feat: show a loading indicator on gateway attachments while they open (#917)

Tapping a gateway attachment gave zero feedback while the file
downloaded (a 100MB file could sit there silently for tens of seconds).
Mirror the save spinner: ChatUiState gains openingAttachmentPath, set
when openAttachment starts the download and cleared in a finally, and
the attachment card renders a small CircularProgressIndicator while its
path is being fetched. Wired through FullBleedChatList, ChatBubble and
FullBleedAgentMessage.

Co-authored-by: M57 <hy4ri@users.noreply.github.com>

app/src/main/java/com/m57/hermescontrol/ui/chat/ChatBubble.kt

@@ -92,6 +92,7 @@ fun ChatBubble(
     onOpenAttachment: (Attachment) -> Unit = {},
     onSaveAttachment: (Attachment) -> Unit = {},
     savingAttachmentPath: String? = null,
+    openingAttachmentPath: String? = null,
     canSaveAttachment: Boolean = true,
     onImageClick: (ImageViewerModel) -> Unit = {},
     modifier: Modifier = Modifier,
@@ -191,6 +192,7 @@ fun ChatBubble(
                                     onOpen = { onOpenAttachment(it) },
                                     onSave = { onSaveAttachment(it) },
                                     savingPath = savingAttachmentPath,
+                                    openingPath = openingAttachmentPath,
                                     canSave = canSaveAttachment,
                                     onImageClick = onImageClick,
                                 )
@@ -432,11 +434,13 @@ internal fun InlineAttachment(
     onOpen: (Attachment) -> Unit,
     onSave: (Attachment) -> Unit,
     savingPath: String?,
+    openingPath: String?,
     canSave: Boolean,
     onImageClick: (ImageViewerModel) -> Unit,
 ) {
     val attachmentPath = attachment.gatewayUrl?.let(::gatewayPathFromUrl) ?: attachment.name
     val isSaving = savingPath != null && savingPath == attachmentPath
+    val isOpening = openingPath != null && openingPath == attachmentPath
     val clickable = Modifier.clickable { onOpen(attachment) }
     if (attachment.isVideo) {
         var showVideoDialog by remember { mutableStateOf(false) }
@@ -505,6 +509,13 @@ internal fun InlineAttachment(
                         style = MaterialTheme.typography.labelSmall,
                     )
                 }
+                if (isOpening) {
+                    CircularProgressIndicator(
+                        modifier = Modifier.size(20.dp),
+                        strokeWidth = 2.dp,
+                    )
+                    Spacer(modifier = Modifier.width(10.dp))
+                }
                 if (attachment.gatewayUrl != null) {
                     IconButton(
                         onClick = { onSave(attachment) },

app/src/main/java/com/m57/hermescontrol/ui/chat/ChatScreen.kt

@@ -625,6 +625,7 @@ fun ChatScreen(
                     onDismissClarify = viewModel::dismissClarify,
                     onSaveAttachment = onSaveAttachment,
                     savingAttachmentPath = pendingSavePath ?: state.savingAttachmentPath,
+                    openingAttachmentPath = state.openingAttachmentPath,
                     onImageClick = { viewingImage = it },
                 )
 

app/src/main/java/com/m57/hermescontrol/ui/chat/ChatViewModel.kt

@@ -258,6 +258,9 @@ data class ChatUiState(
     // Attachment feedback — surfaced as a non-blocking snackbar (issue #724)
     val openError: String? = null,
     val savingAttachmentPath: String? = null,
+    // Gateway file currently being downloaded for open — drives the inline
+    // loading indicator on the attachment card (issue #913 follow-up).
+    val openingAttachmentPath: String? = null,
     val clarifyRequest: ClarifyUi? = null,
     // Sudo / secret prompts — surfaced as dialogs (issue #524)
     val sudoPrompt: SudoPromptUi? = null,
@@ -3041,31 +3044,40 @@ class ChatViewModel(
         }
         // GATEWAY, or LOCAL direct-open failed → fetch/copy then open.
         val path = gatewayPathFor(attachment)
+        // Show a loading indicator on the attachment card while the file
+        // streams down (mirrors the save spinner; cleared in all outcomes).
+        _uiState.update { it.copy(openingAttachmentPath = path) }
         val cacheDir = java.io.File(ctx.cacheDir, "gateway_files")
         viewModelScope.launch(ioDispatcher) {
-            when (val result = GatewayFileClient.fetch(path, cacheDir)) {
+            try {
-                is GatewayFileResult.Success -> {
+                when (val result = GatewayFileClient.fetch(path, cacheDir)) {
-                    openBytes(ctx, result.file)
+                    is GatewayFileResult.Success -> {
-                }
+                        openBytes(ctx, result.file)
+                    }
 
-                is GatewayFileResult.NotFound -> {
+                    is GatewayFileResult.NotFound -> {
-                    showOpenError("File not found on gateway: ${attachment.name}")
+                        showOpenError("File not found on gateway: ${attachment.name}")
-                }
+                    }
 
-                is GatewayFileResult.Forbidden -> {
+                    is GatewayFileResult.Forbidden -> {
-                    showOpenError("Access denied: ${attachment.name}")
+                        showOpenError("Access denied: ${attachment.name}")
-                }
+                    }
 
-                is GatewayFileResult.TooLarge -> {
+                    is GatewayFileResult.TooLarge -> {
-                    showOpenError("File too large to open: ${attachment.name}")
+                        showOpenError("File too large to open: ${attachment.name}")
-                }
+                    }
 
