fix: robust JSON extraction with try/except + retry in all AI commands

- Added _extract_riddle_answer() with dual fallback: JSON parse first,
  then regex extraction of quoted riddle/answer values directly from text
- _generate_riddle() now retries up to 2 times on parse/network failure
- Hangman, scramble, WYR, and trivia now catch JSONDecodeError and log
  the raw model output instead of letting the exception propagate silently

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

matrixbot/commands.py

@@ -1071,12 +1071,15 @@ async def _generate_trivia_question(category: str) -> dict | None:
             ) as response:
                 data = await response.json()
                 text = data.get("message", {}).get("content", "").strip()
-                # Strip markdown code fences if present
-                if text.startswith("```"):
-                    text = text.split("```")[1]
-                    if text.startswith("json"):
-                        text = text[4:]
-                parsed = json.loads(text)
+                if "```" in text:
+                    text = re.sub(r"```[a-z]*\n?", "", text).strip()
+                m = re.search(r"\{.+\}", text, re.DOTALL)
+                candidate = m.group(0) if m else text
+                try:
+                    parsed = json.loads(candidate)
+                except json.JSONDecodeError:
+                    logger.warning("trivia: JSON parse failed, raw: %.200s", text)
+                    parsed = {}
                 # Validate structure
                 if (
                     isinstance(parsed.get("q"), str)
@@ -1398,9 +1401,12 @@ async def _generate_hangman_word() -> dict | None:
                 if "```" in text:
                     text = re.sub(r"```[a-z]*\n?", "", text).strip()
                 m = re.search(r"\{[^{}]+\}", text, re.DOTALL)
-                if m:
-                    text = m.group(0)
-                parsed = json.loads(text)
+                candidate = m.group(0) if m else text
+                try:
+                    parsed = json.loads(candidate)
+                except json.JSONDecodeError:
+                    logger.warning("hangman: JSON parse failed, raw: %.200s", text)
+                    parsed = {}
                 word = parsed.get("word", "").lower().strip()
                 hint = parsed.get("hint", "").strip()
                 if word.isalpha() and 5 <= len(word) <= 8 and hint:
@@ -1559,9 +1565,12 @@ async def _generate_scramble_word() -> dict | None:
                 if "```" in text:
                     text = re.sub(r"```[a-z]*\n?", "", text).strip()
                 m = re.search(r"\{[^{}]+\}", text, re.DOTALL)
-                if m:
-                    text = m.group(0)
-                parsed = json.loads(text)
+                candidate = m.group(0) if m else text
+                try:
+                    parsed = json.loads(candidate)
+                except json.JSONDecodeError:
+                    logger.warning("scramble: JSON parse failed, raw: %.200s", text)
+                    parsed = {}
                 word = parsed.get("word", "").lower().strip()
                 if word.isalpha() and 4 <= len(word) <= 8:
                     return {"word": word}
@@ -1706,9 +1715,12 @@ async def _generate_wyr() -> dict | None:
                 if "```" in text:
                     text = re.sub(r"```[a-z]*\n?", "", text).strip()
                 m = re.search(r"\{[^{}]+\}", text, re.DOTALL)
-                if m:
-                    text = m.group(0)
-                parsed = json.loads(text)
+                candidate = m.group(0) if m else text
+                try:
+                    parsed = json.loads(candidate)
+                except json.JSONDecodeError:
+                    logger.warning("WYR: JSON parse failed, raw: %.200s", text)
+                    parsed = {}
                 a = parsed.get("option_a", "").strip()
                 b = parsed.get("option_b", "").strip()
                 _HANGING = {"but", "and", "or", "with", "for", "in", "on", "at",
@@ -1824,6 +1836,28 @@ def _save_riddle_cache(riddles: list[str], answers: list[str]) -> None:
 _riddle_recent, _riddle_recent_answers = _load_riddle_cache()
 
