from __future__ import unicode_literals

import functools
from collections import defaultdict
import datetime
import json
import logging
import re
import io
import requests

import pytz

from moto.core.exceptions import DryRunClientError

from jinja2 import Environment, DictLoader, TemplateNotFound

import six
from six.moves.urllib.parse import parse_qs, parse_qsl, urlparse

import xmltodict
from werkzeug.exceptions import HTTPException

import boto3
from moto.compat import OrderedDict
from moto.core.utils import camelcase_to_underscores, method_names_from_class
from moto import settings

log = logging.getLogger(__name__)


def _decode_dict(d):
    decoded = OrderedDict()
    for key, value in d.items():
        if isinstance(key, six.binary_type):
            newkey = key.decode("utf-8")
        elif isinstance(key, (list, tuple)):
            newkey = []
            for k in key:
                if isinstance(k, six.binary_type):
                    newkey.append(k.decode("utf-8"))
                else:
                    newkey.append(k)
        else:
            newkey = key

        if isinstance(value, six.binary_type):
            newvalue = value.decode("utf-8")
        elif isinstance(value, (list, tuple)):
            newvalue = []
            for v in value:
                if isinstance(v, six.binary_type):
                    newvalue.append(v.decode("utf-8"))
                else:
                    newvalue.append(v)
        else:
            newvalue = value

        decoded[newkey] = newvalue
    return decoded


class DynamicDictLoader(DictLoader):
    """
    Note: There's a bug in jinja2 pre-2.7.3 DictLoader where caching does not work.
      Including the fixed (current) method version here to ensure performance benefit
      even for those using older jinja versions.
    """

    def get_source(self, environment, template):
        if template in self.mapping:
            source = self.mapping[template]
            return source, None, lambda: source == self.mapping.get(template)
        raise TemplateNotFound(template)

    def update(self, mapping):
        self.mapping.update(mapping)

    def contains(self, template):
        return bool(template in self.mapping)


class _TemplateEnvironmentMixin(object):
    LEFT_PATTERN = re.compile(r"[\s\n]+<")
    RIGHT_PATTERN = re.compile(r">[\s\n]+")

    def __init__(self):
        super(_TemplateEnvironmentMixin, self).__init__()
        self.loader = DynamicDictLoader({})
        self.environment = Environment(
            loader=self.loader, autoescape=self.should_autoescape
        )

    @property
    def should_autoescape(self):
        # Allow for subclass to overwrite
        return False

    def contains_template(self, template_id):
        return self.loader.contains(template_id)

    def response_template(self, source):
        template_id = id(source)
        if not self.contains_template(template_id):
            collapsed = re.sub(
                self.RIGHT_PATTERN, ">", re.sub(self.LEFT_PATTERN, "<", source)
            )
            self.loader.update({template_id: collapsed})
            self.environment = Environment(
                loader=self.loader,
                autoescape=self.should_autoescape,
                trim_blocks=True,
                lstrip_blocks=True,
            )
        return self.environment.get_template(template_id)


class ActionAuthenticatorMixin(object):

    request_count = 0

    def _authenticate_and_authorize_action(self, iam_request_cls):
        if (
            ActionAuthenticatorMixin.request_count
            >= settings.INITIAL_NO_AUTH_ACTION_COUNT
        ):
            iam_request = iam_request_cls(
                method=self.method, path=self.path, data=self.data, headers=self.headers
            )
            iam_request.check_signature()
            iam_request.check_action_permitted()
        else:
            ActionAuthenticatorMixin.request_count += 1

    def _authenticate_and_authorize_normal_action(self):
        from moto.iam.access_control import IAMRequest

        self._authenticate_and_authorize_action(IAMRequest)

    def _authenticate_and_authorize_s3_action(self):
        from moto.iam.access_control import S3IAMRequest

        self._authenticate_and_authorize_action(S3IAMRequest)

    @staticmethod
    def set_initial_no_auth_action_count(initial_no_auth_action_count):
        def decorator(function):
            def wrapper(*args, **kwargs):
                if settings.TEST_SERVER_MODE:
                    response = requests.post(
                        "http://localhost:5000/moto-api/reset-auth",
                        data=str(initial_no_auth_action_count).encode("utf-8"),
                    )
                    original_initial_no_auth_action_count = response.json()[
                        "PREVIOUS_INITIAL_NO_AUTH_ACTION_COUNT"
                    ]
                else:
                    original_initial_no_auth_action_count = (
                        settings.INITIAL_NO_AUTH_ACTION_COUNT
                    )
                    original_request_count = ActionAuthenticatorMixin.request_count
                    settings.INITIAL_NO_AUTH_ACTION_COUNT = initial_no_auth_action_count
                    ActionAuthenticatorMixin.request_count = 0
                try:
                    result = function(*args, **kwargs)
                finally:
                    if settings.TEST_SERVER_MODE:
                        requests.post(
                            "http://localhost:5000/moto-api/reset-auth",
                            data=str(original_initial_no_auth_action_count).encode(
                                "utf-8"
                            ),
                        )
                    else:
                        ActionAuthenticatorMixin.request_count = original_request_count
                        settings.INITIAL_NO_AUTH_ACTION_COUNT = (
                            original_initial_no_auth_action_count
                        )
                return result

            functools.update_wrapper(wrapper, function)
            wrapper.__wrapped__ = function
            return wrapper

        return decorator


class BaseResponse(_TemplateEnvironmentMixin, ActionAuthenticatorMixin):

    default_region = "us-east-1"
    # to extract region, use [^.]
    region_regex = re.compile(r"\.(?P<region>[a-z]{2}-[a-z]+-\d{1})\.amazonaws\.com")
    region_from_useragent_regex = re.compile(
        r"region/(?P<region>[a-z]{2}-[a-z]+-\d{1})"
    )
    param_list_regex = re.compile(r"(.*)\.(\d+)\.")
    access_key_regex = re.compile(
        r"AWS.*(?P<access_key>(?<![A-Z0-9])[A-Z0-9]{20}(?![A-Z0-9]))[:/]"
    )
    aws_service_spec = None

