# -*- coding: utf-8 -*-
"""API客户端"""
import requests
from urllib3.util.retry import Retry
from requests.adapters import HTTPAdapter

class APIClient:
    """HTTP API客户端"""
    
    def __init__(self, base_url: str, token: str = None, timeout: int = 20,
                 retry_max: int = 3, headers_extra: dict = None):
        self.base_url = base_url.rstrip("/")
        self.token = token
        self.timeout = timeout
        self.retry_max = retry_max
        self.headers_extra = headers_extra or {}
        self._session = None
    
    def _get_session(self):
        """获取或创建会话"""
        if self._session is None:
            self._session = requests.Session()
            
            retries = max(0, int(self.retry_max) - 1)
            retry = Retry(
                total=None,
                connect=retries,
                read=retries,
                status=retries,
                allowed_methods=frozenset(["GET"]),
                status_forcelist=(429, 500, 502, 503, 504),
                backoff_factor=1.0,
                respect_retry_after_header=True,
                raise_on_status=False,
            )
            
            adapter = HTTPAdapter(max_retries=retry)
            self._session.mount("http://", adapter)
            self._session.mount("https://", adapter)
            
            if self.headers_extra:
                self._session.headers.update(self.headers_extra)
        
        return self._session
    
    def get(self, endpoint: str, params: dict = None) -> dict:
        """执行GET请求"""
        url = f"{self.base_url}/{endpoint.lstrip('/')}"
        headers = {"Authorization": self.token} if self.token else {}
        headers.update(self.headers_extra)
        
        sess = self._get_session()
        resp = sess.get(url, headers=headers, params=params, timeout=self.timeout)
        resp.raise_for_status()
        return resp.json()
    
    def iter_paginated(
        self,
        endpoint: str,
        params: dict | None,
        page_size: int = 200,
        page_field: str = "pageIndex",
        size_field: str = "pageSize",
        data_path: tuple = ("data",),
        list_key: str | None = None,
    ):
        """分页迭代器：逐页拉取数据并产出 (page_no, records, request_params, raw_response)。"""
        base_params = dict(params or {})
        page = 1

        while True:
            page_params = dict(base_params)
            page_params[page_field] = page
            page_params[size_field] = page_size

            payload = self.get(endpoint, page_params)
            records = self._extract_list(payload, data_path, list_key)

            yield page, records, page_params, payload

            if len(records) < page_size:
                break

            if len(records) == 0:
                break

            page += 1

    def get_paginated(self, endpoint: str, params: dict, page_size: int = 200,
                      page_field: str = "pageIndex", size_field: str = "pageSize",
                      data_path: tuple = ("data",), list_key: str = None) -> tuple:
        """分页获取数据并将所有记录汇总在一个列表中。"""
        records, pages_meta = [], []

        for page_no, page_records, request_params, response in self.iter_paginated(
            endpoint=endpoint,
            params=params,
            page_size=page_size,
            page_field=page_field,
            size_field=size_field,
            data_path=data_path,
            list_key=list_key,
        ):
            records.extend(page_records)
            pages_meta.append(
                {"page": page_no, "request": request_params, "response": response}
            )

        return records, pages_meta

    @staticmethod
    def _extract_list(payload: dict, data_path: tuple, list_key: str | None):
        """辅助函数：根据 data_path/list_key 提取列表结构。"""
        cur = payload
        for key in data_path:
            if isinstance(cur, dict):
                cur = cur.get(key)
            else:
                cur = None
            if cur is None:
                break

        if list_key and isinstance(cur, dict):
            cur = cur.get(list_key)

        if not isinstance(cur, list):
            cur = []

        return cur