fix(chat): preserve attachment references from JSON RPC results (#1210)

Co-authored-by: M57 <41645758+Hy4ri@users.noreply.github.com>

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

@@ -196,7 +196,14 @@ internal fun mapServerMessages(
             return@forEachIndexed
         }
 
-        var finalContent = rawContent
+        // Context-reference preprocessing can persist model-facing attachment
+        // contents after the user's text. A cold reload / second device has no
+        // optimistic local bubble to hide that enriched REST representation,
+        // so project the producer-owned suffix out at hydration time too.
+        // Keep the actual @file:/@image: token here: unlike the dedupe path,
+        // REST-only hydration cannot prove that reference was not user-authored.
+        var finalContent =
+            if (role == MessageRole.USER) stripGatewayAttachedContext(rawContent) else rawContent
         var attachments: List<Attachment>? = null
         if (role == MessageRole.ASSISTANT && rawContent.contains("MEDIA:")) {
             val items = HostMediaExtractor.extract(rawContent)

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

@@ -6,6 +6,38 @@ import kotlinx.serialization.json.JsonElement
 import kotlinx.serialization.json.JsonObject
 import kotlinx.serialization.json.JsonPrimitive
 
+private val ATTACHED_CONTEXT_MARKER_RE =
+    Regex("""(?:^|\n)--- Attached Context ---\s*\n""")
+
+private val CONTEXT_REF_RE =
+    Regex(
+        """@(file|folder|url|image|tool|terminal):(?:"[^"\n]+"|'[^'\n]+'|`[^`\n]+`|\S+)""",
+    )
+
+/**
+ * Remove a gateway-generated `--- Attached Context ---` suffix while
+ * preserving the user-authored portion of the message.
+ *
+ * The marker itself is plain text a user can legitimately type, so do not
+ * treat it as a producer boundary unless the suffix also contains a context
+ * reference of the shape emitted by the gateway.
+ *
+ * Unlike [stripAttachmentRefLines], this intentionally keeps `@file:` /
+ * `@image:` references in the visible text. REST-only hydration has no local
+ * optimistic bubble proving those references were injected by Mobile, and
+ * users may have authored context references themselves.
+ */
+internal fun stripGatewayAttachedContext(content: String): String {
+    val marker = ATTACHED_CONTEXT_MARKER_RE.find(content) ?: return content
+    val attachedContext = content.substring(marker.range.last + 1)
+
+    if (!CONTEXT_REF_RE.containsMatchIn(attachedContext)) {
+        return content
+    }
+
+    return content.substring(0, marker.range.first).trimEnd()
+}
+
 /**
  * Canonical comparison key for a tool message's result payload.
  *
@@ -127,7 +159,7 @@ internal fun sameLogicalMessage(
  * run_agent). Blank lines left behind are dropped too.
  */
 internal fun stripAttachmentRefLines(content: String): String =
-    content
+    stripGatewayAttachedContext(content)
         .lines()
         .map { it.trim() }
         .filterNot { line ->

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

@@ -1877,7 +1877,7 @@ class ChatViewModel(
                                             "filename" to attachment.name,
                                             "ext" to attachment.fileExtension,
                                         ),
-                                )
+                                ).let { if (it is JsonElement) it.toAny() else it }
                             if (result != null) {
                                 @Suppress("UNCHECKED_CAST")
                                 val ok = (result as? Map<String, Any?>)?.get("attached") as? Boolean
@@ -1897,7 +1897,10 @@ class ChatViewModel(
                                         "data_url" to "data:${attachment.mimeType};base64,$b64",
                                         "name" to attachment.name,
                                     ),
-                            )?.let { result ->
+                            )?.let { response ->
+                                // request() returns raw JsonElement values; normalize before reading Kotlin types.
+                                val result = if (response is JsonElement) response.toAny() else response
+
                                 @Suppress("UNCHECKED_CAST")
                                 val refText =
                                     (result as? Map<String, Any?>)?.get("ref_text") as? String

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

@@ -120,6 +120,100 @@ class ChatViewModelTest {
         assertEquals("ws-local-1", merged.single().id)
     }
 
