"""Util functions for the package."""


import boto3


def cut_list(seq, size):
    """Cut flat iterable object.

    Cuts flat list into a list with lists of passed size.

    Args:
        seq (sequence): Iterable object.
        size (int): Size of the groups in the result.

    Returns:
        generator: Cut iterable object.

    """
    return (seq[i::size] for i in range(size))


def keys_in_s3_location(bucket_name, path):
    """List keys in S3 location.

    Args:
        bucket_name (str): S3 bucket name.
        path (str): S3 path.

    Returns:
        list(str): List of S3 keys in the location.

    """
    s3_resource = boto3.resource('s3')
    bucket = s3_resource.Bucket(bucket_name)
    return [
        's3://{}/{}'.format(bucket_name, key.key)
        for key in bucket.objects.filter(Prefix=path)]


def bucket_and_path_from_s3_list(s3_link):
    """Get S3 bucket and the rest of the link.

    Args:
        s3_link (str): S3 link in the following format:
            s3://bucket-name/target/path/

    Returns:
        tuple(str, str): S3 bucket name and S3 path.

    """
    parts = s3_link.split('/')
    return parts[2], '/'.join(parts[3:])


def delete_s3_key(s3_path):
    """Delete S3 key.

    Args:
        s3_path (str): S3 link in the following format:
            s3://bucket-name/target/path/
    """
    bucket, path = bucket_and_path_from_s3_list(s3_path)
    s3_resource = boto3.resource('s3')
    obj = s3_resource.Object(bucket, path)
    obj.delete()


def find_exception(seq):
    """Find first Exception object in the sequence.

    Args:
        seq (sequence): Iterable object.

    Returns:
        Exception: Returns Exception object if any found, otherwise None.

    """
    return next((item for item in seq if isinstance(item, Exception)), None)