# Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
# SPDX-License-Identifier: Apache-2.0

"""
Helper functions for S3
"""

import boto3
from botocore.client import Config
from typing import List


def get_s3_client():
    """
    Get a default S3 client, configured to use Virtual Hosted-Style addressing.

    Virtual Hosted-Style addressing ensures pre-signed URLs generated by this client will avoid potential HTTP 307
    Temporary Redirect errors that may occur within the first 24 hours after the bucket is first created.
    See: https://aws.amazon.com/premiumsupport/knowledge-center/s3-http-307-response/

    DO NOT USE this client if your bucket is configured with CORS (Cross-Origin Resource Sharing), otherwise you may
    face errors during the first several hours after the bucket is created due to DNS changes having not propagated yet.
    For CORS-configured buckets, you need to initially use Path-Style addressing.
    See: https://boto3.amazonaws.com/v1/documentation/api/1.9.42/guide/s3.html#changing-the-addressing-style

    For more information on S3 addressing styles, please see:
    https://docs.aws.amazon.com/AmazonS3/latest/userguide/VirtualHosting.html
    """
    return boto3.client(
        service_name='s3',
        config=Config(s3={'addressing_style': 'virtual'})
    )


def get_bucket(bucket_name: str):
    return boto3.resource('s3', config=Config(s3={'addressing_style': 'path'})).Bucket(bucket_name)


def delete_items(keys: List[str], s3_bucket):
    """Delete the specified keys from the provided S3 bucket and return the S3 response."""
    delete_request = {
        'Objects': [{'Key': key} for key in keys]
    }

    print(f'Deleting keys {keys} from bucket {s3_bucket.name}')
    return s3_bucket.delete_objects(Delete=delete_request)