-                is GatewayFileResult.Unauthorized -> {
+                    is GatewayFileResult.Unauthorized -> {
-                    showOpenError("Session expired — reconnect to open: ${attachment.name}")
+                        showOpenError("Session expired — reconnect to open: ${attachment.name}")
-                }
+                    }
 
-                is GatewayFileResult.Failure -> {
+                    is GatewayFileResult.Failure -> {
-                    showOpenError("Could not open ${attachment.name}: ${result.throwable.message}")
+                        showOpenError("Could not open ${attachment.name}: ${result.throwable.message}")
+                    }
+                }
+            } finally {
+                _uiState.update {
+                    if (it.openingAttachmentPath == path) it.copy(openingAttachmentPath = null) else it
                 }
             }
         }

app/src/main/java/com/m57/hermescontrol/ui/chat/fullbleed/FullBleedAgentMessage.kt

@@ -66,6 +66,7 @@ internal fun FullBleedAgentMessage(
     onOpenAttachment: (Attachment) -> Unit = {},
     onSaveAttachment: (Attachment) -> Unit = {},
     savingAttachmentPath: String? = null,
+    openingAttachmentPath: String? = null,
     canSaveAttachment: Boolean = true,
     onImageClick: (ImageViewerModel) -> Unit = {},
     modifier: Modifier = Modifier,
@@ -124,6 +125,7 @@ internal fun FullBleedAgentMessage(
                     onOpen = { onOpenAttachment(it) },
                     onSave = { onSaveAttachment(it) },
                     savingPath = savingAttachmentPath,
+                    openingPath = openingAttachmentPath,
                     canSave = canSaveAttachment,
                     onImageClick = onImageClick,
                 )

app/src/main/java/com/m57/hermescontrol/ui/chat/fullbleed/FullBleedChatList.kt

@@ -66,6 +66,7 @@ fun FullBleedChatList(
     onDismissClarify: (() -> Unit)? = null,
     onSaveAttachment: (com.m57.hermescontrol.data.model.Attachment) -> Unit = {},
     savingAttachmentPath: String? = null,
+    openingAttachmentPath: String? = null,
     onImageClick: (ImageViewerModel) -> Unit = {},
 ) {
     if (messages.isEmpty() && !isLoading) {
@@ -150,6 +151,7 @@ fun FullBleedChatList(
                                     onOpenAttachment = viewModel::openAttachment,
                                     onSaveAttachment = onSaveAttachment,
                                     savingAttachmentPath = savingAttachmentPath,
+                                    openingAttachmentPath = openingAttachmentPath,
                                     onImageClick = onImageClick,
                                 )
                                 milestone?.let { count ->
@@ -225,6 +227,7 @@ fun FullBleedChatList(
                                                     onOpenAttachment = viewModel::openAttachment,
                                                     onSaveAttachment = onSaveAttachment,
                                                     savingAttachmentPath = savingAttachmentPath,
+                                                    openingAttachmentPath = openingAttachmentPath,
                                                     canSaveAttachment = savingAttachmentPath == null,
                                                     onImageClick = onImageClick,
                                                 )
@@ -300,6 +303,7 @@ private fun renderChatBubble(
     onOpenAttachment: (com.m57.hermescontrol.data.model.Attachment) -> Unit,
     onSaveAttachment: (com.m57.hermescontrol.data.model.Attachment) -> Unit,
     savingAttachmentPath: String?,
+    openingAttachmentPath: String?,
     onImageClick: (ImageViewerModel) -> Unit,
 ) {
     ChatBubble(
@@ -309,6 +313,7 @@ private fun renderChatBubble(
         onOpenAttachment = onOpenAttachment,
         onSaveAttachment = onSaveAttachment,
         savingAttachmentPath = savingAttachmentPath,
+        openingAttachmentPath = openingAttachmentPath,
         canSaveAttachment = savingAttachmentPath == null,
         onImageClick = onImageClick,
     )

app/src/test/java/com/m57/hermescontrol/ui/chat/ChatViewModelTest.kt

@@ -3643,4 +3643,44 @@ class ChatViewModelTest {
                     .contains("missing.pdf"),
             )
         }
+
+    @Test
+    fun `openAttachment shows opening state while fetch is in flight and clears it after`() =
+        runTest {
+            mockkObject(GatewayFileClient)
+            val cacheDir =
+                java.io.File(
+                    System.getProperty("java.io.tmpdir"),
+                    "gw_open_${System.nanoTime()}",
+                ).apply { mkdirs() }
+            every { app.cacheDir } returns cacheDir
+            every { app.applicationContext } returns app
+            every { app.getApplicationContext() } returns app
+            val firstResult = CompletableDeferred<GatewayFileResult>()
+            val fetchedPaths = mutableListOf<String>()
+            coEvery { GatewayFileClient.fetch(capture(fetchedPaths), any()) } coAnswers { firstResult.await() }
+
+            val vm = createViewModel()
+            val attachment =
+                Attachment(
+                    uri = "gateway:/tmp/big.pdf",
+                    name = "big.pdf",
+                    mimeType = "application/pdf",
+                    source = AttachmentSource.GATEWAY,
+                )
+
+            vm.openAttachment(attachment)
+            runCurrent()
+
+            // Indicator visible while the download is in flight…
+            assertEquals(listOf("/tmp/big.pdf"), fetchedPaths)
+            assertEquals("/tmp/big.pdf", vm.uiState.value.openingAttachmentPath)
+
+            firstResult.complete(GatewayFileResult.NotFound)
+            advanceUntilIdle()
+
+            // …and cleared in all outcomes.
+            assertNull(vm.uiState.value.openingAttachmentPath)
+            assertTrue(vm.uiState.value.openError.orEmpty().contains("big.pdf"))
+        }
 }