app/openai_client.py

from __future__ import annotations
import os
import json
import httpx

OPENAI_BASE = os.environ.get("OPENAI_BASE", "https://api.openai.com/v1")
OPENAI_MODEL = os.environ.get("OPENAI_MODEL", "gpt-4o-mini")
OPENAI_API_KEY = os.environ.get("OPENAI_API_KEY")

HEADERS = {
    "Authorization": f"Bearer {OPENAI_API_KEY}" if OPENAI_API_KEY else "",
    "Content-Type": "application/json",
}


async def openai_chat(messages, temperature: float = 0.7, max_tokens: int = 300) -> str:
    """自由回答（プレーンテキスト）"""
    if not OPENAI_API_KEY:
        raise RuntimeError("OPENAI_API_KEY is not set in environment variables.")

    url = f"{OPENAI_BASE}/chat/completions"
    payload = {
        "model": OPENAI_MODEL,
        "messages": messages,
        "temperature": float(temperature),
        "max_tokens": int(max_tokens),
    }
    async with httpx.AsyncClient(timeout=60) as client:
        r = await client.post(url, headers=HEADERS, json=payload)
        r.raise_for_status()
        data = r.json()
        return data["choices"][0]["message"]["content"].strip()


async def openai_chat_json(messages, temperature: float = 0.2, max_tokens: int = 1200) -> dict:
    """JSONモード（出力は厳密なJSON文字列）"""
    if not OPENAI_API_KEY:
        raise RuntimeError("OPENAI_API_KEY is not set in environment variables.")

    url = f"{OPENAI_BASE}/chat/completions"
    payload = {
        "model": OPENAI_MODEL,
        "messages": messages,
        "temperature": float(temperature),
        "max_tokens": int(max_tokens),
        "response_format": {"type": "json_object"},
    }
    async with httpx.AsyncClient(timeout=60) as client:
        r = await client.post(url, headers=HEADERS, json=payload)
        r.raise_for_status()
        data = r.json()
        content = data["choices"][0]["message"]["content"].strip()
        return json.loads(content)


def openai_judge(system: str, user: str) -> dict:
    """審査用（JSONモード）。同期呼び出し"""
    if not OPENAI_API_KEY:
        raise RuntimeError("OPENAI_API_KEY is not set in environment variables.")

    url = f"{OPENAI_BASE}/chat/completions"
    payload = {
        "model": OPENAI_MODEL,
        "messages": [
            {"role": "system", "content": system},
            {"role": "user", "content": user},
        ],
        "response_format": {"type": "json_object"},
        "temperature": 0.0,
        "max_tokens": 400,
    }
    with httpx.Client(timeout=60) as client:
        r = client.post(url, headers=HEADERS, json=payload)
        r.raise_for_status()
        data = r.json()
        content = data["choices"][0]["message"]["content"].strip()
        return json.loads(content)