Improve background BLE stability and nearby alerts (#864)

* Harden background BLE restoration and notifications

* Guard BLE restoration paths to iOS

---------

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

bitchat.xcodeproj/xcshareddata/xcschemes/bitchat (iOS).xcscheme

@@ -98,8 +98,8 @@
       </BuildableProductRunnable>
       <EnvironmentVariables>
          <EnvironmentVariable
-            key = "-DBITCHAT_DEV_ALLOW_CLEARNET"
-            value = ""
+            key = "BITCHAT_LOG_LEVEL"
+            value = "debug"
             isEnabled = "YES">
          </EnvironmentVariable>
       </EnvironmentVariables>

bitchat/BitchatApp.swift

@@ -246,7 +246,7 @@ final class NotificationDelegate: NSObject, UNUserNotificationCenterDelegate {
             // Get peer ID from userInfo
             if let peerID = userInfo["peerID"] as? String {
                 // Don't show notification if the private chat is already open
-                if chatViewModel?.selectedPrivateChatPeer == peerID {
+                if chatViewModel?.selectedPrivateChatPeer == PeerID(str: peerID) {
                     completionHandler([])
                     return
                 }

bitchat/Features/media/ImageUtils.swift

@@ -13,10 +13,10 @@ enum ImageUtilsError: Error {
 }
 
 enum ImageUtils {
-    private static let compressionQuality: CGFloat = 0.85
-    private static let targetImageBytes: Int = 60_000
+    private static let compressionQuality: CGFloat = 0.82
+    private static let targetImageBytes: Int = 45_000
 
-    static func processImage(at url: URL, maxDimension: CGFloat = 512) throws -> URL {
+    static func processImage(at url: URL, maxDimension: CGFloat = 448) throws -> URL {
         // Security H1: Check file size BEFORE reading into memory
         let attrs = try FileManager.default.attributesOfItem(atPath: url.path)
         guard let fileSize = attrs[.size] as? Int else {
@@ -38,7 +38,7 @@ enum ImageUtils {
     }
 
     #if os(iOS)
-    static func processImage(_ image: UIImage, maxDimension: CGFloat = 512) throws -> URL {
+    static func processImage(_ image: UIImage, maxDimension: CGFloat = 448) throws -> URL {
         return try autoreleasepool {
             // Scale the image first
             let scaled = scaledImage(image, maxDimension: maxDimension)
@@ -106,7 +106,7 @@ enum ImageUtils {
         return data as Data
     }
     #else
-    static func processImage(_ image: NSImage, maxDimension: CGFloat = 512) throws -> URL {
+    static func processImage(_ image: NSImage, maxDimension: CGFloat = 448) throws -> URL {
         return try autoreleasepool {
             let scaled = scaledImage(image, maxDimension: maxDimension)
             guard let inputCG = scaled.cgImage(forProposedRect: nil, context: nil, hints: nil) else {

bitchat/Features/voice/VoiceRecorder.swift

@@ -14,6 +14,7 @@ final class VoiceRecorder: NSObject, AVAudioRecorderDelegate {
 
     private let queue = DispatchQueue(label: "com.bitchat.voice-recorder")
     private let paddingInterval: TimeInterval = 0.5
+    private let maxRecordingDuration: TimeInterval = 120
 
     private var recorder: AVAudioRecorder?
     private var currentURL: URL?
@@ -75,14 +76,14 @@ final class VoiceRecorder: NSObject, AVAudioRecorderDelegate {
                 AVFormatIDKey: kAudioFormatMPEG4AAC,
                 AVSampleRateKey: 16_000,
                 AVNumberOfChannelsKey: 1,
-                AVEncoderBitRateKey: 20_000
+                AVEncoderBitRateKey: 16_000
             ]
 
             let audioRecorder = try AVAudioRecorder(url: outputURL, settings: settings)
             audioRecorder.delegate = self
             audioRecorder.isMeteringEnabled = true
             audioRecorder.prepareToRecord()
-            audioRecorder.record()
+            audioRecorder.record(forDuration: maxRecordingDuration)
 
             recorder = audioRecorder
             currentURL = outputURL

bitchat/Models/PeerID.swift

@@ -35,7 +35,7 @@ struct PeerID: Equatable, Hashable {
     // Private so the callers have to go through a convenience init
     private init(prefix: Prefix, bare: any StringProtocol) {
         self.prefix = prefix
-        self.bare = String(bare)
+        self.bare = String(bare).lowercased()
     }
 }
 
@@ -76,6 +76,12 @@ extension PeerID {
     init(hexData: Data) {
         self.init(str: hexData.hexEncodedString())
     }
+    
+    /// Convenience init to "hide" hex-encoding implementation detail
+    init?(hexData: Data?) {
+        guard let hexData else { return nil }
+        self.init(hexData: hexData)
+    }
 }
 
 // MARK: - Noise Public Key Helpers
@@ -191,9 +197,7 @@ extension PeerID: Comparable {
     }
 }
 
-// MARK: - String Interop Helpers
-
-// MARK: CustomStringConvertible
+// MARK: - CustomStringConvertible
 
 extension PeerID: CustomStringConvertible {
     /// So it returns the actual `id` like before even inside another String
@@ -201,17 +205,3 @@ extension PeerID: CustomStringConvertible {
         id
     }
 }
-
-// MARK: Custom Equatable w/ String & Optionality
-
-// PeerID <> String
-extension Optional where Wrapped == PeerID {
-    static func ==(lhs: Optional<Wrapped>, rhs: Optional<String>) -> Bool   { lhs?.id == rhs }
-    static func !=(lhs: Optional<Wrapped>, rhs: Optional<String>) -> Bool   { lhs?.id != rhs }
-}
-
-// String <> PeerID
-extension Optional where Wrapped == String {
-    static func ==(lhs: Optional<Wrapped>, rhs: Optional<PeerID>) -> Bool   { lhs == rhs?.id }
-    static func !=(lhs: Optional<Wrapped>, rhs: Optional<PeerID>) -> Bool   { lhs != rhs?.id }
-}

bitchat/Models/RequestSyncPacket.swift

@@ -8,6 +8,14 @@ struct RequestSyncPacket {
     let p: Int
     let m: UInt32
     let data: Data
+    let types: SyncTypeFlags?
+
+    init(p: Int, m: UInt32, data: Data, types: SyncTypeFlags? = nil) {
+        self.p = p
+        self.m = m
+        self.data = data
+        self.types = types
+    }
 
     func encode() -> Data {
         var out = Data()
@@ -25,6 +33,9 @@ struct RequestSyncPacket {
         putTLV(0x02, withUnsafeBytes(of: &mBE) { Data($0) })
         // data
         putTLV(0x03, data)
+        if let typesData = types?.toData() {
+            putTLV(0x04, typesData)
+        }
         return out
     }
 
@@ -33,6 +44,7 @@ struct RequestSyncPacket {
         var p: Int? = nil
         var m: UInt32? = nil
         var payload: Data? = nil
+        var types: SyncTypeFlags? = nil
 
         while off + 3 <= data.count {
             let t = Int(data[off]); off += 1
@@ -52,12 +64,16 @@ struct RequestSyncPacket {
             case 0x03:
                 if v.count > maxAcceptBytes { return nil }
                 payload = v
+            case 0x04:
+                if let decoded = SyncTypeFlags.decode(v) {
+                    types = decoded
+                }
             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)
+        return RequestSyncPacket(p: pp, m: mm, data: dd, types: types)
     }
 }

bitchat/Nostr/GeoRelayDirectory.swift

@@ -284,7 +284,10 @@ final class GeoRelayDirectory {
             object: nil,
             queue: .main
         ) { [weak self] _ in
-            self?.prefetchIfNeeded(force: true)
+            guard let self else { return }
+            Task { @MainActor in
+                self.prefetchIfNeeded(force: true)
+            }
         }
         observers.append(torReady)
 
@@ -294,7 +297,10 @@ final class GeoRelayDirectory {
             object: nil,
             queue: .main
         ) { [weak self] _ in
-            self?.prefetchIfNeeded()
+            guard let self else { return }
+            Task { @MainActor in
+                self.prefetchIfNeeded()
+            }
         }
         observers.append(didBecomeActive)
 #elseif os(macOS)
@@ -303,7 +309,10 @@ final class GeoRelayDirectory {
             object: nil,
             queue: .main
         ) { [weak self] _ in
-            self?.prefetchIfNeeded()
+            guard let self else { return }
+            Task { @MainActor in
+                self.prefetchIfNeeded()
+            }
         }
         observers.append(didBecomeActive)
 #endif

bitchat/Protocols/BitchatProtocol.swift

@@ -178,7 +178,7 @@ protocol BitchatDelegate: AnyObject {
 
     // Bluetooth state updates for user notifications
     func didUpdateBluetoothState(_ state: CBManagerState)
-    func didReceivePublicMessage(from peerID: PeerID, nickname: String, content: String, timestamp: Date)
+    func didReceivePublicMessage(from peerID: PeerID, nickname: String, content: String, timestamp: Date, messageID: String?)
 }
 
 // Provide default implementation to make it effectively optional
@@ -195,7 +195,7 @@ extension BitchatDelegate {
         // Default empty implementation
     }
 
-    func didReceivePublicMessage(from peerID: PeerID, nickname: String, content: String, timestamp: Date) {
+    func didReceivePublicMessage(from peerID: PeerID, nickname: String, content: String, timestamp: Date, messageID: String?) {
         // Default empty implementation
     }
 }

bitchat/Services/BLE/MimeType.swift

@@ -0,0 +1,195 @@
+//
+// MimeType.swift
+// bitchat
+//
+// This is free and unencumbered software released into the public domain.
+// For more information, see <https://unlicense.org>
+//
+
+import UniformTypeIdentifiers
+
+// MARK: - Extensions for missing UTTypes
+
+extension UTType {
+    static let webP = UTType(importedAs: "image/webp")
+    static let aac  = UTType(importedAs: "audio/aac")
+    static let m4a  = UTType(importedAs: "audio/m4a")
+    static let ogg  = UTType(importedAs: "audio/ogg")
+}
+
+// MARK: - MimeType Enum
+
+enum MimeType: CaseIterable, Hashable {
+    case jpeg
+    case jpg
+    case png
+    case gif
+    case webp
+    case mp4Audio
+    case m4a
+    case aac
+    case mpeg
+    case mp3
+    case wav
+    case xWav
+    case ogg
+    case pdf
+    case octetStream
+
+    var utType: UTType {
+        switch self {
+        case .jpeg, .jpg:   .jpeg
+        case .png:          .png
+        case .gif:          .gif
+        case .webp:         .webP
+        case .aac:          .aac
+        case .m4a:          .m4a
+        case .mp4Audio:     .mpeg4Audio
+        case .mp3, .mpeg:   .mp3
+        case .wav, .xWav:   .wav
+        case .ogg:          .ogg
+        case .pdf:          .pdf
+        case .octetStream:  .data
+        }
+    }
+    
+    var category: Category {
+        switch self {
+        case .jpeg, .jpg, .png, .gif, .webp:
+            return .image
+        case .aac, .m4a, .mp4Audio, .mpeg, .mp3, .wav, .xWav, .ogg:
+            return .audio
+        case .pdf, .octetStream:
+            return .file
+        }
+    }
+
+
+    var mimeString: String {
+        switch self {
+        case .jpeg, .jpg:   "image/jpeg"
+        case .png:          "image/png"
+        case .gif:          "image/gif"
+        case .webp:         "image/webp"
+        case .mp4Audio:     "audio/mp4"
+        case .m4a:          "audio/m4a"
+        case .aac:          "audio/aac"
+        case .mpeg:         "audio/mpeg"
+        case .mp3:          "audio/mp3"
+        case .wav:          "audio/wav"
+        case .xWav:         "audio/x-wav"
+        case .ogg:          "audio/ogg"
+        case .pdf:          "application/pdf"
+        case .octetStream:  "application/octet-stream"
+        }
+    }
+    
+    var defaultExtension: String {
+        switch self {
+        case .jpeg, .jpg:           "jpg"
+        case .png:                  "png"
+        case .webp:                 "webp"
+        case .gif:                  "gif"
+        case .mp4Audio, .m4a, .aac: "m4a"
+        case .mpeg, .mp3:           "mp3"
+        case .wav, .xWav:           "wav"
+        case .ogg:                  "ogg"
+        case .pdf:                  "pdf"
+        case .octetStream:          "bin"
+        }
+    }
+
+    static var allowed: Set<MimeType> = [
+        .jpeg, .jpg, .png, .gif, .webp,
+        .mp4Audio, .m4a, .aac, .mpeg, .mp3,
+        .wav, .xWav, .ogg,
+        .pdf, .octetStream
+    ]
+
+    var isAllowed: Bool {
+        Self.allowed.contains(self)
+    }
+
+    // MARK: - Byte signature validation
+    func matches(data: Data) -> Bool {
+        guard !data.isEmpty else { return false }
+
+        // Generic type → skip validation
+        if self == .octetStream { return true }
+
+        switch self {
+        case .jpeg, .jpg:
+            return data.count >= 3 && data[0] == 0xFF && data[1] == 0xD8 && data[2] == 0xFF
+
+        case .png:
+            return data.count >= 8 &&
+                   data[0] == 0x89 && data[1] == 0x50 && data[2] == 0x4E && data[3] == 0x47 &&
+                   data[4] == 0x0D && data[5] == 0x0A && data[6] == 0x1A && data[7] == 0x0A
+
+        case .gif:
+            return data.count >= 6 && data[0] == 0x47 && data[1] == 0x49 && data[2] == 0x46 &&
+                   data[3] == 0x38 && (data[4] == 0x37 || data[4] == 0x39) && data[5] == 0x61
+
+        case .webp:
+            return data.count >= 12 &&
+                   data[0] == 0x52 && data[1] == 0x49 && data[2] == 0x46 && data[3] == 0x46 &&
+                   data[8] == 0x57 && data[9] == 0x45 && data[10] == 0x42 && data[11] == 0x50
+
+        case .m4a, .mp4Audio, .aac:
+            // AVAudioRecorder output varies by platform - be lenient
+            // Security: size already capped + sandboxed execution
+            return data.count > 100
+
+        case .mpeg, .mp3:
+            if data.count >= 3 && data[0] == 0x49 && data[1] == 0x44 && data[2] == 0x33 {
+                return true // ID3 header
+            }
+            return data.count >= 2 && data[0] == 0xFF && (data[1] & 0xE0) == 0xE0
+
+        case .wav, .xWav:
+            return data.count >= 12 &&
+                   data[0] == 0x52 && data[1] == 0x49 && data[2] == 0x46 && data[3] == 0x46 &&
+                   data[8] == 0x57 && data[9] == 0x41 && data[10] == 0x56 && data[11] == 0x45
+
+        case .ogg:
+            return data.count >= 4 &&
+                   data[0] == 0x4F && data[1] == 0x67 && data[2] == 0x67 && data[3] == 0x53
+
+        case .pdf:
+            return data.count >= 4 &&
+                   data[0] == 0x25 && data[1] == 0x50 && data[2] == 0x44 && data[3] == 0x46
+
+        default:
+            return false
+        }
+    }
+
+    // MARK: - Convenience Initializers
+
+    init?(_ mimeString: String?) {
+        guard let mimeString else { return nil }
+        
+        let normalized = mimeString.lowercased()
+
+        // Direct match with our canonical list
+        if let match = MimeType.allCases.first(where: { $0.mimeString == normalized }) {
+            self = match
+            return
+        }
+
+        // Let UTType normalize aliases like "image/jpg", "audio/x-wav", etc.
+        if let type = UTType(mimeType: normalized),
+           let match = MimeType.allCases.first(where: { type.conforms(to: $0.utType) }) {
+            self = match
+            return
+        }
+
+        return nil
+    }
+}
+
+extension MimeType {
+    enum Category: String {
+        case audio, image, file
+    }
+}

