"""Lambda shared module."""
import json
import uuid

import botocore
from marshmallow import ValidationError

from .constants import errors
from .lambda_exceptions import CloudwatchEventError
from .lambda_exceptions import LambdaEventError
from .lambda_exceptions import S3Error
from .validators import validate_encoding_route_lambda_event
from .validators import validate_lambda_event


def generate_unique_filename():
    """Generate unique str sequence from uuid.

    Returns:
        str: Unique sequence.

    """
    return str(uuid.uuid4()).replace('-', '_')


def extract_triggered_key(cloudwatch_event):
    """Get S3 bucket and key from CloudWatch event.

    Args:
        cloudwatch_event (dict): AWS CloudWatch event data object.
    Returns:
         (str, str): Tuple of bucket and key names.

    """
    request_params = cloudwatch_event['detail']['requestParameters']
    bucket_name = request_params.get('bucketName')
    key = request_params.get('key')
    if not (bucket_name and key):
        raise CloudwatchEventError(json.dumps(cloudwatch_event))
    return bucket_name, key


def extract_event(event):
    """Get bucket, key and asset config from lambda event.

    Args:
        event (dict): AWS Lambda Event event data object.
    Returns:
         (str, str): Tuple of bucket and key names.

    """
    try:
        lambda_event = validate_lambda_event(event)
        return (
            lambda_event.get('bucket'),
            lambda_event.get('key'),
            lambda_event.get('config'),
            lambda_event.get('file_type')
        )
    except ValidationError as e:
        raise LambdaEventError(json.dumps(e.messages))


def extract_encoding_route_event(event):
    """Get bucket, key and asset config from lambda event.

    Args:
        event (dict): AWS Lambda Event event data object.
    Returns:
         (str, str): Tuple of bucket and key names.

    """
    try:
        lambda_event = validate_encoding_route_lambda_event(event)
        return lambda_event.get('bucket'), lambda_event.get('key'), lambda_event.get('config')
    except ValidationError as e:
        raise LambdaEventError(json.dumps(e.messages))


def boto3_error_handling(func):
    """Decorate all boto3 methods for exception handling. Used in s3, sns and elastic_transcoder modules."""
    def func_wrapper(*args, **kwargs):
        try:
            return func(*args, **kwargs)
        except botocore.exceptions.ClientError as e:
            error_code = errors.S3_ERROR_CODE
            error_params = {
                'code': e.response['ResponseMetadata']['HTTPStatusCode'],
                'message': str(e)
            }

            if e.response['Error']['Code'] == '404':
                error_code = errors.S3_FILE_NOT_FOUND_CODE
                error_params = {'key': kwargs.get('key') or args[1], 'bucket': kwargs.get('bucket') or args[0]}

            raise S3Error(
                error_code=error_code,
                error_params=error_params
            )
    return func_wrapper