from dataclasses import dataclass
from typing import BinaryIO

import boto3
from botocore.config import Config
from django.conf import settings


@dataclass(frozen=True)
class StoredObject:
    bucket: str
    object_key: str
    content_type: str
    size_bytes: int


class TosStorage:
    def __init__(self) -> None:
        tos = settings.TOS
        self.bucket = tos["bucket"]
        self.client = boto3.client(
            "s3",
            endpoint_url=tos["endpoint"],
            aws_access_key_id=tos["access_key_id"],
            aws_secret_access_key=tos["secret_access_key"],
            region_name="cn-shanghai",
            config=Config(s3={"addressing_style": "virtual"}),
        )

    def upload_fileobj(self, *, fileobj: BinaryIO, object_key: str, content_type: str) -> StoredObject:
        fileobj.seek(0, 2)
        size = fileobj.tell()
        fileobj.seek(0)
        self.client.upload_fileobj(
            fileobj,
            self.bucket,
            object_key,
            ExtraArgs={"ContentType": content_type},
        )
        return StoredObject(
            bucket=self.bucket,
            object_key=object_key,
            content_type=content_type,
            size_bytes=size,
        )

    def presigned_get_url(self, *, object_key: str, expires_in: int = 3600) -> str:
        return self.client.generate_presigned_url(
            "get_object",
            Params={"Bucket": self.bucket, "Key": object_key},
            ExpiresIn=expires_in,
        )