from botocore.exceptions import ClientError
from chalicelib.utils.helper import environ

import boto3

from botocore.client import Config

client = boto3.client('s3', endpoint_url=environ["S3_HOST"],
                      aws_access_key_id=environ["S3_KEY"],
                      aws_secret_access_key=environ["S3_SECRET"],
                      config=Config(signature_version='s3v4'),
                      region_name='us-east-1')


def exists(bucket, key):
    response = client.list_objects_v2(
        Bucket=bucket,
        Prefix=key,
    )
    for obj in response.get('Contents', []):
        if obj['Key'] == key:
            return True
    return False


def get_presigned_url_for_sharing(bucket, expires_in, key, check_exists=False):
    if check_exists and not exists(bucket, key):
        return None

    return client.generate_presigned_url(
        'get_object',
        Params={
            'Bucket': bucket,
            'Key': key
        },
        ExpiresIn=expires_in
    )


def get_presigned_url_for_upload(bucket, expires_in, key):
    return client.generate_presigned_url(
        'put_object',
        Params={
            'Bucket': bucket,
            'Key': key
        },
        ExpiresIn=expires_in
    )


def get_file(source_bucket, source_key):
    try:
        result = client.get_object(
            Bucket=source_bucket,
            Key=source_key
        )
    except ClientError as ex:
        if ex.response['Error']['Code'] == 'NoSuchKey':
            print(f'======> No object found - returning None for {source_bucket}/{source_key}')
            return None
        else:
            raise ex
    return result["Body"].read().decode()