"""Small S3-compatible object-storage adapter shared by backend features."""

from __future__ import annotations

import boto3
from botocore.config import Config
from botocore.exceptions import ClientError

import settings


def _client():
    return boto3.client(
        "s3",
        endpoint_url=settings.S3_ENDPOINT_URL,
        aws_access_key_id=settings.S3_ACCESS_KEY,
        aws_secret_access_key=settings.S3_SECRET_KEY,
        region_name=settings.S3_REGION,
        config=Config(signature_version="s3v4", s3={"addressing_style": "path"}),
    )


def put_object(key: str, data: bytes, mime_type: str) -> None:
    client = _client()
    try:
        client.head_bucket(Bucket=settings.S3_BUCKET)
    except ClientError as exc:
        status = exc.response.get("ResponseMetadata", {}).get("HTTPStatusCode")
        if status != 404:
            raise
        client.create_bucket(Bucket=settings.S3_BUCKET)
    client.put_object(
        Bucket=settings.S3_BUCKET,
        Key=key,
        Body=data,
        ContentType=mime_type,
    )


def get_object(key: str) -> bytes:
    response = _client().get_object(Bucket=settings.S3_BUCKET, Key=key)
    return response["Body"].read()


def delete_object(key: str) -> None:
    _client().delete_object(Bucket=settings.S3_BUCKET, Key=key)


def storage_uri(key: str) -> str:
    return f"s3://{settings.S3_BUCKET}/{key.lstrip('/')}"


def key_from_storage_uri(uri: str) -> str:
    prefix = f"s3://{settings.S3_BUCKET}/"
    if not uri.startswith(prefix):
        raise ValueError("不支持的会话附件存储地址")
    key = uri[len(prefix) :].strip("/")
    if not key:
        raise ValueError("会话附件存储地址缺少对象键")
    return key