"""媒体代理

- /m3u8/proxy   ：源站路径转发（playlist 内 TS 链接带时效签名，每次回源拉新鲜版本）
- /m3u8/aidrama ：91 短剧单集播放列表（上游 m3u8 地址 4 小时过期，播放时现取）
- /img/aidrama  ：91 封面图解密代理（CDN 返回 AES 加密图片字节，代理解密后输出）
"""
import logging
import re

import httpx
from fastapi import APIRouter, Depends, Query, Response
from sqlalchemy.ext.asyncio import AsyncSession

from app.core.errors import NOT_FOUND, PARAM_ERROR
from app.core.response import BizException
from app.database import get_db
from app.services.collection_service import HEADERS, UPSTREAM

logger = logging.getLogger(__name__)

router = APIRouter(prefix="/m3u8", tags=["媒体"])
img_router = APIRouter(prefix="/img", tags=["媒体"])

# 只允许相对资源路径，防 SSRF
_PATH_RE = re.compile(r"^[A-Za-z0-9][A-Za-z0-9/._-]*$")


@router.get("/proxy")
async def m3u8_proxy(path: str = Query(min_length=1, max_length=300)):
    if ".." in path or not _PATH_RE.match(path):
        raise BizException(PARAM_ERROR, "非法路径")

    url = f"{UPSTREAM}/api/v1/m3u8/proxy"
    async with httpx.AsyncClient(follow_redirects=True) as client:
        resp = await client.get(url, params={"path": path}, headers=HEADERS, timeout=20)

    text = resp.text
    if resp.status_code != 200 or not text.lstrip().startswith("#EXTM3U"):
        raise BizException(NOT_FOUND, "播放列表获取失败")

    return Response(
        content=text,
        media_type="application/vnd.apple.mpegurl",
        headers={"Cache-Control": "no-cache", "Access-Control-Allow-Origin": "*"},
    )


@router.get("/aidrama")
async def aidrama_playlist(
    d: int = Query(gt=0, description="源站短剧 id"),
    e: int = Query(gt=0, description="源站集 id"),
    n: int | None = Query(None, ge=1, description="集号（用于定位分页）"),
    db: AsyncSession = Depends(get_db),
):
    """91 短剧播放列表：上游每次播放重新签发 TS 地址，避免存下来的签名过期"""
    from app.services import aidrama91_service

    try:
        source = await aidrama91_service.get_collection_source(db)
        text = await aidrama91_service.fetch_playlist(source, d, e, n)
    except Exception:
        logger.exception("91 播放列表获取失败 drama=%s ep=%s", d, e)
        raise BizException(NOT_FOUND, "播放列表获取失败")

    return Response(
        content=text,
        media_type="application/vnd.apple.mpegurl",
        headers={"Cache-Control": "no-cache", "Access-Control-Allow-Origin": "*"},
    )


@router.get("/vlog")
async def vlog_playlist(
    vid: int = Query(gt=0, description="源站短视频 id"),
    db: AsyncSession = Depends(get_db),
):
    """91 短视频播放列表：playUrl 带时效签名，播放时现取"""
    from app.services import aidrama91_service

    try:
        source = await aidrama91_service.get_vlog_source(db)
        text = await aidrama91_service.fetch_vlog_playlist(source, vid)
    except Exception:
        logger.exception("91 vlog 播放列表获取失败 vid=%s", vid)
        raise BizException(NOT_FOUND, "播放列表获取失败")

    return Response(
        content=text,
        media_type="application/vnd.apple.mpegurl",
        headers={"Cache-Control": "no-cache", "Access-Control-Allow-Origin": "*"},
    )


@img_router.get("/aidrama", include_in_schema=False)
async def aidrama_image(u: str = Query(min_length=10, max_length=600)):
    """91 封面解密代理：CDN 图为 AES-128-CBC 加密字节，解密后输出真实图片"""
    from urllib.parse import urlparse

    from app.services import aidrama91_service

    parsed = urlparse(u)
    if parsed.scheme not in ("http", "https") or not parsed.hostname:
        raise BizException(PARAM_ERROR, "非法图片地址")
    host = parsed.hostname.lower()
    if not (host == aidrama91_service.IMG_HOST_SUFFIX.lstrip(".")
            or host.endswith(aidrama91_service.IMG_HOST_SUFFIX)):
        raise BizException(PARAM_ERROR, "图片域名不在白名单")

    async with httpx.AsyncClient(follow_redirects=True) as client:
        resp = await client.get(u, headers={
            "User-Agent": "Mozilla/5.0 (Linux; Android 10; SM-G973F) AppleWebKit/537.36 "
                          "(KHTML, like Gecko) Chrome/120.0.0.0 Mobile Safari/537.36",
        }, timeout=20)
    if resp.status_code != 200 or not resp.content:
        raise BizException(NOT_FOUND, "图片获取失败")

    try:
        data = aidrama91_service.decrypt_image(resp.content)
    except Exception:
        logger.exception("91 封面解密失败 url=%s", u[:120])
        raise BizException(NOT_FOUND, "图片解密失败")

    # 识别真实格式（密文无 padding，尾部可能有 1 字节冗余，浏览器可正常渲染）
    if data[:3] == b"\xff\xd8\xff":
        mime = "image/jpeg"
    elif data[:8] == b"\x89PNG\r\n\x1a\n":
        mime = "image/png"
    elif data[:6] in (b"GIF87a", b"GIF89a"):
        mime = "image/gif"
    else:
        raise BizException(NOT_FOUND, "图片解密异常")

    return Response(
        content=data,
        media_type=mime,
        headers={"Cache-Control": "public, max-age=86400",
                 "Access-Control-Allow-Origin": "*"},
    )