"""
image_cdn.py - 将内容中的外站图片 URL 转换为自有 CDN 链接

使用场景：在 write_json / write_file 落盘前调用，自动把
  小红书、B站、知乎、微博等平台的图片链接替换为 res.cybertogether.net CDN 链接，
  防止外站图片过期/防盗链导致后续流程无法访问。
"""

import hashlib
import json
import logging
import re
from typing import Any, Union
import httpx

logger = logging.getLogger(__name__)

# ── 匹配需要转存的外站图片 URL（只抓图片后缀或明显的图床域名）──────────────────
_IMG_URL_RE = re.compile(
    r'https?://(?!'  # 排除自有 CDN，不重复上传
    r'res\.cybertogether\.net'
    r')'
    r'[^\s"\'<>]+'  # URL 主体
    r'(?:'
        r'\.(?:jpg|jpeg|png|gif|webp|avif|bmp|svg)'  # 明确图片后缀
        r'|'
        r'(?:xhscdn\.com|bdimg\.com|hdslb\.com|zhihu\.com/p/[^/]+\.(?:jpg|png)'
        r'|sinaimg\.cn|wx\d+\.sinaimg\.cn|mmbiz\.qpic\.cn'  # 微博/微信图床
        r'|imagev[12]\.meitudata\.com'  # 美图
        r'|p[0-9]\.douyinpic\.com'  # 抖音封面
        r'|i0\.hdslb\.com|article\.biliimg\.com'  # B站
        r')'
    r')',
    re.IGNORECASE,
)

BUCKET_NAME = "aigc-admin"
BUCKET_PATH = "crawler/image"
CDN_BASE = "https://res.cybertogether.net"


async def _upload_bytes_to_oss(data: bytes, filename: str) -> str:
    """上传 bytes 到 OSS 并返回 CDN URL，失败时抛出异常"""
    from cyber_sdk.ali_oss import _upload_v2
    result = await _upload_v2(
        file_name=filename,
        file_content=data,
        bucket_path=BUCKET_PATH,
        bucket_name=BUCKET_NAME,
    )
    oss_key = result.get("oss_object_key")
    if not oss_key:
        raise ValueError(f"OSS response missing oss_object_key: {result}")
    return f"{CDN_BASE}/{oss_key}"


async def _download_image(url: str) -> bytes:
    """下载图片 bytes，失败抛出异常"""
    async with httpx.AsyncClient(timeout=30.0, follow_redirects=True) as client:
        resp = await client.get(url, headers={"Referer": url, "User-Agent": "Mozilla/5.0"})
        resp.raise_for_status()
        return resp.content


def _ext_from_url(url: str) -> str:
    """从 URL 猜测文件扩展名，默认 jpg"""
    path = url.split("?")[0].lower()
    for ext in ("png", "gif", "webp", "avif", "bmp", "svg", "jpg", "jpeg"):
        if path.endswith(f".{ext}"):
            return ext
    return "jpg"


async def replace_image_urls(text: str) -> str:
    """
    扫描 text 中所有外站图片 URL，下载并上传到自有 OSS，原地替换为 CDN 链接。

    - 已是 res.cybertogether.net 的 URL 直接跳过
    - 下载/上传失败的 URL 保留原值，只打 WARNING 日志
    - 同一 URL 使用 MD5 去重（同一次调用内）
    """
    urls = list(dict.fromkeys(_IMG_URL_RE.findall(text)))  # 去重但保留顺序
    if not urls:
        return text

    import asyncio

    async def _process_single_url(url: str) -> tuple[str, str]:
        url_hash = hashlib.md5(url.encode()).hexdigest()[:12]
        ext = _ext_from_url(url)
        filename = f"{url_hash}.{ext}"
        try:
            data = await _download_image(url)
            cdn_url = await _upload_bytes_to_oss(data, filename)
            logger.info("[ImageCDN] %s → %s", url[:60], cdn_url)
            return url, cdn_url
        except Exception as e:
            logger.warning("[ImageCDN] Failed to mirror %s: %s (%s)", url[:60], str(e) or repr(e), type(e).__name__)
            return url, url

    tasks = [_process_single_url(u) for u in urls]
    results = await asyncio.gather(*tasks)
    url_map: dict[str, str] = dict(results)

    for orig, cdn in url_map.items():
        if orig != cdn:
            text = text.replace(orig, cdn)

    replaced = sum(1 for o, c in url_map.items() if o != c)
    if replaced:
        logger.info("[ImageCDN] Replaced %d/%d image URLs with CDN links", replaced, len(urls))

    return text


async def replace_image_urls_in_obj(obj: Any) -> Any:
    """
    递归扫描 dict/list 中所有字符串值，替换其中的外站图片 URL。
    先整体 JSON 序列化再做替换，再反序列化，效率高且避免遗漏嵌套字段。
    """
    raw = json.dumps(obj, ensure_ascii=False)
    replaced = await replace_image_urls(raw)
    if replaced == raw:
        return obj
    return json.loads(replaced)