[Woo POS][Barcodes] i2 Use GameController framework for detecting scanner input (#15877)

Author: staskus

WooCommerce/Classes/POS/Presentation/Barcode Scanning/BarcodeScannerContainer.swift

@@ -39,79 +39,35 @@ struct BarcodeScannerContainerRepresentable: UIViewControllerRepresentable {
     let configuration: HIDBarcodeParserConfiguration
     let onScan: (Result<String, Error>) -> Void
 
-    func makeUIViewController(context: Context) -> BarcodeScannerHostingController {
-        let controller = BarcodeScannerHostingController(
+    func makeUIViewController(context: Context) -> UIViewController {
+        return GameControllerBarcodeScannerHostingController(
             configuration: configuration,
             onScan: onScan
         )
-        return controller
     }
 
-    func updateUIViewController(_ uiViewController: BarcodeScannerHostingController, context: Context) {}
+    func updateUIViewController(_ uiViewController: UIViewController, context: Context) {}
 }
 
-/// A UIHostingController that handles keyboard input events for barcode scanning.
-/// This controller captures keyboard input and interprets it as barcode data when a terminating
-/// character is detected.
-class BarcodeScannerHostingController: UIHostingController<EmptyView> {
-    private let configuration: HIDBarcodeParserConfiguration
-    private let scanner: HIDBarcodeParser
+/// A UIHostingController that handles GameController keyboard input events for barcode scanning.
+/// This controller uses GameController framework exclusively for language-independent barcode scanning.
+final class GameControllerBarcodeScannerHostingController: UIHostingController<EmptyView> {
+    private var gameControllerBarcodeObserver: GameControllerBarcodeObserver?
 
     init(
         configuration: HIDBarcodeParserConfiguration,
         onScan: @escaping (Result<String, Error>) -> Void
     ) {
-        self.configuration = configuration
-        self.scanner = HIDBarcodeParser(configuration: configuration,
-                                        onScan: onScan)
         super.init(rootView: EmptyView())
+
+        gameControllerBarcodeObserver = GameControllerBarcodeObserver(configuration: configuration, onScan: onScan)
     }
 
     @MainActor required dynamic init?(coder aDecoder: NSCoder) {
         fatalError("init(coder:) has not been implemented")
     }
 
-    override var canBecomeFirstResponder: Bool { true }
-
-    override func viewDidAppear(_ animated: Bool) {
-        super.viewDidAppear(animated)
-        becomeFirstResponder()
-    }
-
-    override func viewDidDisappear(_ animated: Bool) {
-        super.viewDidDisappear(animated)
-        resignFirstResponder()
-    }
-
-    override func pressesBegan(_ presses: Set<UIPress>, with event: UIPressesEvent?) {
-        /// We don't call super here because it helps prevent the system from hiding the software keyboard when
-        /// a textfield is next used.
-    }
-
-    /// Handles the end of keyboard press events, interpreting them as barcode input.
-    /// When a terminating character is detected, the accumulated buffer is treated as a complete
-    /// barcode and passed to the onScan callback.
-    /// We don't call `super` here because we don't other responder chain items to handle our barcode as well,
-    /// as this could cause unexpected behavior.
-    override func pressesEnded(_ presses: Set<UIPress>, with event: UIPressesEvent?) {
-        /// While a scanner should just "press" each key once, in theory it's possible for presses to be cancelled
-        /// or change between the `began` call and the `ended` call.
-        /// It's better practice for barcode scanning to only consider the presses when they end.
-        for press in presses {
-            guard let key = press.key else { continue }
-            scanner.processKeyPress(key)
-        }
-    }
-
-    override func pressesChanged(_ presses: Set<UIPress>, with event: UIPressesEvent?) {
-        super.pressesChanged(presses, with: event)
-    }
-
-    /// `pressesCancelled` is rarely called, but Apple's documentation suggests it's possible and that crashes may occur if it's not handled.
-    /// It makes sense to clear the buffer when this happens.
-    /// We call super in case other presses are handled elsewhere in the responder chain.
-    override func pressesCancelled(_ presses: Set<UIPress>, with event: UIPressesEvent?) {
-        scanner.cancel()
-        super.pressesCancelled(presses, with: event)
+    deinit {
+        gameControllerBarcodeObserver = nil
     }
 }

WooCommerce/Classes/POS/Presentation/Barcode Scanning/GameControllerBarcodeObserver.swift

