import base64
import contextlib
import json
import re
from collections import OrderedDict
from collections.abc import Iterable, Iterator
from datetime import timedelta
from functools import lru_cache
from typing import Any, cast

import cryptography
import requests
from cryptography.hazmat.primitives import hashes, serialization
from cryptography.hazmat.primitives.asymmetric import padding, rsa
from cryptography.x509 import Name, NameAttribute
from cryptography.x509.oid import NameOID

from moto.core import DEFAULT_ACCOUNT_ID
from moto.core.base_backend import BackendDict, BaseBackend
from moto.core.common_models import BaseModel, CloudFormationModel
from moto.core.resource_tagging import TaggableResourcesMixin, TaggedResource
from moto.core.utils import (
    camelcase_to_underscores,
    iso_8601_datetime_with_milliseconds,
    unix_time,
    utcnow,
)
from moto.moto_api._internal import mock_random
from moto.sqs import sqs_backends
from moto.sqs.exceptions import MissingParameter, QueueDoesNotExist
from moto.sqs.models import SQSBackend
from moto.utilities.arns import parse_arn
from moto.utilities.paginator import paginate
from moto.utilities.utils import get_partition

from .exceptions import (
    BatchEntryIdsNotDistinct,
    DuplicateSnsEndpointError,
    InternalError,
    InvalidParameterValue,
    ResourceNotFoundError,
    SnsEndpointDisabled,
    SNSInvalidParameter,
    SNSNotFoundError,
    TagLimitExceededError,
    TooManyEntriesInBatchRequest,
    TopicNotFound,
)
from .utils import (
    FilterPolicyMatcher,
    is_e164,
    make_arn_for_subscription,
    make_arn_for_topic,
)

DEFAULT_PAGE_SIZE = 100
MAXIMUM_MESSAGE_LENGTH = 262144  # 256 KiB
MAXIMUM_SMS_MESSAGE_BYTES = 1600  # Amazon limit for a single publish SMS action

PAGINATION_MODEL = {
    "list_config_service_resources": {
        "input_token": "next_token",
        "limit_key": "limit",
        "limit_default": 100,
        "unique_attribute": "id",
    }
}


class SMS(BaseModel):
    def __init__(self, message_id: str, phone_number: str, message: str):
        self.message_id = message_id
        self.phone_number = phone_number
        self.message = message


class Topic(CloudFormationModel):
    def __init__(self, name: str, sns_backend: "SNSBackend"):
        self.name = name
        self.sns_backend = sns_backend
        self.account_id = sns_backend.account_id
        self.display_name = ""
        self.delivery_policy = ""
        self.kms_master_key_id = ""
        self.effective_delivery_policy = json.dumps(DEFAULT_EFFECTIVE_DELIVERY_POLICY)
        self.arn = make_arn_for_topic(self.account_id, name, sns_backend.region_name)

        self.subscriptions_pending = 0
        self.subscriptions_confimed = 0
        self.subscriptions_deleted = 0
        self.sent_notifications: list[
            tuple[str, str, str | None, dict[str, Any] | None, str | None]
        ] = []

        self._policy_json = self._create_default_topic_policy(
            sns_backend.region_name, self.account_id, name
        )
        self._tags: dict[str, str] = {}
        self.fifo_topic = False
        self.content_based_deduplication = False

    def publish(
        self,
        message: str,
        subject: str | None = None,
        message_attributes: dict[str, Any] | None = None,
        group_id: str | None = None,
        deduplication_id: str | None = None,
        message_structure: str | None = None,
    ) -> str:
        message_id = str(mock_random.uuid4())
        subscriptions, _ = self.sns_backend.list_subscriptions_by_topic(
            topic_arn=self.arn
        )
        for subscription in subscriptions:
            subscription.publish(
                message,
                message_id,
                subject=subject,
                message_attributes=message_attributes,
                group_id=group_id,
                deduplication_id=deduplication_id,
                message_structure=message_structure,
            )

        self.sent_notifications.append(
            (message_id, message, subject, message_attributes, group_id)
        )
        return message_id

    @classmethod
    def has_cfn_attr(cls, attr: str) -> bool:
        return attr in ["TopicName"]

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

        if attribute_name == "TopicName":
            return self.name
        raise UnformattedGetAttTemplateException()

    @property
    def physical_resource_id(self) -> str:
        return self.arn

    @property
    def policy(self) -> str:
        return json.dumps(self._policy_json, separators=(",", ":"))

    @policy.setter
    def policy(self, policy: Any) -> None:
        self._policy_json = json.loads(policy)

    @staticmethod
    def cloudformation_name_type() -> str:
        return "TopicName"

    @staticmethod
    def cloudformation_type() -> str:
        # https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-sns-topic.html
        return "AWS::SNS::Topic"

    @classmethod
    def create_from_cloudformation_json(  # type: ignore[misc]
        cls,
        resource_name: str,
        cloudformation_json: Any,
        account_id: str,
        region_name: str,
        **kwargs: Any,
    ) -> "Topic":
        sns_backend = sns_backends[account_id][region_name]
        properties = cloudformation_json["Properties"]

        topic = sns_backend.create_topic(resource_name, properties)
        for subscription in properties.get("Subscription", []):
            sns_backend.subscribe(
                topic.arn, subscription["Endpoint"], subscription["Protocol"]
            )
        return topic

