Added P2P pinging logic.

SignalServiceKit/src/Loki/API/LokiAPI+P2P.swift

@@ -1,10 +1,72 @@
 
 extension LokiAPI {
+    
     private static let messageSender: MessageSender = SSKEnvironment.shared.messageSender
+    
+    /// A p2p state struct
+    internal struct P2PDetails {
+        var address: String
+        var port: UInt32
+        var isOnline: Bool
+        var timerDuration: Double
+        var pingTimer: WeakTimer? = nil
+        
+        var target: Target {
+            return Target(address: address, port: port)
+        }
+    }
+    
     internal static var ourP2PAddress: Target? = nil
     
     /// This is where we store the p2p details of our contacts
-    internal static var contactP2PDetails = [String: Target]()
+    internal static var contactP2PDetails = [String: P2PDetails]()
+    
+    /// Handle P2P logic when we receive a `LokiAddressMessage`
+    ///
+    /// - Parameters:
+    ///   - pubKey: The other users pubKey
+    ///   - address: The pther users p2p address
+    ///   - port: The other users p2p port
+    ///   - receivedThroughP2P: Wether we received the message through p2p
+    @objc public static func didReceiveLokiAddressMessage(forContact pubKey: String, address: String, port: UInt32, receivedThroughP2P: Bool) {
+        // Stagger the ping timers so that contacts don't ping each other at the same time
+        let timerDuration = pubKey < ourHexEncodedPubKey ? 1 * kMinuteInterval : 2 * kMinuteInterval
+        
+        // Get out current contact details
+        let oldContactDetails = contactP2PDetails[pubKey]
+        
+        // Set the new contact details
+        // A contact is always assumed to be offline unless the specific conditions below are met
+        let details = P2PDetails(address: address, port: port, isOnline: false, timerDuration: timerDuration, pingTimer: nil)
+        
+        // Set up our checks
+        let oldContactExists = oldContactDetails != nil
+        let wasOnline = oldContactDetails?.isOnline ?? false
+        let p2pDetailsMatch = oldContactDetails?.address == address && oldContactDetails?.port == port
+        
+        /*
+         We need to check if we should ping the user.
+         We don't ping the user IF:
+            - We had old contact details
+            - We got a P2P message
+            - The old contact was set as `Online`
+            - The new p2p details match the old one
+         */
+        if oldContactExists && receivedThroughP2P && wasOnline && p2pDetailsMatch {
+            // TODO: Set contact to online and start the ping timers
+            return;
+        }
+        
+        /*
+         Ping the contact.
+         This happens in the following scenarios:
+            1. We didn't have the contact, we need to ping them to let them know our details.
+            2. wasP2PMessage = false, so we assume the contact doesn't have our details.
+            3. We had the contact marked as offline, we need to make sure that we can reach their server.
+            4. The other contact details have changed, we need to make sure that we can reach their new server.
+         */
+        // TODO: Ping the contact
+    }
     
     /// Set the Contact p2p details
     ///
@@ -13,8 +75,8 @@ extension LokiAPI {
     ///   - address: The contacts p2p address
     ///   - port: The contacts p2p port
     @objc public static func setContactP2PDetails(forContact pubKey: String, address: String, port: UInt32) {
-         let target = Target(address: address, port: port)
-        contactP2PDetails[pubKey] = target
+        let details = P2PDetails(address: address, port: port, isOnline: false, timerDuration: 10, pingTimer: nil)
+        contactP2PDetails[pubKey] = details
     }
     
     /// Set our local P2P address

SignalServiceKit/src/Loki/API/LokiAPI.swift

@@ -87,7 +87,7 @@ import PromiseKit
         // TODO: probably only send to p2p if user is online or we are pinging them
         // p2pDetails && (isPing || peerIsOnline)
         if let p2pDetails = contactP2PDetails[destination] {
-            let targets = Promise.wrap([p2pDetails])
+            let targets = Promise.wrap([p2pDetails.target])
             return sendMessage(message, targets: targets).recover { _ in return sendThroughStorageServer() }
         }
         

SignalServiceKit/src/Messages/OWSMessageManager.m

@@ -435,7 +435,9 @@ NS_ASSUME_NONNULL_BEGIN
         
         // Loki: Check if we got p2p address
         if (contentProto.lokiAddressMessage) {
-            [LokiAPI setContactP2PDetailsForContact:envelope.source address:contentProto.lokiAddressMessage.ptpAddress port:contentProto.lokiAddressMessage.ptpPort];
+            NSString *address = contentProto.lokiAddressMessage.ptpAddress;
+            uint32_t port = contentProto.lokiAddressMessage.ptpPort;
+            [LokiAPI didReceiveLokiAddressMessageForContact:envelope.source address:address port:port receivedThroughP2P:envelope.isPtpMessage]
         }
 
         if (contentProto.syncMessage) {