Correlate private media delivery receipts

bitchat/Protocols/BitchatFilePacket.swift

@@ -154,3 +154,90 @@ struct BitchatFilePacket {
         )
     }
 }
+
+/// Wire-compatible identity for private media exchanged by clients using the
+/// current iOS entropy-bearing filenames, without extending the deployed file
+/// TLV. Android clients reject unknown file tags, so eligible senders and
+/// receivers derive the receipt key from fields already on the wire.
+///
+/// Locally-created image and voice-note filenames contain a UUID or live-voice
+/// burst ID. Including the normalized direction keeps a reused filename
+/// distinct across chats while allowing short and full Noise-key peer IDs to
+/// converge. Android and older-iOS timestamp-only names remain ineligible and
+/// retain their legacy random local IDs (transfer-compatible, no receipts).
+enum PrivateMediaMessageIdentity {
+    private static let domain = Data("bitchat-private-media-message-v1".utf8)
+    private static let idPrefix = "media-"
+    private static let digestHexLength = 32
+
+    static func isStableID(_ candidate: String) -> Bool {
+        guard candidate.hasPrefix(idPrefix) else { return false }
+        let digest = candidate.dropFirst(idPrefix.count)
+        guard digest.utf8.count == digestHexLength else { return false }
+        return digest.utf8.allSatisfy { byte in
+            (UInt8(ascii: "0")...UInt8(ascii: "9")).contains(byte)
+                || (UInt8(ascii: "a")...UInt8(ascii: "f")).contains(byte)
+        }
+    }
+
+    static func stableID(
+        senderPeerID: PeerID,
+        recipientPeerID: PeerID,
+        fileName: String?
+    ) -> String? {
+        guard let fileName, !fileName.isEmpty else { return nil }
+        let leafName = (fileName as NSString).lastPathComponent
+        guard leafName == fileName else { return nil }
+
+        let path = leafName as NSString
+        let stem = path.deletingPathExtension
+        let fileExtension = path.pathExtension.lowercased()
+        switch true {
+        case stem.hasPrefix("img_"):
+            guard fileExtension == "jpg" || fileExtension == "jpeg" else { return nil }
+        case stem.hasPrefix("voice_"):
+            guard fileExtension == "m4a" else { return nil }
+        default:
+            return nil
+        }
+        let entropyToken = stem.split(separator: "_").last.map(String.init)
+        let hasUUIDEntropy = entropyToken.flatMap(UUID.init(uuidString:)) != nil
+        let voiceBurstID = stem.hasPrefix("voice_")
+            ? String(stem.dropFirst("voice_".count))
+            : ""
+        let hasBurstEntropy = voiceBurstID.count == 16
+            && voiceBurstID.allSatisfy(\.isHexDigit)
+        guard hasUUIDEntropy || hasBurstEntropy else {
+            return nil
+        }
+
+        let fields = [
+            Data(senderPeerID.toShort().bare.utf8),
+            Data(recipientPeerID.toShort().bare.utf8),
+            Data(leafName.utf8)
+        ]
+        var input = domain
+        for field in fields {
+            guard let length = UInt32(exactly: field.count) else { return nil }
+            var bigEndianLength = length.bigEndian
+            withUnsafeBytes(of: &bigEndianLength) {
+                input.append(contentsOf: $0)
+            }
+            input.append(field)
+        }
+
+        return "\(idPrefix)\(input.sha256Hex().prefix(digestHexLength))"
+    }
+
+    static func stableID(
+        for packet: BitchatFilePacket,
+        senderPeerID: PeerID,
+        recipientPeerID: PeerID
+    ) -> String? {
+        stableID(
+            senderPeerID: senderPeerID,
+            recipientPeerID: recipientPeerID,
+            fileName: packet.fileName
+        )
+    }
+}

bitchat/Services/BLE/BLEFileTransferHandler.swift

@@ -32,17 +32,63 @@ struct BLEFileTransferHandlerEnvironment {
         _ fallbackExtension: String?,
         _ defaultPrefix: String
     ) -> URL?
+    /// Checks the authenticated sender before any private-media disk work.
+    let isPrivateMediaSenderBlocked: (PeerID) -> Bool
     /// Updates the registry last-seen timestamp for the peer (async barrier write).
     let updatePeerLastSeen: (PeerID) -> Void
+    /// Re-acknowledges a stable private-media duplicate without saving or
+    /// re-delivering it. This lets a sender recover from a lost ACK.
+    let acknowledgePrivateMediaDuplicate: (_ messageID: String, _ peerID: PeerID) -> Void
     /// Delivers `.messageReceived` to the UI as one main-actor hop.
     let deliverMessage: (BitchatMessage) -> Void
 }
 
