"""Utils for AWS S3 operations."""

import re

import boto3
from botocore.exceptions import ClientError

_S3_HTTP_PATH = r"^https://(?P<bucket>.+)\.s3\.amazonaws\.com/(?P<key>.+)$"
_S3_PROTOCOL_PATH = r"^s3://(?P<bucket>[^/]+)/(?P<key>.+)$"


def extract_bucket_path(url):
    """Extract bucket name and object key from url.

    Args:
        url (str): S3 URL like
            'https://bucket-name.s3.amazonaws.com/path/to/file.txt'.

    Return:
        tuple: bucket name and bucket path.
    """
    match = re.search(_S3_HTTP_PATH, url)
    if not match:
        match = re.search(_S3_PROTOCOL_PATH, url)

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

    return match.group("bucket"), match.group("key")


def get_presigned_url(bucket, key, expiration_time=3600):
    """Get presigned url.

    Args:
       bucket (str): s3 bucket name.
       key (str): s3 key.
       expiration_time (int): seconds after which link will be expired.

    Returns:
       str: presigned url.
    """
    s3 = boto3.client("s3")
    return s3.generate_presigned_url(
        ClientMethod="get_object",
        Params={"Bucket": bucket, "Key": key},
        ExpiresIn=expiration_time,
    )


def object_exists(bucket, key):
    """Check if s3 object exists.

    Args:
        bucket (str): Bucket name. For example, myBucket
        key (str): full path to s3 object. For example,
            archives/file_part1.gz
    Returns:

        bool: True if exists, False otherwise.
    """
    try:
        client = boto3.client("s3")
        client.head_object(Bucket=bucket, Key=key)
        return True
    except ClientError as error:
        if error.response["Error"]["Code"] == "404":
            return False
        raise


def delete_object(bucket: str, key: str):
    """Delete object from bucket.

    Args:
        bucket (str): Bucket name. For example, myBucket
        key (str): full path to s3 object. For example,
            archives/file_part1.gz
    """
    client = boto3.client("s3")
    client.delete_object(Bucket=bucket, Key=key)