"""图片代理：绕过源站防盗链，供前端 <img> 预览与生图参考使用。

参考 laowang.putumiao.shop 的 /api/proxy-image?url=... 形式。
"""
from __future__ import annotations

from urllib.parse import urlparse

from fastapi import APIRouter, HTTPException, Query, Response

from services import storage

router = APIRouter(prefix="/api", tags=["proxy"])

# 域名片段 → 防盗链所需 Referer
_REFERER_BY_DOMAIN: list[tuple[str, str]] = [
    ("alicdn.com", "https://www.taobao.com"),
    ("taobao.com", "https://www.taobao.com"),
    ("tmall.com", "https://www.tmall.com"),
    ("1688.com", "https://www.1688.com"),
    ("ozon.ru", "https://www.ozon.ru"),
    ("ozon.kz", "https://www.ozon.ru"),
    ("ozon.by", "https://www.ozon.ru"),
    ("ozonusercontent.com", "https://www.ozon.ru"),
]


def guess_referer(url: str) -> str | None:
    host = (urlparse(url).hostname or "").lower()
    for frag, referer in _REFERER_BY_DOMAIN:
        if frag in host:
            return referer
    return None


@router.get("/proxy-image")
async def proxy_image(url: str = Query(..., description="源站图片 URL")):
    scheme = urlparse(url).scheme
    if scheme not in ("http", "https"):
        raise HTTPException(status_code=400, detail="仅支持 http/https URL")
    try:
        data, ctype = await storage.download_bytes(url, referer=guess_referer(url))
    except Exception as exc:  # noqa: BLE001
        raise HTTPException(status_code=502, detail=f"图片拉取失败: {exc}") from exc
    if not ctype.startswith("image/"):
        ctype = "image/jpeg"
    return Response(
        content=data,
        media_type=ctype,
        headers={
            "Cache-Control": "public, max-age=86400",
            "Access-Control-Allow-Origin": "*",
        },
    )