from __future__ import unicode_literals

import datetime
import time
import re
import six
import itertools

from operator import attrgetter
from hashlib import md5

from boto3 import Session

from moto.compat import OrderedDict
from moto.core import BaseBackend, BaseModel, CloudFormationModel
from moto.core.utils import unix_time
from moto.core import ACCOUNT_ID
from .exceptions import (
    StreamNotFoundError,
    ShardNotFoundError,
    ResourceInUseError,
    ResourceNotFoundError,
    InvalidArgumentError,
)
from .utils import (
    compose_shard_iterator,
    compose_new_shard_iterator,
    decompose_shard_iterator,
)


class Record(BaseModel):
    def __init__(self, partition_key, data, sequence_number, explicit_hash_key):
        self.partition_key = partition_key
        self.data = data
        self.sequence_number = sequence_number
        self.explicit_hash_key = explicit_hash_key
        self.created_at_datetime = datetime.datetime.utcnow()
        self.created_at = unix_time(self.created_at_datetime)

    def to_json(self):
        return {
            "Data": self.data,
            "PartitionKey": self.partition_key,
            "SequenceNumber": str(self.sequence_number),
            "ApproximateArrivalTimestamp": self.created_at,
        }


class Shard(BaseModel):
    def __init__(self, shard_id, starting_hash, ending_hash):
        self._shard_id = shard_id
        self.starting_hash = starting_hash
        self.ending_hash = ending_hash
        self.records = OrderedDict()
        self.is_open = True

    @property
    def shard_id(self):
        return "shardId-{0}".format(str(self._shard_id).zfill(12))

    def get_records(self, last_sequence_id, limit):
        last_sequence_id = int(last_sequence_id)
        results = []
        secs_behind_latest = 0

        for sequence_number, record in self.records.items():
            if sequence_number > last_sequence_id:
                results.append(record)
                last_sequence_id = sequence_number

                very_last_record = self.records[next(reversed(self.records))]
                secs_behind_latest = very_last_record.created_at - record.created_at

            if len(results) == limit:
                break

        millis_behind_latest = int(secs_behind_latest * 1000)
        return results, last_sequence_id, millis_behind_latest

    def put_record(self, partition_key, data, explicit_hash_key):
        # Note: this function is not safe for concurrency
        if self.records:
            last_sequence_number = self.get_max_sequence_number()
        else:
            last_sequence_number = 0
        sequence_number = last_sequence_number + 1
        self.records[sequence_number] = Record(
            partition_key, data, sequence_number, explicit_hash_key
        )
        return sequence_number

    def get_min_sequence_number(self):
        if self.records:
            return list(self.records.keys())[0]
        return 0

    def get_max_sequence_number(self):
        if self.records:
            return list(self.records.keys())[-1]
        return 0

    def get_sequence_number_at(self, at_timestamp):
        if not self.records or at_timestamp < list(self.records.values())[0].created_at:
            return 0
        else:
            # find the last item in the list that was created before
            # at_timestamp
            r = next(
                (
                    r
                    for r in reversed(self.records.values())
                    if r.created_at < at_timestamp
                ),
                None,
            )
            return r.sequence_number

    def to_json(self):
        response = {
            "HashKeyRange": {
                "EndingHashKey": str(self.ending_hash),
                "StartingHashKey": str(self.starting_hash),
            },
            "SequenceNumberRange": {
                "StartingSequenceNumber": self.get_min_sequence_number(),
            },
            "ShardId": self.shard_id,
        }
        if not self.is_open:
            response["SequenceNumberRange"][
                "EndingSequenceNumber"
            ] = self.get_max_sequence_number()
        return response


class Stream(CloudFormationModel):
    def __init__(self, stream_name, shard_count, retention_period_hours, region_name):
        self.stream_name = stream_name
        self.creation_datetime = datetime.datetime.now()
        self.region = region_name
        self.account_number = ACCOUNT_ID
        self.shards = {}
        self.tags = {}
        self.status = "ACTIVE"
        self.shard_count = None
        self.update_shard_count(shard_count)
        self.retention_period_hours = (
            retention_period_hours if retention_period_hours else 24
        )

