Improve BLE relay reliability (#665)

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

bitchat/Services/BLEService.swift

@@ -264,7 +264,9 @@ final class BLEService: NSObject {
     // MARK: - Helpers: IDs, selection, and write backpressure
     private func makeMessageID(for packet: BitchatPacket) -> String {
         let senderID = packet.senderID.hexEncodedString()
-        return "\(senderID)-\(packet.timestamp)-\(packet.type)"
+        let digest = SHA256.hash(data: packet.payload)
+        let digestPrefix = digest.prefix(4).map { String(format: "%02x", $0) }.joined()
+        return "\(senderID)-\(packet.timestamp)-\(packet.type)-\(digestPrefix)"
     }
 
     private func subsetSizeForFanout(_ n: Int) -> Int {
@@ -1183,6 +1185,13 @@ final class BLEService: NSObject {
         // Determine last-hop link for this message to avoid echoing back
         let messageID = makeMessageID(for: packet)
         let ingressLink: LinkID? = collectionsQueue.sync { ingressByMessageID[messageID]?.link }
+        let directedPeerHint: String? = {
+            if let explicit = directedOnlyPeer { return explicit }
+            if let recipient = packet.recipientID?.hexEncodedString(), !recipient.isEmpty {
+                return recipient
+            }
+            return nil
+        }()
 
         let states = snapshotPeripheralStates()
         var minCentralWriteLen: Int?
@@ -1236,7 +1245,7 @@ final class BLEService: NSObject {
         // Special-case control/presence messages: do NOT subset to maximize immediate coverage
         var selectedPeripheralIDs = Set(allowedPeripheralIDs)
         var selectedCentralIDs = Set(allowedCentralIDs)
-        if directedOnlyPeer == nil
+        if directedPeerHint == nil
             && packet.type != MessageType.fragment.rawValue
             && packet.type != MessageType.announce.rawValue
             && packet.type != MessageType.requestSync.rawValue {
@@ -1247,7 +1256,7 @@ final class BLEService: NSObject {
         }
 
         // If directed and we currently have no links to forward on, spool for a short window
-        if let only = directedOnlyPeer,
+        if let only = directedPeerHint,
            selectedPeripheralIDs.isEmpty && selectedCentralIDs.isEmpty,
            (packet.type == MessageType.noiseEncrypted.rawValue || packet.type == MessageType.noiseHandshake.rawValue) {
             spoolDirectedPacket(packet, recipientPeerID: only)

bitchat/Services/RelayController.swift

@@ -18,13 +18,17 @@ struct RelayController {
                        isAnnounce: Bool,
                        degree: Int,
                        highDegreeThreshold: Int) -> RelayDecision {
+        let ttlCap = min(ttl, TransportConfig.messageTTLDefault)
+
         // Suppress obvious non-relays
-        if ttl <= 1 || senderIsSelf { return RelayDecision(shouldRelay: false, newTTL: ttl, delayMs: 0) }
+        if ttlCap <= 1 || senderIsSelf {
+            return RelayDecision(shouldRelay: false, newTTL: ttlCap, delayMs: 0)
+        }
 
         // For session-critical or directed traffic, be deterministic and reliable
         if isHandshake || isDirectedFragment || isDirectedEncrypted {
             // Always relay with no TTL cap for these types
-            let newTTL = (ttl &- 1)
+            let newTTL = ttlCap &- 1
             // Slight jitter to desynchronize without adding too much latency
             // Tighter for faster multi-hop handshakes and directed DMs
             let delayRange: ClosedRange<Int> = isHandshake ? 10...35 : 20...60
@@ -32,28 +36,17 @@ struct RelayController {
             return RelayDecision(shouldRelay: true, newTTL: newTTL, delayMs: delayMs)
         }
 
-        // Degree-aware probability to reduce floods in dense graphs (broadcast/public)
-        let baseProb: Double
-        switch degree {
-        case 0...2: baseProb = 1.0
-        case 3...4: baseProb = 0.9
-        case 5...6: baseProb = 0.7
-        case 7...9: baseProb = 0.55
-        default:    baseProb = 0.45
-        }
-        let prob = baseProb
-        let shouldRelay = Double.random(in: 0...1) <= prob
-
         // TTL clamping for broadcast
-        // - Dense graphs: keep very low to avoid floods
-        // - Sparse graphs: allow slightly longer reach for multi-hop discovery
-        // - Announces in sparse graphs get a bit more headroom
-        let ttlCap: UInt8 = {
-            if degree >= highDegreeThreshold { return 3 }
-            return isAnnounce ? 7 : 6
+        // - Dense graphs: keep lower but still allow multi-hop bridging
+        // - Announces get a bit more headroom
+        let ttlLimit: UInt8 = {
+            if degree >= highDegreeThreshold {
+                return max(UInt8(2), min(ttlCap, UInt8(5)))
+            }
+            let preferred = UInt8(isAnnounce ? 7 : 6)
+            return max(UInt8(2), min(ttlCap, preferred))
         }()
-        let clamped = max(1, min(ttl, ttlCap))
-        let newTTL = clamped &- 1
+        let newTTL = ttlLimit &- 1
 
         // Wider jitter window to allow duplicate suppression to win more often
         // For sparse graphs (<=2), relay quickly to avoid cancellation races
@@ -64,6 +57,6 @@ struct RelayController {
         case 6...9: delayMs = Int.random(in: 80...180)
         default:    delayMs = Int.random(in: 100...220)
         }
-        return RelayDecision(shouldRelay: shouldRelay, newTTL: newTTL, delayMs: delayMs)
+        return RelayDecision(shouldRelay: true, newTTL: newTTL, delayMs: delayMs)
     }
 }