ios: better network handling

ios/Packages/Sybil/Tests/SybilTests/SybilTests.swift

@@ -19,6 +19,10 @@ private actor MockSybilClient: SybilAPIClienting {
     private let searchDetails: [String: SearchDetail]
 
     private var snapshot = MockClientCallSnapshot()
+    private var completionStreamNetworkErrorMessage: String?
+    private var completionStreamDelayNanoseconds: UInt64 = 0
+    private var searchStreamNetworkErrorMessage: String?
+    private var searchStreamDelayNanoseconds: UInt64 = 0
 
     init(
         chatsResponse: [ChatSummary] = [],
@@ -36,6 +40,16 @@ private actor MockSybilClient: SybilAPIClienting {
         snapshot
     }
 
+    func setCompletionStreamNetworkError(_ message: String, delayNanoseconds: UInt64 = 0) {
+        completionStreamNetworkErrorMessage = message
+        completionStreamDelayNanoseconds = delayNanoseconds
+    }
+
+    func setSearchStreamNetworkError(_ message: String, delayNanoseconds: UInt64 = 0) {
+        searchStreamNetworkErrorMessage = message
+        searchStreamDelayNanoseconds = delayNanoseconds
+    }
+
     func verifySession() async throws -> AuthSession {
         AuthSession(authenticated: true, mode: "open")
     }
@@ -98,6 +112,12 @@ private actor MockSybilClient: SybilAPIClienting {
         body: CompletionStreamRequest,
         onEvent: @escaping @Sendable (CompletionStreamEvent) async -> Void
     ) async throws {
+        if completionStreamDelayNanoseconds > 0 {
+            try await Task.sleep(nanoseconds: completionStreamDelayNanoseconds)
+        }
+        if let completionStreamNetworkErrorMessage {
+            throw APIError.networkError(message: completionStreamNetworkErrorMessage)
+        }
         throw UnexpectedClientCall()
     }
 
@@ -106,6 +126,12 @@ private actor MockSybilClient: SybilAPIClienting {
         body: SearchRunRequest,
         onEvent: @escaping @Sendable (SearchStreamEvent) async -> Void
     ) async throws {
+        if searchStreamDelayNanoseconds > 0 {
+            try await Task.sleep(nanoseconds: searchStreamDelayNanoseconds)
+        }
+        if let searchStreamNetworkErrorMessage {
+            throw APIError.networkError(message: searchStreamNetworkErrorMessage)
+        }
         throw UnexpectedClientCall()
     }
 }
@@ -267,6 +293,84 @@ private func makeSearchDetail(id: String, date: Date, answer: String) -> SearchD
     #expect(viewModel.selectedSearch?.answerText == "fresh answer")
 }
 
+@MainActor
+@Test func backgroundChatStreamInterruptionIsSuppressedUntilForegroundRefresh() async throws {
+    let date = Date(timeIntervalSince1970: 1_700_000_300)
+    let chat = makeChatSummary(id: "chat-3", date: date)
+    let initialDetail = makeChatDetail(id: "chat-3", date: date, body: "stale transcript")
+    let refreshedDetail = makeChatDetail(id: "chat-3", date: date, body: "fresh transcript")
+    let client = MockSybilClient(
+        chatsResponse: [chat],
+        chatDetails: ["chat-3": refreshedDetail]
+    )
+    await client.setCompletionStreamNetworkError(
+        "Network error -1005 while requesting POST: The network connection was lost.",
+        delayNanoseconds: 50_000_000
+    )
+    let viewModel = SybilViewModel(settings: testSettings(named: #function)) { _ in client }
+    viewModel.isAuthenticated = true
+    viewModel.isCheckingSession = false
+    viewModel.selectedItem = .chat("chat-3")
+    viewModel.selectedChat = initialDetail
+    viewModel.composer = "continue"
+
+    let sendTask = Task {
+        await viewModel.sendComposer()
+    }
+    try await Task.sleep(nanoseconds: 10_000_000)
+    viewModel.markAppInactiveForNetwork()
+    await sendTask.value
+
+    #expect(viewModel.errorMessage == nil)
+    #expect(viewModel.composer.isEmpty)
+    #expect(!viewModel.isSending)
+    #expect(viewModel.selectedChat?.messages.first?.content == "stale transcript")
+
+    await viewModel.refreshAfterAppBecameActive(refreshCollections: false, refreshSelection: true)
+
+    let snapshot = await client.currentSnapshot()
+    #expect(snapshot.getChat == 1)
+    #expect(viewModel.errorMessage == nil)
+    #expect(viewModel.selectedChat?.messages.first?.content == "fresh transcript")
+}
+
+@MainActor
+@Test func backgroundSearchStreamInterruptionIsSuppressedUntilForegroundRefresh() async throws {
+    let date = Date(timeIntervalSince1970: 1_700_000_400)
+    let refreshedDetail = makeSearchDetail(id: "search-3", date: date, answer: "fresh answer")
+    let client = MockSybilClient(
+        searchDetails: ["search-3": refreshedDetail]
+    )
+    await client.setSearchStreamNetworkError(
+        "Network error -1005 while requesting POST: The network connection was lost.",
+        delayNanoseconds: 50_000_000
+    )
+    let viewModel = SybilViewModel(settings: testSettings(named: #function)) { _ in client }
+    viewModel.isAuthenticated = true
+    viewModel.isCheckingSession = false
+    viewModel.selectedItem = .search("search-3")
+    viewModel.selectedSearch = makeSearchDetail(id: "search-3", date: date, answer: "stale answer")
+    viewModel.composer = "refresh me"
+
+    let sendTask = Task {
+        await viewModel.sendComposer()
+    }
+    try await Task.sleep(nanoseconds: 10_000_000)
+    viewModel.markAppInactiveForNetwork()
+    await sendTask.value
+
+    #expect(viewModel.errorMessage == nil)
+    #expect(viewModel.composer.isEmpty)
+    #expect(!viewModel.isSending)
+
+    await viewModel.refreshAfterAppBecameActive(refreshCollections: false, refreshSelection: true)
+
+    let snapshot = await client.currentSnapshot()
+    #expect(snapshot.getSearch == 1)
+    #expect(viewModel.errorMessage == nil)
+    #expect(viewModel.selectedSearch?.answerText == "fresh answer")
+}
+
 @Test func newChatSwipeMetricsClampProgressAndLatch() async throws {
     let width: CGFloat = 390
     let maxTravel = NewChatSwipeMetrics.maxTravel(for: width)