import re
import time
from typing import Any

import requests

from config import Config


class CrawlerError(RuntimeError):
    pass


CRAWLER_SESSION = requests.Session()
# 爬虫服务为明确配置的直连地址，不应继承 macOS 系统代理。
# 否则 requests 会经由 127.0.0.1:7890，约 30 秒后被代理返回 502。
CRAWLER_SESSION.trust_env = False


def normalize_collection_keywords(keywords: list[str]) -> list[str]:
    """清理影响小红书问一问卡片匹配的末尾标点，并保持关键词顺序。"""

    normalized: list[str] = []
    for keyword in keywords:
        value = re.sub(r"[?？!！。．.]+$", "", str(keyword).strip()).strip()
        if value and value not in normalized:
            normalized.append(value)
    if not normalized:
        raise CrawlerError("关键词不能为空")
    return normalized


def _post(
    path: str,
    body: dict[str, Any],
    *,
    retry_transient: bool = True,
) -> dict[str, Any]:
    url = f"{Config.CRAWLER_BASE_URL}{path}"
    retry_times = max(1, Config.CRAWLER_RETRY_TIMES) if retry_transient else 1
    response: requests.Response | None = None

    for attempt in range(1, retry_times + 1):
        try:
            response = CRAWLER_SESSION.post(
                url,
                json=body,
                timeout=Config.CRAWLER_TIMEOUT_SECONDS,
            )
            # 网关临时异常时自动重试，避免直接将业务任务标记为失败。
            if response.status_code in {502, 503, 504} and attempt < retry_times:
                time.sleep(Config.CRAWLER_RETRY_DELAY_SECONDS * attempt)
                continue
            response.raise_for_status()
            payload = response.json()
            break
        except (requests.ConnectionError, requests.Timeout) as exc:
            if attempt < retry_times:
                time.sleep(Config.CRAWLER_RETRY_DELAY_SECONDS * attempt)
                continue
            raise CrawlerError(f"爬虫服务请求失败（已重试 {retry_times} 次）：{exc}") from exc
        except requests.RequestException as exc:
            detail = response.text[:500] if response is not None else ""
            message = f"爬虫服务请求失败：{exc}"
            if detail:
                message += f"，响应：{detail}"
            raise CrawlerError(message) from exc
        except ValueError as exc:
            raise CrawlerError("爬虫服务返回的不是有效 JSON") from exc
    else:
        raise CrawlerError(f"爬虫服务请求失败（已重试 {retry_times} 次）")

    if payload.get("code") != 200 or not payload.get("success", False):
        raise CrawlerError(payload.get("msg") or "爬虫服务返回失败")
    data = payload.get("data")
    if not isinstance(data, dict):
        raise CrawlerError("爬虫服务响应缺少 data")
    return data


def start_collection(mode: str, keywords: list[str]) -> dict[str, Any]:
    """深度任务走 sources，轻度/常规任务走 overview。"""

    collection_keywords = normalize_collection_keywords(keywords)
    path = "/api/v1/xhs/wen/sources" if mode == "deep" else "/api/v1/xhs/wen/overview"
    # 远程 overview 只有接收数组时才创建异步任务并立即返回 task_id。
    # 因此轻度任务即使只有一个关键词也必须传数组，避免单关键词走同步
    # overview 并因采集耗时超过网关时限而返回 502。
    keyword: str | list[str] = (
        collection_keywords if mode == "mild" else collection_keywords[0]
    )
    # 轻度 overview 在首次计算超过网关时限后，远程通常已经写好缓存，
    # 允许受控重试以取得结果；深度 sources 会启动长任务，禁止盲目重试，
    # 避免远程请求虽断开但后台继续执行时产生重复采集任务。
    return _post(
        path,
        {"keyword": keyword},
        retry_transient=(mode != "deep"),
    )


def query_collection(crawler_task_id: str) -> dict[str, Any]:
    return _post("/api/v1/xhs/wen/tasks/query", {"task_id": crawler_task_id})


def cancel_collection(crawler_task_id: str) -> dict[str, Any]:
    """通知爬虫任务在下一个安全检查点停止并保存部分结果。"""

    return _post(f"/api/v1/xhs/wen/tasks/{crawler_task_id}/cancel", {})


def resume_collection(crawler_task_id: str) -> dict[str, Any]:
    """沿用原爬虫任务 ID，从 framework 保存的检查点继续采集。"""

    return _post(f"/api/v1/xhs/wen/tasks/{crawler_task_id}/resume", {})