Persist private media delivery receipts

bitchatTests/ChatMediaTransferCoordinatorContextTests.swift

@@ -8,7 +8,7 @@
 // `ChatPrivateConversationCoordinatorContextTests` exemplars.
 //
 // Real file/codec work remains covered by `ChatMediaPreparationTests`. These
-// tests inject a paused voice-note preparer to exercise cancellation ownership
+// tests inject paused media preparers to exercise cancellation ownership
 // across the detached-preparation/MainActor boundary deterministically.
 //
 
@@ -216,6 +216,59 @@ private final class PausedVoiceNotePreparer: @unchecked Sendable {
     }
 }
 
+private final class StaticVoiceNotePreparer: @unchecked Sendable {
+    private let packet: BitchatFilePacket
+
+    init(fileName: String, content: Data = Data("voice".utf8)) {
+        packet = BitchatFilePacket(
+            fileName: fileName,
+            fileSize: UInt64(content.count),
+            mimeType: "audio/mp4",
+            content: content
+        )
+    }
+
+    func prepare(_ _: URL) throws -> BitchatFilePacket {
+        packet
+    }
+}
+
+private final class DeterministicMediaTransferIDFactory:
+    @unchecked Sendable {
+    private let lock = NSLock()
+    private var nextOrdinal = 0
+
+    func make(messageID: String) -> String {
+        lock.lock()
+        defer {
+            nextOrdinal += 1
+            lock.unlock()
+        }
+        return "\(messageID)-attempt-\(nextOrdinal)"
+    }
+}
+
+private final class MutableMediaRetryClock: @unchecked Sendable {
+    private let lock = NSLock()
+    private var value: Date
+
+    init(_ value: Date) {
+        self.value = value
+    }
+
+    func now() -> Date {
+        lock.lock()
+        defer { lock.unlock() }
+        return value
+    }
+
+    func advance(by interval: TimeInterval) {
+        lock.lock()
+        value = value.addingTimeInterval(interval)
+        lock.unlock()
+    }
+}
+
 // MARK: - Coordinator Tests Against Mock Context
 
 /// Exercises `ChatMediaTransferCoordinator` against
@@ -502,6 +555,58 @@ struct ChatMediaTransferCoordinatorContextTests {
         coordinator.cleanupLocalFile(forMessage: message)
     }
 
+    @Test @MainActor
+    func panicDuringImagePreparationDeletesStaleOutputWithoutSideEffects() async throws {
+        let context = MockChatMediaTransferContext()
+        let peerID = PeerID(str: "99aabbccddeeff00")
+        context.selectedPrivateChatPeer = peerID
+        let sourceURL = try makeCoordinatorTestImageURL()
+        let outputURL = FileManager.default.temporaryDirectory
+            .appendingPathComponent(
+                "panic-stale-image-\(UUID().uuidString).jpg"
+            )
+        let preparer = PausedImagePreparer(outputURL: outputURL)
+        let coordinator = ChatMediaTransferCoordinator(
+            context: context,
+            prepareImagePacket: { url in try preparer.prepare(url) }
+        )
+        defer {
+            preparer.release()
+            try? FileManager.default.removeItem(at: sourceURL)
+            try? FileManager.default.removeItem(at: outputURL)
+        }
+
+        coordinator.sendImage(from: sourceURL)
+        #expect(await TestHelpers.waitUntil(
+            { preparer.hasStarted },
+            timeout: TestConstants.longTimeout
+        ))
+
+        DispatchQueue.global(qos: .userInitiated).asyncAfter(
+            deadline: .now() + .milliseconds(100)
+        ) {
+            preparer.release()
+        }
+        coordinator.resetForPanic()
+
+        #expect(await TestHelpers.waitUntil(
+            { preparer.hasFinished },
+            timeout: TestConstants.longTimeout
+        ))
+        #expect(await TestHelpers.waitUntil(
+            { !FileManager.default.fileExists(atPath: outputURL.path) },
+            timeout: TestConstants.longTimeout
+        ))
+        #expect(context.privateChats[peerID]?.isEmpty != false)
+        #expect(context.appendedPublicMessages.isEmpty)
+        #expect(context.privateFileSends.isEmpty)
+        #expect(context.broadcastFileSends.isEmpty)
+        #expect(context.systemMessages.isEmpty)
+        #expect(context.deliveryStatusUpdates.isEmpty)
+        #expect(coordinator.transferIdToMessageIDs.isEmpty)
+        #expect(coordinator.messageIDToTransferId.isEmpty)
+    }
+
     @Test @MainActor
     func cancelVoiceNoteDuringDetachedPreparationCannotSendOrRestoreMapping() async throws {
         let context = MockChatMediaTransferContext()