Add stop action to receiver selectors

app/selector/mac/fx_cast_selector/ReceiverView.swift

@@ -2,6 +2,7 @@ import Cocoa
 
 protocol ReceiverViewDelegate : AnyObject {
     func didCast (_ receiver: Receiver)
+    func didStop (_ receiver: Receiver)
 }
 
 class ReceiverView : NSStackView {
@@ -74,6 +75,23 @@ class ReceiverView : NSStackView {
         self.addArrangedSubview(self.castButton)
 
         self.distribution = .fill
+        
+        NSEvent.addLocalMonitorForEvents(
+                matching: .flagsChanged) { event in
+
+            if !self.receiver.status.application.isIdleScreen &&
+                    event.modifierFlags.contains(.option) {
+                self.castButton.title =
+                        InitDataProvider.shared.data.i18n_stopButtonTitle
+                self.castButton.action = #selector(ReceiverView.onStop)
+            } else {
+                self.castButton.title =
+                        InitDataProvider.shared.data.i18n_castButtonTitle
+                self.castButton.action = #selector(ReceiverView.onCast)
+            }
+
+            return event
+        }
     }
 
     override func updateConstraints () {
@@ -103,4 +121,9 @@ class ReceiverView : NSStackView {
         self.castingSpinner.isHidden = false
         self.castingSpinner.startAnimation(nil)
     }
+
+    @objc
+    func onStop () {
+        self.receiverViewDelegate?.didStop(self.receiver);
+    }
 }

app/selector/mac/fx_cast_selector/ViewController.swift

@@ -197,4 +197,20 @@ extension ViewController : ReceiverViewDelegate {
             fatalError("Error: Failed to encode output data")
         }
     }
+
+    func didStop (_ receiver: Receiver) {
+        // TODO: Use separate type and do proper JSON encoding
+        let selection = ReceiverSelection(
+                receiver: receiver
+              , mediaType: nil
+              , filePath: nil)
+
+        if let jsonData = try? JSONEncoder().encode(selection)
+         , let jsonString = String(data: jsonData, encoding: .utf8) {
+            print(jsonString)
+            fflush(stdout)
+        } else {
+            fatalError("Error: Failed to encode output data")
+        }
+    }
 }

app/selector/mac/fx_cast_selector/models/InitData.swift

@@ -10,6 +10,7 @@ struct InitData : Decodable {
     
     let i18n_extensionName: String
     let i18n_castButtonTitle: String
+    let i18n_stopButtonTitle: String
     let i18n_mediaTypeApp: String
     let i18n_mediaTypeTab: String
     let i18n_mediaTypeScreen: String

app/selector/mac/fx_cast_selector/models/ReceiverSelection.swift

@@ -1,5 +1,5 @@
 struct ReceiverSelection : Codable {
     let receiver: Receiver
-    let mediaType: MediaType
+    let mediaType: MediaType?
     let filePath: String?
 }