    @classmethod
    def update_from_cloudformation_json(  # type: ignore[misc]
        cls,
        original_resource: "Topic",
        new_resource_name: str,
        cloudformation_json: Any,
        account_id: str,
        region_name: str,
    ) -> "Topic":
        original_resource.delete(account_id, region_name)
        return cls.create_from_cloudformation_json(
            new_resource_name, cloudformation_json, account_id, region_name
        )

    def delete(self, account_id: str, region_name: str) -> None:
        sns_backend: SNSBackend = sns_backends[account_id][region_name]
        sns_backend.delete_topic(self.arn)

    def _create_default_topic_policy(
        self, region_name: str, account_id: str, name: str
    ) -> dict[str, Any]:
        return {
            "Version": "2008-10-17",
            "Id": "__default_policy_ID",
            "Statement": [
                {
                    "Effect": "Allow",
                    "Sid": "__default_statement_ID",
                    "Principal": {"AWS": "*"},
                    "Action": [
                        "SNS:GetTopicAttributes",
                        "SNS:SetTopicAttributes",
                        "SNS:AddPermission",
                        "SNS:RemovePermission",
                        "SNS:DeleteTopic",
                        "SNS:Subscribe",
                        "SNS:ListSubscriptionsByTopic",
                        "SNS:Publish",
                    ],
                    "Resource": make_arn_for_topic(self.account_id, name, region_name),
                    "Condition": {"StringEquals": {"AWS:SourceOwner": str(account_id)}},
                }
            ],
        }


class Subscription(BaseModel):
    def __init__(self, account_id: str, topic: Topic, endpoint: str, protocol: str):
        self.account_id = account_id
        self.owner = account_id
        self.topic = topic
        self.endpoint = endpoint
        self.protocol = protocol
        self.arn = make_arn_for_subscription(self.topic.arn)
        self.attributes: dict[str, Any] = {}
        self._filter_policy = None  # filter policy as a dict, not json.
        self._filter_policy_matcher: FilterPolicyMatcher | None = None
        self.confirmed = False

    @property
    def topic_arn(self) -> str:
        return self.topic.arn

    def publish(
        self,
        message: str,
        message_id: str,
        subject: str | None = None,
        message_attributes: dict[str, Any] | None = None,
        group_id: str | None = None,
        deduplication_id: str | None = None,
        message_structure: str | None = None,
    ) -> None:
        if self._filter_policy_matcher is not None:
            if not self._filter_policy_matcher.matches(message_attributes, message):
                return

        if message_structure == "json":
            message = self._parse_message_structure(message, self.protocol)

        if self.protocol == "sqs":
            queue_name = self.endpoint.split(":")[-1]
            region = self.endpoint.split(":")[3]

            backend: SQSBackend = sqs_backends[self.account_id][region]

            if not self.attributes.get("RawMessageDelivery"):
                backend.send_message(
                    queue_name,
                    json.dumps(
                        self.get_post_data(
                            message,
                            message_id,
                            subject,
                            message_attributes=message_attributes,
                        ),
                        sort_keys=True,
                        indent=2,
                        separators=(",", ": "),
                    ),
                    deduplication_id=deduplication_id,
                    group_id=group_id,
                    validate_group_id=False,
                )
            else:
                raw_message_attributes = {}
                for key, value in (message_attributes or {}).items():
                    attr_type = "StringValue"
                    type_value = value["Value"]
                    if value["Type"].startswith("Binary"):
                        attr_type = "BinaryValue"
                    elif value["Type"].startswith("Number"):
                        type_value = str(value["Value"])

                    raw_message_attributes[key] = {
                        "DataType": value["Type"],
                        attr_type: type_value,
                    }

                backend.send_message(
                    queue_name,
                    message,
                    message_attributes=raw_message_attributes,
                    deduplication_id=deduplication_id,
                    group_id=group_id,
                    validate_group_id=False,
                )
        elif self.protocol in ["http", "https"]:
            post_data = self.get_post_data(message, message_id, subject)
            requests.post(
                self.endpoint,
                json=post_data,
                headers={"Content-Type": "text/plain; charset=UTF-8"},
            )
        elif self.protocol == "lambda":
            # TODO: support bad function name
            # http://docs.aws.amazon.com/general/latest/gr/aws-arns-and-namespaces.html
            arr = self.endpoint.split(":")
            region = arr[3]
            qualifier = None
            if len(arr) == 7:
                assert arr[5] == "function"
                function_name = arr[-1]
            elif len(arr) == 8:
                assert arr[5] == "function"
                qualifier = arr[-1]
                function_name = arr[-2]
            else:
                raise AssertionError()

            from moto.awslambda.utils import get_backend

            get_backend(self.account_id, region).send_sns_message(
                function_name, message, subject=subject, qualifier=qualifier
            )

    def get_post_data(
        self,
        message: str,
        message_id: str,
        subject: str | None,
        message_attributes: dict[str, Any] | None = None,
    ) -> dict[str, Any]:
        key = self.private_key()
        cert_subject = [NameAttribute(NameOID.COMMON_NAME, "sns.amazonaws.com")]
        issuer = [
            NameAttribute(NameOID.COUNTRY_NAME, "US"),
            NameAttribute(NameOID.ORGANIZATION_NAME, "Amazon"),
            NameAttribute(NameOID.COMMON_NAME, "Amazon RSA 2048 M01"),
        ]
        # SNS supports two signing algorithms
        # User can choose which algorithm they want by updating the topic attribute 'SignatureVersion'
        # Signature Version "1" == SHA1, "2" == SHA256
        #
        # Because cryptography doesn't support SHA1 anymore for certificates, we always use SignatureVersion="2"
        signature_version = "2"
        algo = hashes.SHA256() if signature_version == "2" else hashes.SHA1()
        cert = (
            cryptography.x509.CertificateBuilder()
            .subject_name(Name(cert_subject))
            .issuer_name(Name(issuer))
            .public_key(key.public_key())
            .serial_number(cryptography.x509.random_serial_number())
            .not_valid_before(utcnow())
            .not_valid_after(utcnow() + timedelta(days=365))
            .sign(key, algo)  # type: ignore
        )
        key_name = (
            f"SimpleNotificationService-{str(mock_random.uuid4()).replace('-', '')}.pem"
        )

        timestamp = iso_8601_datetime_with_milliseconds()
        string_to_sign = f"""Message
{message}
MessageId
{message_id}
Timestamp
{timestamp}
TopicArn
{self.topic.arn}
Type
Notification
"""
        signature = key.sign(
            string_to_sign.encode("UTF-8"), padding.PKCS1v15(), hashes.SHA256()
        )

