from __future__ import unicode_literals

from moto.core.responses import BaseResponse

from .models import dynamodbstreams_backends


class DynamoDBStreamsHandler(BaseResponse):
    @property
    def backend(self):
        return dynamodbstreams_backends[self.region]

    def describe_stream(self):
        arn = self._get_param("StreamArn")
        return self.backend.describe_stream(arn)

    def list_streams(self):
        table_name = self._get_param("TableName")
        return self.backend.list_streams(table_name)

    def get_shard_iterator(self):
        arn = self._get_param("StreamArn")
        shard_id = self._get_param("ShardId")
        shard_iterator_type = self._get_param("ShardIteratorType")
        sequence_number = self._get_param("SequenceNumber")
        # according to documentation sequence_number param should be string
        if isinstance(sequence_number, str):
            sequence_number = int(sequence_number)

        return self.backend.get_shard_iterator(
            arn, shard_id, shard_iterator_type, sequence_number
        )

    def get_records(self):
        arn = self._get_param("ShardIterator")
        limit = self._get_param("Limit")
        if limit is None:
            limit = 1000
        return self.backend.get_records(arn, limit)