"""S3 module."""

import boto3
from botocore.exceptions import ClientError

from asset_transcoder.utils import exceptions


client = boto3.client('s3')
resource = boto3.resource('s3')


def update_file_metadata(key, bucket, metadata):
    """Update a file's metadata using the REPLACE directive.

    Args:
        key (str): filename with the extension
        bucket (str): bucket
        metadata (dict): key / value pairs to be merged with the file's existing metadata
    """
    try:
        response = client.head_object(
            Bucket=bucket,
            Key=key
        )

        asset_metadata = {
            'ContentType': response['ContentType'],
            'Metadata': response['Metadata'],
            'MetadataDirective': 'REPLACE'
        }
        asset_metadata.update(metadata)

        if 'Metadata' in metadata:
            asset_metadata['Metadata'].update(response['Metadata'])

        copy_source = {
            'Bucket': bucket,
            'Key': key
        }
        resource.meta.client.copy(
            copy_source,
            bucket,
            key,
            ExtraArgs=asset_metadata,
            SourceClient=client
        )

    except ClientError as e:
        error_message = 'error updating metadata for {key} in bucket {bucket}'.format(key=key, bucket=bucket)
        raise exceptions.OwsError.from_boto3_client_error(e, error_message)