dingdanquanliucheng/backend/app/services/file_service.py

from datetime import datetime

from sqlalchemy.exc import SQLAlchemyError
from sqlalchemy.orm import Session

from backend.app.core.config import get_settings
from backend.app.core.error_codes import ErrorCode
from backend.app.core.exceptions import AppException
from backend.app.repositories.file_repository import FileRepository
from backend.app.services.audit_service import audit_service
from backend.app.services.storage_service import storage_service


class FileService:
    def __init__(self) -> None:
        self.settings = get_settings()
        self.repository = FileRepository()

    def create_upload_token(self, payload: dict, session: Session | None = None) -> dict:
        if not payload["file_name"].strip():
            raise AppException(code=ErrorCode.PARAM_ERROR, message="文件名不能为空", status_code=400)
        if not payload["biz_type"].strip():
            raise AppException(code=ErrorCode.PARAM_ERROR, message="业务类型不能为空", status_code=400)

        file_category = self._detect_file_category(payload["file_type"], payload["file_name"])
        self._validate_file_size(file_category, payload["file_size"])
        token_payload = storage_service.create_upload_token(
            payload["biz_type"],
            payload["biz_id"],
            payload["file_name"],
            payload["file_size"],
        )
        token_payload["file_category"] = file_category
        return token_payload

    def save_attachment(self, payload: dict, session: Session | None = None) -> dict:
        if session is None:
            raise AppException(code=ErrorCode.INTERNAL_ERROR, message="数据库连接不可用", status_code=500)
        attachment_payload = self.build_attachment_payload(payload, created_by=payload.get("created_by"))
        try:
            attachment = self.repository.create_attachment(session, attachment_payload)
            audit_service.write_log(
                session,
                {
                    "operate_type": "attachment_create",
                    "biz_type": payload["biz_type"],
                    "biz_id": payload["biz_id"],
                    "before_value": None,
                    "after_value": self._map_attachment(attachment),
                    "remark": f"保存附件 {payload['file_name']}",
                },
            )
            session.commit()
            return self._map_attachment(attachment)
        except AppException:
            session.rollback()
            raise
        except SQLAlchemyError as exc:
            session.rollback()
            raise AppException(code=ErrorCode.INTERNAL_ERROR, message="数据库异常", status_code=500) from exc

    def build_attachment_payload(
        self,
        payload: dict,
        created_by: int | None = None,
        require_file_size: bool = True,
    ) -> dict:
        if not payload["biz_type"].strip():
            raise AppException(code=ErrorCode.PARAM_ERROR, message="业务类型不能为空", status_code=400)
        if not payload["file_name"].strip():
            raise AppException(code=ErrorCode.PARAM_ERROR, message="文件名不能为空", status_code=400)
        if not payload["file_url"].strip():
            raise AppException(code=ErrorCode.PARAM_ERROR, message="文件地址不能为空", status_code=400)

        file_name = payload["file_name"]
        file_url = payload["file_url"]
        file_type = payload.get("file_type") or None
        file_size = payload.get("file_size")
        if require_file_size and (file_size is None or int(file_size) <= 0):
            raise AppException(code=ErrorCode.PARAM_ERROR, message="文件大小不能为空", status_code=400)

        file_category = self._detect_file_category(file_type or "", file_name)
        if file_size is not None and int(file_size) > 0:
            self._validate_file_size(file_category, int(file_size))

        object_key = storage_service.extract_object_key(file_url)
        file_ext = self._extract_file_ext(file_name)
        self._validate_attachment_file(file_name, file_url, object_key)

        # 司机任务操作里可能只有文件名和 URL，这里允许 MIME 和大小为空，但仍统一沉淀附件元数据。
        return {
            "biz_type": payload["biz_type"],
            "biz_id": payload["biz_id"],
            "file_name": file_name,
            "file_url": file_url,
            "file_type": file_type,
            "file_size": int(file_size) if file_size is not None else None,
            "created_by": created_by,
            "storage_provider": "aliyun_oss",
            "bucket_name": self.settings.aliyun_oss_bucket,
            "object_key": object_key,
            "content_type": file_type,
            "file_ext": file_ext,
            "file_category": file_category,
        }

    def _validate_attachment_file(self, file_name: str, file_url: str, object_key: str) -> None:
        expected_name = file_name.strip()
        object_name = object_key.rsplit("/", 1)[-1]
        # 保存附件时再次核对 object key 与文件名，避免前端绕过上传凭证直接塞入不匹配文件。
        if expected_name and expected_name not in object_name:
            raise AppException(code=ErrorCode.FILE_UPLOAD_FAILED, message="附件文件名与对象地址不匹配", status_code=400)
        if not file_url.startswith(("http://", "https://")):
            raise AppException(code=ErrorCode.FILE_UPLOAD_FAILED, message="附件地址格式不正确", status_code=400)

    def _detect_file_category(self, file_type: str, file_name: str) -> str:
        content_type = (file_type or "").lower()
        suffix = self._extract_file_ext(file_name).lower()
        if content_type.startswith("image/") or suffix in {"jpg", "jpeg", "png", "gif", "webp"}:
            return "image"
        if content_type.startswith("video/") or suffix in {"mp4", "mov", "avi"}:
            return "video"
        if suffix in {"xlsx", "xls", "csv"}:
            return "import"
        return "document"

    def _validate_file_size(self, file_category: str, file_size: int) -> None:
        max_mb = (
            self.settings.oss_upload_max_image_mb
            if file_category == "image"
            else self.settings.oss_upload_max_video_mb
            if file_category == "video"
            else max(self.settings.oss_upload_max_image_mb, self.settings.oss_upload_max_video_mb)
        )
        if file_size > max_mb * 1024 * 1024:
            raise AppException(code=ErrorCode.FILE_UPLOAD_FAILED, message="文件大小超出限制", status_code=400)

    def _extract_file_ext(self, file_name: str) -> str:
        parts = file_name.rsplit(".", 1)
        return parts[1] if len(parts) == 2 else ""

    def _map_attachment(self, attachment) -> dict:
        return {
            "attachment_id": attachment.id,
            "biz_type": attachment.biz_type,
            "biz_id": attachment.biz_id,
            "file_name": attachment.file_name,
            "file_url": attachment.file_url,
            "file_type": attachment.file_type,
            "file_size": attachment.file_size,
            "storage_provider": attachment.storage_provider,
            "bucket_name": attachment.bucket_name,
            "object_key": attachment.object_key,
            "content_type": attachment.content_type,
            "file_ext": attachment.file_ext,
            "file_category": attachment.file_category,
            "created_at": attachment.created_at.strftime("%Y-%m-%d %H:%M:%S") if attachment.created_at else "",
        }


file_service = FileService()