refactor: replace _ensure_junction/_ensure_link with batch Directus ops in generate_questions

- Remove per-call _ensure_junction (junction tables already exist)
- Load existing word/question links upfront (2 GET requests instead of N)
- Batch POST all new words_objects links in a single request
- Batch POST related_words and distractor_words per new question
- Eliminates O(N) serial GET+POST pattern in favour of O(1) upfront dedup + batch writes

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app.py

@@ -1145,14 +1145,6 @@ def generate_questions(obj_id: str):
     if not levels:
         return jsonify({"error": "No levels in AI response"}), 500
 
-    # Junction-Collections sicherstellen (einmalig)
-    for col, f1, f2 in [
-        ("words_objects", "words_id", "objects_id"),
-        ("questions_objects", "questions_id", "objects_id"),
-        ("questions_distractor_words", "questions_id", "words_id"),
-    ]:
-        _ensure_junction(col, f1, f2, token)
-
     stats = {
         "words_created": 0,
         "words_linked": 0,
@@ -1173,6 +1165,21 @@ def generate_questions(obj_id: str):
             # Mehrwortige Einträge → überspringen (KI-Fehler)
         return tokens
 
+    # Bestehende Verlinkungen vorab laden (Dedup ohne N×GET)
+    ew_data, _ = _directus(
+        "GET",
+        f"/items/words_objects?filter[objects_id][_eq]={obj_id}&fields[]=words_id&limit=2000",
+        token,
+    )
+    existing_word_ids: set[str] = {e["words_id"] for e in (ew_data.get("data") or [])}
+
+    eq_data, _ = _directus(
+        "GET",
+        f"/items/questions_objects?filter[objects_id][_eq]={obj_id}&fields[]=questions_id&limit=200",
+        token,
+    )
+    existing_question_ids: set[str] = {e["questions_id"] for e in (eq_data.get("data") or [])}
+
     # Alle eindeutigen Wörter aus allen Leveln vorab sammeln und einmalig laden
     all_words_by_level: dict[str, int] = {}  # title_de → first level seen
     for lvl in levels:
@@ -1185,20 +1192,22 @@ def generate_questions(obj_id: str):
 
     # Wörter einmalig anlegen / finden (globaler Cache über alle Level)
     global_word_map: dict[str, str] = {}  # title_de → id
+    new_word_links: list[dict] = []
     for w, lvl_num in all_words_by_level.items():
         try:
             wid, is_new = _find_or_create_word(w, lvl_num, token)
             global_word_map[w] = wid
-            _ensure_link(
+            if wid not in existing_word_ids:
-                "words_objects",
+                new_word_links.append({"words_id": wid, "objects_id": obj_id})
-                {"words_id": wid, "objects_id": obj_id},
+                existing_word_ids.add(wid)
-                {"words_id": wid, "objects_id": obj_id},
-                token,
-            )
             stats["words_created" if is_new else "words_linked"] += 1
         except Exception as e:
             print(f"[generate_questions] word error '{w}': {e}")
 
+    # Alle neuen Wort-Verlinkungen in einem Batch speichern
+    if new_word_links:
+        _directus("POST", "/items/words_objects", token, new_word_links)
+
     for lvl in levels:
         level = int(lvl.get("level") or 1)
         q_de = (lvl.get("question") or "").strip()
@@ -1221,33 +1230,27 @@ def generate_questions(obj_id: str):
 
         stats["questions_created" if q_is_new else "questions_linked"] += 1
 
-        # Frage ↔ Objekt
+        # Frage ↔ Objekt (nur wenn noch nicht verknüpft)
-        _ensure_link(
+        if q_id not in existing_question_ids:
-            "questions_objects",
+            _directus("POST", "/items/questions_objects", token,
-            {"questions_id": q_id, "objects_id": obj_id},
+                      {"questions_id": q_id, "objects_id": obj_id})
-            {"questions_id": q_id, "objects_id": obj_id},
+            existing_question_ids.add(q_id)
-            token,
-        )
 
-        # related_words
+        # related_words + distractor_words nur für neue Fragen (batch)
-        for w in words_list:
+        if q_is_new:
-            if w in global_word_map:
+            rw_links = [
-                _ensure_link(
+                {"questions_id": q_id, "words_id": global_word_map[w]}
-                    "questions_words",
+                for w in words_list if w in global_word_map
-                    {"questions_id": q_id, "words_id": global_word_map[w]},
+            ]
-                    {"questions_id": q_id, "words_id": global_word_map[w]},
+            if rw_links:
-                    token,
+                _directus("POST", "/items/questions_words", token, rw_links)
-                )
 
-        # distractor_words
+            dw_links = [
-        for w in distractor_list:
+                {"questions_id": q_id, "words_id": global_word_map[w]}
-            if w in global_word_map:
+                for w in distractor_list if w in global_word_map
-                _ensure_link(
+            ]
-                    "questions_distractor_words",
+            if dw_links:
-                    {"questions_id": q_id, "words_id": global_word_map[w]},
+                _directus("POST", "/items/questions_distractor_words", token, dw_links)
-                    {"questions_id": q_id, "words_id": global_word_map[w]},
-                    token,
-                )
 
     print(f"[generate_questions] obj={obj_id} stats={stats}")
     return jsonify({"ok": True, "object_id": obj_id, "stats": stats})