        # Retrieving the PEM is done via an unauthorized request
        # We don't know in what account this was done - so just store in the default account
        # We do know what region it is in, as the URL is `sns.{region}.amazonaws.com/name.pem`
        region = self.topic.sns_backend.region_name
        default_sns_backend = sns_backends[DEFAULT_ACCOUNT_ID][region]
        default_sns_backend._message_public_keys[key_name] = cert.public_bytes(
            serialization.Encoding.PEM
        )

        post_data: dict[str, Any] = {
            "Type": "Notification",
            "MessageId": message_id,
            "TopicArn": self.topic.arn,
            "Message": message,
            "Timestamp": timestamp,
            "SignatureVersion": signature_version,
            "Signature": base64.b64encode(signature).decode("utf-8"),
            "SigningCertURL": f"https://sns.{region}.amazonaws.com/{key_name}",
            "UnsubscribeURL": f"https://sns.us-east-1.amazonaws.com/?Action=Unsubscribe&SubscriptionArn=arn:aws:sns:us-east-1:{self.account_id}:{self.topic.name}:2bcfbf39-05c3-41de-beaa-fcfcc21c8f55",
        }
        if subject:
            post_data["Subject"] = subject
        if message_attributes:
            post_data["MessageAttributes"] = message_attributes
        return post_data

    @lru_cache
    def private_key(self) -> rsa.RSAPrivateKey:
        return rsa.generate_private_key(public_exponent=65537, key_size=2048)

    def _parse_message_structure(self, message: str, protocol: str) -> str:
        try:
            structured_message = json.loads(message)
            message = (
                structured_message.get(self.protocol) or structured_message["default"]
            )

            return message
        except json.JSONDecodeError:
            raise InvalidParameterValue(
                "Message is not valid JSON.",
            )
        except KeyError:
            raise InvalidParameterValue(
                f"Message does not contain {protocol} or default keys.",
            )


class PlatformApplication(BaseModel):
    def __init__(
        self,
        account_id: str,
        region: str,
        name: str,
        platform: str,
        attributes: dict[str, str],
    ):
        self.region = region
        self.name = name
        self.platform = platform
        self.attributes = attributes
        self.arn = f"arn:{get_partition(region)}:sns:{region}:{account_id}:app/{platform}/{name}"


class PlatformEndpoint(BaseModel):
    def __init__(
        self,
        account_id: str,
        region: str,
        application: PlatformApplication,
        custom_user_data: str,
        token: str,
        attributes: dict[str, Any],
    ):
        self.region = region
        self.application = application
        self.custom_user_data = custom_user_data
        self.token = token
        self.attributes = attributes
        self.id = mock_random.uuid4()
        self.arn = f"arn:{get_partition(region)}:sns:{region}:{account_id}:endpoint/{self.application.platform}/{self.application.name}/{self.id}"
        self.messages: dict[str, str] = OrderedDict()
        self.__fixup_attributes()

    def __fixup_attributes(self) -> None:
        # When AWS returns the attributes dict, it always contains these two elements, so we need to
        # automatically ensure they exist as well.
        if "Token" not in self.attributes:
            self.attributes["Token"] = self.token
        if "Enabled" not in self.attributes:
            self.attributes["Enabled"] = True

    @property
    def enabled(self) -> bool:
        return self.attributes.get("Enabled", True) is True

    def publish(self, message: str) -> str:
        if not self.enabled:
            raise SnsEndpointDisabled("Endpoint is disabled")

        # This is where we would actually send a message
        message_id = str(mock_random.uuid4())
        self.messages[message_id] = message
        return message_id


class SNSBackend(BaseBackend, TaggableResourcesMixin):
    """
    Responsible for mocking calls to SNS. Integration with SQS/HTTP/etc is supported.

    If you're using the decorators, you can verify the message signature send to an HTTP endpoint.

    Messages published to a topic are persisted in the backend. If you need to verify that a message was published successfully, you can use the internal API to check the message was published successfully:

    .. sourcecode:: python

        from moto.core import DEFAULT_ACCOUNT_ID
        from moto.sns import sns_backends
        sns_backend = sns_backends[DEFAULT_ACCOUNT_ID]["us-east-1"]  # Use the appropriate account/region
        all_send_notifications = sns_backend.topics[topic_arn].sent_notifications

    Note that, as this is an internal API, the exact format may differ per versions.
    """

    SERVICE_NAMESPACE = "sns"

    def __init__(self, region_name: str, account_id: str):
        super().__init__(region_name, account_id)
        self.topics: dict[str, Topic] = OrderedDict()
        self.subscriptions: OrderedDict[str, Subscription] = OrderedDict()
        self.applications: dict[str, PlatformApplication] = {}
        self.platform_endpoints: dict[str, PlatformEndpoint] = {}
        self.region_name = region_name
        self.sms_attributes: dict[str, str] = {}
        # We're storing the messages twice here
        # The tuple is for backwards compatibility; the object is to expose this data to the MotoAPI
        # We should combine these in a next major release, when we're allowed to break compatibility
        self.sms_messages: dict[str, tuple[str, str]] = OrderedDict()
        self.sms_message_objects: dict[str, SMS] = {}
        self.opt_out_numbers = [
            "+447420500600",
            "+447420505401",
            "+447632960543",
            "+447632960028",
            "+447700900149",
            "+447700900550",
            "+447700900545",
            "+447700900907",
        ]

        self._message_public_keys: dict[str, bytes] = {}

    def get_sms_attributes(self, filter_list: set[str]) -> dict[str, str]:
        if len(filter_list) > 0:
            return {k: v for k, v in self.sms_attributes.items() if k in filter_list}
        else:
            return self.sms_attributes

    def set_sms_attributes(self, attrs: dict[str, str]) -> None:
        self.sms_attributes.update(attrs)

    def create_topic(
        self,
        name: str,
        attributes: dict[str, str] | None = None,
        tags: dict[str, str] | None = None,
    ) -> Topic:
        if attributes is None:
            attributes = {}
        if attributes.get("FifoTopic"):
            fails_constraints = not re.match(r"^[a-zA-Z0-9_-]{1,256}\.fifo$", name)
            msg = "Fifo Topic names must end with .fifo and must be made up of only uppercase and lowercase ASCII letters, numbers, underscores, and hyphens, and must be between 1 and 256 characters long."