    def update_shard_count(self, shard_count):
        # ToDo: This was extracted from init.  It's only accurate for new streams.
        #  It doesn't (yet) try to accurately mimic the more complex re-sharding behavior.
        #  It makes the stream as if it had been created with this number of shards.
        #  Logically consistent, but not what AWS does.
        self.shard_count = shard_count

        step = 2 ** 128 // shard_count
        hash_ranges = itertools.chain(
            map(lambda i: (i, i * step, (i + 1) * step), range(shard_count - 1)),
            [(shard_count - 1, (shard_count - 1) * step, 2 ** 128)],
        )
        for index, start, end in hash_ranges:
            shard = Shard(index, start, end)
            self.shards[shard.shard_id] = shard

    @property
    def arn(self):
        return "arn:aws:kinesis:{region}:{account_number}:{stream_name}".format(
            region=self.region,
            account_number=self.account_number,
            stream_name=self.stream_name,
        )

    def get_shard(self, shard_id):
        if shard_id in self.shards:
            return self.shards[shard_id]
        else:
            raise ShardNotFoundError(shard_id)

    def get_shard_for_key(self, partition_key, explicit_hash_key):
        if not isinstance(partition_key, six.string_types):
            raise InvalidArgumentError("partition_key")
        if len(partition_key) > 256:
            raise InvalidArgumentError("partition_key")

        if explicit_hash_key:
            if not isinstance(explicit_hash_key, six.string_types):
                raise InvalidArgumentError("explicit_hash_key")

            key = int(explicit_hash_key)

            if key >= 2 ** 128:
                raise InvalidArgumentError("explicit_hash_key")

        else:
            key = int(md5(partition_key.encode("utf-8")).hexdigest(), 16)

        for shard in self.shards.values():
            if shard.starting_hash <= key < shard.ending_hash:
                return shard

    def put_record(
        self, partition_key, explicit_hash_key, sequence_number_for_ordering, data
    ):
        shard = self.get_shard_for_key(partition_key, explicit_hash_key)

        sequence_number = shard.put_record(partition_key, data, explicit_hash_key)
        return sequence_number, shard.shard_id

    def to_json(self):
        return {
            "StreamDescription": {
                "StreamARN": self.arn,
                "StreamName": self.stream_name,
                "StreamStatus": self.status,
                "HasMoreShards": False,
                "RetentionPeriodHours": self.retention_period_hours,
                "Shards": [shard.to_json() for shard in self.shards.values()],
            }
        }

    def to_json_summary(self):
        return {
            "StreamDescriptionSummary": {
                "StreamARN": self.arn,
                "StreamName": self.stream_name,
                "StreamStatus": self.status,
                "StreamCreationTimestamp": six.text_type(self.creation_datetime),
                "OpenShardCount": self.shard_count,
            }
        }

    @staticmethod
    def cloudformation_name_type():
        return "Name"

    @staticmethod
    def cloudformation_type():
        # https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-kinesis-stream.html
        return "AWS::Kinesis::Stream"

    @classmethod
    def create_from_cloudformation_json(
        cls, resource_name, cloudformation_json, region_name
    ):
        properties = cloudformation_json.get("Properties", {})
        shard_count = properties.get("ShardCount", 1)
        retention_period_hours = properties.get("RetentionPeriodHours", resource_name)
        tags = {
            tag_item["Key"]: tag_item["Value"]
            for tag_item in properties.get("Tags", [])
        }

        backend = kinesis_backends[region_name]
        stream = backend.create_stream(
            resource_name, shard_count, retention_period_hours, region_name
        )
        if any(tags):
            backend.add_tags_to_stream(stream.stream_name, tags)
        return stream

