"""Boto3 s3 file operations."""

from botocore.exceptions import ClientError

from podcast.connectors import s3
from podcast.utils.exc import OwsError


def check_s3_file_exists(bucket_name, file_key):
    """Check the file exists in provided s3 bucket.

    Args:
        bucket_name (str): name of bucket where file is stored.
        file_key (str): path to file for which url should be generated.

    Returns:
        Response: Response with success or error.
    """
    try:
        s3_client = s3.get_s3_client()
        s3_client.head_object(Bucket=bucket_name, Key=file_key)
    except ClientError as e:
        error_message = 'error looking for {key} in bucket {bucket}'.format(key=file_key, bucket=bucket_name)
        raise OwsError.from_boto3_client_error(e, error_message)


def copy_s3_file(source_bucket, source_key, destination_bucket, destination_key):
    """Copy S3 object from one bucket to another.

    This is a managed transfer which will perform a multipart copy in multiple threads if necessary.
    Document: https://boto3.amazonaws.com/v1/documentation/api/latest/reference/services/s3.html#S3.Client.copy

    Args:
        source_bucket (str): Bucket name for source S3 object.
        source_key (str): Key name of the source S3 object.
        destination_bucket (str):Bucket name for destination S3 object.
        destination_key (str):  Key name of the destination S3 object.

    Returns:
        dict: Response from S3.

    """
    try:
        s3_client = s3.get_s3_client()
        s3_client.copy(
            CopySource={'Bucket': source_bucket, 'Key': source_key},
            Bucket=destination_bucket, Key=destination_key
        )
    except ClientError as e:
        error_message = 'error while copying file: {} from input bucket: {} to output bucket: {}'.format(
            source_key, source_bucket, destination_bucket)
        raise OwsError.from_boto3_client_error(e, error_message)