        else:
            fails_constraints = not re.match(r"^[a-zA-Z0-9_-]{1,256}$", name)
            msg = "Topic names must be made up of only uppercase and lowercase ASCII letters, numbers, underscores, and hyphens, and must be between 1 and 256 characters long."

        if fails_constraints:
            raise InvalidParameterValue(msg)

        candidate_topic = Topic(name, self)
        if attributes:
            for attribute in attributes:
                setattr(
                    candidate_topic,
                    camelcase_to_underscores(attribute),
                    attributes[attribute],
                )
        if tags:
            candidate_topic._tags = tags
        if candidate_topic.arn in self.topics:
            return self.topics[candidate_topic.arn]
        else:
            self.topics[candidate_topic.arn] = candidate_topic
            return candidate_topic

    def _get_values_nexttoken(
        self, values_map: dict[str, Any], next_token: str | None = None
    ) -> tuple[list[Any], int | None]:
        i_next_token = int(next_token or "0")
        values = list(values_map.values())[
            i_next_token : i_next_token + DEFAULT_PAGE_SIZE
        ]
        if len(values) == DEFAULT_PAGE_SIZE:
            i_next_token = i_next_token + DEFAULT_PAGE_SIZE
        else:
            i_next_token = None  # type: ignore
        return values, i_next_token

    def _get_topic_subscriptions(self, topic: Topic) -> list[Subscription]:
        return [sub for sub in self.subscriptions.values() if sub.topic == topic]

    def list_topics(
        self, next_token: str | None = None
    ) -> tuple[list[Topic], int | None]:
        return self._get_values_nexttoken(self.topics, next_token)

    def delete_topic_subscriptions(self, topic: Topic) -> None:
        for key, value in dict(self.subscriptions).items():
            if value.topic == topic:
                self.subscriptions.pop(key)

    def delete_topic(self, arn: str) -> None:
        with contextlib.suppress(TopicNotFound):
            topic = self.get_topic(arn)
            self.delete_topic_subscriptions(topic)
            parsed_arn = parse_arn(arn)
            sns_backends[parsed_arn.account][parsed_arn.region].topics.pop(arn, None)

    def get_topic(self, arn: str) -> Topic:
        parsed_arn = parse_arn(arn)
        try:
            return sns_backends[parsed_arn.account][self.region_name].topics[arn]
        except KeyError:
            raise TopicNotFound

    def set_topic_attribute(
        self, topic_arn: str, attribute_name: str, attribute_value: str
    ) -> None:
        topic = self.get_topic(topic_arn)
        setattr(topic, attribute_name, attribute_value)

    def subscribe(self, topic_arn: str, endpoint: str, protocol: str) -> Subscription:
        topic = self.get_topic(topic_arn)
        if protocol == "sms":
            if re.search(r"[./-]{2,}", endpoint) or re.search(
                r"(^[./-]|[./-]$)", endpoint
            ):
                raise SNSInvalidParameter(f"Invalid SMS endpoint: {endpoint}")

            reduced_endpoint = re.sub(r"[./-]", "", endpoint)

            if not is_e164(reduced_endpoint):
                raise SNSInvalidParameter(f"Invalid SMS endpoint: {endpoint}")

        if protocol == "sqs":
            try:
                arn = parse_arn(endpoint)
            except ValueError:
                raise SNSInvalidParameter("Invalid parameter: SQS endpoint ARN")

            backend: SQSBackend = sqs_backends[arn.account][arn.region]
            topic = self.get_topic(topic_arn)
            try:
                queue = backend.get_queue(arn.resource_id)
                if not topic.fifo_topic and queue.fifo_queue:
                    raise SNSInvalidParameter(
                        "Invalid parameter: Invalid parameter: Endpoint Reason: FIFO SQS Queues can not be subscribed to standard SNS topics"
                    )
            except QueueDoesNotExist:
                # Subscribing to an unknown queue is apparently not a problem
                pass

        # AWS doesn't create duplicates
        old_subscription = self._find_subscription(topic_arn, endpoint, protocol)
        if old_subscription:
            return old_subscription

        if protocol == "application":
            try:
                # Validate the endpoint exists, assuming it's a new subscription
                # Existing subscriptions are still found if an endpoint is deleted, at least for a short period
                self.get_endpoint(endpoint)
            except SNSNotFoundError:
                # Space between `arn{endpoint}` is lacking in AWS as well
                raise SNSInvalidParameter(
                    f"Invalid parameter: Endpoint Reason: Endpoint does not exist for endpoint arn{endpoint}"
                )

        subscription = Subscription(self.account_id, topic, endpoint, protocol)
        attributes = {
            "PendingConfirmation": False,
            "ConfirmationWasAuthenticated": True,
            "Endpoint": endpoint,
            "TopicArn": topic_arn,
            "Protocol": protocol,
            "SubscriptionArn": subscription.arn,
            "Owner": self.account_id,
            "RawMessageDelivery": False,
        }

        if protocol in ["http", "https"]:
            attributes["EffectiveDeliveryPolicy"] = topic.effective_delivery_policy