bitchat/Services/NoiseEncryptionService.swift

@@ -177,18 +177,18 @@ final class NoiseEncryptionService {
     private let rekeyCheckInterval: TimeInterval = 60.0 // Check every minute
     
     // Callbacks
-    private var onPeerAuthenticatedHandlers: [((String, String) -> Void)] = [] // Array of handlers for peer authentication
+    private var onPeerAuthenticatedHandlers: [((PeerID, String) -> Void)] = [] // Array of handlers for peer authentication
     var onHandshakeRequired: ((PeerID) -> Void)? // peerID needs handshake
     
     // Add a handler for peer authentication
-    func addOnPeerAuthenticatedHandler(_ handler: @escaping (String, String) -> Void) {
+    func addOnPeerAuthenticatedHandler(_ handler: @escaping (PeerID, String) -> Void) {
         serviceQueue.async(flags: .barrier) { [weak self] in
             self?.onPeerAuthenticatedHandlers.append(handler)
         }
     }
     
     // Legacy support - setting this will add to the handlers array
-    var onPeerAuthenticated: ((String, String) -> Void)? {
+    var onPeerAuthenticated: ((PeerID, String) -> Void)? {
         get { nil } // Always return nil for backward compatibility
         set {
             if let handler = newValue {
@@ -546,7 +546,7 @@ final class NoiseEncryptionService {
         // Notify all handlers about authentication
         serviceQueue.async { [weak self] in
             self?.onPeerAuthenticatedHandlers.forEach { handler in
-                handler(peerID.id, fingerprint)
+                handler(peerID, fingerprint)
             }
         }
     }

bitchat/Services/NotificationService.swift

@@ -29,28 +29,30 @@ final class NotificationService {
         }
     }
     
-    func sendLocalNotification(title: String, body: String, identifier: String, userInfo: [String: Any]? = nil) {
-        // For now, skip app state check entirely to avoid thread issues
-        // The NotificationDelegate will handle foreground presentation
-        DispatchQueue.main.async {
-            let content = UNMutableNotificationContent()
-            content.title = title
-            content.body = body
-            content.sound = .default
-            if let userInfo = userInfo {
-                content.userInfo = userInfo
-            }
-            
-            let request = UNNotificationRequest(
-                identifier: identifier,
-                content: content,
-                trigger: nil // Deliver immediately
-            )
-            
-            UNUserNotificationCenter.current().add(request) { _ in
-                // Notification added
-            }
+    func sendLocalNotification(
+        title: String,
+        body: String,
+        identifier: String,
+        userInfo: [String: Any]? = nil,
+        interruptionLevel: UNNotificationInterruptionLevel = .active
+    ) {
+        let content = UNMutableNotificationContent()
+        content.title = title
+        content.body = body
+        content.sound = .default
+        content.interruptionLevel = interruptionLevel
+
+        if let userInfo = userInfo {
+            content.userInfo = userInfo
         }
+
+        let request = UNNotificationRequest(
+            identifier: identifier,
+            content: content,
+            trigger: nil // Deliver immediately
+        )
+
+        UNUserNotificationCenter.current().add(request)
     }
     
     func sendMentionNotification(from sender: String, message: String) {
@@ -61,11 +63,11 @@ final class NotificationService {
         sendLocalNotification(title: title, body: body, identifier: identifier)
     }
     
-    func sendPrivateMessageNotification(from sender: String, message: String, peerID: String) {
+    func sendPrivateMessageNotification(from sender: String, message: String, peerID: PeerID) {
         let title = "🔒 DM from \(sender)"
         let body = message
         let identifier = "private-\(UUID().uuidString)"
-        let userInfo = ["peerID": peerID, "senderName": sender]
+        let userInfo = ["peerID": peerID.id, "senderName": sender]
         
         sendLocalNotification(title: title, body: body, identifier: identifier, userInfo: userInfo)
     }
@@ -83,25 +85,12 @@ final class NotificationService {
         let title = "👥 bitchatters nearby!"
         let body = peerCount == 1 ? "1 person around" : "\(peerCount) people around"
         let identifier = "network-available-\(Date().timeIntervalSince1970)"
-        
-        // For network notifications, we want to show them even in foreground
-        // No app state check - let the notification delegate handle presentation
-        DispatchQueue.main.async {
-            let content = UNMutableNotificationContent()
-            content.title = title
-            content.body = body
-            content.sound = .default
-            content.interruptionLevel = .timeSensitive  // Make it more prominent
-            
-            let request = UNNotificationRequest(
-                identifier: identifier,
-                content: content,
-                trigger: nil // Deliver immediately
-            )
-            
-            UNUserNotificationCenter.current().add(request) { _ in
-                // Notification added
-            }
-        }
+
+        sendLocalNotification(
+            title: title,
+            body: body,
+            identifier: identifier,
+            interruptionLevel: .timeSensitive
+        )
     }
 }

bitchat/Services/RelayController.swift

@@ -13,6 +13,7 @@ struct RelayController {
                        senderIsSelf: Bool,
                        isEncrypted: Bool,
                        isDirectedEncrypted: Bool,
+                       isFragment: Bool,
                        isDirectedFragment: Bool,
                        isHandshake: Bool,
                        isAnnounce: Bool,
@@ -36,6 +37,16 @@ struct RelayController {
             return RelayDecision(shouldRelay: true, newTTL: newTTL, delayMs: delayMs)
         }
 
+        if isFragment {
+            let ttlLimit = min(ttlCap, TransportConfig.bleFragmentRelayTtlCap)
+            guard ttlLimit > 1 else {
+                return RelayDecision(shouldRelay: false, newTTL: ttlLimit, delayMs: 0)
+            }
+            let newTTL = ttlLimit &- 1
+            let delayMs = Int.random(in: TransportConfig.bleFragmentRelayMinDelayMs...TransportConfig.bleFragmentRelayMaxDelayMs)
+            return RelayDecision(shouldRelay: true, newTTL: newTTL, delayMs: delayMs)
+        }
+
         // TTL clamping for broadcast
         // - Dense graphs: keep lower but still allow multi-hop bridging
         // - Announces get a bit more headroom

bitchat/Services/Transport.swift

@@ -45,6 +45,7 @@ protocol Transport: AnyObject {
 
     // Messaging
     func sendMessage(_ content: String, mentions: [String])
+    func sendMessage(_ content: String, mentions: [String], messageID: String, timestamp: Date)
     func sendPrivateMessage(_ content: String, to peerID: PeerID, recipientNickname: String, messageID: String)
     func sendReadReceipt(_ receipt: ReadReceipt, to peerID: PeerID)
     func sendFavoriteNotification(to peerID: PeerID, isFavorite: Bool)
@@ -65,6 +66,10 @@ extension Transport {
     func sendFileBroadcast(_ packet: BitchatFilePacket, transferId: String) {}
     func sendFilePrivate(_ packet: BitchatFilePacket, to peerID: PeerID, transferId: String) {}
     func cancelTransfer(_ transferId: String) {}
+
+    func sendMessage(_ content: String, mentions: [String], messageID: String, timestamp: Date) {
+        sendMessage(content, mentions: mentions)
+    }
 }
 
 protocol TransportPeerEventsDelegate: AnyObject {

bitchat/Services/TransportConfig.swift

@@ -8,6 +8,10 @@ enum TransportConfig {
     static let messageTTLDefault: UInt8 = 7                 // Default TTL for mesh flooding
     static let bleMaxInFlightAssemblies: Int = 128          // Cap concurrent fragment assemblies
     static let bleHighDegreeThreshold: Int = 6              // For adaptive TTL/probabilistic relays
+    static let bleMaxConcurrentTransfers: Int = 2           // Limit simultaneous large media sends
+    static let bleFragmentRelayMinDelayMs: Int = 8          // Faster forwarding for media fragments
+    static let bleFragmentRelayMaxDelayMs: Int = 25         // Upper jitter bound for fragment relays
+    static let bleFragmentRelayTtlCap: UInt8 = 5            // Clamp fragment TTL to contain floods
 
     // UI / Storage Caps
     static let privateChatCap: Int = 1337
@@ -66,6 +70,7 @@ enum TransportConfig {
     static let uiAnimationMediumSeconds: TimeInterval = 0.2
     static let uiAnimationSidebarSeconds: TimeInterval = 0.25
     static let uiRecentCutoffFiveMinutesSeconds: TimeInterval = 5 * 60
+    static let uiMeshEmptyConfirmationSeconds: TimeInterval = 30.0
 
     // BLE maintenance & thresholds
     static let bleMaintenanceInterval: TimeInterval = 5.0

bitchat/Sync/GossipSyncManager.swift

@@ -8,6 +8,55 @@ final class GossipSyncManager {
         func signPacketForBroadcast(_ packet: BitchatPacket) -> BitchatPacket
     }
 
+    private struct PacketStore {
+        private(set) var packets: [String: BitchatPacket] = [:]
+        private(set) var order: [String] = []
+
+        mutating func insert(idHex: String, packet: BitchatPacket, capacity: Int) {
+            guard capacity > 0 else { return }
+            if packets[idHex] != nil {
+                packets[idHex] = packet
+                return
+            }
+            packets[idHex] = packet
+            order.append(idHex)
+            while order.count > capacity {
+                let victim = order.removeFirst()
+                packets.removeValue(forKey: victim)
+            }
+        }
+
+        func allPackets(isFresh: (BitchatPacket) -> Bool) -> [BitchatPacket] {
+            order.compactMap { key in
+                guard let packet = packets[key], isFresh(packet) else { return nil }
+                return packet
+            }
+        }
+
+        mutating func remove(where shouldRemove: (BitchatPacket) -> Bool) {
+            var nextOrder: [String] = []
+            for key in order {
+                guard let packet = packets[key] else { continue }
+                if shouldRemove(packet) {
+                    packets.removeValue(forKey: key)
+                } else {
+                    nextOrder.append(key)
+                }
+            }
+            order = nextOrder
+        }
+
+        mutating func removeExpired(isFresh: (BitchatPacket) -> Bool) {
+            remove { !isFresh($0) }
+        }
+    }
+
+    private struct SyncSchedule {
+        let types: SyncTypeFlags
+        let interval: TimeInterval
+        var lastSent: Date
+    }
+
     struct Config {
         var seenCapacity: Int = 1000          // max packets per sync (cap across types)
         var gcsMaxBytes: Int = 400           // filter size budget (128..1024)
@@ -16,25 +65,43 @@ final class GossipSyncManager {
         var maintenanceIntervalSeconds: TimeInterval = 30.0
         var stalePeerCleanupIntervalSeconds: TimeInterval = 60.0
         var stalePeerTimeoutSeconds: TimeInterval = 60.0
+        var fragmentCapacity: Int = 600
+        var fileTransferCapacity: Int = 200
+        var fragmentSyncIntervalSeconds: TimeInterval = 30.0
+        var fileTransferSyncIntervalSeconds: TimeInterval = 60.0
+        var messageSyncIntervalSeconds: TimeInterval = 15.0
     }
 
     private let myPeerID: PeerID
     private let config: Config
     weak var delegate: Delegate?
 
