"""文件上传 & 静态文件访问"""
import os
import uuid

from fastapi import APIRouter, UploadFile, File, HTTPException, status
from fastapi.responses import FileResponse

router = APIRouter(prefix="/upload", tags=["文件上传"])

# Docker: os.getcwd() = /app → /app/uploads → host:backend/uploads
BASE_DIR = os.environ.get("PROJECT_ROOT", os.getcwd())
UPLOAD_DIR = os.path.join(BASE_DIR, "uploads")
os.makedirs(UPLOAD_DIR, exist_ok=True)

ALLOWED_EXTENSIONS = {"png", "jpg", "jpeg", "gif", "bmp", "webp", "pdf", "doc", "docx", "xls", "xlsx", "zip", "rar", "7z"}
MAX_SIZE = 50 * 1024 * 1024  # 50MB


@router.post("/")
async def upload_file(file: UploadFile = File(...)) -> dict:
    """上传文件 → 保存到 uploads/uuid.ext → 返回可访问 URL"""
    if not file.filename:
        raise HTTPException(status_code=400, detail="文件名为空")

    ext = file.filename.rsplit(".", 1)[-1].lower() if "." in file.filename else ""
    if ext not in ALLOWED_EXTENSIONS:
        raise HTTPException(status_code=400, detail=f"不支持的文件类型: .{ext}")

    # 检查大小
    content = await file.read()
    if len(content) > MAX_SIZE:
        raise HTTPException(status_code=400, detail="文件超过 50MB 限制")
    await file.seek(0)

    os.makedirs(UPLOAD_DIR, exist_ok=True)
    filename = f"{uuid.uuid4().hex}.{ext}"
    filepath = os.path.join(UPLOAD_DIR, filename)

    with open(filepath, "wb") as f:
        f.write(await file.read())

    return {"url": f"/api/v1/upload/files/{filename}"}


@router.get("/files/{filename}")
async def serve_file(filename: str):
    """直接返回物理文件"""
    filepath = os.path.join(UPLOAD_DIR, filename)
    if not os.path.exists(filepath):
        raise HTTPException(status_code=404, detail="文件不存在")
    return FileResponse(filepath)