import mimetypes
from pathlib import Path
from uuid import uuid4

from fastapi import APIRouter, HTTPException, Request, status
from starlette.datastructures import UploadFile

from app.config import oss_settings
from app.schemas import UploadResponse


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

MAX_IMAGE_SIZE = 5 * 1024 * 1024
ALLOWED_IMAGE_TYPES = {"image/jpeg", "image/png", "image/webp", "image/gif"}


def get_public_url(object_key: str) -> str:
    if oss_settings.public_base_url:
        return f"{oss_settings.public_base_url.rstrip('/')}/{object_key}"

    endpoint = oss_settings.endpoint.replace("https://", "").replace("http://", "").rstrip("/")
    return f"https://{oss_settings.bucket_name}.{endpoint}/{object_key}"


def build_object_key(filename: str | None, folder: str) -> str:
    suffix = Path(filename or "").suffix.lower()
    if not suffix:
        suffix = mimetypes.guess_extension("image/jpeg") or ".jpg"

    safe_folder = folder.strip("/ ") or oss_settings.upload_prefix
    return f"{oss_settings.upload_prefix.strip('/')}/{safe_folder}/{uuid4().hex}{suffix}"


@router.post("/images", response_model=UploadResponse)
async def upload_image(request: Request) -> UploadResponse:
    if not oss_settings.is_configured:
        raise HTTPException(
            status_code=status.HTTP_503_SERVICE_UNAVAILABLE,
            detail="OSS 配置未完成，请先填写 app/config.py 中的 OSS 配置。",
        )

    form = await request.form()
    file = form.get("file")
    folder_value = form.get("folder")
    folder = str(folder_value) if folder_value else "products"

    if not isinstance(file, UploadFile):
        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="请选择要上传的图片")

    content_type = file.content_type or "application/octet-stream"
    if content_type not in ALLOWED_IMAGE_TYPES:
        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="只支持上传图片文件")

    data = await file.read()
    if len(data) > MAX_IMAGE_SIZE:
        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="图片大小不能超过 5MB")

    try:
        import oss2
    except ImportError as exc:
        raise HTTPException(
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
            detail="缺少 oss2 依赖，请先安装 requirements.txt 中的依赖。",
        ) from exc

    object_key = build_object_key(file.filename, folder)
    auth = oss2.Auth(oss_settings.access_key_id, oss_settings.access_key_secret)
    bucket = oss2.Bucket(auth, oss_settings.upload_endpoint, oss_settings.bucket_name)
    bucket.put_object(object_key, data, headers={"Content-Type": content_type})

    return UploadResponse(url=get_public_url(object_key), object_key=object_key)