fix(ios): supply missing push notification sound at handoff

Signed-off-by: Tom Brow <tomb@block.xyz>

mobile/ios/BuzzPushKit/Sources/BuzzPushKit/BuzzNotificationSound.swift

@@ -0,0 +1,15 @@
+import UserNotifications
+
+/// Applies the ordinary alert sound policy at the final service-extension handoff.
+public enum BuzzNotificationSound {
+  /// Preserves the incoming APNs sound, or adds the default when no sound exists.
+  public static func preparing(
+    _ content: UNNotificationContent,
+    originalSound: UNNotificationSound?
+  ) -> UNNotificationContent {
+    // UNNotificationContent's NSMutableCopying contract returns its mutable counterpart.
+    let prepared = content.mutableCopy() as! UNMutableNotificationContent
+    prepared.sound = originalSound ?? content.sound ?? .default
+    return prepared
+  }
+}

mobile/ios/BuzzPushKit/Tests/BuzzPushKitTests/BuzzNotificationSoundTests.swift

@@ -0,0 +1,110 @@
+import Testing
+import UserNotifications
+
+@testable import BuzzPushKit
+
+struct BuzzNotificationSoundTests {
+  @Test func `Missing sound receives default without changing presentation`() {
+    let content = UNMutableNotificationContent()
+    content.title = "Sender"
+    content.body = "Message"
+    content.userInfo = ["navigation": "target"]
+    let result = BuzzNotificationSound.preparing(content, originalSound: nil)
+    #expect(result.sound != nil)
+    #expect(content.sound == nil)
+    #expect(result.title == content.title)
+    #expect(result.body == content.body)
+    #expect(result.userInfo["navigation"] as? String == "target")
+  }
+
+  @Test func `Gateway sound survives enrichment that omits or replaces it`() {
+    let gatewaySound = UNNotificationSound(named: UNNotificationSoundName("gateway.caf"))
+    for enrichedSound in [nil, UNNotificationSound.default] {
+      let enriched = UNMutableNotificationContent()
+      enriched.sound = enrichedSound
+      let result = BuzzNotificationSound.preparing(enriched, originalSound: gatewaySound)
+      #expect(result.sound?.isEqual(gatewaySound) == true)
+    }
+  }
+
+  @Test func `Existing enriched sound survives when gateway supplied none`() {
+    let enriched = UNMutableNotificationContent()
+    let custom = UNNotificationSound(named: UNNotificationSoundName("enriched.caf"))
+    enriched.sound = custom
+    let result = BuzzNotificationSound.preparing(enriched, originalSound: nil)
+    #expect(result.sound?.isEqual(custom) == true)
+  }
+
+  @Test(arguments: [true, false])
+  func `Final handoff applies sound to resolved and restricted content once`(allowed: Bool) {
+    var delivered: [UNNotificationContent] = []
+    let original = UNMutableNotificationContent()
+    let handoff = BuzzNotificationHandoff<UNNotificationContent> { content in
+      delivered.append(BuzzNotificationSound.preparing(content, originalSound: original.sound))
+    }
+    let resolved = UNMutableNotificationContent()
+    resolved.title = "Sender"
+    let fallback = UNMutableNotificationContent()
+    fallback.title = "Buzz"
+    for _ in 0..<2 {
+      handoff.finish(
+        resolved,
+        restrictedFallback: fallback,
+        handoffIfAllowed: { deliver in
+          if allowed { deliver() }
+          return allowed
+        },
+        cleanup: { #expect(delivered.first?.sound != nil) }
+      )
+    }
+    #expect(delivered.count == 1)
+    #expect(delivered.first?.title == (allowed ? "Sender" : "Buzz"))
+    #expect(delivered.first?.sound != nil)
+  }
+
+  @Test func `Expiration receives sound before a late resolution is ignored`() {
+    var delivered: [UNNotificationContent] = []
+    let handoff = BuzzNotificationHandoff<UNNotificationContent> { content in
+      delivered.append(BuzzNotificationSound.preparing(content, originalSound: nil))
+    }
+    for body in ["Reconnect to your relay now", "Resolved message"] {
+      let content = UNMutableNotificationContent()
+      content.body = body
+      handoff.finish(
+        content, restrictedFallback: content,
+        handoffIfAllowed: { deliver in deliver(); return true }, cleanup: {}
+      )
+    }
+    #expect(delivered.count == 1)
+    #expect(delivered.first?.body == "Reconnect to your relay now")
+    #expect(delivered.first?.sound != nil)
+  }
+}
+
+#if os(iOS)
+  import Intents
+
+  extension BuzzNotificationSoundTests {
+    @Test func `Real communication intent update retains the original sound at handoff`() throws {
+      let descriptor = BuzzCommunicationNotificationDescriptor(
+        senderDisplayName: "Alice", senderIdentifier: "sender",
+        senderAvatarPNG: nil, messageBody: "Hello", conversationIdentifier: "conversation",
+        conversationDisplayName: "General", recipientCount: 1
+      )
+      let intent = BuzzCommunicationNotificationPresenter.makeIntent(descriptor)
+      for incomingSound in [nil, UNNotificationSound(named: UNNotificationSoundName("gateway.caf"))] {
+        let original = UNMutableNotificationContent()
+        original.sound = incomingSound
+        let specialized = try original.updating(from: intent)
+        let result = BuzzNotificationSound.preparing(specialized, originalSound: original.sound)
+        if let incomingSound {
+          #expect(result.sound?.isEqual(incomingSound) == true)
+        } else {
+          #expect(result.sound != nil)
+        }
+        #expect(result.title == specialized.title)
+        #expect(result.body == specialized.body)
+      }
+    }
+  }
+#endif

mobile/ios/NotificationService/NotificationService.swift

@@ -100,7 +100,10 @@ final class NotificationService: UNNotificationServiceExtension {
     withContentHandler contentHandler: @escaping (UNNotificationContent) -> Void
   ) {
     resolvedScope = nil
-    handoff = BuzzNotificationHandoff(handler: contentHandler)
+    let originalSound = request.content.sound
+    handoff = BuzzNotificationHandoff { content in
+      contentHandler(BuzzNotificationSound.preparing(content, originalSound: originalSound))
+    }
     restrictedFallbackContent = Self.restrictedFallback(from: request.content)
     guard let content = request.content.mutableCopy() as? UNMutableNotificationContent else {
       finish(request.content)