#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
异步批量抓取 E-H 画廊图片链接，按专辑保存 json
python eh_crawler.py
"""
from __future__ import annotations

import asyncio
import json
import logging
import re
import sys
from pathlib import Path
from typing import Dict, List, Optional, Tuple

import aiofiles
import httpx
from bs4 import BeautifulSoup
from tqdm.asyncio import tqdm_asyncio
from aiopath import AsyncPath

# -------------------- 可配置常量 --------------------
CONCURRENCY = 20                 # 并发页数
MAX_PAGE = 100                   # 单专辑最大翻页
RETRY_PER_PAGE = 5               # 单页重试
TIMEOUT = httpx.Timeout(10.0)    # 请求超时
PROXY = "http://127.0.0.1:7890"  # 科学上网代理，不需要留空
IMG_SELECTOR = "#gdt"            # 图片入口区域
FAILED_RECORD = "failed_keys.json"
LOG_LEVEL = logging.INFO
# ----------------------------------------------------

logging.basicConfig(
    level=LOG_LEVEL,
    format="[%(asctime)s] [%(levelname)s] %(message)s",
    handlers=[
        logging.StreamHandler(sys.stdout),
        logging.FileHandler("crawl.log", encoding="utf-8"),
    ],
)
log = logging.getLogger("eh_crawler")

# 预编译正则
ILLEGAL_CHARS = re.compile(r'[<>:"/\\|?*\x00-\x1F]')


# -------------------- 工具函数 --------------------
def clean_folder_name(title: str) -> str:
    """清洗文件夹名"""
    return ILLEGAL_CHARS.sub("_", title).replace(" ", "").replace("_", "").strip() or "gallery"


def load_targets() -> List[str]:
    """读取 targets.txt"""
    tgt = Path("targets.txt")
    if not tgt.exists():
        log.error("targets.txt 不存在，已自动创建，请先填写 URL")
        tgt.touch()
        sys.exit(0)
    lines = [ln.strip() for ln in tgt.read_text(encoding="utf-8").splitlines() if ln.strip()]
    if not lines:
        log.error("targets.txt 为空，请先填写 URL")
        sys.exit(0)
    return list(set(lines))  # 去重


def load_failed() -> List[str]:
    if Path(FAILED_RECORD).exists():
        try:
            return json.loads(Path(FAILED_RECORD).read_text(encoding="utf-8"))
        except Exception as exc:
            log.warning(f"加载失败记录失败 -> {exc}")
    return []


def save_failed(keys: List[str]) -> None:
    Path(FAILED_RECORD).write_text(json.dumps(keys, ensure_ascii=False, indent=2), encoding="utf-8")


# -------------------- 爬虫核心 --------------------
async def fetch_page(client: httpx.AsyncClient, url: str) -> Optional[str]:
    """获取单页 HTML"""
    for attempt in range(1, RETRY_PER_PAGE + 1):
        try:
            resp = await client.get(url)
            resp.raise_for_status()
            return resp.text
        except httpx.HTTPError as exc:
            log.error(f"[{attempt}/{RETRY_PER_PAGE}] 请求失败 {url} -> {exc}")
            await asyncio.sleep(2 ** attempt)
    return None


async def crawl_single_gallery(
    client: httpx.AsyncClient, sem: asyncio.Semaphore, gallery_url: str
) -> bool:
    """抓取单个画廊，成功返回 True"""
    async with sem:
        base_url = gallery_url.rstrip("/")
        key = base_url.split("/")[-1]  # 用最后一截当 key
        json_name = f"{key}.json"

        folder_path: Optional[AsyncPath] = None
        json_data: Dict[str, str] = {}
        img_count = 1
        last_page = False

        for page in range(MAX_PAGE):
            if last_page:
                break
            url = f"{base_url}?p={page}"
            html = await fetch_page(client, url)
            if html is None:
                continue

            soup = BeautifulSoup(html, "lxml")
            title = soup.title.string if soup.title else "gallery"
            clean_title = clean_folder_name(title)
            folder_path = AsyncPath("downloads") / clean_title
            await folder_path.mkdir(parents=True, exist_ok=True)

            # 如果 json 已存在则跳过整个画廊
            json_path = folder_path / json_name
            if await json_path.exists():
                log.info(f"{json_name} 已存在，跳过")
                return True

            log.info(f"当前页码：{page + 1}  {url}")

            selected = soup.select_one(IMG_SELECTOR)
            if not selected:
                log.warning(f"未找到选择器 {IMG_SELECTOR}")
                continue

            links = re.findall(r'<a href="(.*?)"', selected.prettify())
            if not links:
                log.info("本页无图片入口，视为最后一页")
                last_page = True
                continue

            for img_entry in links:
                if img_entry in json_data.values():
                    last_page = True
                    break
                json_data[f"{img_count:04d}"] = img_entry
                img_count += 1

        if json_data:
            await json_path.write_text(
                json.dumps(json_data, ensure_ascii=False, indent=2), encoding="utf-8"
            )
            log.info(f"保存成功 -> {json_path}  ({len(json_data)} 张)")
            return True
        else:
            log.warning(f"{key} 未解析到任何图片链接")
            return False


# -------------------- 主流程 --------------------
async def main() -> None:
    targets = load_targets()
    failed = load_failed()
    if failed:
        log.info(f"优先重试上次失败画廊: {len(failed)} 个")
    all_urls = list(set(targets + failed))

    proxy = PROXY if PROXY else None
    limits = httpx.Limits(max_keepalive_connections=20, max_connections=50)
    async with httpx.AsyncClient(
        limits=limits, timeout=TIMEOUT, proxies=proxy, verify=True
    ) as client:
        sem = asyncio.Semaphore(CONCURRENCY)
        results = await tqdm_asyncio.gather(
            *[crawl_single_gallery(client, sem, u) for u in all_urls],
            desc="Galleries",
            total=len(all_urls),
        )

    # 失败持久化
    new_failed = [u for u, ok in zip(all_urls, results) if not ok]
    if new_failed:
        save_failed(new_failed)
        log.warning(f"本轮仍有 {len(new_failed)} 个画廊失败，已写入 {FAILED_RECORD}")
    else:
        Path(FAILED_RECORD).unlink(missing_ok=True)
        log.info("全部画廊抓取完成！")


if __name__ == "__main__":
    try:
        asyncio.run(main())
    except KeyboardInterrupt:
        log.info("用户中断，抓取结束")