"""Connector for AWS S3."""
import boto3
from botocore.exceptions import ClientError
from oto import response
from sentry_sdk import capture_exception

from blacklist_manager import config

s3_client = None


def get_s3_client():
    """Connect to S3.

    Returns:
         botocore.client.S3 : Client object provides access to s3.
    """
    global s3_client
    if not s3_client:
        s3_client = boto3.client('s3')
    return s3_client


def check_if_file_exists(file_key):
    """File lookup in s3 bucket.

    Args:
        file_key (str): path to a file

    Returns:
        bool: Whether file exists
    """
    if not file_key:
        return False
    try:
        get_s3_client().head_object(
            Bucket=config.EXPORT_BUCKET_NAME, Key=file_key)
    except ClientError as error:
        return int(error.response['Error']['Code']) != 404
    return True


def get_signed_url(file_key, expires_in=86400):
    """Generate generate a pre-signed URL for file on S3 for expires_in time.

    Args:
        file_key (str): path to file for which url should be generated.
        expires_in (int): lifetime of url in sec. Default is 1 day.

    Returns:
        Response: Response with url in message or with errors.
    """
    bucket_name = config.EXPORT_BUCKET_NAME
    if not check_if_file_exists(file_key):
        return response.create_not_found_response(
            message=f'{file_key} not found in {bucket_name} bucket')

    url = get_s3_client().generate_presigned_url(
        'get_object',
        Params={'Bucket': bucket_name, 'Key': file_key},
        ExpiresIn=expires_in
    )
    return response.Response(message=url)


def upload_file_from_disk(file_key, disk_file_path):
    """Upload file from disk to S3.

    Args:
        file_key (str): key of a file that should be uploaded to s3 bucket.
        disk_file_path (str): file path that is to be uploaded.
    """
    try:
        get_s3_client().upload_file(
            disk_file_path, config.EXPORT_BUCKET_NAME, file_key)
        return response.Response(
            f'Successfully uploaded to {config.EXPORT_BUCKET_NAME}/{file_key}')
    except FileNotFoundError as err:
        capture_exception(err)
        return response.create_not_found_response(
            f'Temp file {file_key} not found')