#
# All or portions of this file Copyright (c) Amazon.com, Inc. or its affiliates or
# its licensors.
#
# For complete copyright and license terms please see the LICENSE at the root of this
# distribution (the "License"). All use of this software is governed by the License,
# or, if provided, by the license below or the license accompanying this file. Do not
# remove or modify any license notices. This file is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#

from __future__ import print_function
import random
import time
import metric_constant as c
import util
from botocore.exceptions import ClientError


def try_with_backoff(context, cmd, **kwargs):
    # http://www.awsarchitectureblog.com/2015/03/backoff.html
    backoff = context[c.KEY_BACKOFF_BASE_SECONDS] if c.KEY_BACKOFF_BASE_SECONDS in context else 0.1
    max_seconds = context[c.KEY_BACKOFF_MAX_SECONDS] if c.KEY_BACKOFF_MAX_SECONDS in context else 20.0
    max_retry = context[c.KEY_BACKOFF_MAX_TRYS] if c.KEY_BACKOFF_MAX_TRYS in context else 5
    count = 1

    while True:
        try:
            response = cmd(**kwargs)
            __check_response(response)
            util.debug_print("{}\n{}".format(cmd, kwargs))
            util.debug_print(response)
            return response
        except ClientError as e:
            __print_error(e, cmd, kwargs)
            if e.response['Error']['Code'] == 'ValidationException':
                raise e
            response = str(e)
        except Exception as general_error:
            __print_error(general_error, cmd, kwargs)
            response = str(general_error)

        backoff = min(max_seconds, random.uniform(max_seconds, backoff * 3.0))
        util.debug_print("Backing off for {}s".format(backoff))
        time.sleep(backoff)
        count += 1
        if count > max_retry:
            print(response)
            raise Exception("Max retry attempts have been made")


def __print_error(error, cmd, kwargs):
    print(error)
    print("Command: {}".format(cmd))
    print("Args: {}".format(kwargs))


def __check_response(response):
    # Should apply a chain of command pattern here if we find more custom retry cases
    # SQS batch failure
    sqs_error = response.get("Failed", None)
    if sqs_error is not None:
        raise Exception(response)

    # s3 batch failure
    s3_error = response.get("Errors", [])
    if len(s3_error) > 0:
        raise Exception(response)