    @classmethod
    def update_from_cloudformation_json(
        cls, original_resource, new_resource_name, cloudformation_json, region_name,
    ):
        properties = cloudformation_json["Properties"]

        if Stream.is_replacement_update(properties):
            resource_name_property = cls.cloudformation_name_type()
            if resource_name_property not in properties:
                properties[resource_name_property] = new_resource_name
            new_resource = cls.create_from_cloudformation_json(
                properties[resource_name_property], cloudformation_json, region_name
            )
            properties[resource_name_property] = original_resource.name
            cls.delete_from_cloudformation_json(
                original_resource.name, cloudformation_json, region_name
            )
            return new_resource

        else:  # No Interruption
            if "ShardCount" in properties:
                original_resource.update_shard_count(properties["ShardCount"])
            if "RetentionPeriodHours" in properties:
                original_resource.retention_period_hours = properties[
                    "RetentionPeriodHours"
                ]
            if "Tags" in properties:
                original_resource.tags = {
                    tag_item["Key"]: tag_item["Value"]
                    for tag_item in properties.get("Tags", [])
                }
            return original_resource

    @classmethod
    def delete_from_cloudformation_json(
        cls, resource_name, cloudformation_json, region_name
    ):
        backend = kinesis_backends[region_name]
        backend.delete_stream(resource_name)

    @staticmethod
    def is_replacement_update(properties):
        properties_requiring_replacement_update = ["BucketName", "ObjectLockEnabled"]
        return any(
            [
                property_requiring_replacement in properties
                for property_requiring_replacement in properties_requiring_replacement_update
            ]
        )

    def get_cfn_attribute(self, attribute_name):
        from moto.cloudformation.exceptions import UnformattedGetAttTemplateException

        if attribute_name == "Arn":
            return self.arn
        raise UnformattedGetAttTemplateException()

    @property
    def physical_resource_id(self):
        return self.stream_name


class FirehoseRecord(BaseModel):
    def __init__(self, record_data):
        self.record_id = 12345678
        self.record_data = record_data


class DeliveryStream(BaseModel):
    def __init__(self, stream_name, **stream_kwargs):
        self.name = stream_name
        self.redshift_username = stream_kwargs.get("redshift_username")
        self.redshift_password = stream_kwargs.get("redshift_password")
        self.redshift_jdbc_url = stream_kwargs.get("redshift_jdbc_url")
        self.redshift_role_arn = stream_kwargs.get("redshift_role_arn")
        self.redshift_copy_command = stream_kwargs.get("redshift_copy_command")

        self.s3_config = stream_kwargs.get("s3_config")
        self.extended_s3_config = stream_kwargs.get("extended_s3_config")

        self.redshift_s3_role_arn = stream_kwargs.get("redshift_s3_role_arn")
        self.redshift_s3_bucket_arn = stream_kwargs.get("redshift_s3_bucket_arn")
        self.redshift_s3_prefix = stream_kwargs.get("redshift_s3_prefix")
        self.redshift_s3_compression_format = stream_kwargs.get(
            "redshift_s3_compression_format", "UNCOMPRESSED"
        )
        self.redshift_s3_buffering_hints = stream_kwargs.get(
            "redshift_s3_buffering_hints"
        )

        self.records = []
        self.status = "ACTIVE"
        self.created_at = datetime.datetime.utcnow()
        self.last_updated = datetime.datetime.utcnow()

    @property
    def arn(self):
        return "arn:aws:firehose:us-east-1:{1}:deliverystream/{0}".format(
            self.name, ACCOUNT_ID
        )

    def destinations_to_dict(self):
        if self.s3_config:
            return [
                {"DestinationId": "string", "S3DestinationDescription": self.s3_config}
            ]
        elif self.extended_s3_config:
            return [
                {
                    "DestinationId": "string",
                    "ExtendedS3DestinationDescription": self.extended_s3_config,
                }
            ]
        else:
            return [
                {
                    "DestinationId": "string",
                    "RedshiftDestinationDescription": {
                        "ClusterJDBCURL": self.redshift_jdbc_url,
                        "CopyCommand": self.redshift_copy_command,
                        "RoleARN": self.redshift_role_arn,
                        "S3DestinationDescription": {
                            "BucketARN": self.redshift_s3_bucket_arn,
                            "BufferingHints": self.redshift_s3_buffering_hints,
                            "CompressionFormat": self.redshift_s3_compression_format,
                            "Prefix": self.redshift_s3_prefix,
                            "RoleARN": self.redshift_s3_role_arn,
                        },
                        "Username": self.redshift_username,
                    },
                }
            ]