        subscription.attributes = attributes
        self.subscriptions[subscription.arn] = subscription
        return subscription

    def _find_subscription(
        self, topic_arn: str, endpoint: str, protocol: str
    ) -> Subscription | None:
        for subscription in self.subscriptions.values():
            if (
                subscription.topic.arn == topic_arn
                and subscription.endpoint == endpoint
                and subscription.protocol == protocol
            ):
                return subscription
        return None

    def unsubscribe(self, subscription_arn: str) -> None:
        self.subscriptions.pop(subscription_arn, None)

    def list_subscriptions(
        self, next_token: str | None = None
    ) -> tuple[list[Subscription], int | None]:
        return self._get_values_nexttoken(self.subscriptions, next_token)

    def list_subscriptions_by_topic(
        self, topic_arn: str, next_token: str | None = None
    ) -> tuple[list[Subscription], int | None]:
        topic = self.get_topic(topic_arn)
        filtered = OrderedDict(
            [(sub.arn, sub) for sub in self._get_topic_subscriptions(topic)]
        )
        return self._get_values_nexttoken(filtered, next_token)

    def publish(
        self,
        message: str,
        arn: str | None,
        phone_number: str | None = None,
        subject: str | None = None,
        message_attributes: dict[str, Any] | None = None,
        group_id: str | None = None,
        deduplication_id: str | None = None,
        message_structure: str | None = None,
    ) -> str:
        if subject is not None and len(subject) > 100:
            # Note that the AWS docs around length are wrong: https://github.com/getmoto/moto/issues/1503
            raise ValueError("Subject must be less than 100 characters")

        if phone_number:
            # This is only an approximation. In fact, we should try to use GSM-7 or UCS-2 encoding to count used bytes
            if len(message) > MAXIMUM_SMS_MESSAGE_BYTES:
                raise ValueError("SMS message must be less than 1600 bytes")

            message_id = str(mock_random.uuid4())
            self.sms_messages[message_id] = (phone_number, message)
            self.sms_message_objects[message_id] = SMS(
                message_id, phone_number, message
            )
            return message_id

        if len(message) > MAXIMUM_MESSAGE_LENGTH:
            raise InvalidParameterValue(
                "An error occurred (InvalidParameter) when calling the Publish operation: Invalid parameter: Message too long"
            )

        if message_structure is not None and message_structure != "json":
            raise InvalidParameterValue("MessageStructure must be 'json' if provided")

        try:
            topic = self.get_topic(arn)  # type: ignore

            if topic.fifo_topic:
                if not group_id:
                    # MessageGroupId is a mandatory parameter for all
                    # messages in a fifo queue
                    raise MissingParameter("MessageGroupId")
                deduplication_id_required = not topic.content_based_deduplication
                if not deduplication_id and deduplication_id_required:
                    raise InvalidParameterValue(
                        "The topic should either have ContentBasedDeduplication enabled or MessageDeduplicationId provided explicitly"
                    )
            elif deduplication_id:
                raise InvalidParameterValue(
                    "Invalid parameter: MessageDeduplicationId "
                    "Reason: The request includes MessageDeduplicationId parameter that is not valid for this topic type"
                )

            message_id = topic.publish(
                message,
                subject=subject,
                message_attributes=message_attributes,
                group_id=group_id,
                deduplication_id=deduplication_id,
                message_structure=message_structure,
            )
        except SNSNotFoundError:
            endpoint = self.get_endpoint(arn)  # type: ignore
            message_id = endpoint.publish(message)
        return message_id

    def create_platform_application(
        self, name: str, platform: str, attributes: dict[str, str]
    ) -> PlatformApplication:
        application = PlatformApplication(
            self.account_id, self.region_name, name, platform, attributes
        )
        self.applications[application.arn] = application
        return application

    def get_application(self, arn: str) -> PlatformApplication:
        try:
            return self.applications[arn]
        except KeyError:
            raise SNSNotFoundError("PlatformApplication does not exist")

    def set_platform_application_attributes(
        self, arn: str, attributes: dict[str, Any]
    ) -> PlatformApplication:
        application = self.get_application(arn)
        application.attributes.update(attributes)
        return application

    def list_platform_applications(self) -> Iterable[PlatformApplication]:
        return self.applications.values()

    def delete_platform_application(self, platform_arn: str) -> None:
        self.applications.pop(platform_arn)
        endpoints = self.list_endpoints_by_platform_application(platform_arn)
        for endpoint in endpoints:
            self.platform_endpoints.pop(endpoint.arn)

    def create_platform_endpoint(
        self,
        application: PlatformApplication,
        custom_user_data: str,
        token: str,
        attributes: dict[str, str],
    ) -> PlatformEndpoint:
        for endpoint in self.platform_endpoints.values():
            if token == endpoint.token:
                same_user_data = custom_user_data == endpoint.custom_user_data
                same_attrs = (
                    attributes.get("Enabled", True) == endpoint.attributes["Enabled"]
                )

                if same_user_data and same_attrs:
                    return endpoint
                raise DuplicateSnsEndpointError(
                    f"Invalid parameter: Token Reason: Endpoint {endpoint.arn} already exists with the same Token, but different attributes."
                )
        platform_endpoint = PlatformEndpoint(
            self.account_id,
            self.region_name,
            application,
            custom_user_data,
            token,
            attributes,
        )
        self.platform_endpoints[platform_endpoint.arn] = platform_endpoint
        return platform_endpoint

    def list_endpoints_by_platform_application(
        self, application_arn: str
    ) -> list[PlatformEndpoint]:
        return [
            endpoint
            for endpoint in self.platform_endpoints.values()
            if endpoint.application.arn == application_arn
        ]

    def get_endpoint(self, arn: str) -> PlatformEndpoint:
        try:
            return self.platform_endpoints[arn]
        except KeyError:
            raise SNSNotFoundError("Endpoint does not exist")

