Use receiver application statusText instead of host:port when not idle

app/NativeMacReceiverSelector/AppDelegate.swift

@@ -24,7 +24,7 @@ class AppDelegate : NSObject, NSApplicationDelegate {
             // Decode and store initialization JSON data
             self.initData = try JSONDecoder().decode(InitData.self, from: data)
         } catch {
-            fputs("Error: Failed to parse input data\n", stderr)
+            fputs("Error: Failed to parse input data\n (\(error))", stderr)
             exit(1)
         }
 

app/NativeMacReceiverSelector/ReceiverView.swift

@@ -37,9 +37,13 @@ class ReceiverView : NSStackView {
 
         self.receiver = receiver
 
+        let statusText = receiver.status.application.isIdleScreen
+            ? "\(receiver.host):\(receiver.port)"
+            : receiver.status.application.statusText
+
         let metaStackView = NSStackView(views: [
             makeLabel(receiver.friendlyName, size: 14)
-          , makeLabel("\(receiver.host):\(receiver.port)"
+          , makeLabel(statusText
                   , size: NSFont.smallSystemFontSize
                   , color: .secondaryLabelColor)
         ])

app/NativeMacReceiverSelector/models/Receiver.swift

@@ -1,6 +1,23 @@
 struct Receiver : Codable {
+    struct Status: Codable {
+        let application: Application
+        let volume: Volume
+    }
+
+    struct Application: Codable {
+        let displayName: String
+        let isIdleScreen: Bool
+        let statusText: String
+    }
+
+    struct Volume: Codable {
+        let level: Double
+        let muted: Bool
+    }
+
     let friendlyName: String
     let host: String
     let id: String
     let port: Int
+    let status: Status
 }