app/main.py

import os
import json
from typing import Literal, Dict, Any

import httpx
from fastapi import FastAPI, Query, HTTPException
from fastapi.responses import JSONResponse

app = FastAPI()

CEREBRAS_API_KEY = os.getenv("CEREBRAS_API_KEY")
CEREBRAS_API_URL = "https://api.cerebras.ai/v1/chat/completions"


def build_prompt(difficulty: str, language: str) -> str:
    return f"""
あなたはクイズ作成者です。
難易度: {difficulty}
言語: {language}

次のフォーマットの JSON だけを返してください（前後に一切の文章を付けないこと）:
**出力には{language}を使ってください。**
{{
  "questions": [
    {{
      "question": "問題文（{language}）",
      "choices": ["選択肢1", "選択肢2", "選択肢3", "選択肢4"],
      "correctIndex": 0
    }},
    {{
      "question": "問題文（{language}）",
      "choices": ["選択肢1", "選択肢2", "選択肢3", "選択肢4"],
      "correctIndex": 0
    }},
    {{
      "question": "問題文（{language}）",
      "choices": ["選択肢1", "選択肢2", "選択肢3", "選択肢4"],
      "correctIndex": 0
    }}
  ]
}}

制約:
- 質問は必ず3問
- 各問題は4択
- テーマは一般教養レベル（雑学など）で OK
- 難易度は easy, medium, hard に応じて調整
- 最終的なアウトプットは {language}に合わせて出力
"""


async def call_cerebras_quiz_api(difficulty: str, language: str) -> Dict[str, Any]:
    if not CEREBRAS_API_KEY:
        raise RuntimeError("CEREBRAS_API_KEY is not set")

    prompt = build_prompt(difficulty, language)

    headers = {
        "Content-Type": "application/json",
        "Authorization": f"Bearer {CEREBRAS_API_KEY}",
    }

    payload = {
        "model": "gpt-oss-120b",
        "messages": [
            {"role": "system", "content": "You are a helpful quiz generator."},
            {"role": "user", "content": prompt},
        ],
        "temperature": 0.8,
        "max_tokens": 1024,
    }

    async with httpx.AsyncClient(timeout=30.0) as client:
        resp = await client.post(CEREBRAS_API_URL, headers=headers, json=payload)
        if resp.status_code != 200:
            raise RuntimeError(f"Cerebras API error: {resp.status_code}, {resp.text}")

        data = resp.json()

    content = data.get("choices", [{}])[0].get("message", {}).get("content", "")

    # たまにモデルが ```json ... ``` で囲んでくる可能性があるので軽く掃除
    cleaned = content.strip()
    if cleaned.startswith("```"):
        # ```json or ``` で始まるケースに対応
        cleaned = cleaned.strip("`")
        # 先頭行に "json" とか残っていたら落とす
        if cleaned.startswith("json"):
            cleaned = cleaned[len("json") :].lstrip()

    try:
        quiz = json.loads(cleaned)
    except json.JSONDecodeError as e:
        # デバッグ用に content を見たい場合は log に出す
        print("Failed to parse JSON from model:", content)
        raise RuntimeError(f"JSON parse error: {e}")

    return quiz


@app.get("/quiz")
async def get_quiz(
    difficulty: Literal["easy", "medium", "hard"] = Query("medium"),
    language: str = Query("en")
):
    """
    クイズを3問返すAPI。
    レスポンス形式:
    {
      "questions": [
        {
          "question": "....",
          "choices": ["..", "..", "..", ".."],
          "correctIndex": 1
        },
        ...
      ]
    }
    """
    try:
        quiz = await call_cerebras_quiz_api(difficulty, language)
    except Exception as e:
        # 拡張側が扱いやすいように 500 + メッセージだけ返す
        raise HTTPException(status_code=500, detail=str(e))

    # 最低限のバリデーション（壊れたJSONでないかチェック）
    if not isinstance(quiz, dict) or "questions" not in quiz:
        raise HTTPException(status_code=500, detail="Invalid quiz format")

    return JSONResponse(content=quiz)