CallViewController only accesses CallService via the CallUIAdapter

This is an effort to better define boundaries and simplify
relationships.

This also fixes a theoretical problem where CallKit was showing the in-app
call screen before the call was successfully answered, now we wait until
the action is fulfilled.

// FREEBIE

Signal/src/call/CallService.swift

@@ -578,8 +578,6 @@ fileprivate let timeoutSeconds = 60
         let callRecord = TSCall(timestamp: NSDate.ows_millisecondTimeStamp(), withCallNumber: call.remotePhoneNumber, callType: RPRecentCallTypeIncoming, in: thread)
         callRecord.save()
 
-        callUIAdapter.answerCall(call)
-
         let message = DataChannelMessage.forConnected(callId: call.signalingId)
         if peerConnectionClient.sendDataChannelMessage(data: message.asData()) {
             Logger.debug("\(TAG) sendDataChannelMessage returned true")

Signal/src/call/NonCallKitCallUIAdaptee.swift

@@ -48,7 +48,9 @@ class NonCallKitCallUIAdaptee: CallUIAdaptee {
     }
 
     internal func answerCall(_ call: SignalCall) {
-        // NO-OP
+        CallService.signalingQueue.async {
+            self.callService.handleAnswerCall(call)
+        }
     }
 
     internal func declineCall(_ call: SignalCall) {

Signal/src/call/Speakerbox/CallKitCallManager.swift

@@ -5,7 +5,11 @@ import UIKit
 import CallKit
 
 /**
- * Based on SpeakerboxCallManager, from the Apple CallKit Example app. Though, it's responsibilities are mostly mirrored (and delegated from) CallKitCallUIAdaptee.
+ * Requests actions from CallKit
+ *
+ * @Discussion:
+ *   Based on SpeakerboxCallManager, from the Apple CallKit Example app. Though, it's responsibilities are mostly 
+ *   mirrored (and delegated from) CallKitCallUIAdaptee.
  *   TODO: Would it simplify things to merge this into CallKitCallUIAdaptee?
  */
 @available(iOS 10.0, *)
@@ -52,6 +56,14 @@ final class CallKitCallManager: NSObject {
         requestTransaction(transaction)
     }
 
+    func answer(call: SignalCall) {
+        let answerCallAction = CXAnswerCallAction(call: call.localId)
+        let transaction = CXTransaction()
+        transaction.addAction(answerCallAction)
+
+        requestTransaction(transaction)
+    }
+
     private func requestTransaction(_ transaction: CXTransaction) {
         callController.request(transaction) { error in
             if let error = error {

Signal/src/call/Speakerbox/CallKitCallUIAdaptee.swift

@@ -7,10 +7,10 @@ import CallKit
 import AVFoundation
 
 /**
- * Connects user interface to the CallService usin CallKit.
+ * Connects user interface to the CallService using CallKit.
  *
- * User interface is mapped to CXCall action requests, and if the CXProvider accepts them,
- * their corresponding consequences are requested via the CallService
+ * User interface is routed to the CallManager which requests CXCallActions, and if the CXProvider accepts them,
+ * their corresponding consequences are implmented in the CXProviderDelegate methods, e.g. using the CallService
  */
 @available(iOS 10.0, *)
 final class CallKitCallUIAdaptee: NSObject, CallUIAdaptee, CXProviderDelegate {
@@ -84,7 +84,7 @@ final class CallKitCallUIAdaptee: NSObject, CallUIAdaptee, CXProviderDelegate {
     }
 
     internal func answerCall(_ call: SignalCall) {
-        showCall(call)
+        callManager.answer(call: call)
     }
 
     internal func declineCall(_ call: SignalCall) {
@@ -182,14 +182,12 @@ final class CallKitCallUIAdaptee: NSObject, CallUIAdaptee, CXProviderDelegate {
         //        // Trigger the call to be answered via the underlying network service.
         //        call.answerSpeakerboxCall()
 
-        // Synchronous to ensure work is done before call is displayed as "answered"
-        CallService.signalingQueue.sync {
+        CallService.signalingQueue.async {
             self.callService.handleAnswerCall(call)
-        }
-
-        // Signal to the system that the action has been successfully performed.
+            self.showCall(call)
             action.fulfill()
         }
+    }
 
     public func provider(_ provider: CXProvider, perform action: CXEndCallAction) {
         Logger.debug("\(TAG) Received \(#function) CXEndCallAction")

Signal/src/view controllers/CallViewController.swift

@@ -135,7 +135,7 @@ class CallViewController: UIViewController, CallDelegate {
     let TAG = "[CallViewController]"
 
     // Dependencies
-    let callService: CallService
+    
     let callUIAdapter: CallUIAdapter
     let contactsManager: OWSContactsManager
     let audioService: CallAudioService
@@ -165,7 +165,7 @@ class CallViewController: UIViewController, CallDelegate {
 
     required init?(coder aDecoder: NSCoder) {
         contactsManager = Environment.getCurrent().contactsManager
-        callService = Environment.getCurrent().callService
+        let callService = Environment.getCurrent().callService!
         callUIAdapter = callService.callUIAdapter
         audioService = CallAudioService()
         super.init(coder: aDecoder)
@@ -173,7 +173,7 @@ class CallViewController: UIViewController, CallDelegate {
 
     required init() {
         contactsManager = Environment.getCurrent().contactsManager
-        callService = Environment.getCurrent().callService
+        let callService = Environment.getCurrent().callService!
         callUIAdapter = callService.callUIAdapter
         audioService = CallAudioService()
         super.init(nibName: nil, bundle: nil)
@@ -286,7 +286,7 @@ class CallViewController: UIViewController, CallDelegate {
         if let call = self.call {
             callUIAdapter.toggleMute(call: call, isMuted: muteButton.isSelected)
         } else {
-            Logger.warn("\(TAG) hung up, but call was unexpectedly nil")
+            Logger.warn("\(TAG) pressed mute, but call was unexpectedly nil")
         }
     }
 
@@ -308,9 +308,7 @@ class CallViewController: UIViewController, CallDelegate {
             return
         }
 
-        CallService.signalingQueue.async {
-            self.callService.handleAnswerCall(call)
-        }
+        callUIAdapter.answerCall(call)
     }
 
     /**
@@ -338,7 +336,6 @@ class CallViewController: UIViewController, CallDelegate {
     }
 
     internal func muteDidChange(call: SignalCall, isMuted: Bool) {
-        Logger.debug("\(TAG) in \(#function)")
         DispatchQueue.main.async {
             self.muteButton.isSelected = call.isMuted
         }