    def set_endpoint_attributes(
        self, arn: str, attributes: dict[str, Any]
    ) -> PlatformEndpoint:
        endpoint = self.get_endpoint(arn)
        endpoint.attributes.update(attributes)
        return endpoint

    def delete_endpoint(self, arn: str) -> None:
        try:
            del self.platform_endpoints[arn]
        except KeyError:
            pass  # idempotent operation

    def get_subscription_attributes(self, arn: str) -> dict[str, Any]:
        subscription = self.subscriptions.get(arn)

        if not subscription:
            raise SNSNotFoundError("Subscription does not exist")
        # AWS does not return the FilterPolicy scope if the FilterPolicy is not set
        # if the FilterPolicy is set and not the FilterPolicyScope, it returns the default value
        attributes = {**subscription.attributes}
        if "FilterPolicyScope" in attributes and not attributes.get("FilterPolicy"):
            attributes.pop("FilterPolicyScope", None)
            attributes.pop("FilterPolicy", None)

        elif "FilterPolicy" in attributes and "FilterPolicyScope" not in attributes:
            attributes["FilterPolicyScope"] = "MessageAttributes"

        return attributes

    def set_subscription_attributes(self, arn: str, name: str, value: Any) -> None:
        if name not in [
            "RawMessageDelivery",
            "DeliveryPolicy",
            "FilterPolicy",
            "FilterPolicyScope",
            "RedrivePolicy",
            "SubscriptionRoleArn",
        ]:
            raise SNSInvalidParameter("AttributeName")

        # TODO: should do validation
        _subscription = [_ for _ in self.subscriptions.values() if _.arn == arn]
        if not _subscription:
            raise SNSNotFoundError(f"Subscription with arn {arn} not found")
        subscription = _subscription[0]

        if name == "FilterPolicy":
            if value:
                filter_policy = json.loads(value)
                # we validate the filter policy differently depending on the scope
                # we need to always set the scope first
                filter_policy_scope = subscription.attributes.get("FilterPolicyScope")
                self._validate_filter_policy(filter_policy, scope=filter_policy_scope)
                subscription._filter_policy = filter_policy
                subscription._filter_policy_matcher = FilterPolicyMatcher(
                    filter_policy, filter_policy_scope
                )
            else:
                subscription._filter_policy = None
                subscription._filter_policy_matcher = None

        subscription.attributes[name] = value

    def _validate_filter_policy(self, value: Any, scope: str | None) -> None:
        combinations = 1

        def aggregate_rules(
            filter_policy: dict[str, Any], depth: int = 1
        ) -> list[list[Any]]:
            """
            This method evaluate the filter policy recursively, and returns only a list of lists of rules.
            It also calculates the combinations of rules, calculated depending on the nesting of the rules.
            Example:
            nested_filter_policy = {
                "key_a": {
                    "key_b": {
                        "key_c": ["value_one", "value_two", "value_three", "value_four"]
                    }
                },
                "key_d": {
                    "key_e": ["value_one", "value_two", "value_three"]
                }
            }
            This function then iterates on the values of the top level keys of the filter policy: ("key_a", "key_d")
            If the iterated value is not a list, it means it is a nested property. If the scope is `MessageBody`, it is
            allowed, we call this method on the value, adding a level to the depth to keep track on how deep the key is.
            If the value is a list, it means it contains rules: we will append this list of rules in _rules, and
            calculate the combinations it adds.
            For the example filter policy containing nested properties, we calculate it this way
            The first array has four values in a three-level nested key, and the second has three values in a two-level
            nested key. 3 x 4 x 2 x 3 = 72
            The return value would be:
            [["value_one", "value_two", "value_three", "value_four"], ["value_one", "value_two", "value_three"]]
            It allows us to later iterate of the list of rules in an easy way, to verify its conditions.

            :param filter_policy: a dict, starting at the FilterPolicy
            :param depth: the depth/level of the rules we are evaluating
            :return: a list of lists of rules
            """
            nonlocal combinations
            _rules = []
            for key, _value in filter_policy.items():
                if isinstance(_value, dict):
                    if scope == "MessageBody":
                        # From AWS docs: "unlike attribute-based policies, payload-based policies support property nesting."
                        _rules.extend(aggregate_rules(_value, depth=depth + 1))
                    else:
                        raise SNSInvalidParameter(
                            "Invalid parameter: Filter policy scope MessageAttributes does not support nested filter policy"
                        )
                elif isinstance(_value, list):
                    if key == "$or":
                        for val in _value:
                            _rules.extend(aggregate_rules(val, depth=depth + 1))
                    else:
                        _rules.append(_value)
                    combinations = combinations * len(_value) * depth
                else:
                    raise SNSInvalidParameter(
                        f'Invalid parameter: FilterPolicy: "{key}" must be an object or an array'
                    )
            return _rules

        # A filter policy can have a maximum of five attribute names. For a nested policy, only parent keys are counted.
        if len(value.values()) > 5:
            raise SNSInvalidParameter(
                "Invalid parameter: FilterPolicy: Filter policy can not have more than 5 keys"
            )

        aggregated_rules = aggregate_rules(value)
        # For the complexity of the filter policy, the total combination of values must not exceed 150.
        # https://docs.aws.amazon.com/sns/latest/dg/subscription-filter-policy-constraints.html
        if combinations > 150:
            raise SNSInvalidParameter(
                "Invalid parameter: FilterPolicy: Filter policy is too complex"
            )

        for rules in aggregated_rules:
            for rule in rules:
                if rule is None:
                    continue
                if isinstance(rule, str):
                    continue
                if isinstance(rule, bool):
                    continue
                if isinstance(rule, (int, float)):
                    if rule <= -1000000000 or rule >= 1000000000:
                        raise InternalError("Unknown")
                    continue
                if isinstance(rule, dict):
                    keyword = list(rule.keys())[0]
                    attributes = list(rule.values())[0]
                    if keyword in ["anything-but", "equals-ignore-case"]:
                        continue
                    elif keyword == "exists":
                        if not isinstance(attributes, bool):
                            raise SNSInvalidParameter(
                                "Invalid parameter: FilterPolicy: exists match pattern must be either true or false."
                            )
                        continue
                    elif keyword == "numeric":
                        # TODO: All of the exceptions listed below contain column pointing where the error is (in AWS response)
                        # Example: 'Value of < must be numeric\n at [Source: (String)"{"price":[{"numeric":["<","100"]}]}"; line: 1, column: 28]'
                        # While it probably can be implemented, it doesn't feel as important as the general parameter checking

