feat(healthchat): ring calls via gateway VoIP push

CallKit rejects the NSE hand-off without the filtering entitlement.

ElementX/Sources/Services/ElementCall/ElementCallService.swift

@@ -32,6 +32,7 @@ class ElementCallService: NSObject, ElementCallServiceProtocol, PKPushRegistryDe
     private let callController = CXCallController()
     private let callProvider: CXProviderProtocol
     private let timeProvider: TimeProvider
+    private let appSettings: AppSettings
     
     private weak var clientProxy: ClientProxyProtocol? {
         didSet {
@@ -67,10 +68,11 @@ class ElementCallService: NSObject, ElementCallServiceProtocol, PKPushRegistryDe
     
     private var declineListenerHandle: TaskHandle?
     
-    init(callProvider: CXProviderProtocol? = nil, timeProvider: TimeProvider? = nil) {
+    init(callProvider: CXProviderProtocol? = nil, timeProvider: TimeProvider? = nil, appSettings: AppSettings) {
         pushRegistry = PKPushRegistry(queue: nil)
         
         self.timeProvider = timeProvider ?? TimeProvider(clock: ContinuousClock(), now: Date.init)
+        self.appSettings = appSettings
         
         if let callProvider {
             self.callProvider = callProvider
@@ -157,7 +159,16 @@ class ElementCallService: NSObject, ElementCallServiceProtocol, PKPushRegistryDe
     
     // MARK: - PKPushRegistryDelegate
     
-    func pushRegistry(_ registry: PKPushRegistry, didUpdate pushCredentials: PKPushCredentials, for type: PKPushType) { }
+    func pushRegistry(_ registry: PKPushRegistry, didUpdate pushCredentials: PKPushCredentials, for type: PKPushType) {
+        // HealthChat: stored for the NSE, which requests a VoIP push through the push gateway
+        // for ringing calls as long as the notification filtering entitlement is missing.
+        appSettings.pushKitDeviceToken = pushCredentials.token.base64EncodedString()
+        appSettings.voipPushGatewayNotifyURL = appSettings.pushGatewayNotifyEndpoint.absoluteString
+    }
+    
+    func pushRegistry(_ registry: PKPushRegistry, didInvalidatePushTokenFor type: PKPushType) {
+        appSettings.pushKitDeviceToken = nil
+    }
     
     func pushRegistry(_ registry: PKPushRegistry, didReceiveIncomingPushWith payload: PKPushPayload, for type: PKPushType, completion: @escaping () -> Void) {
         guard let roomID = payload.dictionaryPayload[ElementCallServiceNotificationKey.roomID.rawValue] as? String else {
@@ -189,7 +200,7 @@ class ElementCallService: NSObject, ElementCallServiceProtocol, PKPushRegistryDe
         let callID = CallID(callKitID: UUID(), roomID: roomID, rtcNotificationID: rtcNotificationID, isVoiceCall: isVoiceCall)
         incomingCallID = callID
         
-        guard let expirationDate = (payload.dictionaryPayload[ElementCallServiceNotificationKey.expirationDate.rawValue] as? Date) else {
+        guard let expirationDate = Self.expirationDate(from: payload.dictionaryPayload) else {
             MXLog.error("Something went wrong, missing expiration timestamp for incoming voip call: \(payload)")
             assertionFailure("Incoming voip push is missing the expiration timestamp")
             clearIncomingCallState()
@@ -353,6 +364,19 @@ class ElementCallService: NSObject, ElementCallServiceProtocol, PKPushRegistryDe
     /// a call and immediately end it. `callerInfo` names the call after the room so the brief
     /// system UI and the Recents entry show the room rather than "Unknown", and the entry can be
     /// tapped to call back.
+    /// CallKit hands the NSE's payload over as-is, so the expiration arrives as a `Date`. A VoIP push
+    /// requested from the push gateway travels as JSON, where the same key is seconds since 1970.
+    private static func expirationDate(from payload: [AnyHashable: Any]) -> Date? {
+        switch payload[ElementCallServiceNotificationKey.expirationDate.rawValue] {
+        case let date as Date:
+            date
+        case let secondsSince1970 as TimeInterval:
+            Date(timeIntervalSince1970: secondsSince1970)
+        default:
+            nil
+        }
+    }
+    
     private func reportImmediatelyEndedCall(reason: CXCallEndedReason,
                                             callerInfo: (roomID: String, roomDisplayName: String?)? = nil,
                                             completion: @escaping () -> Void) {