-    // Storage: broadcast messages (ordered by insert), and latest announce per sender
-    private var messages: [String: BitchatPacket] = [:] // idHex -> packet
-    private var messageOrder: [String] = []
-    private var latestAnnouncementByPeer: [String: (id: String, packet: BitchatPacket)] = [:]
+    // Storage: broadcast packets by type, and latest announce per sender
+    private var messages = PacketStore()
+    private var fragments = PacketStore()
+    private var fileTransfers = PacketStore()
+    private var latestAnnouncementByPeer: [PeerID: (id: String, packet: BitchatPacket)] = [:]
 
     // Timer
     private var periodicTimer: DispatchSourceTimer?
     private let queue = DispatchQueue(label: "mesh.sync", qos: .utility)
     private var lastStalePeerCleanup: Date = .distantPast
+    private var syncSchedules: [SyncSchedule] = []
 
     init(myPeerID: PeerID, config: Config = Config()) {
         self.myPeerID = myPeerID
         self.config = config
+        var schedules: [SyncSchedule] = []
+        if config.seenCapacity > 0 && config.messageSyncIntervalSeconds > 0 {
+            schedules.append(SyncSchedule(types: .publicMessages, interval: config.messageSyncIntervalSeconds, lastSent: .distantPast))
+        }
+        if config.fragmentCapacity > 0 && config.fragmentSyncIntervalSeconds > 0 {
+            schedules.append(SyncSchedule(types: .fragment, interval: config.fragmentSyncIntervalSeconds, lastSent: .distantPast))
+        }
+        if config.fileTransferCapacity > 0 && config.fileTransferSyncIntervalSeconds > 0 {
+            schedules.append(SyncSchedule(types: .fileTransfer, interval: config.fileTransferSyncIntervalSeconds, lastSent: .distantPast))
+        }
+        syncSchedules = schedules
     }
 
     func start() {
@@ -55,7 +122,18 @@ final class GossipSyncManager {
 
     func scheduleInitialSyncToPeer(_ peerID: PeerID, delaySeconds: TimeInterval = 5.0) {
         queue.asyncAfter(deadline: .now() + delaySeconds) { [weak self] in
-            self?.sendRequestSync(to: peerID)
+            guard let self = self else { return }
+            self.sendRequestSync(to: peerID, types: .publicMessages)
+            if self.config.fragmentCapacity > 0 && self.config.fragmentSyncIntervalSeconds > 0 {
+                self.queue.asyncAfter(deadline: .now() + 0.5) { [weak self] in
+                    self?.sendRequestSync(to: peerID, types: .fragment)
+                }
+            }
+            if self.config.fileTransferCapacity > 0 && self.config.fileTransferSyncIntervalSeconds > 0 {
+                self.queue.asyncAfter(deadline: .now() + 1.0) { [weak self] in
+                    self?.sendRequestSync(to: peerID, types: .fileTransfer)
+                }
+            }
         }
     }
 
@@ -87,47 +165,45 @@ final class GossipSyncManager {
     }
 
     private func _onPublicPacketSeen(_ packet: BitchatPacket) {
-        let mt = MessageType(rawValue: packet.type)
+        guard let messageType = MessageType(rawValue: packet.type) else { return }
         let isBroadcastRecipient: Bool = {
             guard let r = packet.recipientID else { return true }
             return r.count == 8 && r.allSatisfy { $0 == 0xFF }
         }()
-        let isBroadcastMessage = (mt == .message && isBroadcastRecipient)
-        let isAnnounce = (mt == .announce)
-        guard isBroadcastMessage || isAnnounce else { return }
 
-        // Reject expired packets to prevent ghost peers and old messages
-        guard isPacketFresh(packet) else { return }
-
-        if isAnnounce {
+        switch messageType {
+        case .announce:
+            guard isPacketFresh(packet) else { return }
             guard isAnnouncementFresh(packet) else {
-                let sender = packet.senderID.hexEncodedString().lowercased()
-                removeState(forNormalizedPeerID: sender)
+                let sender = PeerID(hexData: packet.senderID)
+                removeState(for: sender)
                 return
             }
-        }
-
-        let idHex = PacketIdUtil.computeId(packet).hexEncodedString()
-
-        if isBroadcastMessage {
-            if messages[idHex] == nil {
-                messages[idHex] = packet
-                messageOrder.append(idHex)
-                // Enforce capacity
-                let cap = max(1, config.seenCapacity)
-                while messageOrder.count > cap {
-                    let victim = messageOrder.removeFirst()
-                    messages.removeValue(forKey: victim)
-                }
-            }
-        } else if isAnnounce {
-            let sender = packet.senderID.hexEncodedString().lowercased()
+            let idHex = PacketIdUtil.computeId(packet).hexEncodedString()
+            let sender = PeerID(hexData: packet.senderID)
             latestAnnouncementByPeer[sender] = (id: idHex, packet: packet)
+        case .message:
+            guard isBroadcastRecipient else { return }
+            guard isPacketFresh(packet) else { return }
+            let idHex = PacketIdUtil.computeId(packet).hexEncodedString()
+            messages.insert(idHex: idHex, packet: packet, capacity: max(1, config.seenCapacity))
+        case .fragment:
+            guard isBroadcastRecipient else { return }
+            guard isPacketFresh(packet) else { return }
+            let idHex = PacketIdUtil.computeId(packet).hexEncodedString()
+            fragments.insert(idHex: idHex, packet: packet, capacity: max(1, config.fragmentCapacity))
+        case .fileTransfer:
+            guard isBroadcastRecipient else { return }
+            guard isPacketFresh(packet) else { return }
+            let idHex = PacketIdUtil.computeId(packet).hexEncodedString()
+            fileTransfers.insert(idHex: idHex, packet: packet, capacity: max(1, config.fileTransferCapacity))
+        default:
+            break
         }
     }
 
-    private func sendRequestSync() {
-        let payload = buildGcsPayload()
+    private func sendRequestSync(for types: SyncTypeFlags) {
+        let payload = buildGcsPayload(for: types)
         let pkt = BitchatPacket(
             type: MessageType.requestSync.rawValue,
             senderID: Data(hexString: myPeerID.id) ?? Data(),
@@ -141,8 +217,8 @@ final class GossipSyncManager {
         delegate?.sendPacket(signed)
     }
 
-    private func sendRequestSync(to peerID: PeerID) {
-        let payload = buildGcsPayload()
+    private func sendRequestSync(to peerID: PeerID, types: SyncTypeFlags) {
+        let payload = buildGcsPayload(for: types)
         var recipient = Data()
         var temp = peerID.id
         while temp.count >= 2 && recipient.count < 8 {
@@ -170,6 +246,7 @@ final class GossipSyncManager {
     }
 
     private func _handleRequestSync(from peerID: PeerID, request: RequestSyncPacket) {
+        let requestedTypes = (request.types ?? .publicMessages)
         // Decode GCS into sorted set and prepare membership checker
         let sorted = GCSFilter.decodeToSortedSet(p: request.p, m: request.m, data: request.data)
         func mightContain(_ id: Data) -> Bool {
@@ -177,60 +254,100 @@ final class GossipSyncManager {
             return GCSFilter.contains(sortedValues: sorted, candidate: bucket)
         }
 
-        // 1) Announcements: send latest per peer if requester lacks them (and not expired)
-        for (_, pair) in latestAnnouncementByPeer {
-            let (idHex, pkt) = pair
-            guard isPacketFresh(pkt) else { continue }
-            let idBytes = Data(hexString: idHex) ?? Data()
-            if !mightContain(idBytes) {
-                var toSend = pkt
-                toSend.ttl = 0
-                delegate?.sendPacket(to: peerID, packet: toSend)
+        if requestedTypes.contains(.announce) {
+            for (_, pair) in latestAnnouncementByPeer {
+                let (idHex, pkt) = pair
+                guard isPacketFresh(pkt) else { continue }
+                let idBytes = Data(hexString: idHex) ?? Data()
+                if !mightContain(idBytes) {
+                    var toSend = pkt
+                    toSend.ttl = 0
+                    delegate?.sendPacket(to: peerID, packet: toSend)
+                }
             }
         }
 
-        // 2) Broadcast messages: send all missing (and not expired)
-        let toSendMsgs = messageOrder.compactMap { messages[$0] }
-        for pkt in toSendMsgs {
-            guard isPacketFresh(pkt) else { continue }
-            let idBytes = PacketIdUtil.computeId(pkt)
-            if !mightContain(idBytes) {
-                var toSend = pkt
-                toSend.ttl = 0
-                delegate?.sendPacket(to: peerID, packet: toSend)
+        if requestedTypes.contains(.message) {
+            let toSendMsgs = messages.allPackets(isFresh: isPacketFresh)
+            for pkt in toSendMsgs {
+                let idBytes = PacketIdUtil.computeId(pkt)
+                if !mightContain(idBytes) {
+                    var toSend = pkt
+                    toSend.ttl = 0
+                    delegate?.sendPacket(to: peerID, packet: toSend)
+                }
+            }
+        }
+
+        if requestedTypes.contains(.fragment) {
+            let frags = fragments.allPackets(isFresh: isPacketFresh)
+            for pkt in frags {
+                let idBytes = PacketIdUtil.computeId(pkt)
+                if !mightContain(idBytes) {
+                    var toSend = pkt
+                    toSend.ttl = 0
+                    delegate?.sendPacket(to: peerID, packet: toSend)
+                }
+            }
+        }
+
+        if requestedTypes.contains(.fileTransfer) {
+            let files = fileTransfers.allPackets(isFresh: isPacketFresh)
+            for pkt in files {
+                let idBytes = PacketIdUtil.computeId(pkt)
+                if !mightContain(idBytes) {
+                    var toSend = pkt
+                    toSend.ttl = 0
+                    delegate?.sendPacket(to: peerID, packet: toSend)
+                }
             }
         }
     }
 
     // Build REQUEST_SYNC payload using current candidates and GCS params
-    private func buildGcsPayload() -> Data {
-        // Collect candidates: latest announce per peer + broadcast messages (only fresh)
+    private func buildGcsPayload(for types: SyncTypeFlags) -> Data {
         var candidates: [BitchatPacket] = []
-        candidates.reserveCapacity(latestAnnouncementByPeer.count + messageOrder.count)
-        for (_, pair) in latestAnnouncementByPeer {
-            if isPacketFresh(pair.packet) {
+        if types.contains(.announce) {
+            for (_, pair) in latestAnnouncementByPeer where isPacketFresh(pair.packet) {
                 candidates.append(pair.packet)
             }
         }
-        for id in messageOrder {
-            if let p = messages[id], isPacketFresh(p) {
-                candidates.append(p)
-            }
+        if types.contains(.message) {
+            candidates.append(contentsOf: messages.allPackets(isFresh: isPacketFresh))
         }
+        if types.contains(.fragment) {
+            candidates.append(contentsOf: fragments.allPackets(isFresh: isPacketFresh))
+        }
+        if types.contains(.fileTransfer) {
+            candidates.append(contentsOf: fileTransfers.allPackets(isFresh: isPacketFresh))
+        }
+        if candidates.isEmpty {
+            let p = GCSFilter.deriveP(targetFpr: config.gcsTargetFpr)
+            let req = RequestSyncPacket(p: p, m: 1, data: Data(), types: types)
+            return req.encode()
+        }
+
         // Sort by timestamp desc
         candidates.sort { $0.timestamp > $1.timestamp }
 
         let p = GCSFilter.deriveP(targetFpr: config.gcsTargetFpr)
         let nMax = GCSFilter.estimateMaxElements(sizeBytes: config.gcsMaxBytes, p: p)
-        let cap = max(1, config.seenCapacity)
+        let cap: Int
+        if types == .fragment {
+            cap = max(1, config.fragmentCapacity)
+        } else if types == .fileTransfer {
+            cap = max(1, config.fileTransferCapacity)
+        } else {
+            cap = max(1, config.seenCapacity)
+        }
         let takeN = min(candidates.count, min(nMax, cap))
         if takeN <= 0 {
-            let req = RequestSyncPacket(p: p, m: 1, data: Data())
+            let req = RequestSyncPacket(p: p, m: 1, data: Data(), types: types)
             return req.encode()
         }
         let ids: [Data] = candidates.prefix(takeN).map { PacketIdUtil.computeId($0) }
         let params = GCSFilter.buildFilter(ids: ids, maxBytes: config.gcsMaxBytes, targetFpr: config.gcsTargetFpr)
-        let req = RequestSyncPacket(p: params.p, m: params.m, data: params.data)
+        let req = RequestSyncPacket(p: params.p, m: params.m, data: params.data, types: types)
         return req.encode()
     }
 
@@ -241,20 +358,21 @@ final class GossipSyncManager {
             isPacketFresh(pair.packet)
         }
 
-        // Remove expired messages
-        let expiredMessageIds = messages.compactMap { id, pkt in
-            isPacketFresh(pkt) ? nil : id
-        }
-        for id in expiredMessageIds {
-            messages.removeValue(forKey: id)
-            messageOrder.removeAll { $0 == id }
-        }
+        messages.removeExpired(isFresh: isPacketFresh)
+        fragments.removeExpired(isFresh: isPacketFresh)
+        fileTransfers.removeExpired(isFresh: isPacketFresh)
     }
 
     private func performPeriodicMaintenance(now: Date = Date()) {
         cleanupExpiredMessages()
         cleanupStaleAnnouncementsIfNeeded(now: now)
-        sendRequestSync()
+        for index in syncSchedules.indices {
+            guard syncSchedules[index].interval > 0 else { continue }
+            if syncSchedules[index].lastSent == .distantPast || now.timeIntervalSince(syncSchedules[index].lastSent) >= syncSchedules[index].interval {
+                syncSchedules[index].lastSent = now
+                sendRequestSync(for: syncSchedules[index].types)
+            }
+        }
     }
 
     private func cleanupStaleAnnouncementsIfNeeded(now: Date) {
@@ -270,40 +388,27 @@ final class GossipSyncManager {
         let nowMs = UInt64(now.timeIntervalSince1970 * 1000)
         guard nowMs >= timeoutMs else { return }
         let cutoff = nowMs - timeoutMs
-        let stalePeerIDs = latestAnnouncementByPeer.compactMap { (peerHex, pair) -> String? in
-            pair.packet.timestamp < cutoff ? peerHex.lowercased() : nil
+        let stalePeerIDs = latestAnnouncementByPeer.compactMap { peerID, pair in
+            pair.packet.timestamp < cutoff ? peerID : nil
         }
         guard !stalePeerIDs.isEmpty else { return }
         for peerKey in stalePeerIDs {
-            removeState(forNormalizedPeerID: peerKey)
+            removeState(for: peerKey)
         }
     }
 
