handle offer message might come in earlier than pre offer message

Session/Calls/Call Management/SessionCall.swift

@@ -161,6 +161,7 @@ public final class SessionCall: NSObject, WebRTCSessionDelegate {
     }
     
     func didReceiveRemoteSDP(sdp: RTCSessionDescription) {
+        print("[Calls] Did receive remote sdp.")
         remoteSDP = sdp
         if hasStartedConnecting {
             webRTCSession.handleRemoteSDP(sdp, from: sessionID) // This sends an answer message internally

Session/Meta/AppDelegate.swift

@@ -22,17 +22,24 @@ extension AppDelegate {
     
     @objc func setUpCallHandling() {
         // Pre offer messages
-        MessageReceiver.handlePreOfferCallMessage = { (message, transaction) in
+        MessageReceiver.handleNewCallOfferMessageIfNeeded = { (message, transaction) in
             guard CurrentAppContext().isMainApp else { return }
             let callManager = AppEnvironment.shared.callManager
+            // Ignore pre offer message afte the same call instance has been generated
+            if let currentCall = callManager.currentCall, currentCall.uuid == message.uuid! { return }
             guard callManager.currentCall == nil && SSKPreferences.areCallsEnabled else {
                 callManager.handleIncomingCallOfferInBusyOrUnenabledState(offerMessage: message, using: transaction)
                 return
             }
-            DispatchQueue.main.async {
+            // Create incoming call message
+            let thread = TSContactThread.getOrCreateThread(withContactSessionID: message.sender!, transaction: transaction)
+            let tsMessage = TSIncomingMessage.from(message, associatedWith: thread)
+            tsMessage.save(with: transaction)
+            // Handle UI
             if let caller = message.sender, let uuid = message.uuid {
                 let call = SessionCall(for: caller, uuid: uuid, mode: .answer)
                 call.callMessageTimestamp = message.sentTimestamp
+                DispatchQueue.main.async {
                     if CurrentAppContext().isMainAppAndActive {
                         guard let presentingVC = CurrentAppContext().frontmostViewController() else { preconditionFailure() } // TODO: Handle more gracefully
                         if let conversationVC = presentingVC as? ConversationVC, let contactThread = conversationVC.thread as? TSContactThread, contactThread.contactSessionID() == caller {
@@ -51,7 +58,6 @@ extension AppDelegate {
                         }
                     }
                 }
-                
             }
         }
         // Offer messages

SessionMessagingKit/Sending & Receiving/MessageReceiver+Handling.swift

@@ -268,21 +268,11 @@ extension MessageReceiver {
         case .preOffer:
             print("[Calls] Received pre-offer message.")
             let transaction = transaction as! YapDatabaseReadWriteTransaction
-            if SSKPreferences.areCallsEnabled {
-                let storage = SNMessagingKitConfiguration.shared.storage
-                if let threadID = storage.getOrCreateThread(for: message.sender!, groupPublicKey: message.groupPublicKey, openGroupID: nil, using: transaction),
-                    let thread = TSThread.fetch(uniqueId: threadID, transaction: transaction) {
-                    let tsMessage = TSIncomingMessage.from(message, associatedWith: thread)
-                    tsMessage.save(with: transaction)
-                }
-            }
-            handlePreOfferCallMessage?(message, transaction)
+            handleNewCallOfferMessageIfNeeded?(message, transaction)
         case .offer:
             print("[Calls] Received offer message.")
-            if WebRTCSession.current?.uuid != message.uuid! {
-                // TODO: Call in progress, put the new call on hold/reject
-                return
-            }
+            let transaction = transaction as! YapDatabaseReadWriteTransaction
+            handleNewCallOfferMessageIfNeeded?(message, transaction)
             handleOfferCallMessage?(message)
         case .answer:
             print("[Calls] Received answer message.")

SessionMessagingKit/Sending & Receiving/MessageReceiver.swift

@@ -2,7 +2,7 @@ import SessionUtilitiesKit
 
 public enum MessageReceiver {
     private static var lastEncryptionKeyPairRequest: [String:Date] = [:]
-    public static var handlePreOfferCallMessage: ((CallMessage, YapDatabaseReadWriteTransaction) -> Void)?
+    public static var handleNewCallOfferMessageIfNeeded: ((CallMessage, YapDatabaseReadWriteTransaction) -> Void)?
     public static var handleOfferCallMessage: ((CallMessage) -> Void)?
     public static var handleAnswerCallMessage: ((CallMessage) -> Void)?
     public static var handleEndCallMessage: ((CallMessage) -> Void)?