"""OpenAI 兼容异步客户端：JSON 决策与自由文本发言，自动降级重试。"""
from __future__ import annotations

import asyncio
import json
import re

from ...config import CONFIG, LLMConfig


def parse_json_obj(text: str) -> dict | None:
    if not text:
        return None
    text = text.strip()
    text = re.sub(r"^```(?:json)?\s*|\s*```$", "", text, flags=re.S)
    start, end = text.find("{"), text.rfind("}")
    if start == -1 or end <= start:
        return None
    try:
        data = json.loads(text[start:end + 1])
        return data if isinstance(data, dict) else None
    except json.JSONDecodeError:
        return None


class LLMClient:
    def __init__(self, cfg: LLMConfig) -> None:
        from openai import AsyncOpenAI
        self.model = cfg.model
        self.temperature = cfg.temperature
        self._client = AsyncOpenAI(
            base_url=cfg.base_url, api_key=cfg.api_key, timeout=30, max_retries=0)

    async def _create(self, system: str, user: str, *, json_mode: bool, timeout: float) -> str:
        kwargs: dict = {
            "model": self.model,
            "temperature": self.temperature,
            "messages": [
                {"role": "system", "content": system},
                {"role": "user", "content": user},
            ],
            "timeout": timeout,
        }
        if json_mode:
            kwargs["response_format"] = {"type": "json_object"}
            try:
                resp = await self._client.chat.completions.create(**kwargs)
                return resp.choices[0].message.content or ""
            except Exception:
                kwargs.pop("response_format", None)  # 部分兼容端点不支持 response_format
        resp = await self._client.chat.completions.create(**kwargs)
        return resp.choices[0].message.content or ""

    async def chat_json(self, system: str, user: str, *, timeout: float = 22.0) -> dict:
        last = ""
        for _ in range(2):
            text = await self._create(system, user, json_mode=True, timeout=timeout)
            data = parse_json_obj(text)
            if data is not None:
                return data
            last = text
        raise ValueError(f"LLM 未返回有效 JSON: {last[:120]}")

    async def chat_text(self, system: str, user: str, *, timeout: float = 40.0) -> str:
        return (await self._create(system, user, json_mode=False, timeout=timeout)).strip()


_client: LLMClient | None = None


def get_llm_client() -> LLMClient:
    global _client
    if _client is None:
        _client = LLMClient(CONFIG.llm)
    return _client