     // Explicit removal hook for LEAVE/stale peer
     func removeAnnouncementForPeer(_ peerID: PeerID) {
         queue.async { [weak self] in
-            self?._removeAnnouncementForPeer(peerID)
+            self?.removeState(for: peerID)
         }
     }
 
-    private func _removeAnnouncementForPeer(_ peerID: PeerID) {
-        let normalizedPeerID = peerID.id.lowercased()
-        removeState(forNormalizedPeerID: normalizedPeerID)
-    }
-
-    private func removeState(forNormalizedPeerID normalizedPeerID: String) {
-        _ = latestAnnouncementByPeer.removeValue(forKey: normalizedPeerID)
-        // Remove messages from this peer
-        // Collect IDs to remove first to avoid concurrent modification
-        let messageIdsToRemove = messages.compactMap { (id, message) -> String? in
-            message.senderID.hexEncodedString().lowercased() == normalizedPeerID ? id : nil
-        }
-        
-        // Remove messages and update messageOrder
-        for id in messageIdsToRemove {
-            messages.removeValue(forKey: id)
-            messageOrder.removeAll { $0 == id }
-        }
+    private func removeState(for peerID: PeerID) {
+        _ = latestAnnouncementByPeer.removeValue(forKey: peerID)
+        messages.remove { PeerID(hexData: $0.senderID) == peerID }
+        fragments.remove { PeerID(hexData: $0.senderID) == peerID }
+        fileTransfers.remove { PeerID(hexData: $0.senderID) == peerID }
     }
 }
 
@@ -317,13 +422,13 @@ extension GossipSyncManager {
 
     func _hasAnnouncement(for peerID: PeerID) -> Bool {
         queue.sync {
-            latestAnnouncementByPeer[peerID.id.lowercased()] != nil
+            latestAnnouncementByPeer[peerID] != nil
         }
     }
 
     func _messageCount(for peerID: PeerID) -> Int {
         queue.sync {
-            messages.values.filter { $0.senderID.hexEncodedString().lowercased() == peerID.id.lowercased() }.count
+            messages.allPackets { _ in true }.filter { PeerID(hexData: $0.senderID) == peerID }.count
         }
     }
 }

bitchat/Sync/SyncTypeFlags.swift

@@ -0,0 +1,104 @@
+import Foundation
+
+/// Bitfield describing which message types are covered by a REQUEST_SYNC round.
+/// Matches the Android mapping (bit index -> message type).
+struct SyncTypeFlags: OptionSet {
+    let rawValue: UInt64
+
+    init(rawValue: UInt64) {
+        self.rawValue = rawValue & 0x00FF_FFFF_FFFF_FFFF // Trim to max 8 bytes
+    }
+
+    private static func bitIndex(for type: MessageType) -> Int? {
+        switch type {
+        case .announce: return 0
+        case .message: return 1
+        case .leave: return 2
+        case .noiseHandshake: return 3
+        case .noiseEncrypted: return 4
+        case .fragment: return 5
+        case .requestSync: return 6
+        case .fileTransfer: return 7
+        }
+    }
+
+    private static func type(forBit index: Int) -> MessageType? {
+        switch index {
+        case 0: return .announce
+        case 1: return .message
+        case 2: return .leave
+        case 3: return .noiseHandshake
+        case 4: return .noiseEncrypted
+        case 5: return .fragment
+        case 6: return .requestSync
+        case 7: return .fileTransfer
+        default:
+            return nil
+        }
+    }
+
+    static let announce = SyncTypeFlags(messageTypes: [.announce])
+    static let message = SyncTypeFlags(messageTypes: [.message])
+    static let fragment = SyncTypeFlags(messageTypes: [.fragment])
+    static let fileTransfer = SyncTypeFlags(messageTypes: [.fileTransfer])
+
+    static let publicMessages = SyncTypeFlags(messageTypes: [.announce, .message])
+
+    init(messageTypes: [MessageType]) {
+        var raw: UInt64 = 0
+        for type in messageTypes {
+            guard let bit = SyncTypeFlags.bitIndex(for: type) else { continue }
+            raw |= (1 << UInt64(bit))
+        }
+        self.init(rawValue: raw)
+    }
+
+    func contains(_ type: MessageType) -> Bool {
+        guard let bit = SyncTypeFlags.bitIndex(for: type) else { return false }
+        return contains(SyncTypeFlags(rawValue: 1 << UInt64(bit)))
+    }
+
+    func union(_ other: SyncTypeFlags) -> SyncTypeFlags {
+        SyncTypeFlags(rawValue: rawValue | other.rawValue)
+    }
+
+    func intersection(_ other: SyncTypeFlags) -> SyncTypeFlags {
+        SyncTypeFlags(rawValue: rawValue & other.rawValue)
+    }
+
+    func toMessageTypes() -> [MessageType] {
+        guard rawValue != 0 else { return [] }
+        var types: [MessageType] = []
+        for bit in 0..<64 {
+            guard (rawValue & (1 << UInt64(bit))) != 0 else { continue }
+            if let type = SyncTypeFlags.type(forBit: bit) {
+                types.append(type)
+            }
+        }
+        return types
+    }
+
+    func toData() -> Data? {
+        guard rawValue != 0 else { return nil }
+        var value = rawValue
+        var bytes: [UInt8] = []
+        while value > 0 && bytes.count < 8 {
+            bytes.append(UInt8(value & 0xFF))
+            value >>= 8
+        }
+        while let last = bytes.last, last == 0 {
+            bytes.removeLast()
+        }
+        guard !bytes.isEmpty, bytes.count <= 8 else { return nil }
+        return Data(bytes)
+    }
+
+    static func decode(_ data: Data) -> SyncTypeFlags? {
+        guard (1...8).contains(data.count) else { return nil }
+        var raw: UInt64 = 0
+        for (index, byte) in data.enumerated() {
+            raw |= UInt64(byte) << UInt64(index * 8)
+        }
+        return SyncTypeFlags(rawValue: raw)
+    }
+}

bitchat/Utils/CompressionUtil.swift

@@ -61,15 +61,13 @@ struct CompressionUtil {
         // 1. Data is too small
         // 2. Data appears to be already compressed (high entropy)
         guard data.count >= compressionThreshold else { return false }
-        
-        // Simple entropy check - count unique bytes
-        var byteFrequency = [UInt8: Int]()
-        for byte in data {
-            byteFrequency[byte, default: 0] += 1
-        }
-        
-        // If we have very high byte diversity, data is likely already compressed
-        let uniqueByteRatio = Double(byteFrequency.count) / Double(min(data.count, 256))
+
+        // Quick uniqueness check — a high diversity of bytes usually means the
+        // payload is already compressed. We only need to know how many unique
+        // values exist rather than keeping full frequency counts.
+        let uniqueByteCount = Set(data).count
+        let sampleSize = min(data.count, 256)
+        let uniqueByteRatio = Double(uniqueByteCount) / Double(sampleSize)
         return uniqueByteRatio < 0.9 // Compress if less than 90% unique bytes
     }
 }

bitchat/Utils/FileTransferLimits.swift

@@ -5,9 +5,9 @@ enum FileTransferLimits {
     /// Absolute ceiling enforced for any file payload (voice, image, other).
     static let maxPayloadBytes: Int = 1 * 1024 * 1024 // 1 MiB
     /// Voice notes stay small for low-latency relays.
-    static let maxVoiceNoteBytes: Int = 1 * 1024 * 1024 // 1 MiB
+    static let maxVoiceNoteBytes: Int = 512 * 1024 // 512 KiB
     /// Compressed images after downscaling should comfortably fit under this budget.
-    static let maxImageBytes: Int = 1 * 1024 * 1024 // 1 MiB
+    static let maxImageBytes: Int = 512 * 1024 // 512 KiB
     /// Worst-case size once TLV metadata and binary packet framing are included for the largest payloads.
     static let maxFramedFileBytes: Int = {
         let maxMetadataBytes = Int(UInt16.max) * 2 // fileName + mimeType TLVs

bitchat/Utils/InputValidator.swift

@@ -1,4 +1,5 @@
 import Foundation
+import BitLogger
 
 /// Comprehensive input validation for BitChat protocol
 /// Prevents injection attacks, buffer overflows, and malformed data
@@ -16,29 +17,28 @@ struct InputValidator {
     // MARK: - String Content Validation
     
     /// Validates and sanitizes user-provided strings used in UI
+    ///
+    /// Rejects strings containing control characters to prevent potential security issues
+    /// and UI rendering problems. This strict approach ensures data integrity at input time.
     static func validateUserString(_ string: String, maxLength: Int) -> String? {
-        // Check empty
-        guard !string.isEmpty else { return nil }
-
-        // Trim whitespace
         let trimmed = string.trimmingCharacters(in: .whitespacesAndNewlines)
         guard !trimmed.isEmpty else { return nil }
-
-        // Check length
         guard trimmed.count <= maxLength else { return nil }
 
-        // Remove control characters
+        // Reject control characters outright instead of rewriting the string.
+        // This prevents injection attacks and ensures consistent UI rendering.
         let controlChars = CharacterSet.controlCharacters
-        let cleaned = trimmed.components(separatedBy: controlChars).joined()
-        
-        // Ensure valid UTF-8 (should already be, but double-check)
-        guard cleaned.data(using: .utf8) != nil else { return nil }
-        
-        // Prevent zero-width characters and other invisible unicode
-        let invisibleChars = CharacterSet(charactersIn: "\u{200B}\u{200C}\u{200D}\u{FEFF}")
-        let visible = cleaned.components(separatedBy: invisibleChars).joined()
-        
-        return visible.isEmpty ? nil : visible
+        if !trimmed.unicodeScalars.allSatisfy({ !controlChars.contains($0) }) {
+            // Log rejection for monitoring, without exposing actual content for privacy
+            let controlCharCount = trimmed.unicodeScalars.filter { controlChars.contains($0) }.count
+            SecureLogger.debug(
+                "Input validation rejected string (length: \(trimmed.count), control chars: \(controlCharCount))",
+                category: .security
+            )
+            return nil
+        }
+
+        return trimmed
     }
     
     /// Validates nickname

bitchat/ViewModels/ChatViewModel.swift

@@ -171,7 +171,7 @@ final class ChatViewModel: ObservableObject, BitchatDelegate {
             if spid.isGeoChat || spid.isGeoDM {
                 let full = (nostrKeyMapping[spid] ?? spid.bare).lowercased()
                 return "nostr:" + full
-            } else if spid.id.count == 16, let full = getNoiseKeyForShortID(spid)?.lowercased() {
+            } else if spid.id.count == 16, let full = getNoiseKeyForShortID(spid)?.id.lowercased() {
                 return "noise:" + full
             } else {
                 return "mesh:" + spid.id.lowercased()
@@ -248,10 +248,10 @@ final class ChatViewModel: ObservableObject, BitchatDelegate {
     @Published var currentColorScheme: ColorScheme = .light
     private let maxMessages = TransportConfig.meshTimelineCap // Maximum messages before oldest are removed
     @Published var isConnected = false
-    private var hasNotifiedNetworkAvailable = false
     private var recentlySeenPeers: Set<PeerID> = []
     private var lastNetworkNotificationTime = Date.distantPast
     private var networkResetTimer: Timer? = nil
+    private var networkEmptyTimer: Timer? = nil
     private let networkResetGraceSeconds: TimeInterval = TransportConfig.networkResetGraceSeconds // avoid refiring on short drops/reconnects
     @Published var nickname: String = "" {
         didSet {
@@ -261,7 +261,7 @@ final class ChatViewModel: ObservableObject, BitchatDelegate {
                 nickname = trimmed
             }
             // Update mesh service nickname if it's initialized
-            if meshService.myPeerID != "" {
+            if !meshService.myPeerID.isEmpty {
                 meshService.setNickname(nickname)
             }
         }
@@ -328,16 +328,16 @@ final class ChatViewModel: ObservableObject, BitchatDelegate {
     private var peerIDToPublicKeyFingerprint: [PeerID: String] = [:]
     private var selectedPrivateChatFingerprint: String? = nil
     // Map stable short peer IDs (16-hex) to full Noise public key hex (64-hex) for session continuity
-    private var shortIDToNoiseKey: [PeerID: String] = [:]
+    private var shortIDToNoiseKey: [PeerID: PeerID] = [:]
 
     // Resolve full Noise key for a peer's short ID (used by UI header rendering)
     @MainActor
-    private func getNoiseKeyForShortID(_ shortPeerID: PeerID) -> String? {
+    private func getNoiseKeyForShortID(_ shortPeerID: PeerID) -> PeerID? {
         if let mapped = shortIDToNoiseKey[shortPeerID] { return mapped }
         // Fallback: derive from active Noise session if available
         if shortPeerID.id.count == 16,
            let key = meshService.getNoiseService().getPeerPublicKeyData(shortPeerID) {
-            let stable = key.hexEncodedString()
+            let stable = PeerID(hexData: key)
             shortIDToNoiseKey[shortPeerID] = stable
             return stable
         }
@@ -346,16 +346,17 @@ final class ChatViewModel: ObservableObject, BitchatDelegate {
 
     // Resolve short mesh ID (16-hex) from a full Noise public key hex (64-hex)
     @MainActor
-    func getShortIDForNoiseKey(_ fullNoiseKeyHex: String) -> PeerID? {
+    func getShortIDForNoiseKey(_ fullNoiseKeyHex: PeerID) -> PeerID {
+        guard fullNoiseKeyHex.id.count == 64 else { return fullNoiseKeyHex }
         // Check known peers for a noise key match
-        if let match = allPeers.first(where: { $0.noisePublicKey.hexEncodedString() == fullNoiseKeyHex }) {
+        if let match = allPeers.first(where: { PeerID(hexData: $0.noisePublicKey) == fullNoiseKeyHex }) {
             return match.peerID
         }
         // Also search cache mapping
         if let pair = shortIDToNoiseKey.first(where: { $0.value == fullNoiseKeyHex }) {
             return pair.key
         }
-        return nil
+        return fullNoiseKeyHex
     }
     private var peerIndex: [PeerID: BitchatPeer] = [:]
     