    def to_dict(self):
        return {
            "DeliveryStreamDescription": {
                "CreateTimestamp": time.mktime(self.created_at.timetuple()),
                "DeliveryStreamARN": self.arn,
                "DeliveryStreamName": self.name,
                "DeliveryStreamStatus": self.status,
                "Destinations": self.destinations_to_dict(),
                "HasMoreDestinations": False,
                "LastUpdateTimestamp": time.mktime(self.last_updated.timetuple()),
                "VersionId": "string",
            }
        }

    def put_record(self, record_data):
        record = FirehoseRecord(record_data)
        self.records.append(record)
        return record


class KinesisBackend(BaseBackend):
    def __init__(self):
        self.streams = OrderedDict()
        self.delivery_streams = {}

    def create_stream(
        self, stream_name, shard_count, retention_period_hours, region_name
    ):
        if stream_name in self.streams:
            raise ResourceInUseError(stream_name)
        stream = Stream(stream_name, shard_count, retention_period_hours, region_name)
        self.streams[stream_name] = stream
        return stream

    def describe_stream(self, stream_name):
        if stream_name in self.streams:
            return self.streams[stream_name]
        else:
            raise StreamNotFoundError(stream_name)

    def describe_stream_summary(self, stream_name):
        return self.describe_stream(stream_name)

    def list_streams(self):
        return self.streams.values()

    def delete_stream(self, stream_name):
        if stream_name in self.streams:
            return self.streams.pop(stream_name)
        raise StreamNotFoundError(stream_name)

    def get_shard_iterator(
        self,
        stream_name,
        shard_id,
        shard_iterator_type,
        starting_sequence_number,
        at_timestamp,
    ):
        # Validate params
        stream = self.describe_stream(stream_name)
        shard = stream.get_shard(shard_id)

        shard_iterator = compose_new_shard_iterator(
            stream_name,
            shard,
            shard_iterator_type,
            starting_sequence_number,
            at_timestamp,
        )
        return shard_iterator

    def get_records(self, shard_iterator, limit):
        decomposed = decompose_shard_iterator(shard_iterator)
        stream_name, shard_id, last_sequence_id = decomposed

        stream = self.describe_stream(stream_name)
        shard = stream.get_shard(shard_id)

        records, last_sequence_id, millis_behind_latest = shard.get_records(
            last_sequence_id, limit
        )

        next_shard_iterator = compose_shard_iterator(
            stream_name, shard, last_sequence_id
        )

        return next_shard_iterator, records, millis_behind_latest

    def put_record(
        self,
        stream_name,
        partition_key,
        explicit_hash_key,
        sequence_number_for_ordering,
        data,
    ):
        stream = self.describe_stream(stream_name)

        sequence_number, shard_id = stream.put_record(
            partition_key, explicit_hash_key, sequence_number_for_ordering, data
        )

        return sequence_number, shard_id

    def put_records(self, stream_name, records):
        stream = self.describe_stream(stream_name)

        response = {"FailedRecordCount": 0, "Records": []}

        for record in records:
            partition_key = record.get("PartitionKey")
            explicit_hash_key = record.get("ExplicitHashKey")
            data = record.get("Data")

            sequence_number, shard_id = stream.put_record(
                partition_key, explicit_hash_key, None, data
            )
            response["Records"].append(
                {"SequenceNumber": sequence_number, "ShardId": shard_id}
            )

        return response

    def split_shard(self, stream_name, shard_to_split, new_starting_hash_key):
        stream = self.describe_stream(stream_name)

        if shard_to_split not in stream.shards:
            raise ResourceNotFoundError(shard_to_split)

        if not re.match(r"0|([1-9]\d{0,38})", new_starting_hash_key):
            raise InvalidArgumentError(new_starting_hash_key)
        new_starting_hash_key = int(new_starting_hash_key)

        shard = stream.shards[shard_to_split]

        last_id = sorted(stream.shards.values(), key=attrgetter("_shard_id"))[
            -1
        ]._shard_id