+    @Test
+    fun mergeTranscriptWithLive_collapsesGatewayAttachmentContextCopy() {
+        val local =
+            ChatMessage(
+                id = "ws-local-attachment",
+                role = MessageRole.USER,
+                content = "What is the secret word in the attached file?",
+                timestamp = 100L,
+            )
+        val rest =
+            ChatMessage(
+                id = "rest-sess-attachment",
+                role = MessageRole.USER,
+                content =
+                    """
+                    @file:files/agent-vault/hermes/attachments/note.txt
+
+                    What is the secret word in the attached file?
+
+                    --- Attached Context ---
+
+                    📄 @file:files/agent-vault/hermes/attachments/note.txt (8 tokens)
+                    ```
+                    THE_SECRET_WORD_IS_MANGO_8421
+                    ```
+                    """.trimIndent(),
+                timestamp = 100L,
+            )
+
+        val merged = mergeTranscriptWithLive(listOf(rest), listOf(local))
+
+        assertEquals(1, merged.size)
+        assertEquals("ws-local-attachment", merged.single().id)
+    }
+
+    @Test
+    fun mapServerMessages_restOnlyAttachmentHidesGatewayContext() {
+        val ref = "@file:files/agent-vault/hermes/attachments/note.txt"
+        val persisted =
+            """
+            $ref
+
+            What is the secret word in the attached file?
+
+            --- Attached Context ---
+
+            📄 $ref (8 tokens)
+            ```
+            THE_SECRET_WORD_IS_MANGO_8421
+            ```
+            """.trimIndent()
+
+        val mapped =
+            mapServerMessages(
+                sessionId = "session-1",
+                messages =
+                    listOf(
+                        SessionMessage(
+                            id = 42,
+                            role = "user",
+                            content = JsonPrimitive(persisted),
+                            timestamp = JsonPrimitive("100"),
+                        ),
+                    ),
+                offset = 0,
+                latestPaging = true,
+                liveMessages = emptyList(),
+            )
+
+        assertEquals(1, mapped.size)
+        assertEquals(
+            """
+            $ref
+
+            What is the secret word in the attached file?
+            """.trimIndent(),
+            mapped.single().content,
+        )
+        assertFalse(mapped.single().content.contains("--- Attached Context ---"))
+        assertFalse(mapped.single().content.contains("THE_SECRET_WORD_IS_MANGO_8421"))
+    }
+
+    @Test
+    fun stripAttachmentRefLines_preservesUserAuthoredAttachedContextHeading() {
+        val authored =
+            """
+            Explain this heading:
+            --- Attached Context ---
+            this is ordinary user-authored text
+            """.trimIndent()
+
+        assertEquals(authored, stripAttachmentRefLines(authored))
+    }
+
     @Before
     fun setUp() {
         Dispatchers.setMain(testDispatcher)
@@ -1981,6 +2075,34 @@ class ChatViewModelTest {
             verify(exactly = 0) { HermesWsClient.sendMessage(any(), any(), any(), any()) }
         }
 
+    @Test
+    fun sendMessage_rawJsonFileAttachmentRetainsReference() =
+        runTest {
+            val (viewModel, _) = createViewModelWithSession()
+            val uriString = "content://test/note"
+            val uri = mockk<Uri>()
+            val resolver = mockk<ContentResolver>()
+            mockkStatic(Uri::class)
+            every { Uri.parse(uriString) } returns uri
+            every { app.contentResolver } returns resolver
+            every { resolver.openInputStream(uri) } answers { "hello".byteInputStream() }
+            every { HermesWsClient.request(WsMethods.FILE_ATTACH, any(), any()) } returns
+                CompletableDeferred<Any?>(
+                    buildJsonObject {
+                        put("attached", true)
+                        put("ref_text", "@file:attachments/note.txt")
+                    },
+                )
+            viewModel.addAttachment(uriString, "note.txt", "text/plain", 5)
+
+            viewModel.sendMessage("Inspect file")
+            advanceUntilIdle()
+
+            verify {
+                HermesWsClient.sendMessage(any(), "@file:attachments/note.txt\n\nInspect file", any(), any())
+            }
+        }
+
     @Test
     fun sendMessage_laterGrowingAttachmentDoesNotPartiallyUploadEarlierAttachments() =
         runTest {