+/// Process-lifetime reservation cache for stable private-media IDs.
+///
+/// The first arrival reserves its ID before quota enforcement and commits it
+/// only after durable save. Concurrent/retried arrivals are rejected before
+/// they can create uniquified orphan files or churn the incoming-media quota.
+private final class PrivateMediaArrivalDeduplicator {
+    enum Reservation {
+        case reserved
+        case pending
+        case accepted
+    }
+
+    private let lock = NSLock()
+    private var accepted = BoundedIDSet(capacity: 4_096)
+    private var pending: Set<String> = []
+
+    func reserve(_ messageID: String) -> Reservation {
+        lock.lock()
+        defer { lock.unlock() }
+        if accepted.contains(messageID) {
+            return .accepted
+        }
+        if pending.contains(messageID) {
+            return .pending
+        }
+
+        pending.insert(messageID)
+        return .reserved
+    }
+
+    func finish(_ messageID: String, accepted didAccept: Bool) {
+        lock.lock()
+        defer { lock.unlock() }
+        pending.remove(messageID)
+        if didAccept {
+            accepted.insert(messageID)
+        }
+    }
+}
+
 /// Orchestrates inbound file transfers: self-echo policy, sender display-name
 /// resolution, delivery planning, payload validation, quota-checked storage,
 /// and UI delivery.
 final class BLEFileTransferHandler {
     private let environment: BLEFileTransferHandlerEnvironment
+    private let privateMediaArrivals = PrivateMediaArrivalDeduplicator()
 
     init(environment: BLEFileTransferHandlerEnvironment) {
         self.environment = environment
@@ -129,6 +175,7 @@ final class BLEFileTransferHandler {
         env: BLEFileTransferHandlerEnvironment
     ) -> Bool {
 
+        let localPeerID = env.localPeerID()
         let filePacket: BitchatFilePacket
         let mime: MimeType
         switch BLEIncomingFileValidator.validate(payload: payload) {
@@ -149,6 +196,51 @@ final class BLEFileTransferHandler {
             return false
         }
 
+        if isPrivate, env.isPrivateMediaSenderBlocked(peerID) {
+            SecureLogger.debug(
+                "🚫 Dropping private media from blocked peer \(peerID.id.prefix(8))… before disk write",
+                category: .security
+            )
+            return true
+        }
+
+        let messageID = isPrivate
+            ? PrivateMediaMessageIdentity.stableID(
+                for: filePacket,
+                senderPeerID: peerID,
+                recipientPeerID: localPeerID
+            )
+            : nil
+        if let messageID {
+            switch privateMediaArrivals.reserve(messageID) {
+            case .reserved:
+                break
+            case .pending:
+                // The first arrival has not reached durable storage yet.
+                // Coalesce this retry without ACKing so a failed first save
+                // remains retryable by the sender.
+                SecureLogger.debug(
+                    "📁 Coalesced in-flight private media id=\(messageID.prefix(12))… from \(peerID.id.prefix(8))…",
+                    category: .session
+                )
+                return true
+            case .accepted:
+                env.updatePeerLastSeen(peerID)
+                env.acknowledgePrivateMediaDuplicate(messageID, peerID)
+                SecureLogger.debug(
+                    "📁 Ignored durable private media duplicate id=\(messageID.prefix(12))… from \(peerID.id.prefix(8))…",
+                    category: .session
+                )
+                return true
+            }
+        }
+        var acceptedStableMedia = false
+        defer {
+            if let messageID {
+                privateMediaArrivals.finish(messageID, accepted: acceptedStableMedia)
+            }
+        }
+
         // BCH-01-002: Enforce storage quota before saving
         env.enforceStorageQuota(filePacket.content.count)
 