        if shard.starting_hash < new_starting_hash_key < shard.ending_hash:
            new_shard = Shard(last_id + 1, new_starting_hash_key, shard.ending_hash)
            shard.ending_hash = new_starting_hash_key
            stream.shards[new_shard.shard_id] = new_shard
        else:
            raise InvalidArgumentError(new_starting_hash_key)

        records = shard.records
        shard.records = OrderedDict()

        for index in records:
            record = records[index]
            stream.put_record(
                record.partition_key, record.explicit_hash_key, None, record.data
            )

    def merge_shards(self, stream_name, shard_to_merge, adjacent_shard_to_merge):
        stream = self.describe_stream(stream_name)

        if shard_to_merge not in stream.shards:
            raise ResourceNotFoundError(shard_to_merge)

        if adjacent_shard_to_merge not in stream.shards:
            raise ResourceNotFoundError(adjacent_shard_to_merge)

        shard1 = stream.shards[shard_to_merge]
        shard2 = stream.shards[adjacent_shard_to_merge]

        if shard1.ending_hash == shard2.starting_hash:
            shard1.ending_hash = shard2.ending_hash
        elif shard2.ending_hash == shard1.starting_hash:
            shard1.starting_hash = shard2.starting_hash
        else:
            raise InvalidArgumentError(adjacent_shard_to_merge)

        del stream.shards[shard2.shard_id]
        for index in shard2.records:
            record = shard2.records[index]
            shard1.put_record(
                record.partition_key, record.data, record.explicit_hash_key
            )

    def increase_stream_retention_period(self, stream_name, retention_period_hours):
        stream = self.describe_stream(stream_name)
        if (
            retention_period_hours <= stream.retention_period_hours
            or retention_period_hours < 24
            or retention_period_hours > 8760
        ):
            raise InvalidArgumentError(retention_period_hours)
        stream.retention_period_hours = retention_period_hours

    def decrease_stream_retention_period(self, stream_name, retention_period_hours):
        stream = self.describe_stream(stream_name)
        if (
            retention_period_hours >= stream.retention_period_hours
            or retention_period_hours < 24
            or retention_period_hours > 8760
        ):
            raise InvalidArgumentError(retention_period_hours)
        stream.retention_period_hours = retention_period_hours

    """ Firehose """

    def create_delivery_stream(self, stream_name, **stream_kwargs):
        stream = DeliveryStream(stream_name, **stream_kwargs)
        self.delivery_streams[stream_name] = stream
        return stream

    def get_delivery_stream(self, stream_name):
        if stream_name in self.delivery_streams:
            return self.delivery_streams[stream_name]
        else:
            raise StreamNotFoundError(stream_name)

    def list_delivery_streams(self):
        return self.delivery_streams.values()

    def delete_delivery_stream(self, stream_name):
        self.delivery_streams.pop(stream_name)

    def put_firehose_record(self, stream_name, record_data):
        stream = self.get_delivery_stream(stream_name)
        record = stream.put_record(record_data)
        return record

    def list_tags_for_stream(
        self, stream_name, exclusive_start_tag_key=None, limit=None
    ):
        stream = self.describe_stream(stream_name)

        tags = []
        result = {"HasMoreTags": False, "Tags": tags}
        for key, val in sorted(stream.tags.items(), key=lambda x: x[0]):
            if limit and len(tags) >= limit:
                result["HasMoreTags"] = True
                break
            if exclusive_start_tag_key and key < exclusive_start_tag_key:
                continue

            tags.append({"Key": key, "Value": val})

        return result

    def add_tags_to_stream(self, stream_name, tags):
        stream = self.describe_stream(stream_name)
        stream.tags.update(tags)

    def remove_tags_from_stream(self, stream_name, tag_keys):
        stream = self.describe_stream(stream_name)
        for key in tag_keys:
            if key in stream.tags:
                del stream.tags[key]


kinesis_backends = {}
for region in Session().get_available_regions("kinesis"):
    kinesis_backends[region] = KinesisBackend()
for region in Session().get_available_regions("kinesis", partition_name="aws-us-gov"):
    kinesis_backends[region] = KinesisBackend()
for region in Session().get_available_regions("kinesis", partition_name="aws-cn"):
    kinesis_backends[region] = KinesisBackend()