                        attributes_copy = attributes[:]
                        if not attributes_copy:
                            raise SNSInvalidParameter(
                                "Invalid parameter: Attributes Reason: FilterPolicy: Invalid member in numeric match: ]\n at ..."
                            )

                        operator = attributes_copy.pop(0)

                        if not isinstance(operator, str):
                            raise SNSInvalidParameter(
                                f"Invalid parameter: Attributes Reason: FilterPolicy: Invalid member in numeric match: {(str(operator))}\n at ..."
                            )

                        if operator not in ("<", "<=", "=", ">", ">="):
                            raise SNSInvalidParameter(
                                f"Invalid parameter: Attributes Reason: FilterPolicy: Unrecognized numeric range operator: {(str(operator))}\n at ..."
                            )

                        try:
                            value = attributes_copy.pop(0)
                        except IndexError:
                            value = None

                        if value is None or not isinstance(value, (int, float)):
                            raise SNSInvalidParameter(
                                f"Invalid parameter: Attributes Reason: FilterPolicy: Value of {(str(operator))} must be numeric\n at ..."
                            )

                        if not attributes_copy:
                            continue

                        if operator not in (">", ">="):
                            raise SNSInvalidParameter(
                                "Invalid parameter: Attributes Reason: FilterPolicy: Too many elements in numeric expression\n at ..."
                            )

                        second_operator = attributes_copy.pop(0)

                        if second_operator not in ("<", "<="):
                            raise SNSInvalidParameter(
                                f"Invalid parameter: Attributes Reason: FilterPolicy: Bad numeric range operator: {(str(second_operator))}\n at ..."
                            )

                        try:
                            second_value = attributes_copy.pop(0)
                        except IndexError:
                            second_value = None

                        if second_value is None or not isinstance(
                            second_value, (int, float)
                        ):
                            raise SNSInvalidParameter(
                                f"Invalid parameter: Attributes Reason: FilterPolicy: Value of {(str(second_operator))} must be numeric\n at ..."
                            )

                        if second_value <= value:
                            raise SNSInvalidParameter(
                                "Invalid parameter: Attributes Reason: FilterPolicy: Bottom must be less than top\n at ..."
                            )

                        continue
                    elif keyword in ["prefix", "suffix"]:
                        continue
                    else:
                        raise SNSInvalidParameter(
                            f"Invalid parameter: FilterPolicy: Unrecognized match type {keyword}"
                        )

                raise SNSInvalidParameter(
                    "Invalid parameter: FilterPolicy: Match value must be String, number, true, false, or null"
                )

    def add_permission(
        self,
        region_name: str,
        topic_arn: str,
        label: str,
        aws_account_ids: list[str],
        action_names: list[str],
    ) -> None:
        topic = self.get_topic(topic_arn)
        policy = topic._policy_json
        statement = next(
            (
                statement
                for statement in policy["Statement"]
                if statement["Sid"] == label
            ),
            None,
        )

        if statement:
            raise SNSInvalidParameter("Statement already exists")

        if any(action_name not in VALID_POLICY_ACTIONS for action_name in action_names):
            raise SNSInvalidParameter("Policy statement action out of service scope!")

        principals = [
            f"arn:{get_partition(region_name)}:iam::{account_id}:root"
            for account_id in aws_account_ids
        ]
        actions = [f"SNS:{action_name}" for action_name in action_names]

        statement = {
            "Sid": label,
            "Effect": "Allow",
            "Principal": {"AWS": principals[0] if len(principals) == 1 else principals},
            "Action": actions[0] if len(actions) == 1 else actions,
            "Resource": topic_arn,
        }

        topic._policy_json["Statement"].append(statement)

    def remove_permission(self, topic_arn: str, label: str) -> None:
        topic = self.get_topic(topic_arn)
        statements = topic._policy_json["Statement"]
        statements = [
            statement for statement in statements if statement["Sid"] != label
        ]

        topic._policy_json["Statement"] = statements

    def list_tags_for_resource(self, resource_arn: str) -> dict[str, str]:
        if resource_arn not in self.topics:
            raise ResourceNotFoundError

        return self.topics[resource_arn]._tags

    def publish_batch(
        self, topic_arn: str, publish_batch_request_entries: list[dict[str, Any]]
    ) -> tuple[list[dict[str, str]], list[dict[str, Any]]]:
        """
        The MessageDeduplicationId-parameter has not yet been implemented.
        """
        topic = self.get_topic(topic_arn)

        if len(publish_batch_request_entries) > 10:
            raise TooManyEntriesInBatchRequest

        ids = [m["Id"] for m in publish_batch_request_entries]
        if len(set(ids)) != len(ids):
            raise BatchEntryIdsNotDistinct

        if topic.fifo_topic:
            if not all(
                "MessageGroupId" in entry for entry in publish_batch_request_entries
            ):
                raise SNSInvalidParameter(
                    "Invalid parameter: The MessageGroupId parameter is required for FIFO topics"
                )

        successful: list[dict[str, str]] = []
        failed: list[dict[str, Any]] = []