 
+def _extract_riddle_answer(text: str) -> tuple[str, str] | None:
+    """Try JSON parse, then fall back to regex extraction of riddle/answer values."""
+    if "```" in text:
+        text = re.sub(r"```[a-z]*\n?", "", text).strip()
+    m = re.search(r"\{[^{}]+\}", text, re.DOTALL)
+    candidate = m.group(0) if m else text
+    try:
+        parsed = json.loads(candidate)
+        riddle = parsed.get("riddle", "").strip()
+        answer = parsed.get("answer", "").strip()
+        if riddle and answer:
+            return riddle, answer
+    except (json.JSONDecodeError, AttributeError):
+        pass
+    # Fallback: extract quoted values for "riddle" and "answer" keys
+    rm = re.search(r'"riddle"\s*[:\s]+["“]([^"”]{10,})["”]', text)
+    am = re.search(r'"answer"\s*[:\s]+["“]([^"”]{1,50})["”]', text)
+    if rm and am:
+        return rm.group(1).strip(), am.group(1).strip()
+    return None
+
+
 async def _generate_riddle() -> dict | None:
     avoid_riddles = (
         " Do NOT reuse any of these recent riddles: "
@@ -1847,41 +1881,37 @@ async def _generate_riddle() -> dict | None:
         "- Avoid 'shadow' as an answer. Prefer concrete things: candle, mirror, clock, river, echo, stamp, key, glove, envelope, etc."
     )
     user_msg = f"Generate a clever, original riddle with a clear unambiguous answer.{avoid_answers}{avoid_riddles}"
-    try:
-        timeout = aiohttp.ClientTimeout(total=60)
-        async with aiohttp.ClientSession(timeout=timeout) as session:
-            async with session.post(
-                f"{OLLAMA_URL}/api/chat",
-                json={
-                    "model": CREATIVE_MODEL,
-                    "stream": False,
-                    "messages": [
-                        {"role": "system", "content": system_msg},
-                        {"role": "user", "content": user_msg},
-                    ],
-                },
-            ) as response:
-                data = await response.json()
-                text = data.get("message", {}).get("content", "").strip()
-                if "```" in text:
-                    text = re.sub(r"```[a-z]*\n?", "", text).strip()
-                m = re.search(r"\{[^{}]+\}", text, re.DOTALL)
-                if m:
-                    text = m.group(0)
-                parsed = json.loads(text)
-                riddle = parsed.get("riddle", "").strip()
-                answer = parsed.get("answer", "").strip()
-                if riddle and answer:
-                    _riddle_recent.append(riddle)
-                    if len(_riddle_recent) > _RIDDLE_RECENT_MAX:
-                        _riddle_recent.pop(0)
-                    _riddle_recent_answers.append(answer.lower())
-                    if len(_riddle_recent_answers) > _RIDDLE_RECENT_MAX:
-                        _riddle_recent_answers.pop(0)
-                    _save_riddle_cache(_riddle_recent, _riddle_recent_answers)
-                    return {"riddle": riddle, "answer": answer}
-    except Exception as e:
-        logger.error(f"riddle generation error: {e}", exc_info=True)
+    for attempt in range(2):
+        try:
+            timeout = aiohttp.ClientTimeout(total=60)
+            async with aiohttp.ClientSession(timeout=timeout) as session:
+                async with session.post(
+                    f"{OLLAMA_URL}/api/chat",
+                    json={
+                        "model": CREATIVE_MODEL,
+                        "stream": False,
+                        "messages": [
+                            {"role": "system", "content": system_msg},
+                            {"role": "user", "content": user_msg},
+                        ],
+                    },
+                ) as response:
+                    data = await response.json()
+                    text = data.get("message", {}).get("content", "").strip()
+                    result = _extract_riddle_answer(text)
+                    if result:
+                        riddle, answer = result
+                        _riddle_recent.append(riddle)
+                        if len(_riddle_recent) > _RIDDLE_RECENT_MAX:
+                            _riddle_recent.pop(0)
+                        _riddle_recent_answers.append(answer.lower())
+                        if len(_riddle_recent_answers) > _RIDDLE_RECENT_MAX:
+                            _riddle_recent_answers.pop(0)
+                        _save_riddle_cache(_riddle_recent, _riddle_recent_answers)
+                        return {"riddle": riddle, "answer": answer}
+                    logger.warning("riddle attempt %d: could not extract from: %.200s", attempt + 1, text)
+        except Exception as e:
+            logger.error(f"riddle generation error (attempt {attempt + 1}): {e}", exc_info=True)
     return None