@@ -1154,7 +1155,7 @@ final class ChatViewModel: ObservableObject, BitchatDelegate {
                 NotificationService.shared.sendPrivateMessageNotification(
                     from: senderName,
                     message: pm.content,
-                    peerID: convKey.id
+                    peerID: convKey
                 )
             }
         }
@@ -1528,15 +1529,25 @@ final class ChatViewModel: ObservableObject, BitchatDelegate {
 
         // UI updates automatically via @Published var messages
 
-        updateChannelActivityTimeThenSend(content: content, trimmed: trimmed, mentions: mentions, geoContext: geoContext)
+        updateChannelActivityTimeThenSend(content: content,
+                                          trimmed: trimmed,
+                                          mentions: mentions,
+                                          geoContext: geoContext,
+                                          messageID: message.id,
+                                          timestamp: message.timestamp)
     }
 
-    private func updateChannelActivityTimeThenSend(content: String, trimmed: String, mentions: [String], geoContext: GeoOutgoingContext?) {
+    private func updateChannelActivityTimeThenSend(content: String,
+                                                   trimmed: String,
+                                                   mentions: [String],
+                                                   geoContext: GeoOutgoingContext?,
+                                                   messageID: String,
+                                                   timestamp: Date) {
         switch activeChannel {
         case .mesh:
             lastPublicActivityAt["mesh"] = Date()
             // Send via mesh with mentions
-            meshService.sendMessage(content, mentions: mentions)
+            meshService.sendMessage(content, mentions: mentions, messageID: messageID, timestamp: timestamp)
         case .location(let ch):
             lastPublicActivityAt["geo:\(ch.geohash)"] = Date()
             guard let context = geoContext, context.channel.geohash == ch.geohash else {
@@ -1875,7 +1886,7 @@ final class ChatViewModel: ObservableObject, BitchatDelegate {
             NotificationService.shared.sendPrivateMessageNotification(
                 from: senderName,
                 message: pm.content,
-                peerID: convKey.id
+                peerID: convKey
             )
         }
         
@@ -1955,8 +1966,7 @@ final class ChatViewModel: ObservableObject, BitchatDelegate {
     func isSelfSender(peerID: PeerID?, displayName: String?) -> Bool {
         guard let peerID else { return false }
         if peerID == meshService.myPeerID { return true }
-        let lowerPeer = peerID.id.lowercased()
-        guard lowerPeer.hasPrefix("nostr") else { return false }
+        guard peerID.isGeoDM || peerID.isGeoChat else { return false }
 
         if let mapped = nostrKeyMapping[peerID]?.lowercased(),
            let gh = currentGeohash,
@@ -1966,10 +1976,7 @@ final class ChatViewModel: ObservableObject, BitchatDelegate {
 
         if let gh = currentGeohash,
            let myIdentity = try? idBridge.deriveIdentity(forGeohash: gh) {
-            let myLower = myIdentity.publicKeyHex.lowercased()
-            let shortLen = TransportConfig.nostrShortKeyDisplayLength
-            let shortKey = "nostr:" + myLower.prefix(shortLen)
-            if lowerPeer == shortKey { return true }
+            if peerID == PeerID(nostr: myIdentity.publicKeyHex) { return true }
             let suffix = myIdentity.publicKeyHex.suffix(4)
             let expected = (nickname + "#" + suffix).lowercased()
             if let display = displayName?.lowercased(), display == expected { return true }
@@ -2452,7 +2459,7 @@ final class ChatViewModel: ObservableObject, BitchatDelegate {
         }
 
         let targetPeer = selectedPrivateChatPeer
-        let message = enqueueMediaMessage(content: "[voice] \(url.lastPathComponent)", targetPeer: targetPeer?.id)
+        let message = enqueueMediaMessage(content: "[voice] \(url.lastPathComponent)", targetPeer: targetPeer)
         let messageID = message.id
         let transferId = makeTransferID(messageID: messageID)
 
@@ -2531,7 +2538,7 @@ final class ChatViewModel: ObservableObject, BitchatDelegate {
                 )
                 guard packet.encode() != nil else { throw MediaSendError.encodingFailed }
                 await MainActor.run {
-                    let message = self.enqueueMediaMessage(content: "[image] \(outputURL.lastPathComponent)", targetPeer: targetPeer?.id)
+                    let message = self.enqueueMediaMessage(content: "[image] \(outputURL.lastPathComponent)", targetPeer: targetPeer)
                     let messageID = message.id
                     let transferId = self.makeTransferID(messageID: messageID)
                     self.registerTransfer(transferId: transferId, messageID: messageID)
@@ -2573,7 +2580,7 @@ final class ChatViewModel: ObservableObject, BitchatDelegate {
     }
 
     @MainActor
-    private func enqueueMediaMessage(content: String, targetPeer: String?) -> BitchatMessage {
+    private func enqueueMediaMessage(content: String, targetPeer: PeerID?) -> BitchatMessage {
         let timestamp = Date()
         let message: BitchatMessage
 
@@ -2590,7 +2597,7 @@ final class ChatViewModel: ObservableObject, BitchatDelegate {
                 deliveryStatus: .sending
             )
             var chats = privateChats
-            chats[PeerID(str: peerID), default: []].append(message)
+            chats[peerID, default: []].append(message)
             privateChats = chats
             trimMessagesIfNeeded()
         } else {
@@ -2603,7 +2610,7 @@ final class ChatViewModel: ObservableObject, BitchatDelegate {
                 originalSender: nil,
                 isPrivate: false,
                 recipientNickname: nil,
-                senderPeerID: PeerID(str: senderPeerID),
+                senderPeerID: senderPeerID,
                 deliveryStatus: .sending
             )
             messages.append(message)
@@ -2628,29 +2635,28 @@ final class ChatViewModel: ObservableObject, BitchatDelegate {
         return message
     }
 
-    private func currentPublicSender() -> (name: String, peerID: String) {
+    private func currentPublicSender() -> (name: String, peerID: PeerID) {
         var displaySender = nickname
         var senderPeerID = meshService.myPeerID
         if case .location(let ch) = activeChannel,
            let identity = try? idBridge.deriveIdentity(forGeohash: ch.geohash) {
             let suffix = String(identity.publicKeyHex.suffix(4))
             displaySender = nickname + "#" + suffix
-            let shortKey = identity.publicKeyHex.prefix(TransportConfig.nostrShortKeyDisplayLength)
-            senderPeerID = PeerID(str: "nostr:\(shortKey)")
+            senderPeerID = PeerID(nostr: identity.publicKeyHex)
         }
-        return (displaySender, senderPeerID.id)
+        return (displaySender, senderPeerID)
     }
 
     @MainActor
-    private func nicknameForPeer(_ peerID: String) -> String {
-        if let name = meshService.peerNickname(peerID: PeerID(str: peerID)) {
+    private func nicknameForPeer(_ peerID: PeerID) -> String {
+        if let name = meshService.peerNickname(peerID: peerID) {
             return name
         }
-        if let favorite = FavoritesPersistenceService.shared.getFavoriteStatus(forPeerID: PeerID(str: peerID)),
+        if let favorite = FavoritesPersistenceService.shared.getFavoriteStatus(forPeerID: peerID),
            !favorite.peerNickname.isEmpty {
             return favorite.peerNickname
         }
-        if let noiseKey = Data(hexString: peerID),
+        if let noiseKey = Data(hexString: peerID.id),
            let favorite = FavoritesPersistenceService.shared.getFavoriteStatus(for: noiseKey),
            !favorite.peerNickname.isEmpty {
             return favorite.peerNickname
@@ -3339,7 +3345,10 @@ final class ChatViewModel: ObservableObject, BitchatDelegate {
             // In public chat - send to active public channel
             switch activeChannel {
             case .mesh:
-                meshService.sendMessage(screenshotMessage, mentions: [])
+                meshService.sendMessage(screenshotMessage,
+                                        mentions: [],
+                                        messageID: UUID().uuidString,
+                                        timestamp: Date())
             case .location(let ch):
                 Task { @MainActor in
                     do {
@@ -4107,7 +4116,7 @@ final class ChatViewModel: ObservableObject, BitchatDelegate {
             if let spid = message.senderPeerID {
                 if case .location(let ch) = activeChannel, spid.id.hasPrefix("nostr:") {
                     if let myGeo = try? idBridge.deriveIdentity(forGeohash: ch.geohash) {
-                        return spid == "nostr:\(myGeo.publicKeyHex.prefix(TransportConfig.nostrShortKeyDisplayLength))"
+                        return spid == PeerID(nostr: myGeo.publicKeyHex)
                     }
                 }
                 return spid == meshService.myPeerID
@@ -4260,13 +4269,7 @@ final class ChatViewModel: ObservableObject, BitchatDelegate {
         let noiseService = meshService.getNoiseService()
         
         if noiseService.hasEstablishedSession(with: peerID) {
-            // Check if fingerprint is verified using our persisted data
-            if let fingerprint = getFingerprint(for: peerID),
-               verifiedFingerprints.contains(fingerprint) {
-                peerEncryptionStatus[peerID] = .noiseVerified
-            } else {
-                peerEncryptionStatus[peerID] = .noiseSecured
-            }
+            peerEncryptionStatus[peerID] = encryptionStatus(for: peerID)
         } else if noiseService.hasSession(with: peerID) {
             // Session exists but not established - handshaking
             peerEncryptionStatus[peerID] = .noiseHandshaking
@@ -4301,27 +4304,12 @@ final class ChatViewModel: ObservableObject, BitchatDelegate {
         // Determine status based on session state
         switch sessionState {
         case .established:
-            // We have encryption, now check if it's verified
-            if let fingerprint = getFingerprint(for: peerID) {
-                if verifiedFingerprints.contains(fingerprint) {
-                    status = .noiseVerified
-                } else {
-                    status = .noiseSecured
-                }
-            } else {
-                // We have a session but no fingerprint yet - still secured
-                status = .noiseSecured
-            }
+            status = encryptionStatus(for: peerID)
         case .handshaking, .handshakeQueued:
             // If we've ever established a session, show secured instead of handshaking
             if hasEverEstablishedSession {
                 // Check if it was verified before
-                if let fingerprint = getFingerprint(for: peerID),
-                   verifiedFingerprints.contains(fingerprint) {
-                    status = .noiseVerified
-                } else {
-                    status = .noiseSecured
-                }
+                status = encryptionStatus(for: peerID)
             } else {
                 // First time establishing - show handshaking
                 status = .noiseHandshaking
@@ -4330,12 +4318,7 @@ final class ChatViewModel: ObservableObject, BitchatDelegate {
             // If we've ever established a session, show secured instead of no handshake
             if hasEverEstablishedSession {
                 // Check if it was verified before
-                if let fingerprint = getFingerprint(for: peerID),
-                   verifiedFingerprints.contains(fingerprint) {
-                    status = .noiseVerified
-                } else {
-                    status = .noiseSecured
-                }
+                status = encryptionStatus(for: peerID)
             } else {
                 // Never established - show no handshake
                 status = .noHandshake
@@ -4344,12 +4327,7 @@ final class ChatViewModel: ObservableObject, BitchatDelegate {
             // If we've ever established a session, show secured instead of failed
             if hasEverEstablishedSession {
                 // Check if it was verified before
-                if let fingerprint = getFingerprint(for: peerID),
-                   verifiedFingerprints.contains(fingerprint) {
-                    status = .noiseVerified
-                } else {
-                    status = .noiseSecured
-                }
+                status = encryptionStatus(for: peerID)
             } else {
                 // Never established - show failed
                 status = .none
@@ -4423,7 +4401,7 @@ final class ChatViewModel: ObservableObject, BitchatDelegate {
 
     @MainActor
     private func meshSeed(for peerID: PeerID) -> String {
-        if let full = getNoiseKeyForShortID(peerID)?.lowercased() {
+        if let full = getNoiseKeyForShortID(peerID)?.id.lowercased() {
             return "noise:" + full
         }
         return peerID.id.lowercased()
@@ -4740,16 +4718,7 @@ final class ChatViewModel: ObservableObject, BitchatDelegate {
         let noiseService = meshService.getNoiseService()
         
         if noiseService.hasEstablishedSession(with: peerID) {
-            if let fingerprint = getFingerprint(for: peerID) {
-                if verifiedFingerprints.contains(fingerprint) {
-                    peerEncryptionStatus[peerID] = .noiseVerified
-                } else {
-                    peerEncryptionStatus[peerID] = .noiseSecured
-                }
-            } else {
-                // Session established but no fingerprint yet
-                peerEncryptionStatus[peerID] = .noiseSecured
-            }
+            peerEncryptionStatus[peerID] = encryptionStatus(for: peerID)
         } else if noiseService.hasSession(with: peerID) {
             peerEncryptionStatus[peerID] = .noiseHandshaking
         } else {
@@ -4779,6 +4748,16 @@ final class ChatViewModel: ObservableObject, BitchatDelegate {
         return unifiedPeerService.getFingerprint(for: peerID)
     }
     
+    /// Check if fingerprint is verified using our persisted data
+    @MainActor
+    private func encryptionStatus(for peerID: PeerID) -> EncryptionStatus {
+        if let fp = getFingerprint(for: peerID), verifiedFingerprints.contains(fp) {
+            return .noiseVerified
+        } else {
+            return .noiseSecured
+        }
+    }
+    
     /// Helper to resolve nickname for a peer ID through various sources
     @MainActor
     private func resolveNickname(for peerID: PeerID) -> String {
@@ -4880,7 +4859,6 @@ final class ChatViewModel: ObservableObject, BitchatDelegate {
         noiseService.onPeerAuthenticated = { [weak self] peerID, fingerprint in
             DispatchQueue.main.async {
                 guard let self = self else { return }
-                let peerID = PeerID(str: peerID)
 
