import time
import threading
import logging
import requests
from datetime import datetime, timedelta

logger = logging.getLogger(__name__)


class SampleCenterError(Exception):
    """样本中心交互异常。"""
    pass


class SampleCenterClient:
    """样本中心 API 客户端，封装 token 管理和接口调用。"""

    TOKEN_REFRESH_THRESHOLD = 300  # token 过期前 5 分钟自动刷新

    def __init__(self, base_url, app_id, app_secret):
        self.base_url = base_url.rstrip("/")
        self.app_id = app_id
        self.app_secret = app_secret
        self._access_token = None
        self._token_expires_at = None
        self._lock = threading.Lock()

    def _ensure_token(self):
        """线程安全地确保 access_token 有效。"""
        now = datetime.utcnow()
        if (self._access_token and self._token_expires_at
                and now < self._token_expires_at - timedelta(seconds=self.TOKEN_REFRESH_THRESHOLD)):
            return self._access_token

        with self._lock:
            now = datetime.utcnow()
            if (self._access_token and self._token_expires_at
                    and now < self._token_expires_at - timedelta(seconds=self.TOKEN_REFRESH_THRESHOLD)):
                return self._access_token
            self._refresh_token()
            return self._access_token

    def _refresh_token(self):
        """调用样本中心换 token 接口。"""
        url = f"{self.base_url}/api/v1/auth/token"
        logger.info(f"请求 Token: url={url}, app_id={self.app_id}")
        try:
            resp = requests.post(url, json={
                "app_id": self.app_id,
                "app_secret": self.app_secret,
            }, timeout=15)
            logger.info(f"Token 响应: status={resp.status_code}, body={resp.text[:500]}")
            if resp.status_code != 200:
                raise SampleCenterError(f"Token request failed: {resp.status_code} {resp.text}")
            result = resp.json()
            if result.get("code") != "000000":
                raise SampleCenterError(f"Token error: {result.get('message', result)}")
            data = result["data"]
            self._access_token = data["access_token"]
            expires_in = data.get("expires_in", 7200)
            self._token_expires_at = datetime.utcnow() + timedelta(seconds=expires_in)
            logger.info(f"Token 获取成功: expires_in={expires_in}")
        except requests.exceptions.RequestException as e:
            logger.error(f"Token 请求异常: {e}")
            raise SampleCenterError(f"Token request exception: {e}")

    def _headers(self):
        return {
            "Authorization": f"Bearer {self._ensure_token()}",
            "X-App-Id": self.app_id,
        }

    def _parse(self, resp):
        """统一解析样本中心响应。"""
        if resp.status_code != 200:
            logger.error(f"HTTP 错误: status={resp.status_code}, body={resp.text[:500]}")
            raise SampleCenterError(f"HTTP {resp.status_code}: {resp.text}")
        body = resp.json()
        if body.get("code") != "000000":
            logger.error(f"业务错误: code={body.get('code')}, message={body.get('message')}")
            raise SampleCenterError(
                f"SampleCenter error [{body.get('code')}]: {body.get('message', 'unknown')}"
            )
        return body

    # -- 业务接口 --

    def list_knowledge_bases(self, page=1, page_size=20):
        """GET /api/v1/knowledge-bases -- 知识库列表。"""
        url = f"{self.base_url}/api/v1/knowledge-bases"
        logger.info(f"请求知识库列表: url={url}, page={page}, page_size={page_size}")
        resp = requests.get(
            url,
            headers=self._headers(),
            params={"page": page, "page_size": page_size},
            timeout=30,
        )
        logger.info(f"知识库列表响应: status={resp.status_code}, body={resp.text[:500]}")
        return self._parse(resp)

    def get_knowledge_base(self, kb_id):
        """GET /api/v1/knowledge-bases/{id} -- 知识库详情。"""
        url = f"{self.base_url}/api/v1/knowledge-bases/{kb_id}"
        logger.info(f"请求知识库详情: url={url}")
        resp = requests.get(url, headers=self._headers(), timeout=15)
        return self._parse(resp)

    def batch_import(self, kb_id, task_no, parents, children=None, callback_url=None):
        """POST /api/v1/knowledge-bases/{kb_id}/batch-import -- 批量入库。"""
        url = f"{self.base_url}/api/v1/knowledge-bases/{kb_id}/batch-import"
        payload = {
            "task_no": task_no,
            "parents": parents,
        }
        if children:
            payload["children"] = children
        if callback_url:
            payload["callback_url"] = callback_url
        logger.info(f"请求批量入库: url={url}, task_no={task_no}")
        resp = requests.post(
            url,
            headers=self._headers(),
            json=payload,
            timeout=60,
        )
        return self._parse(resp)

    def get_import_task(self, task_id):
        """GET /api/v1/knowledge-bases/batch-import/{task_id} -- 入库任务查询。"""
        url = f"{self.base_url}/api/v1/knowledge-bases/batch-import/{task_id}"
        logger.info(f"请求入库任务: url={url}")
        resp = requests.get(url, headers=self._headers(), timeout=15)
        return self._parse(resp)