@@ -167,6 +259,7 @@ final class BLEFileTransferHandler {
         }
 
         let message = BitchatMessage(
+            id: messageID,
             sender: senderNickname,
             content: "\(mime.category.messagePrefix)\(destination.lastPathComponent)",
             timestamp: timestamp,
@@ -185,6 +278,7 @@ final class BLEFileTransferHandler {
 
         SecureLogger.debug("📁 Stored incoming media from \(peerID.id.prefix(8))… -> \(destination.lastPathComponent)", category: .session)
 
+        acceptedStableMedia = messageID != nil
         env.deliverMessage(message)
         return true
     }

bitchat/Services/BLE/BLEService.swift

@@ -2527,9 +2527,30 @@ final class BLEService: NSObject {
                     defaultPrefix: defaultPrefix
                 )
             },
+            isPrivateMediaSenderBlocked: { [weak self] peerID in
+                guard let self else { return false }
+                let senderStaticKey = self.noiseService.getPeerPublicKeyData(peerID)
+                    ?? self.collectionsQueue.sync {
+                        self.peerRegistry.info(for: peerID)?.noisePublicKey
+                    }
+                guard let senderStaticKey else { return false }
+                return self.identityManager.isBlocked(
+                    fingerprint: senderStaticKey.sha256Fingerprint()
+                )
+            },
             updatePeerLastSeen: { [weak self] peerID in
                 self?.updatePeerLastSeen(peerID)
             },
+            acknowledgePrivateMediaDuplicate: { [weak self] messageID, peerID in
+                guard let self,
+                      let senderStaticKey = self.noiseService.getPeerPublicKeyData(peerID),
+                      !self.identityManager.isBlocked(
+                        fingerprint: senderStaticKey.sha256Fingerprint()
+                      ) else {
+                    return
+                }
+                self.sendDeliveryAck(for: messageID, to: peerID)
+            },
             deliverMessage: { [weak self] message in
                 // Single main-actor hop delivering `.messageReceived`.
                 self?.emitTransportEvent(.messageReceived(message))

bitchat/ViewModels/ChatLiveVoiceCoordinator.swift

@@ -10,6 +10,7 @@ import Foundation
 @MainActor
 protocol ChatLiveVoiceContext: AnyObject {
     var nickname: String { get }
+    var myPeerID: PeerID { get }
     var selectedPrivateChatPeer: PeerID? { get }
     /// Whether the public mesh timeline is what's on screen (autoplay gate
     /// for public bursts).
@@ -30,6 +31,12 @@ protocol ChatLiveVoiceContext: AnyObject {
     func upsertPublicMeshMessage(_ message: BitchatMessage)
     @discardableResult
     func removePrivateMessage(withID messageID: String) -> BitchatMessage?
+    /// Records and sends the finalized note's read receipt after a live
+    /// bubble adopts its wire-derivable message ID.
+    func hasSentReadReceipt(_ messageID: String) -> Bool
+    @discardableResult
+    func markReadReceiptSent(_ messageID: String) -> Bool
+    func sendMeshReadReceipt(_ receipt: ReadReceipt, to peerID: PeerID)
     /// Removes a message from whichever conversation holds it.
     func removeMessage(withID messageID: String, cleanupFile: Bool)
     /// Publishes who is currently talking live in the public mesh channel
@@ -272,8 +279,16 @@ final class ChatLiveVoiceCoordinator {
         guard let entry = finishedBursts.first(where: { matches($0.key) }) else { return false }
         let finished = entry.value
 