        for entry in publish_batch_request_entries:
            try:
                message_id = self.publish(
                    message=entry["Message"],
                    arn=topic_arn,
                    subject=entry.get("Subject"),
                    message_attributes=entry.get("MessageAttributes", {}),
                    group_id=entry.get("MessageGroupId"),
                    deduplication_id=entry.get("MessageDeduplicationId"),
                    message_structure=entry.get("MessageStructure"),
                )
                successful.append({"MessageId": message_id, "Id": entry["Id"]})
            except Exception as e:
                if isinstance(e, InvalidParameterValue):
                    failed.append(
                        {
                            "Id": entry["Id"],
                            "Code": "InvalidParameter",
                            "Message": e.message,
                            "SenderFault": True,
                        }
                    )
        return successful, failed

    def check_if_phone_number_is_opted_out(self, number: str) -> bool:
        """
        Current implementation returns True for all numbers ending in '99'
        """
        return number.endswith("99")

    def list_phone_numbers_opted_out(self) -> list[str]:
        return self.opt_out_numbers

    def opt_in_phone_number(self, number: str) -> None:
        try:
            self.opt_out_numbers.remove(number)
        except ValueError:
            pass

    @paginate(pagination_model=PAGINATION_MODEL)  # type: ignore[misc]
    def list_config_service_resources(  # type: ignore[misc]
        self,
        resource_ids: list[str] | None = None,
        resource_name: str | None = None,
    ) -> list[dict[str, Any]]:
        """List SNS topics for AWS Config."""
        topics = list(self.topics.values())

        if resource_ids:
            topics = [t for t in topics if t.arn in resource_ids]

        if resource_name:
            topics = [t for t in topics if t.name == resource_name]

        config_resources = []
        for topic in topics:
            config_resources.append(
                {
                    "type": "AWS::SNS::Topic",
                    "id": topic.arn,
                    "name": topic.name,
                    "region": self.region_name,
                }
            )

        return config_resources

    def get_config_resource(self, resource_id: str) -> dict[str, Any] | None:
        """Get a specific SNS topic configuration for AWS Config."""
        if resource_id not in self.topics:
            return None

        topic = self.topics[resource_id]

        config_item = {
            "version": "1.3",
            "accountId": self.account_id,
            "configurationItemCaptureTime": unix_time(),
            "configurationItemStatus": "ResourceDiscovered",
            "configurationStateId": "1",
            "resourceType": "AWS::SNS::Topic",
            "resourceId": topic.arn,
            "resourceName": topic.name,
            "arn": topic.arn,
            "awsRegion": self.region_name,
            "availabilityZone": "Not Applicable",
            "tags": dict(topic._tags),
            "configuration": {
                "topicArn": topic.arn,
                "displayName": topic.display_name,
                "policy": topic._policy_json,
                "deliveryPolicy": topic.delivery_policy,
                "effectiveDeliveryPolicy": json.loads(topic.effective_delivery_policy),
                "subscriptionsConfirmed": topic.subscriptions_confimed,
                "subscriptionsPending": topic.subscriptions_pending,
                "subscriptionsDeleted": topic.subscriptions_deleted,
            },
            "supplementaryConfiguration": {
                "Tags": json.dumps(
                    [{"key": k, "value": v} for k, v in topic._tags.items()]
                )
            },
            "configurationItemMD5Hash": "",
        }
        configuration = cast(dict[str, Any], config_item["configuration"])

        if topic.kms_master_key_id:
            configuration["kmsMasterKeyId"] = topic.kms_master_key_id

        if topic.fifo_topic:
            configuration["fifoTopic"] = True
            configuration["contentBasedDeduplication"] = (
                topic.content_based_deduplication
            )

        return config_item

    def confirm_subscription(self) -> None:
        pass

    def get_endpoint_attributes(self, arn: str) -> dict[str, str]:
        endpoint = self.get_endpoint(arn)
        return endpoint.attributes

    def get_platform_application_attributes(self, arn: str) -> dict[str, str]:
        application = self.get_application(arn)
        return application.attributes

    def get_topic_attributes(self) -> None:
        pass

    # Resource Groups Tagging API (TaggableResourcesMixin method overrides)
    def iter_tagged_resources(self) -> Iterator[TaggedResource]:
        for topic in self.topics.values():
            yield TaggedResource(
                arn=topic.arn,
                tags=dict(topic._tags or {}),
                resource_type="sns:topic",
            )

    def tag_resource(self, resource_arn: str, tags: dict[str, str]) -> None:
        if resource_arn not in self.topics:
            raise ResourceNotFoundError

        updated_tags = self.topics[resource_arn]._tags.copy()
        updated_tags.update(tags)

        if len(updated_tags) > 50:
            raise TagLimitExceededError

        self.topics[resource_arn]._tags = updated_tags

    def untag_resource(self, resource_arn: str, tag_keys: list[str]) -> None:
        if resource_arn not in self.topics:
            raise ResourceNotFoundError

        for key in tag_keys:
            self.topics[resource_arn]._tags.pop(key, None)


sns_backends = BackendDict(SNSBackend, "sns")


DEFAULT_EFFECTIVE_DELIVERY_POLICY = {
    "defaultHealthyRetryPolicy": {
        "numNoDelayRetries": 0,
        "numMinDelayRetries": 0,
        "minDelayTarget": 20,
        "maxDelayTarget": 20,
        "numMaxDelayRetries": 0,
        "numRetries": 3,
        "backoffFunction": "linear",
    },
    "sicklyRetryPolicy": None,
    "throttlePolicy": None,
    "guaranteed": False,
}


VALID_POLICY_ACTIONS = [
    "GetTopicAttributes",
    "SetTopicAttributes",
    "AddPermission",
    "RemovePermission",
    "DeleteTopic",
    "Subscribe",
    "ListSubscriptionsByTopic",
    "Publish",
    "Receive",
]