@@ -0,0 +1,115 @@
+import Foundation
+import GameController
+
+/// An observer that uses the `GameController` framework to monitor for connected barcode scanners/keyboards
+/// and parse their input into barcode strings.
+///
+/// This class handles the low-level details of observing keyboard connections, processing raw `GCKeyCode` inputs,
+/// and using the `GameControllerBarcodeParser` to produce a final barcode.
+///
+final class GameControllerBarcodeObserver {
+    /// A closure that is called when a barcode scan is completed.
+    /// The result will be a `success` with the barcode string or a `failure` with an error.
+    let onScan: (Result<String, Error>) -> Void
+
+    /// Track the coalesced keyboard and its parser
+    /// According to Apple's documentation, all connected keyboards are coalesced into one keyboard object
+    /// (GCKeyboard.coalesced), so notification about connection/disconnection will only be delivered once
+    /// until the last keyboard disconnects.
+    private var coalescedKeyboard: GCKeyboard?
+    private var barcodeParser: GameControllerBarcodeParser?
+    private let configuration: HIDBarcodeParserConfiguration
+
+    /// Tracks current shift state to be applied to the next character key
+    private var isShiftPressed: Bool = false
+
+    /// Initializes a new barcode scanner observer.
+    /// - Parameters:
+    ///   - configuration: The configuration to use for the barcode parser. Defaults to the standard configuration.
+    ///   - onScan: The closure to be called when a scan is completed.
+    init(configuration: HIDBarcodeParserConfiguration = .default, onScan: @escaping (Result<String, Error>) -> Void) {
+        self.onScan = onScan
+        self.configuration = configuration
+        addObservers()
+        setupCoalescedKeyboard()
+    }
+
+    deinit {
+        removeObservers()
+        cleanupKeyboard()
+    }
+
+    /// Starts observing for keyboard connection and disconnection events.
+    private func addObservers() {
+        NotificationCenter.default.addObserver(
+            self,
+            selector: #selector(handleKeyboardDidConnect),
+            name: .GCKeyboardDidConnect,
+            object: nil
+        )
+        NotificationCenter.default.addObserver(
+            self,
+            selector: #selector(handleKeyboardDidDisconnect),
+            name: .GCKeyboardDidDisconnect,
+            object: nil
+        )
+    }
+
+    /// Stops observing for keyboard events.
+    private func removeObservers() {
+        NotificationCenter.default.removeObserver(self, name: .GCKeyboardDidConnect, object: nil)
+        NotificationCenter.default.removeObserver(self, name: .GCKeyboardDidDisconnect, object: nil)
+    }
+
+    /// Sets up the coalesced keyboard if one is available at initialization.
+    private func setupCoalescedKeyboard() {
+        if let keyboard = GCKeyboard.coalesced {
+            setupKeyboard(keyboard)
+        }
+    }
+
+    /// Handles the connection of a keyboard (coalesced).
+    @objc private func handleKeyboardDidConnect(_ notification: Notification) {
+        guard let keyboard = notification.object as? GCKeyboard else {
+            return
+        }
+        setupKeyboard(keyboard)
+    }
+
+    /// Handles the disconnection of the keyboard (coalesced).
+    @objc private func handleKeyboardDidDisconnect(_ notification: Notification) {
+        cleanupKeyboard()
+    }
+
+    /// Sets up the coalesced keyboard to handle key press events.
+    /// - Parameter keyboard: The coalesced `GCKeyboard` to set up.
+    private func setupKeyboard(_ keyboard: GCKeyboard) {
+        // Clean up any existing setup first
+        cleanupKeyboard()
+
+        coalescedKeyboard = keyboard
+        barcodeParser = GameControllerBarcodeParser(configuration: configuration, onScan: onScan)
+
+        keyboard.keyboardInput?.keyChangedHandler = { [weak self] _, _, keyCode, pressed in
+            guard let self = self else { return }
+
+            if keyCode == .leftShift || keyCode == .rightShift {
+                self.isShiftPressed = pressed
+                return
+            }
+
+            guard pressed else { return }
+
+            self.barcodeParser?.processKeyPress(keyCode, isShiftPressed: isShiftPressed)
+        }
+    }
+
+    /// Cleans up the coalesced keyboard and its parser.
+    private func cleanupKeyboard() {
+        coalescedKeyboard?.keyboardInput?.keyChangedHandler = nil
+        barcodeParser?.cancel()
+        coalescedKeyboard = nil
+        barcodeParser = nil
+        isShiftPressed = false
+    }
+}