                 SecureLogger.debug("🔐 Authenticated: \(peerID)", category: .security)
 
@@ -4899,9 +4877,9 @@ final class ChatViewModel: ObservableObject, BitchatDelegate {
                 // Cache shortID -> full Noise key mapping as soon as session authenticates
                 if self.shortIDToNoiseKey[peerID] == nil,
                    let keyData = self.meshService.getNoiseService().getPeerPublicKeyData(peerID) {
-                    let stable = keyData.hexEncodedString()
+                    let stable = PeerID(hexData: keyData)
                     self.shortIDToNoiseKey[peerID] = stable
-                    SecureLogger.debug("🗺️ Mapped short peerID to Noise key for header continuity: \(peerID) -> \(stable.prefix(8))…", category: .session)
+                    SecureLogger.debug("🗺️ Mapped short peerID to Noise key for header continuity: \(peerID) -> \(stable.id.prefix(8))…", category: .session)
                 }
 
                 // If a QR verification is pending but not sent yet, send it now that session is authenticated
@@ -5085,12 +5063,12 @@ final class ChatViewModel: ObservableObject, BitchatDelegate {
         }
     }
 
-    func didReceivePublicMessage(from peerID: PeerID, nickname: String, content: String, timestamp: Date) {
+    func didReceivePublicMessage(from peerID: PeerID, nickname: String, content: String, timestamp: Date, messageID: String?) {
         Task { @MainActor in
             let normalized = content.trimmingCharacters(in: .whitespacesAndNewlines)
             let publicMentions = parseMentions(from: normalized)
             let msg = BitchatMessage(
-                id: UUID().uuidString,
+                id: messageID,
                 sender: nickname,
                 content: normalized,
                 timestamp: timestamp,
@@ -5166,7 +5144,7 @@ final class ChatViewModel: ObservableObject, BitchatDelegate {
 
             // Cache mapping to full Noise key for session continuity on disconnect
             if let peer = unifiedPeerService.getPeer(by: peerID) {
-                let noiseKeyHex = peer.noisePublicKey.hexEncodedString()
+                let noiseKeyHex = PeerID(hexData: peer.noisePublicKey)
                 shortIDToNoiseKey[peerID] = noiseKeyHex
             }
 
@@ -5182,15 +5160,14 @@ final class ChatViewModel: ObservableObject, BitchatDelegate {
         identityManager.removeEphemeralSession(peerID: peerID)
 
         // If the open PM is tied to this short peer ID, switch UI context to the full Noise key (offline favorite)
-        var derivedStableKeyHex: String? = shortIDToNoiseKey[peerID]
+        var derivedStableKeyHex = shortIDToNoiseKey[peerID]
         if derivedStableKeyHex == nil,
            let key = meshService.getNoiseService().getPeerPublicKeyData(peerID) {
-            derivedStableKeyHex = key.hexEncodedString()
+            derivedStableKeyHex = PeerID(hexData: key)
             shortIDToNoiseKey[peerID] = derivedStableKeyHex
         }
 
-        if let current = selectedPrivateChatPeer, current == peerID,
-           let stableKeyHex = PeerID(str: derivedStableKeyHex) {
+        if let current = selectedPrivateChatPeer, current == peerID, let stableKeyHex = derivedStableKeyHex {
             // Migrate messages view context to stable key so header shows favorite + Nostr globe
             if let messages = privateChats[peerID] {
                 if privateChats[stableKeyHex] == nil { privateChats[stableKeyHex] = [] }
@@ -5252,34 +5229,29 @@ final class ChatViewModel: ObservableObject, BitchatDelegate {
             self.cleanupStaleUnreadPeerIDs()
             
             // Smart notification logic for "bitchatters nearby"
-            if !peers.isEmpty {
-                // Cancel any pending reset if peers are back
-                self.networkResetTimer?.invalidate()
-                self.networkResetTimer = nil
-                // Count mesh peers that are connected OR recently reachable via mesh relays
-                let meshPeers = peers.filter { peerID in
-                    self.meshService.isPeerConnected(peerID) || self.meshService.isPeerReachable(peerID)
-                }
-                
-                // Rising-edge only: previously zero peers, now > 0 peers
-                let currentPeerSet = Set(meshPeers)
-                let hadNone = self.recentlySeenPeers.isEmpty
-                if meshPeers.count > 0 && hadNone && !self.hasNotifiedNetworkAvailable {
-                    self.hasNotifiedNetworkAvailable = true
-                    self.lastNetworkNotificationTime = Date()
-                    self.recentlySeenPeers = currentPeerSet
-                    NotificationService.shared.sendNetworkAvailableNotification(peerCount: meshPeers.count)
-                    SecureLogger.info("👥 Sent bitchatters nearby notification for \(meshPeers.count) mesh peers", category: .session)
-                }
+            let meshPeers = peers.filter { peerID in
+                self.meshService.isPeerConnected(peerID) || self.meshService.isPeerReachable(peerID)
+            }
+            let meshPeerSet = Set(meshPeers)
+            
+            if meshPeerSet.isEmpty {
+                self.scheduleNetworkEmptyTimer()
             } else {
-                // No peers — immediately reset to allow next rising-edge to notify
-                self.hasNotifiedNetworkAvailable = false
-                self.recentlySeenPeers.removeAll()
-                if self.networkResetTimer != nil {
-                    self.networkResetTimer?.invalidate()
-                    self.networkResetTimer = nil
+                self.invalidateNetworkEmptyTimer()
+                // Trim out peers we no longer observe before comparing for new arrivals
+                self.recentlySeenPeers.formIntersection(meshPeerSet)
+                let newPeers = meshPeerSet.subtracting(self.recentlySeenPeers)
+                
+                if !newPeers.isEmpty {
+                    self.lastNetworkNotificationTime = Date()
+                    self.recentlySeenPeers.formUnion(newPeers)
+                    NotificationService.shared.sendNetworkAvailableNotification(peerCount: meshPeers.count)
+                    SecureLogger.info(
+                        "👥 Sent bitchatters nearby notification for \(meshPeers.count) mesh peers (new: \(newPeers.count))",
+                        category: .session
+                    )
+                    self.scheduleNetworkResetTimer()
                 }
-                SecureLogger.debug("⏳ Mesh empty — reset network notification state", category: .session)
             }
             
             // Register ephemeral sessions for all connected peers
@@ -5349,6 +5321,71 @@ final class ChatViewModel: ObservableObject, BitchatDelegate {
         // Keep only receipts from messages we still have
         cleanupOldReadReceipts()
     }
+
+    @MainActor
+    private func scheduleNetworkResetTimer() {
+        networkResetTimer?.invalidate()
+        networkResetTimer = Timer.scheduledTimer(
+            timeInterval: networkResetGraceSeconds,
+            target: self,
+            selector: #selector(onNetworkResetTimerFired(_:)),
+            userInfo: nil,
+            repeats: false
+        )
+    }
+
+    @MainActor
+    @objc private func onNetworkResetTimerFired(_ timer: Timer) {
+        let activeMeshPeers = meshService
+            .currentPeerSnapshots()
+            .filter { snapshot in
+                snapshot.isConnected || meshService.isPeerReachable(snapshot.peerID)
+            }
+        if activeMeshPeers.isEmpty {
+            recentlySeenPeers.removeAll()
+            SecureLogger.debug("⏱️ Network notification window reset after quiet period", category: .session)
+        } else {
+            SecureLogger.debug("⏱️ Skipped network notification reset; still seeing \(activeMeshPeers.count) mesh peers", category: .session)
+        }
+        networkResetTimer = nil
+    }
+
+    @MainActor
+    private func scheduleNetworkEmptyTimer() {
+        guard networkEmptyTimer == nil else { return }
+        networkEmptyTimer = Timer.scheduledTimer(
+            timeInterval: TransportConfig.uiMeshEmptyConfirmationSeconds,
+            target: self,
+            selector: #selector(onNetworkEmptyTimerFired(_:)),
+            userInfo: nil,
+            repeats: false
+        )
+        SecureLogger.debug("⏳ Mesh empty — waiting before resetting notification state", category: .session)
+    }
+
+    @MainActor
+    private func invalidateNetworkEmptyTimer() {
+        if networkEmptyTimer != nil {
+            networkEmptyTimer?.invalidate()
+            networkEmptyTimer = nil
+        }
+    }
+
+    @MainActor
+    @objc private func onNetworkEmptyTimerFired(_ timer: Timer) {
+        let activeMeshPeers = meshService
+            .currentPeerSnapshots()
+            .filter { snapshot in
+                snapshot.isConnected || meshService.isPeerReachable(snapshot.peerID)
+            }
+        if activeMeshPeers.isEmpty {
+            recentlySeenPeers.removeAll()
+            SecureLogger.debug("⏳ Mesh empty — notification state reset after confirmation", category: .session)
+        } else {
+            SecureLogger.debug("⏳ Mesh empty timer cancelled; \(activeMeshPeers.count) mesh peers detected again", category: .session)
+        }
+        networkEmptyTimer = nil
+    }
     
     private func cleanupOldReadReceipts() {
         // Skip cleanup during startup phase or if privateChats is empty
@@ -5505,6 +5542,9 @@ final class ChatViewModel: ObservableObject, BitchatDelegate {
         )
         // Append to current visible messages
         messages.append(systemMessage)
+        // Track the content key so relayed copies of the same system-style message are ignored
+        let contentKey = normalizedContentKey(systemMessage.content)
+        recordContentKey(contentKey, timestamp: systemMessage.timestamp)
         // Persist into the backing store for the active channel to survive rebinds
         switch activeChannel {
         case .mesh:
@@ -5555,7 +5595,10 @@ final class ChatViewModel: ObservableObject, BitchatDelegate {
             return
         }
         // Default: send over mesh
-        meshService.sendMessage(content, mentions: [])
+        meshService.sendMessage(content,
+                                mentions: [],
+                                messageID: UUID().uuidString,
+                                timestamp: Date())
     }
     
     // MARK: - Simplified Nostr Integration (Inlined from MessageRouter)
@@ -5629,7 +5672,7 @@ final class ChatViewModel: ObservableObject, BitchatDelegate {
             }
 
             // Validate recipient
-            if let rid = packet.recipientID, rid.hexEncodedString() != meshService.myPeerID {
+            if PeerID(hexData: packet.recipientID) != meshService.myPeerID {
                 return
             }
 
@@ -5874,7 +5917,7 @@ final class ChatViewModel: ObservableObject, BitchatDelegate {
             NotificationService.shared.sendPrivateMessageNotification(
                 from: senderNickname,
                 message: messageContent,
-                peerID: targetPeerID.id
+                peerID: targetPeerID
             )
         }
     }
@@ -6267,7 +6310,7 @@ final class ChatViewModel: ObservableObject, BitchatDelegate {
                 NotificationService.shared.sendPrivateMessageNotification(
                     from: message.sender,
                     message: message.content,
-                    peerID: peerID.id
+                    peerID: peerID
                 )
             }
         } else {
@@ -6321,7 +6364,9 @@ final class ChatViewModel: ObservableObject, BitchatDelegate {
         let isGeo = finalMessage.senderPeerID?.isGeoChat == true
 
         // Apply per-sender and per-content rate limits (drop if exceeded)
-        if finalMessage.sender != "system" {
+        // Treat action-style system messages (which carry a senderPeerID) the same as regular user messages
+        let shouldRateLimit = finalMessage.sender != "system" || finalMessage.senderPeerID != nil
+        if shouldRateLimit {
             let senderKey = normalizedSenderKey(for: finalMessage)
             let contentKey = normalizedContentKey(finalMessage.content)
             let now = Date()
@@ -6339,8 +6384,10 @@ final class ChatViewModel: ObservableObject, BitchatDelegate {
 
         // Persist mesh messages to mesh timeline always
         if !isGeo && finalMessage.sender != "system" {
-            meshTimeline.append(finalMessage)
-            trimMeshTimelineIfNeeded()
+            if !meshTimeline.contains(where: { $0.id == finalMessage.id }) {
+                meshTimeline.append(finalMessage)
+                trimMeshTimelineIfNeeded()
+            }
         }
 
         // Persist geochat messages to per-geohash timeline

bitchat/Views/ContentView.swift

@@ -47,7 +47,7 @@ struct ContentView: View {
     @State private var commandSuggestions: [String] = []
     @State private var showMessageActions = false
     @State private var selectedMessageSender: String?
-    @State private var selectedMessageSenderID: String?
+    @State private var selectedMessageSenderID: PeerID?
     @FocusState private var isNicknameFieldFocused: Bool
     @State private var isAtBottomPublic: Bool = true
     @State private var isAtBottomPrivate: Bool = true
@@ -203,7 +203,15 @@ struct ContentView: View {
             }
         }
 #if os(iOS)
-        .sheet(isPresented: $showImagePicker) {
+        // Only present image picker from main view when NOT in a sheet
+        .fullScreenCover(isPresented: Binding(
+            get: { showImagePicker && !showSidebar && viewModel.selectedPrivateChatPeer == nil },
+            set: { newValue in
+                if !newValue {
+                    showImagePicker = false
+                }
+            }
+        )) {
             ImagePickerView(sourceType: imagePickerSourceType) { image in
                 showImagePicker = false
                 if let image = image {
@@ -223,7 +231,15 @@ struct ContentView: View {
         }
 #endif
 #if os(macOS)
-        .sheet(isPresented: $showMacImagePicker) {
+        // Only present Mac image picker from main view when NOT in a sheet
+        .sheet(isPresented: Binding(
+            get: { showMacImagePicker && !showSidebar && viewModel.selectedPrivateChatPeer == nil },
+            set: { newValue in
+                if !newValue {
+                    showMacImagePicker = false
+                }
+            }
+        )) {
             MacImagePickerView { url in
                 showMacImagePicker = false
                 if let url = url {
@@ -269,12 +285,12 @@ struct ContentView: View {
 
