def get_prompt_template(
    basis_stem: str,
    basis_options: Dict[str, str],
    basis_correct: str,
    basis_explanation: Optional[str],
    target_level: Literal["mudah", "sulit"],
    operator_notes: Optional[str] = None,
) -> str:

You are an educational content creator...

Given a "Sedang" question, generate a new question at a different difficulty level.

BASIS QUESTION (Sedang level):
Question: {basis_stem}
Options: {basis_options}
Correct Answer: {basis_correct}
Explanation: {basis_explanation}

TASK:
Generate 1 new question that is {level_desc} than the basis.

REQUIREMENTS:
1. Keep the SAME topic/subject matter
2. Use similar context and terminology
3. Create exactly {option_count} answer options
4. Preserve basis option count and labels (jangan merge/rename)
5. Only ONE correct answer
6. Include explanation
7. Make it noticeably {level_desc}
8. Preserve inline HTML style dari basis

OUTPUT FORMAT:
Return ONLY valid JSON:
{"stem": "...", "options": {"A":"...","B":"...","C":"...","D":"..."},
 "correct": "A", "explanation": "..."}

def parse_ai_response(response_text: str) -> Optional[GeneratedQuestion]:
    """Parse response OpenRouter jadi GeneratedQuestion object."""
    cleaned = response_text.strip()

    # Coba beberapa strategi extract JSON:
    candidates = _extract_json_candidates(cleaned)
    # 1. JSON murni
    # 2. JSON di code block ```json ... ```
    # 3. JSON embedded di teks

    for candidate in candidates:
        try:
            data = json.loads(candidate)
            return validate_and_create_question(data)
        except json.JSONDecodeError:
            continue

    return None  # Gagal parse

def validate_and_create_question(data: Dict) -> Optional[GeneratedQuestion]:
    """
    Validasi:
    - stem tidak kosong
    - options minimal 2 (typically 4)
    - correct adalah salah satu label options
    - explanation ada (recommended)
    """

async def check_cache_reuse(
    db, tryout_id, slot, target_level, wp_user_id, website_id
) -> Optional[Item]:
    """
    Cek apakah sudah ada soal AI di (tryout, slot, target_level) yang
    BELUM pernah dijawab user ini.

    Returns:
    - Item jika ditemukan cache hit yang belum dipakai user
    - None jika cache miss
    """

ai_generation_enabled: bool  # di Tryout

async def build_usage_info(raw_usage: dict, model_id: str) -> AIUsageInfo:
    """Parse OpenRouter usage response + hitung cost."""
    # raw_usage berisi: prompt_tokens, completion_tokens, total_tokens
    # pricing diambil dari get_model_pricing(model_id)
    # cost = (prompt_tokens × input_price) + (completion_tokens × output_price)

def combine_usage(usages: list[AIUsageInfo]) -> AIUsageInfo:
    """Aggregate usage dari multiple AI call (untuk batch)."""