Harden status/date chat behavior and snapshot fallback

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: annawiewer

src/wiesn_agent/api.py

@@ -63,7 +63,8 @@ def _save_chat_log() -> None:
         CHAT_LOG_FILE.parent.mkdir(parents=True, exist_ok=True)
         persistent = [m for m in _chat_log if m.get("role") != "thinking"]
         CHAT_LOG_FILE.write_text(
-            json.dumps(persistent, ensure_ascii=False, indent=2)
+            json.dumps(persistent, ensure_ascii=False, indent=2),
+            encoding="utf-8",
         )
     except Exception as e:
         logger.warning("Failed to save chat log: %s", e)
@@ -74,7 +75,7 @@ def _load_chat_log() -> None:
     if not CHAT_LOG_FILE.exists():
         return
     try:
-        data = json.loads(CHAT_LOG_FILE.read_text())
+        data = json.loads(CHAT_LOG_FILE.read_text(encoding="utf-8"))
         if isinstance(data, list):
             _chat_log.extend(data[-200:])
             logger.info("Restored %d chat messages from disk", len(_chat_log))
@@ -87,7 +88,8 @@ def _save_activity_log() -> None:
     try:
         ACTIVITY_LOG_FILE.parent.mkdir(parents=True, exist_ok=True)
         ACTIVITY_LOG_FILE.write_text(
-            json.dumps(list(_activity_log), ensure_ascii=False, indent=2)
+            json.dumps(list(_activity_log), ensure_ascii=False, indent=2),
+            encoding="utf-8",
         )
     except Exception as e:
         logger.warning("Failed to save activity log: %s", e)
@@ -98,7 +100,7 @@ def _load_activity_log() -> None:
     if not ACTIVITY_LOG_FILE.exists():
         return
     try:
-        data = json.loads(ACTIVITY_LOG_FILE.read_text())
+        data = json.loads(ACTIVITY_LOG_FILE.read_text(encoding="utf-8"))
         if isinstance(data, list):
             _activity_log.extend(data[-200:])
             logger.info("Restored %d activity events from disk", len(_activity_log))
@@ -134,6 +136,32 @@ def _chat_reply(message: str, **extra: Any) -> dict:
     return entry
 
 
+def _build_status_summary(snapshots: dict[str, PortalSnapshot]) -> str:
+    """Build a deterministic status summary from persisted snapshots."""
+    if not snapshots:
+        return "Es liegen noch keine Scan-Daten vor. Starte einen Scan mit **scan all**."
+
+    portal_names = sorted(snapshots.keys())
+    with_dates = [name for name in portal_names if snapshots[name].datum_options]
+    without_dates = [name for name in portal_names if not snapshots[name].datum_options]
+    with_errors = [name for name in portal_names if snapshots[name].error]
+
+    lines = [
+        f"**{len(with_dates)} von {len(portal_names)} Zelten** haben aktuell Termine verfügbar: "
+        f"{', '.join(with_dates)}."
+    ]
+    if without_dates:
+        lines.append(
+            f"**{len(without_dates)} Zelte** sind geschlossen oder haben keine Termine: "
+            f"{', '.join(without_dates)}."
+        )
+    if with_errors:
+        lines.append(
+            f"Hinweis: Bei folgenden Zelten gab es zuletzt Scan-Fehler: {', '.join(with_errors)}."
+        )
+    return "\n\n".join(lines)
+
+
 async def _scan_portals(portals: list, config: WiesnConfig) -> list[dict]:
     """Shared scan logic used by background scanner, chat scan, and API trigger.
 
@@ -568,6 +596,7 @@ def _classify_intent(text: str) -> str:
 @app.post("/api/chat")
 async def post_chat(body: ChatMessage):
     """Handle a user chat message — LLM agent with keyword fallback."""
+    global _thinking_status
     text = body.message.strip()
     if not text:
         raise HTTPException(400, "Empty message")
@@ -581,6 +610,14 @@ async def post_chat(body: ChatMessage):
     _chat_log.append(user_entry)
     _save_chat_log()
 
+    intent = _classify_intent(text)
+
+    # Status answers are deterministic and history-independent by design.
+    if intent == "status":
+        snapshots = load_snapshots()
+        reply = _chat_reply(_build_status_summary(snapshots))
+        return {"user": user_entry, "reply": reply}
+
     # ── Try LLM agent first ───────────────────────
     try:
         from wiesn_agent.chat_agent import chat as llm_chat
@@ -694,9 +731,6 @@ def _on_tool_progress(tool_name: str, tool_args: dict) -> None:
             reply = _chat_reply(f"**{mentioned_portal}** wurde noch nicht gescannt.")
         return {"user": user_entry, "reply": reply}
 
-    # Fall back to keyword classification for generic intents
-    intent = _classify_intent(text)
-
     # ── Intent: Scan ──────────────────────────────
     if intent == "scan":
         config = _load_config()
@@ -712,27 +746,6 @@ def _on_tool_progress(tool_name: str, tool_args: dict) -> None:
 
         return {"user": user_entry, "reply": reply}
 
-    # ── Intent: Status / Summary ──────────────────
-    if intent == "status":
-        snapshots = load_snapshots()
-        config = _load_config()
-        with_dates = [n for n, s in snapshots.items() if s.datum_options]
-        matching = [
-            n for n, s in snapshots.items()
-            if any(matches_wunsch(d.get("text", d.get("value", "")), config) for d in s.datum_options)
-        ]
-
-        lines = [
-            f"**{len(snapshots)}** portals scanned, **{len(with_dates)}** have open dates.",
-        ]
-        if matching:
-            lines.append(f"**{len(matching)}** match your preferred days: {', '.join(matching)}")
-        else:
-            lines.append("No matches on your preferred days yet.")
-
-        reply = _chat_reply("\n".join(lines))
-        return {"user": user_entry, "reply": reply}
-
     # ── Intent: Show matches / evening ────────────
     if intent == "matches":
         snapshots = load_snapshots()