feat: Implement Request Sync Manager (V2 Sync) (#965)

* feat: Implement Request Sync Manager (V2 Sync)

- Add RequestSyncManager to track and attribute sync requests
- Update BitchatPacket and BinaryProtocol to support IS_RSR flag (0x10)
- Update RequestSyncPacket with new TLV fields (sinceTimestamp, fragmentIdFilter)
- Update GossipSyncManager to use unicast sync requests and mark responses as RSR
- Update BLEService to enforce timestamp validation for normal packets and exempt valid RSRs
- Add documentation for the new sync manager mechanism

* fix: Resolve compilation errors in V2 Sync implementation

- Remove duplicate restartGossipManager in BLEService
- Add missing TransportConfig constants for sync
- Add 'sync' log category to BitLogger
- Add missing BitLogger import in GossipSyncManager

* fix: Update tests for V2 Sync changes

- Add requestSyncManager parameter to GossipSyncManager init in tests
- Implement getConnectedPeers stub in RecordingDelegate
- Remove unused variable warning in SubscriptionRateLimitTests

---------

Co-authored-by: a1denvalu3 <>
Co-authored-by: jack <212554440+jackjackbits@users.noreply.github.com>

bitchat/Models/BitchatPacket.swift

@@ -22,8 +22,9 @@ struct BitchatPacket: Codable {
     var signature: Data?
     var ttl: UInt8
     var route: [Data]?
+    var isRSR: Bool
     
-    init(type: UInt8, senderID: Data, recipientID: Data?, timestamp: UInt64, payload: Data, signature: Data?, ttl: UInt8, version: UInt8 = 1, route: [Data]? = nil) {
+    init(type: UInt8, senderID: Data, recipientID: Data?, timestamp: UInt64, payload: Data, signature: Data?, ttl: UInt8, version: UInt8 = 1, route: [Data]? = nil, isRSR: Bool = false) {
         self.version = version
         self.type = type
         self.senderID = senderID
@@ -33,10 +34,11 @@ struct BitchatPacket: Codable {
         self.signature = signature
         self.ttl = ttl
         self.route = route
+        self.isRSR = isRSR
     }
     
     // Convenience initializer for new binary format
-    init(type: UInt8, ttl: UInt8, senderID: PeerID, payload: Data) {
+    init(type: UInt8, ttl: UInt8, senderID: PeerID, payload: Data, isRSR: Bool = false) {
         self.version = 1
         self.type = type
         // Convert hex string peer ID to binary data (8 bytes)
@@ -56,6 +58,7 @@ struct BitchatPacket: Codable {
         self.signature = nil
         self.ttl = ttl
         self.route = nil
+        self.isRSR = isRSR
     }
     
     var data: Data? {
@@ -85,7 +88,8 @@ struct BitchatPacket: Codable {
             signature: nil, // Remove signature for signing
             ttl: 0, // Use fixed TTL=0 for signing to ensure relay compatibility
             version: version,
-            route: route
+            route: route,
+            isRSR: false // RSR flag is mutable and not part of the signature
         )
         return BinaryProtocol.encode(unsignedPacket)
     }

bitchat/Models/RequestSyncPacket.swift

@@ -9,12 +9,16 @@ struct RequestSyncPacket {
     let m: UInt32
     let data: Data
     let types: SyncTypeFlags?
+    let sinceTimestamp: UInt64?
+    let fragmentIdFilter: String?
 
-    init(p: Int, m: UInt32, data: Data, types: SyncTypeFlags? = nil) {
+    init(p: Int, m: UInt32, data: Data, types: SyncTypeFlags? = nil, sinceTimestamp: UInt64? = nil, fragmentIdFilter: String? = nil) {
         self.p = p
         self.m = m
         self.data = data
         self.types = types
+        self.sinceTimestamp = sinceTimestamp
+        self.fragmentIdFilter = fragmentIdFilter
     }
 
     func encode() -> Data {
@@ -36,15 +40,24 @@ struct RequestSyncPacket {
         if let typesData = types?.toData() {
             putTLV(0x04, typesData)
         }
+        if let ts = sinceTimestamp {
+            var tsBE = ts.bigEndian
+            putTLV(0x05, withUnsafeBytes(of: &tsBE) { Data($0) })
+        }
+        if let fid = fragmentIdFilter, let fidData = fid.data(using: .utf8) {
+            putTLV(0x06, fidData)
+        }
         return out
     }
-
+    
     static func decode(from data: Data, maxAcceptBytes: Int = 1024) -> RequestSyncPacket? {
         var off = 0
         var p: Int? = nil
         var m: UInt32? = nil
         var payload: Data? = nil
         var types: SyncTypeFlags? = nil
+        var sinceTimestamp: UInt64? = nil
+        var fragmentIdFilter: String? = nil
 
         while off + 3 <= data.count {
             let t = Int(data[off]); off += 1
@@ -68,12 +81,22 @@ struct RequestSyncPacket {
                 if let decoded = SyncTypeFlags.decode(v) {
                     types = decoded
                 }
+            case 0x05:
+                if v.count == 8 {
+                    var ts: UInt64 = 0
+                    for b in v { ts = (ts << 8) | UInt64(b) }
+                    sinceTimestamp = ts
+                }
+            case 0x06:
+                if let fid = String(data: v, encoding: .utf8) {
+                    fragmentIdFilter = fid
+                }
             default:
                 break // forward compatible; ignore unknown TLVs
             }
         }
 
         guard let pp = p, let mm = m, let dd = payload, pp >= 1, mm > 0 else { return nil }
-        return RequestSyncPacket(p: pp, m: mm, data: dd, types: types)
+        return RequestSyncPacket(p: pp, m: mm, data: dd, types: types, sinceTimestamp: sinceTimestamp, fragmentIdFilter: fragmentIdFilter)
     }
 }