fix(chat): reprise robuste au retour d'un layout non conversationnel (composer verrouillé selon l'état réel, replay complet du scrollback, plus de fausse terminaison 'no reply') (#190)

frontend/src/features/agents/CustomAgentChatView.tsx

@@ -59,6 +59,7 @@ interface CachedChatView {
 }
 
 const chatSessionViewCache = new Map<string, CachedChatView>();
+const EMPTY_MODEL_RESPONSE_MESSAGE = "Le modèle n'a renvoyé aucune réponse.";
 
 export function __clearCustomAgentChatViewCacheForTests() {
   chatSessionViewCache.clear();
@@ -299,17 +300,6 @@ function appendProgress(turns: ChatTurn[], progress: ReplyProgress): ChatTurn[]
   return [...turns, { role: "progress", progress }];
 }
 
-function reattachNotice(missedChunks: number): ChatTurn | null {
-  if (missedChunks <= 0) return null;
-  return {
-    role: "tool",
-    label:
-      missedChunks === 1
-        ? "Reprise effectuée: 1 événement rattrapé pendant l'absence."
-        : `Reprise effectuée: ${missedChunks} événements rattrapés pendant l'absence.`,
-  };
-}
-
 function mergeCompletedProgress(
   running: ReplyProgress,
   completed: ReplyProgress,
@@ -362,6 +352,26 @@ function completeRunningProgress(turns: ChatTurn[]): ChatTurn[] {
   });
 }
 
+function isRecoverableNoResponseTurn(turn: ChatTurn | undefined): boolean {
+  return turn?.role === "error" && turn.text === EMPTY_MODEL_RESPONSE_MESSAGE;
+}
+
+function turnsIndicateBusy(turns: ChatTurn[]): boolean {
+  for (let index = turns.length - 1; index >= 0; index -= 1) {
+    const turn = turns[index];
+    if (turn.role === "final" || turn.role === "error") return false;
+    if (turn.role === "agent" && turn.pending) return true;
+    if (
+      turn.role === "progress" &&
+      !turn.settled &&
+      progressStageBucket(turn.progress) !== "completed"
+    ) {
+      return true;
+    }
+  }
+  return false;
+}
+
 function fileExtension(mime: string): string {
   if (mime === "image/png") return "png";
   if (mime === "image/jpeg") return "jpg";
@@ -490,6 +500,9 @@ function foldChunk(turns: ChatTurn[], raw: unknown): ChatTurn[] {
     raw.kind !== "userPrompt" &&
     raw.kind !== "UserPrompt"
   ) {
+    if (isRecoverableNoResponseTurn(last) && raw.kind !== "error") {
+      return foldChunk(turns.slice(0, -1), raw);
+    }
     return turns;
   }
   switch (raw.kind) {
@@ -556,7 +569,7 @@ export function CustomAgentChatView({
   const [slashActiveIndex, setSlashActiveIndex] = useState(0);
   const [profileDialog, setProfileDialog] =
     useState<ProfileCommandDialogState | null>(null);
-  const [opening, setOpening] = useState(false);
+  const [opening, setOpening] = useState(Boolean(sessionId));
   const [busy, setBusy] = useState(false);
   const [stopping, setStopping] = useState(false);
   const [error, setError] = useState<string | null>(null);
@@ -793,14 +806,10 @@ export function CustomAgentChatView({
       if (!mountedRef.current) return reattached.sessionId;
       setCurrentSession(reattached.sessionId);
       if (options.applyScrollback) {
-        const cachedCount = chatSessionViewCache.get(sid)?.chunkCount ?? 0;
-        scrollbackChunkCountRef.current = Math.max(
-          scrollbackChunkCountRef.current,
-          reattached.scrollback.length,
-        );
+        scrollbackChunkCountRef.current = reattached.scrollback.length;
         const replayed = reattached.scrollback.reduce(foldChunk, [] as ChatTurn[]);
-        const notice = reattachNotice(reattached.scrollback.length - cachedCount);
-        setTurns(notice ? [...replayed, notice] : replayed);
+        setTurns(replayed);
+        setBusy(turnsIndicateBusy(replayed));
       }
       return reattached.sessionId;
     },