+        // A DM live bubble starts before the finalized file exists and
+        // therefore has a receiver-local random ID. Adopt the finalized
+        // message's deterministic ID so delivery/read ACKs address the same
+        // row as the sender's media placeholder. Public notes retain their
+        // live-bubble ID because public transfers have no private receipts.
+        let replacementID = finished.scope == .directMessage
+            ? message.id
+            : finished.messageID
         let replacement = BitchatMessage(
-            id: finished.messageID,
+            id: replacementID,
             sender: message.sender,
             content: message.content,
             timestamp: finished.messageTimestamp,
@@ -287,7 +302,31 @@ final class ChatLiveVoiceCoordinator {
         )
         switch finished.scope {
         case .directMessage:
+            // Capture read state before rekeying. The user may have read the
+            // live bubble and navigated away before the finalized .m4a lands.
+            let shouldSendAdoptedReadReceipt =
+                context.hasSentReadReceipt(finished.messageID)
+                || context.selectedPrivateChatPeer == finished.peerID
+
+            // Insert first so replacing the only row in a DM never
+            // transiently deletes its conversation, unread state, or current
+            // selection. Then remove the receiver-local live-bubble alias.
             context.upsertPrivateMessage(replacement, in: finished.peerID)
+            if replacementID != finished.messageID {
+                context.removePrivateMessage(withID: finished.messageID)
+            }
+            // The live bubble may already have emitted a receiver-local READ
+            // before the sender created its finalized media row. Re-emit once
+            // for the adopted stable ID now that the file has arrived.
+            if shouldSendAdoptedReadReceipt,
+               context.markReadReceiptSent(replacementID) {
+                let receipt = ReadReceipt(
+                    originalMessageID: replacementID,
+                    readerID: context.myPeerID,
+                    readerNickname: context.nickname
+                )
+                context.sendMeshReadReceipt(receipt, to: finished.peerID)
+            }
         case .publicMesh:
             context.upsertPublicMeshMessage(replacement)
         }

bitchat/ViewModels/ChatMediaTransferCoordinator.swift

@@ -252,9 +252,17 @@ final class ChatMediaTransferCoordinator {
         }
 
         let targetPeer = context.selectedPrivateChatPeer
+        let privateMessageID = targetPeer.flatMap { peerID in
+            PrivateMediaMessageIdentity.stableID(
+                senderPeerID: context.myPeerID,
+                recipientPeerID: peerID,
+                fileName: url.lastPathComponent
+            )
+        }
         let message = enqueueMediaMessage(
             content: "\(MimeType.Category.audio.messagePrefix)\(url.lastPathComponent)",
-            targetPeer: targetPeer
+            targetPeer: targetPeer,
+            messageID: privateMessageID
         )
         let messageID = message.id
         let transferId = makeTransferID(messageID: messageID)
@@ -419,9 +427,17 @@ final class ChatMediaTransferCoordinator {
                         try? FileManager.default.removeItem(at: prepared.outputURL)
                         return
                     }
+                    let privateMessageID = targetPeer.flatMap { peerID in
+                        PrivateMediaMessageIdentity.stableID(
+                            for: prepared.packet,
+                            senderPeerID: self.context.myPeerID,
+                            recipientPeerID: peerID
+                        )
+                    }
                     let message = self.enqueueMediaMessage(
                         content: "\(MimeType.Category.image.messagePrefix)\(prepared.outputURL.lastPathComponent)",
-                        targetPeer: targetPeer
+                        targetPeer: targetPeer,
+                        messageID: privateMessageID
                     )
                     let messageID = message.id
                     let transferId = self.makeTransferID(messageID: messageID)
@@ -459,12 +475,17 @@ final class ChatMediaTransferCoordinator {
         }
     }
 
-    func enqueueMediaMessage(content: String, targetPeer: PeerID?) -> BitchatMessage {
+    func enqueueMediaMessage(
+        content: String,
+        targetPeer: PeerID?,
+        messageID: String? = nil
+    ) -> BitchatMessage {
         let timestamp = Date()
         let message: BitchatMessage
 
         if let peerID = targetPeer {
             message = BitchatMessage(
+                id: messageID,
                 sender: context.nickname,
                 content: content,
                 timestamp: timestamp,

bitchat/ViewModels/ChatViewModel.swift

@@ -495,6 +495,12 @@ final class ChatViewModel: ObservableObject, BitchatDelegate, SynchronousMessage
         }
     }
 
+    /// Whether a read receipt has already been recorded for `messageID`.
+    @MainActor
+    func hasSentReadReceipt(_ messageID: String) -> Bool {
+        sentReadReceipts.contains(messageID)
+    }
+
     /// Records that a read receipt is being sent for `messageID`.
     /// Returns `false` when one was already recorded — the caller must skip sending.
     @MainActor