             Button("content.actions.direct_message") {
                 if let peerID = selectedMessageSenderID {
-                    if peerID.hasPrefix("nostr:") {
-                        if let full = viewModel.fullNostrHex(forSenderPeerID: PeerID(str: peerID)) {
+                    if peerID.isGeoChat {
+                        if let full = viewModel.fullNostrHex(forSenderPeerID: peerID) {
                             viewModel.startGeohashDM(withPubkeyHex: full)
                         }
                     } else {
-                        viewModel.startPrivateChat(with: PeerID(str: peerID))
+                        viewModel.startPrivateChat(with: peerID)
                     }
                     withAnimation(.easeInOut(duration: TransportConfig.uiAnimationMediumSeconds)) {
                         showSidebar = true
@@ -296,8 +312,8 @@ struct ContentView: View {
 
             Button("content.actions.block", role: .destructive) {
                 // Prefer direct geohash block when we have a Nostr sender ID
-                if let peerID = selectedMessageSenderID, peerID.hasPrefix("nostr:"),
-                   let full = viewModel.fullNostrHex(forSenderPeerID: PeerID(str: peerID)),
+                if let peerID = selectedMessageSenderID, peerID.isGeoChat,
+                   let full = viewModel.fullNostrHex(forSenderPeerID: peerID),
                    let sender = selectedMessageSender {
                     viewModel.blockGeohashUser(pubkeyHexLowercased: full, displayName: sender)
                 } else if let sender = selectedMessageSender {
@@ -778,7 +794,7 @@ struct ContentView: View {
         case "user":
             let id = url.path.trimmingCharacters(in: CharacterSet(charactersIn: "/"))
             let peerID = PeerID(str: id.removingPercentEncoding ?? id)
-            selectedMessageSenderID = peerID.id
+            selectedMessageSenderID = peerID
 
             if peerID.isGeoDM || peerID.isGeoChat {
                 selectedMessageSender = viewModel.geohashDisplayName(for: peerID)
@@ -906,6 +922,53 @@ struct ContentView: View {
         #if os(macOS)
         .frame(minWidth: 420, minHeight: 520)
         #endif
+        // Present image picker from sheet context when IN a sheet (parent-child pattern)
+        #if os(iOS)
+        .fullScreenCover(isPresented: Binding(
+            get: { showImagePicker && (showSidebar || viewModel.selectedPrivateChatPeer != nil) },
+            set: { newValue in
+                if !newValue {
+                    showImagePicker = false
+                }
+            }
+        )) {
+            ImagePickerView(sourceType: imagePickerSourceType) { image in
+                showImagePicker = false
+                if let image = image {
+                    Task {
+                        do {
+                            let processedURL = try ImageUtils.processImage(image)
+                            await MainActor.run {
+                                viewModel.sendImage(from: processedURL)
+                            }
+                        } catch {
+                            SecureLogger.error("Image processing failed: \(error)", category: .session)
+                        }
+                    }
+                }
+            }
+            .ignoresSafeArea()
+        }
+        #endif
+        #if os(macOS)
+        .sheet(isPresented: $showMacImagePicker) {
+            MacImagePickerView { url in
+                showMacImagePicker = false
+                if let url = url {
+                    Task {
+                        do {
+                            let processedURL = try ImageUtils.processImage(at: url)
+                            await MainActor.run {
+                                viewModel.sendImage(from: processedURL)
+                            }
+                        } catch {
+                            SecureLogger.error("Image processing failed: \(error)", category: .session)
+                        }
+                    }
+                }
+            }
+        }
+        #endif
     }
     
     // MARK: - People Sheet Views
@@ -1150,12 +1213,7 @@ struct ContentView: View {
                     .foregroundColor(textColor)
 
                 if !privatePeerID.isGeoDM {
-                    let statusPeerID: PeerID = {
-                        if privatePeerID.id.count == 64, let short = viewModel.getShortIDForNoiseKey(privatePeerID.id) {
-                            return short
-                        }
-                        return context.headerPeerID
-                    }()
+                    let statusPeerID = viewModel.getShortIDForNoiseKey(privatePeerID)
                     let encryptionStatus = viewModel.getEncryptionStatus(for: statusPeerID)
                     if let icon = encryptionStatus.icon {
                         Image(systemName: icon)
@@ -1189,13 +1247,7 @@ struct ContentView: View {
     }
 
     private func makePrivateHeaderContext(for privatePeerID: PeerID) -> PrivateHeaderContext {
-        let headerPeerID: PeerID = {
-            if privatePeerID.id.count == 64, let short = viewModel.getShortIDForNoiseKey(privatePeerID.id) {
-                return short
-            }
-            return privatePeerID
-        }()
-
+        let headerPeerID = viewModel.getShortIDForNoiseKey(privatePeerID)
         let peer = viewModel.getPeer(byID: headerPeerID)
 
         let displayName: String = {

bitchat/Views/FingerprintView.swift

@@ -65,10 +65,7 @@ struct FingerprintView: View {
             
             VStack(alignment: .leading, spacing: 16) {
                 // Prefer short mesh ID for session/encryption status
-                let statusPeerID: PeerID = {
-                    if peerID.id.count == 64, let short = viewModel.getShortIDForNoiseKey(peerID.id) { return short }
-                    return peerID
-                }()
+                let statusPeerID = viewModel.getShortIDForNoiseKey(peerID)
                 // Resolve a friendly name
                 let peerNickname: String = {
                     if let p = viewModel.getPeer(byID: statusPeerID) { return p.displayName }

bitchatTests/BLEServiceTests.swift

@@ -298,5 +298,5 @@ private final class MockBitchatDelegate: BitchatDelegate {
     func didUpdateMessageDeliveryStatus(_ messageID: String, status: DeliveryStatus) {}
     func didReceiveNoisePayload(from peerID: PeerID, type: NoisePayloadType, payload: Data, timestamp: Date) {}
     func didUpdateBluetoothState(_ state: CBManagerState) {}
-    func didReceivePublicMessage(from peerID: String, nickname: String, content: String, timestamp: Date) {}
+    func didReceivePublicMessage(from peerID: PeerID, nickname: String, content: String, timestamp: Date, messageID: String?) {}
 }

bitchatTests/EndToEnd/PrivateChatE2ETests.swift

@@ -186,11 +186,11 @@ struct PrivateChatE2ETests {
             // Bob relays private messages for Charlie
             bob.packetDeliveryHandler = { packet in
                 if let recipientID = packet.recipientID,
-                   String(data: recipientID, encoding: .utf8) == charlie.peerID {
+                   PeerID(data: recipientID) == charlie.peerID {
                     // Relay to Charlie
                     var relayPacket = packet
                     relayPacket.ttl = packet.ttl - 1
-                    self.charlie.simulateIncomingPacket(relayPacket)
+                    charlie.simulateIncomingPacket(relayPacket)
                 }
             }
             

bitchatTests/EndToEnd/PublicChatE2ETests.swift

@@ -388,7 +388,7 @@ struct PublicChatE2ETests {
 
             if let message = BitchatMessage(packet.payload) {
                 // Don't relay own messages
-                guard message.senderPeerID?.id != node.peerID else { return }
+                guard message.senderPeerID != node.peerID else { return }
                 
                 // Create relay message
                 let relayMessage = BitchatMessage(

bitchatTests/Fragmentation/FragmentationTests.swift

@@ -209,7 +209,7 @@ extension FragmentationTests {
         func didUpdateMessageDeliveryStatus(_ messageID: String, status: DeliveryStatus) {}
         func didReceiveNoisePayload(from peerID: PeerID, type: NoisePayloadType, payload: Data, timestamp: Date) {}
         func didUpdateBluetoothState(_ state: CBManagerState) {}
-        func didReceivePublicMessage(from peerID: PeerID, nickname: String, content: String, timestamp: Date) {
+        func didReceivePublicMessage(from peerID: PeerID, nickname: String, content: String, timestamp: Date, messageID: String?) {
             publicMessages.append((peerID, nickname, content))
         }
         func didReceiveRegionalPublicMessage(from peerID: PeerID, nickname: String, content: String, timestamp: Date) {}

bitchatTests/GossipSyncManagerTests.swift

@@ -125,16 +125,138 @@ struct GossipSyncManagerTests {
         #expect(manager._hasAnnouncement(for: PeerID(str: peerHex)) == false)
         #expect(manager._messageCount(for: PeerID(str: peerHex)) == 0)
     }
+
+    @Test func maintenanceEmitsTypedSyncRequests() throws {
+        var config = GossipSyncManager.Config()
+        config.seenCapacity = 10
+        config.fragmentCapacity = 5
+        config.fileTransferCapacity = 4
+        config.messageSyncIntervalSeconds = 1
+        config.fragmentSyncIntervalSeconds = 1
+        config.fileTransferSyncIntervalSeconds = 1
+        config.maintenanceIntervalSeconds = 0
+
+        let manager = GossipSyncManager(myPeerID: myPeerID, config: config)
+        let delegate = RecordingDelegate()
+        manager.delegate = delegate
+
+        let sender = try #require(Data(hexString: "1122334455667788"))
+        let now = UInt64(Date().timeIntervalSince1970 * 1000)
+
+        let announcePacket = BitchatPacket(
+            type: MessageType.announce.rawValue,
+            senderID: sender,
+            recipientID: nil,
+            timestamp: now,
+            payload: Data(),
+            signature: nil,
+            ttl: 1
+        )
+        let messagePacket = BitchatPacket(
+            type: MessageType.message.rawValue,
+            senderID: sender,
+            recipientID: nil,
+            timestamp: now,
+            payload: Data([0x01]),
+            signature: nil,
+            ttl: 1
+        )
+        let fragmentPacket = BitchatPacket(
+            type: MessageType.fragment.rawValue,
+            senderID: sender,
+            recipientID: nil,
+            timestamp: now,
+            payload: Data([0xAA]),
+            signature: nil,
+            ttl: 1
+        )
+        let filePacket = BitchatPacket(
+            type: MessageType.fileTransfer.rawValue,
+            senderID: sender,
+            recipientID: nil,
+            timestamp: now,
+            payload: Data([0xBB]),
+            signature: nil,
+            ttl: 1,
+            version: 2
+        )
+
+        manager.onPublicPacketSeen(announcePacket)
+        manager.onPublicPacketSeen(messagePacket)
+        manager.onPublicPacketSeen(fragmentPacket)
+        manager.onPublicPacketSeen(filePacket)
+
+        manager._performMaintenanceSynchronously(now: Date())
+
+        let sentPackets = delegate.packets
+        #expect(sentPackets.count == 3)
+        let decoded = sentPackets.compactMap { RequestSyncPacket.decode(from: $0.payload) }
+        #expect(decoded.count == 3)
+        #expect(decoded[0].types == .publicMessages)
+        #expect(decoded[1].types == .fragment)
+        #expect(decoded[2].types == .fileTransfer)
+    }
+
+    @Test func handleRequestSyncHonorsTypeFilter() async throws {
+        var config = GossipSyncManager.Config()
+        config.seenCapacity = 5
+        config.fragmentCapacity = 5
+        config.fileTransferCapacity = 0
+        config.messageSyncIntervalSeconds = 0
+        config.fragmentSyncIntervalSeconds = 0
+        config.fileTransferSyncIntervalSeconds = 0
+
+        let manager = GossipSyncManager(myPeerID: myPeerID, config: config)
+        let delegate = RecordingDelegate()
+        manager.delegate = delegate
+
+        let sender = try #require(Data(hexString: "aabbccddeeff0011"))
+        let now = UInt64(Date().timeIntervalSince1970 * 1000)
+
+        let messagePacket = BitchatPacket(
+            type: MessageType.message.rawValue,
+            senderID: sender,
+            recipientID: nil,
+            timestamp: now,
+            payload: Data([0x10]),
+            signature: nil,
+            ttl: 1
+        )
+
+        let fragmentPacket = BitchatPacket(
+            type: MessageType.fragment.rawValue,
+            senderID: sender,
+            recipientID: nil,
+            timestamp: now,
+            payload: Data([0x20]),
+            signature: nil,
+            ttl: 1
+        )
+
+        manager.onPublicPacketSeen(messagePacket)
+        manager.onPublicPacketSeen(fragmentPacket)
+
+        let peer = PeerID(str: "FFFFFFFFFFFFFFFF")
+        let request = RequestSyncPacket(p: 4, m: 1, data: Data(), types: .fragment)
+        manager.handleRequestSync(from: peer, request: request)
+
+        try await sleep(0.01)
+        let sentPackets = delegate.packets
+        #expect(sentPackets.count == 1)
+        #expect(sentPackets[0].type == MessageType.fragment.rawValue)
+    }
 }
 
 private final class RecordingDelegate: GossipSyncManager.Delegate {
     var onSend: (() -> Void)?
     private(set) var lastPacket: BitchatPacket?
+    private(set) var packets: [BitchatPacket] = []
     private let lock = NSLock()
 
     func sendPacket(_ packet: BitchatPacket) {
         lock.lock()
         lastPacket = packet
+        packets.append(packet)
         lock.unlock()
         onSend?()
     }

