"""
公共工具 —— JSON 提取、LLM 客户端单例、重试机制
"""
import json
import re
import time
from typing import Any

import openai

# ── LLM 客户端单例 ──────────────────────────────────

_llm_client: openai.OpenAI | None = None
_llm_model: str = ""


def get_llm_client(config: dict) -> tuple[openai.OpenAI, str]:
    """获取 LLM 客户端（单例），避免每个组件各建一个"""
    global _llm_client, _llm_model
    if _llm_client is None:
        api_key = config.get("api_key", "")
        if not api_key:
            raise RuntimeError(
                "LLM_API_KEY 未配置！请设置环境变量或在 .env 文件中添加：\n"
                "  LLM_API_KEY=your-key\n"
                "  LLM_BASE_URL=https://api.openai.com/v1\n"
                "  LLM_MODEL=gpt-4o-mini"
            )
        _llm_client = openai.OpenAI(
            api_key=api_key,
            base_url=config["base_url"],
        )
        _llm_model = config["model"]
    return _llm_client, _llm_model


# ── LLM 调用重试包装 ────────────────────────────────

class LLMCallError(Exception):
    """LLM 调用最终失败"""
    pass


def llm_chat(client: openai.OpenAI, model: str, messages: list[dict],
             max_retries: int = 3, **kwargs) -> str:
    """
    带指数退避重试的 LLM 调用。
    处理 429 限频、5xx 超时、网络错误。
    """
    last_err = None
    for attempt in range(max_retries):
        try:
            response = client.chat.completions.create(
                model=model, messages=messages, **kwargs
            )
            return response.choices[0].message.content.strip()
        except openai.RateLimitError as e:
            last_err = e
            # 读取 Retry-After 或使用默认退避
            wait = _get_retry_delay(e, attempt)
            print(f"     ⏳ 限频，等待 {wait:.1f}s 后重试 ({attempt+1}/{max_retries})...")
            time.sleep(wait)
        except (openai.APITimeoutError, openai.APIConnectionError, openai.APIStatusError) as e:
            last_err = e
            wait = min(2 ** attempt * 2, 30)
            print(f"     ⚠️ API 错误: {type(e).__name__}，等待 {wait:.1f}s ({attempt+1}/{max_retries})...")
            time.sleep(wait)
        except Exception as e:
            last_err = e
            if attempt < max_retries - 1:
                wait = min(2 ** attempt * 2, 30)
                time.sleep(wait)
                continue
            raise

    raise LLMCallError(f"LLM 调用失败（{max_retries} 次重试）: {last_err}")


def _get_retry_delay(error, attempt: int) -> float:
    """从错误响应中提取重试等待时间"""
    try:
        if hasattr(error, 'response') and error.response is not None:
            retry_after = error.response.headers.get('Retry-After')
            if retry_after:
                return float(retry_after)
    except Exception:
        pass
    # 指数退避: 2s, 4s, 8s, 最大 30s
    return min(2 ** (attempt + 1), 30)


# ── JSON 提取 ────────────────────────────────────────

def extract_json_object(text: str) -> dict:
    """从 LLM 输出提取 JSON 对象"""
    text = _clean_json_text(text)

    try:
        return json.loads(text)
    except json.JSONDecodeError:
        pass

    for pattern in [r'```json\s*\n(.*?)\n```', r'```\s*\n(.*?)\n```']:
        match = re.search(pattern, text, re.DOTALL)
        if match:
            try:
                return json.loads(_clean_json_text(match.group(1)))
            except json.JSONDecodeError:
                continue

    match = re.search(r'\{[^{}]*(?:\{[^{}]*\}[^{}]*)*\}', text, re.DOTALL)
    if match:
        try:
            return json.loads(_clean_json_text(match.group()))
        except json.JSONDecodeError:
            pass

    return {}


def extract_json_array(text: str) -> list[dict]:
    """从 LLM 输出提取 JSON 数组（处理尾逗号、注释等）"""
    text = _clean_json_text(text)

    try:
        result = json.loads(text)
        if isinstance(result, list):
            return result
    except json.JSONDecodeError:
        pass

    for pattern in [r'```json\s*\n(.*?)\n```', r'```\s*\n(.*?)\n```']:
        match = re.search(pattern, text, re.DOTALL)
        if match:
            try:
                result = json.loads(_clean_json_text(match.group(1)))
                if isinstance(result, list):
                    return result
            except json.JSONDecodeError:
                continue

    match = re.search(r'\[.*\]', text, re.DOTALL)
    if match:
        try:
            return json.loads(_clean_json_text(match.group()))
        except json.JSONDecodeError:
            pass

    return []


def _clean_json_text(s: str) -> str:
    """清理 LLM 常见的非标准 JSON"""
    s = re.sub(r'//.*?\n', '\n', s)
    s = re.sub(r'/\*.*?\*/', '', s, flags=re.DOTALL)
    s = re.sub(r',\s*([}\]])', r'\1', s)
    return s.strip()