"""
AWS Simple Storage Service (S3)
===============================

This module is a set of util functions that relate to AWS S3.
"""


def extract_bucket_path(url):
    """Extract the bucket name and path from the provided S3 url

    Args:
        url (str): S3 URL like 's3://bucket_name/folder1/folder2/'

    Return:
        tuple: bucket name and bucket path
    """

    bucket_path = ''
    bucket_name = ''

    if url.startswith('s3://'):
        split_path = url.split('/', 3)
        bucket_name = split_path[2]

        if len(split_path) > 3:
            bucket_path = split_path[3]

    if not bucket_name:
        raise Exception('The S3 url \'{url}\' is not valid.'.format(url=url))

    return (bucket_name, bucket_path)


def get_destination_s3key_path(bucket, destination_s3_key):
    """Build s3 url from bucket and s3 key

    Args:
        bucket (str): s3 bucket
        destination_s3key (str): s3 key

    Return:
        str: fill s3 object path
    """

    assert bucket and destination_s3_key, 'Invalid destination_s3_key'
    return 's3://{bucket}/{destination_s3_key}' \
        .format(
            bucket=bucket,
            destination_s3_key=destination_s3_key)