static let upArrow = Self(kVK_UpArrow)
    public static let rightArrow = Self(kVK_RightArrow)
    public static let downArrow = Self(kVK_DownArrow)
    public static let leftArrow = Self(kVK_LeftArrow)
    public static let escape = Self(kVK_Escape)
    public static let delete = Self(kVK_Delete)
    public static let deleteForward = Self(kVK_ForwardDelete)
    public static let help = Self(kVK_Help)
    public static let mute = Self(kVK_Mute)
    public static let volumeUp = Self(kVK_VolumeUp)
    public static let volumeDown = Self(kVK_VolumeDown)

    // MARK: Function

    public static let f1 = Self(kVK_F1)
    public static let f2 = Self(kVK_F2)
    public static let f3 = Self(kVK_F3)
    public static let f4 = Self(kVK_F4)
    public static let f5 = Self(kVK_F5)
    public static let f6 = Self(kVK_F6)
    public static let f7 = Self(kVK_F7)
    public static let f8 = Self(kVK_F8)
    public static let f9 = Self(kVK_F9)
    public static let f10 = Self(kVK_F10)
    public static let f11 = Self(kVK_F11)
    public static let f12 = Self(kVK_F12)
    public static let f13 = Self(kVK_F13)
    public static let f14 = Self(kVK_F14)
    public static let f15 = Self(kVK_F15)
    public static let f16 = Self(kVK_F16)
    public static let f17 = Self(kVK_F17)
    public static let f18 = Self(kVK_F18)
    public static let f19 = Self(kVK_F19)
    public static let f20 = Self(kVK_F20)

    // MARK: Keypad

    public static let keypad0 = Self(kVK_ANSI_Keypad0)
    public static let keypad1 = Self(kVK_ANSI_Keypad1)
    public static let keypad2 = Self(kVK_ANSI_Keypad2)
    public static let keypad3 = Self(kVK_ANSI_Keypad3)
    public static let keypad4 = Self(kVK_ANSI_Keypad4)
    public static let keypad5 = Self(kVK_ANSI_Keypad5)
    public static let keypad6 = Self(kVK_ANSI_Keypad6)
    public static let keypad7 = Self(kVK_ANSI_Keypad7)
    public static let keypad8 = Self(kVK_ANSI_Keypad8)
    public static let keypad9 = Self(kVK_ANSI_Keypad9)
    public static let keypadClear = Self(kVK_ANSI_KeypadClear)
    public static let keypadDecimal = Self(kVK_ANSI_KeypadDecimal)
    public static let keypadDivide = Self(kVK_ANSI_KeypadDivide)
    public static let keypadEnter = Self(kVK_ANSI_KeypadEnter)
    public static let keypadEquals = Self(kVK_ANSI_KeypadEquals)
    public static let keypadMinus = Self(kVK_ANSI_KeypadMinus)
    public static let keypadMultiply = Self(kVK_ANSI_KeypadMultiply)
    public static let keypadPlus = Self(kVK_ANSI_KeypadPlus)

    // MARK: Properties

    /**
     The raw key code.
     */
    public let rawValue: Int

    // MARK: Initializers

    /**
     Create a `Key` from a key code.
     */
    public init(rawValue: Int) {
        self.rawValue = rawValue
    }

    private init(_ value: Int) {
        self.init(rawValue: value)
    }
}