feat: key commands for external keyboards

Sources/Views/InputTextView.swift

@@ -133,6 +133,9 @@ open class InputTextView: UITextView {
         }
     }
 
+    open var registeredCommands: [UIKeyCommand] = []
+    open var registeredKeyCallbacks: [String: () -> Void] = [:]
+
     /// A weak reference to the InputBarAccessoryView that the InputTextView is contained within
     open weak var inputBarAccessoryView: InputBarAccessoryView?
 
@@ -231,6 +234,34 @@ open class InputTextView: UITextView {
         }
     }
 
+    // MARK: - Key Command
+
+    open override var keyCommands: [UIKeyCommand]? {
+        return registeredCommands
+    }
+
+    open func observeKeyInput(_ input: String, modifiers: UIKeyModifierFlags, discoverabilityTitle: String?, callback: @escaping (() -> Void)) {
+        if input == "" {
+            return
+        }
+        let keyCommand = UIKeyCommand(input: input, modifierFlags: modifiers, action: #selector(didDetectKeyCommand(_:)))
+        keyCommand.discoverabilityTitle = discoverabilityTitle
+        if #available(iOS 15.0, *) {
+            keyCommand.wantsPriorityOverSystemBehavior = true
+        }
+
+        let key = "\(input)_\(modifiers)"
+        registeredCommands.append(keyCommand)
+        registeredKeyCallbacks[key] = callback
+    }
+
+    @objc private func didDetectKeyCommand(_ keyCommand: UIKeyCommand) {
+        if keyCommand.input == nil { return }
+        let key = "\(String(describing: keyCommand.input!))_\(keyCommand.modifierFlags)"
+        let callback = registeredKeyCallbacks[key]
+        callback?()
+    }
+
     // MARK: - Image Paste Support
 
     open override func canPerformAction(_ action: Selector, withSender sender: Any?) -> Bool {