bitchatTests/InputValidatorTests.swift

@@ -0,0 +1,192 @@
+//
+// InputValidatorTests.swift
+// bitchatTests
+//
+// This is free and unencumbered software released into the public domain.
+// For more information, see <https://unlicense.org>
+//
+
+import Testing
+import Foundation
+@testable import bitchat
+
+struct InputValidatorTests {
+
+    // MARK: - Basic Validation Tests
+
+    @Test func validStringPassesValidation() throws {
+        let result = InputValidator.validateUserString("Hello World", maxLength: 100)
+        #expect(result == "Hello World")
+    }
+
+    @Test func emptyStringReturnsNil() throws {
+        let result = InputValidator.validateUserString("", maxLength: 100)
+        #expect(result == nil)
+    }
+
+    @Test func whitespaceOnlyStringReturnsNil() throws {
+        let result = InputValidator.validateUserString("   \n\t  ", maxLength: 100)
+        #expect(result == nil)
+    }
+
+    @Test func stringExceedingMaxLengthReturnsNil() throws {
+        let longString = String(repeating: "a", count: 101)
+        let result = InputValidator.validateUserString(longString, maxLength: 100)
+        #expect(result == nil)
+    }
+
+    @Test func stringAtMaxLengthIsAccepted() throws {
+        let exactString = String(repeating: "a", count: 100)
+        let result = InputValidator.validateUserString(exactString, maxLength: 100)
+        #expect(result == exactString)
+    }
+
+    @Test func whitespaceIsTrimmed() throws {
+        let result = InputValidator.validateUserString("  Hello  ", maxLength: 100)
+        #expect(result == "Hello")
+    }
+
+    // MARK: - Control Character Tests
+
+    @Test func nullCharacterIsRejected() throws {
+        let stringWithNull = "Hello\u{0000}World"
+        let result = InputValidator.validateUserString(stringWithNull, maxLength: 100)
+        #expect(result == nil)
+    }
+
+    @Test func bellCharacterIsRejected() throws {
+        let stringWithBell = "Hello\u{0007}World"
+        let result = InputValidator.validateUserString(stringWithBell, maxLength: 100)
+        #expect(result == nil)
+    }
+
+    @Test func backspaceCharacterIsRejected() throws {
+        let stringWithBackspace = "Hello\u{0008}World"
+        let result = InputValidator.validateUserString(stringWithBackspace, maxLength: 100)
+        #expect(result == nil)
+    }
+
+    @Test func escapeCharacterIsRejected() throws {
+        let stringWithEscape = "Hello\u{001B}World"
+        let result = InputValidator.validateUserString(stringWithEscape, maxLength: 100)
+        #expect(result == nil)
+    }
+
+    @Test func deleteCharacterIsRejected() throws {
+        let stringWithDelete = "Hello\u{007F}World"
+        let result = InputValidator.validateUserString(stringWithDelete, maxLength: 100)
+        #expect(result == nil)
+    }
+
+    @Test func multipleControlCharactersAreRejected() throws {
+        let stringWithMultiple = "Hello\u{0000}\u{0007}\u{001B}World"
+        let result = InputValidator.validateUserString(stringWithMultiple, maxLength: 100)
+        #expect(result == nil)
+    }
+
+    // MARK: - Unicode and Special Character Tests
+
+    @Test func emojiIsAccepted() throws {
+        let result = InputValidator.validateUserString("Hello 👋 World", maxLength: 100)
+        #expect(result == "Hello 👋 World")
+    }
+
+    @Test func unicodeCharactersAreAccepted() throws {
+        let result = InputValidator.validateUserString("Hello 世界 مرحبا", maxLength: 100)
+        #expect(result == "Hello 世界 مرحبا")
+    }
+
+    @Test func specialCharactersAreAccepted() throws {
+        let result = InputValidator.validateUserString("Hello!@#$%^&*()_+-=[]{}|;':\",./<>?", maxLength: 100)
+        #expect(result == "Hello!@#$%^&*()_+-=[]{}|;':\",./<>?")
+    }
+
+    // MARK: - Nickname Validation Tests
+
+    @Test func validNicknameIsAccepted() throws {
+        let result = InputValidator.validateNickname("Alice")
+        #expect(result == "Alice")
+    }
+
+    @Test func nicknameWithEmojiIsAccepted() throws {
+        let result = InputValidator.validateNickname("Alice 🚀")
+        #expect(result == "Alice 🚀")
+    }
+
+    @Test func nicknameTooLongIsRejected() throws {
+        let longNickname = String(repeating: "a", count: 51)
+        let result = InputValidator.validateNickname(longNickname)
+        #expect(result == nil)
+    }
+
+    @Test func nicknameAtMaxLengthIsAccepted() throws {
+        let exactNickname = String(repeating: "a", count: 50)
+        let result = InputValidator.validateNickname(exactNickname)
+        #expect(result == exactNickname)
+    }
+
+    @Test func nicknameWithControlCharacterIsRejected() throws {
+        let result = InputValidator.validateNickname("Alice\u{0000}")
+        #expect(result == nil)
+    }
+
+    // MARK: - Timestamp Validation Tests
+
+    @Test func currentTimestampIsValid() throws {
+        let now = Date()
+        let result = InputValidator.validateTimestamp(now)
+        #expect(result == true)
+    }
+
+    @Test func timestampWithinOneHourIsValid() throws {
+        let thirtyMinutesAgo = Date().addingTimeInterval(-30 * 60)
+        let result = InputValidator.validateTimestamp(thirtyMinutesAgo)
+        #expect(result == true)
+    }
+
+    @Test func timestampTwoHoursAgoIsInvalid() throws {
+        let twoHoursAgo = Date().addingTimeInterval(-2 * 3600)
+        let result = InputValidator.validateTimestamp(twoHoursAgo)
+        #expect(result == false)
+    }
+
+    @Test func timestampTwoHoursInFutureIsInvalid() throws {
+        let twoHoursFromNow = Date().addingTimeInterval(2 * 3600)
+        let result = InputValidator.validateTimestamp(twoHoursFromNow)
+        #expect(result == false)
+    }
+
+    @Test func timestampAtOneHourBoundaryIsValid() throws {
+        // Just slightly within the one-hour window
+        let almostOneHourAgo = Date().addingTimeInterval(-3599)
+        let result = InputValidator.validateTimestamp(almostOneHourAgo)
+        #expect(result == true)
+    }
+
+    // MARK: - Edge Cases
+
+    @Test func singleCharacterStringIsAccepted() throws {
+        let result = InputValidator.validateUserString("a", maxLength: 100)
+        #expect(result == "a")
+    }
+
+    @Test func stringWithOnlyNewlinesIsRejected() throws {
+        let result = InputValidator.validateUserString("\n\n\n", maxLength: 100)
+        #expect(result == nil)
+    }
+
+    @Test func stringWithMixedWhitespaceIsTrimmed() throws {
+        let result = InputValidator.validateUserString(" \t\nHello\n\t ", maxLength: 100)
+        #expect(result == "Hello")
+    }
+
+    @Test func stringWithLeadingControlCharacterIsRejected() throws {
+        let result = InputValidator.validateUserString("\u{0000}Hello", maxLength: 100)
+        #expect(result == nil)
+    }
+
+    @Test func stringWithTrailingControlCharacterIsRejected() throws {
+        let result = InputValidator.validateUserString("Hello\u{0000}", maxLength: 100)
+        #expect(result == nil)
+    }
+}

bitchatTests/MimeTypeTests.swift

@@ -0,0 +1,90 @@
+//
+// MimeTypeTests.swift
+// bitchatTests
+//
+// This is free and unencumbered software released into the public domain.
+// For more information, see <https://unlicense.org>
+//
+
+import Testing
+import Foundation
+@testable import bitchat
+
+// MARK: - MimeType Mapping and Signature Tests
+
+struct MimeTypeTests {
+
+    // MARK: MIME → Enum Parsing + Default Extension
+    @Test(arguments: [
+        ("image/jpeg", MimeType.jpeg, "jpg"),
+        ("image/jpg", MimeType.jpeg, "jpg"),
+        ("image/png", MimeType.png, "png"),
+        ("image/gif", MimeType.gif, "gif"),
+        ("image/webp", MimeType.webp, "webp"),
+        ("audio/mp4", MimeType.mp4Audio, "m4a"),
+        ("audio/m4a", MimeType.m4a, "m4a"),
+        ("audio/aac", MimeType.aac, "m4a"),
+        ("audio/mpeg", MimeType.mpeg, "mp3"),
+        ("audio/mp3", MimeType.mp3, "mp3"),
+        ("audio/wav", MimeType.wav, "wav"),
+        ("audio/x-wav", MimeType.xWav, "wav"),
+        ("audio/ogg", MimeType.ogg, "ogg"),
+        ("application/pdf", MimeType.pdf, "pdf"),
+        ("application/octet-stream", MimeType.octetStream, "bin")
+    ])
+    func mimeTypeParsingAndExtensions(
+        mimeString: String,
+        expectedType: MimeType,
+        expectedExt: String
+    ) throws {
+        guard let mime = MimeType(mimeString) else {
+            Issue.record("Failed to parse \(mimeString)")
+            return
+        }
+
+        #expect(mime == expectedType, "Expected \(expectedType) for \(mimeString)")
+        #expect(mime.mimeString == expectedType.mimeString)
+        #expect(mime.defaultExtension == expectedExt)
+        #expect(mime.isAllowed)
+    }
+
+    // MARK: - File Signature Validation
+    @Test(arguments: [
+        // === Image types ===
+        (MimeType.jpeg, [0xFF, 0xD8, 0xFF]),
+        (MimeType.png,  [0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A]),
+        (MimeType.gif,  [0x47, 0x49, 0x46, 0x38, 0x39, 0x61]), // "GIF89a"
+        (MimeType.webp, [0x52, 0x49, 0x46, 0x46, 0x00, 0x00, 0x00, 0x00,
+                         0x57, 0x45, 0x42, 0x50]),             // "RIFF....WEBP"
+
+        // === Audio types ===
+        (MimeType.mp3,  [0x49, 0x44, 0x33]),                   // "ID3"
+        (MimeType.wav,  [0x52, 0x49, 0x46, 0x46, 0x00, 0x00, 0x00, 0x00,
+                         0x57, 0x41, 0x56, 0x45]),             // "RIFF....WAVE"
+        (MimeType.ogg,  [0x4F, 0x67, 0x67, 0x53]),             // "OggS"
+
+        // === Application types ===
+        (MimeType.pdf,  [0x25, 0x50, 0x44, 0x46])              // "%PDF"
+    ])
+    func validSignatures(mime: MimeType, bytes: [UInt8]) throws {
+        let data = Data(bytes)
+        #expect(mime.matches(data: data),
+                "Expected \(mime.mimeString) to match its signature")
+    }
+
+    // MARK: - Negative Tests
+    @Test func invalidDataDoesNotMatch() throws {
+        let badData = Data(repeating: 0x00, count: 16)
+        for mime in MimeType.allCases where mime != .octetStream {
+            #expect(!mime.matches(data: badData),
+                    "Unexpectedly matched \(mime.mimeString) with zeroed data")
+        }
+    }
+
+    // MARK: - Octet-stream (generic binary)
+    @Test func octetStreamAlwaysMatches() throws {
+        let randomData = Data([0x00, 0x11, 0x22, 0x33])
+        #expect(MimeType.octetStream.matches(data: randomData),
+                "application/octet-stream should always be considered valid")
+    }
+}

bitchatTests/Mocks/MockBLEService.swift

@@ -203,10 +203,7 @@ final class MockBLEService: NSObject {
                let target = bus.service(for: recipientPeerID) {
                 target.simulateIncomingPacket(packet)
             } else {
-                // Not directly connected: deliver to neighbors for relay; also deliver directly if target is known
-                if let target = bus.service(for: recipientPeerID) {
-                    target.simulateIncomingPacket(packet)
-                }
+                // Not directly connected: deliver to neighbors for relay
                 for neighbor in neighbors() where neighbor.peerID != recipientPeerID {
                     neighbor.simulateIncomingPacket(packet)
                 }

bitchatTests/Utils/PeerIDTests.swift

@@ -273,7 +273,7 @@ struct PeerIDTests {
     @Test func comparable_sorting_and_equality() {
         let p1 = PeerID(str: "aaa")
         let p2 = PeerID(str: "bbb")
-        let p3 = PeerID(str: "bbb")
+        let p3 = PeerID(str: "BBB")
         
         #expect(p1 < p2)
         #expect(p2 >= p1)
@@ -284,44 +284,18 @@ struct PeerIDTests {
     }
     
     @Test func equality() {
-        let string = "aaa"
-        let peerID = PeerID(str: string)
-        let badString = "bbb"
-        
-        // PeerID == String
-        #expect(peerID == string)
-        #expect(peerID == Optional(string))
-        #expect(Optional(peerID) == string)
-        #expect(Optional(peerID) == Optional(string))
-
-        // PeerID != String
-        #expect(peerID != badString)
-        #expect(peerID != Optional(badString))
-        #expect(Optional(peerID) != badString)
-        #expect(Optional(peerID) != Optional(badString))
-        
-        // String == PeerID
-        #expect(string == peerID)
-        #expect(Optional(string) == peerID)
-        #expect(string == Optional(peerID))
-        #expect(Optional(string) == Optional(peerID))
-
-        // String != PeerID
-        #expect(badString != peerID)
-        #expect(Optional(badString) != peerID)
-        #expect(badString != Optional(peerID))
-        #expect(Optional(badString) != Optional(peerID))
+        let peerID = PeerID(str: "aaa")
         
         // Regular PeerID <> PeerID
-        #expect(peerID == PeerID(str: "aaa"))
-        #expect(peerID == Optional(PeerID(str: "aaa")))
-        #expect(PeerID(str: "aaa") == peerID)
-        #expect(Optional(PeerID(str: "aaa")) == Optional(peerID))
+        #expect(peerID == PeerID(str: "AAA"))
+        #expect(peerID == Optional(PeerID(str: "AAA")))
+        #expect(PeerID(str: "AAA") == peerID)
+        #expect(Optional(PeerID(str: "AAA")) == Optional(peerID))
         
-        #expect(peerID != PeerID(str: "bbb"))
-        #expect(peerID != Optional(PeerID(str: "bbb")))
-        #expect(PeerID(str: "bbb") != peerID)
-        #expect(Optional(PeerID(str: "bbb")) != Optional(peerID))
+        #expect(peerID != PeerID(str: "BBB"))
+        #expect(peerID != Optional(PeerID(str: "BBB")))
+        #expect(PeerID(str: "BBB") != peerID)
+        #expect(Optional(PeerID(str: "BBB")) != Optional(peerID))
     }
     
     // MARK: - Computed properties