"""代理可用性验证。"""

from concurrent.futures import ThreadPoolExecutor, as_completed
from typing import Optional

import requests
from loguru import logger


def verify_proxy_url(proxy_url: str, timeout: tuple = (3, 5)) -> tuple[bool, str]:
    """
    验证代理是否可用，只验证斗鱼主站可达。

    超时缩短为 (3, 5) 以减少短效代理在验证期间过期浪费。

    Returns:
        (是否可用, 消息)
    """
    proxies = {'http': proxy_url, 'https': proxy_url}

    # ── 斗鱼主站可达性验证 ──
    try:
        response = requests.get(
            'https://www.douyu.com',
            proxies=proxies,
            timeout=timeout,
            headers={'User-Agent': 'Mozilla/5.0'},
        )
        response.raise_for_status()
        return True, '代理可用 → 斗鱼可达'
    except Exception as exc:
        err_msg = str(exc)
        if 'Tunnel connection failed' in err_msg or '503' in err_msg:
            detail = '代理拒绝连接（白名单可能未生效）'
        elif 'timed out' in err_msg.lower():
            detail = '连接超时'
        else:
            detail = type(exc).__name__
        logger.debug(f"代理验证失败 [{proxy_url}]: 斗鱼主站不可达: {detail}")
        return False, detail


def verify_proxies_concurrent(
    proxy_urls: list[str],
    timeout: tuple = (5, 8),
    max_workers: int = 5,
    return_all: bool = False,
) -> tuple[Optional[str | list[str]], str]:
    """
    并发验证多个代理 URL。

    Returns:
        return_all=False: (可用代理 URL 或 None, 消息)
        return_all=True: (可用代理 URL 列表或 None, 消息)
    """
    if not proxy_urls:
        return None, '无代理可验证'

    if len(proxy_urls) == 1:
        ok, msg = verify_proxy_url(proxy_urls[0], timeout)
        if ok:
            return (proxy_urls if return_all else proxy_urls[0]), msg
        return None, msg

    if return_all:
        available: list[str] = []
        with ThreadPoolExecutor(max_workers=min(max_workers, len(proxy_urls))) as executor:
            future_map = {
                executor.submit(verify_proxy_url, proxy, timeout): proxy
                for proxy in proxy_urls
            }
            for future in as_completed(future_map):
                try:
                    ok, _ = future.result()
                    if ok:
                        available.append(future_map[future])
                except Exception:
                    continue
        if available:
            logger.success(f"并发验证找到 {len(available)}/{len(proxy_urls)} 个可用代理")
            return available, f'找到 {len(available)} 个可用代理'
        return None, f'共 {len(proxy_urls)} 个代理均不可用'

    with ThreadPoolExecutor(max_workers=min(max_workers, len(proxy_urls))) as executor:
        future_map = {
            executor.submit(verify_proxy_url, proxy, timeout): proxy
            for proxy in proxy_urls
        }
        for future in as_completed(future_map):
            proxy_url = future_map[future]
            try:
                ok, msg = future.result()
                if ok:
                    logger.success(f"并发验证找到可用代理: {proxy_url}")
                    for item in future_map:
                        if item != future:
                            item.cancel()
                    return proxy_url, msg
            except Exception:
                continue

    return None, f'共 {len(proxy_urls)} 个代理均不可用'