    @classmethod
    def dispatch(cls, *args, **kwargs):
        return cls()._dispatch(*args, **kwargs)

    def setup_class(self, request, full_url, headers):
        querystring = OrderedDict()
        if hasattr(request, "body"):
            # Boto
            self.body = request.body
        else:
            # Flask server

            # FIXME: At least in Flask==0.10.1, request.data is an empty string
            # and the information we want is in request.form. Keeping self.body
            # definition for back-compatibility
            self.body = request.data

            querystring = OrderedDict()
            for key, value in request.form.items():
                querystring[key] = [value]

        raw_body = self.body
        if isinstance(self.body, six.binary_type):
            self.body = self.body.decode("utf-8")

        if not querystring:
            querystring.update(
                parse_qs(urlparse(full_url).query, keep_blank_values=True)
            )
        if not querystring:
            if (
                "json" in request.headers.get("content-type", [])
                and self.aws_service_spec
            ):
                decoded = json.loads(self.body)

                target = request.headers.get("x-amz-target") or request.headers.get(
                    "X-Amz-Target"
                )
                service, method = target.split(".")
                input_spec = self.aws_service_spec.input_spec(method)
                flat = flatten_json_request_body("", decoded, input_spec)
                for key, value in flat.items():
                    querystring[key] = [value]
            elif self.body:
                try:
                    querystring.update(
                        OrderedDict(
                            (key, [value])
                            for key, value in parse_qsl(
                                raw_body, keep_blank_values=True
                            )
                        )
                    )
                except UnicodeEncodeError:
                    pass  # ignore encoding errors, as the body may not contain a legitimate querystring
        if not querystring:
            querystring.update(headers)

        try:
            querystring = _decode_dict(querystring)
        except UnicodeDecodeError:
            pass  # ignore decoding errors, as the body may not contain a legitimate querystring

        self.uri = full_url
        self.path = urlparse(full_url).path
        self.querystring = querystring
        self.data = querystring
        self.method = request.method
        self.region = self.get_region_from_url(request, full_url)
        self.uri_match = None

        self.headers = request.headers
        if "host" not in self.headers:
            self.headers["host"] = urlparse(full_url).netloc
        self.response_headers = {"server": "amazon.com"}

    def get_region_from_url(self, request, full_url):
        url_match = self.region_regex.search(full_url)
        user_agent_match = self.region_from_useragent_regex.search(
            request.headers.get("User-Agent", "")
        )
        if url_match:
            region = url_match.group(1)
        elif user_agent_match:
            region = user_agent_match.group(1)
        elif (
            "Authorization" in request.headers
            and "AWS4" in request.headers["Authorization"]
        ):
            region = request.headers["Authorization"].split(",")[0].split("/")[2]
        else:
            region = self.default_region
        return region

    def get_current_user(self):
        """
        Returns the access key id used in this request as the current user id
        """
        if "Authorization" in self.headers:
            match = self.access_key_regex.search(self.headers["Authorization"])
            if match:
                return match.group(1)

        if self.querystring.get("AWSAccessKeyId"):
            return self.querystring.get("AWSAccessKeyId")
        else:
            # Should we raise an unauthorized exception instead?
            return "111122223333"

    def _dispatch(self, request, full_url, headers):
        self.setup_class(request, full_url, headers)
        return self.call_action()

    def uri_to_regexp(self, uri):
        """converts uri w/ placeholder to regexp
          '/cars/{carName}/drivers/{DriverName}'
        -> '^/cars/.*/drivers/[^/]*$'

          '/cars/{carName}/drivers/{DriverName}/drive'
        -> '^/cars/.*/drivers/.*/drive$'

        """

        def _convert(elem, is_last):
            if not re.match("^{.*}$", elem):
                return elem
            name = (
                elem.replace("{", "")
                .replace("}", "")
                .replace("+", "")
                .replace("-", "_")
            )
            if is_last:
                return "(?P<%s>[^/]+)" % name
            return "(?P<%s>.*)" % name

        elems = uri.split("/")
        num_elems = len(elems)
        regexp = "^{}$".format(
            "/".join(
                [_convert(elem, (i == num_elems - 1)) for i, elem in enumerate(elems)]
            )
        )
        return regexp

    def _get_action_from_method_and_request_uri(self, method, request_uri):
        """basically used for `rest-json` APIs
        You can refer to example from link below
        https://github.com/boto/botocore/blob/develop/botocore/data/iot/2015-05-28/service-2.json
        """

        # service response class should have 'SERVICE_NAME' class member,
        # if you want to get action from method and url
        if not hasattr(self, "SERVICE_NAME"):
            return None
        service = self.SERVICE_NAME
        conn = boto3.client(service, region_name=self.region)

        # make cache if it does not exist yet
        if not hasattr(self, "method_urls"):
            self.method_urls = defaultdict(lambda: defaultdict(str))
            op_names = conn._service_model.operation_names
            for op_name in op_names:
                op_model = conn._service_model.operation_model(op_name)
                _method = op_model.http["method"]
                uri_regexp = self.uri_to_regexp(op_model.http["requestUri"])
                self.method_urls[_method][uri_regexp] = op_model.name
        regexp_and_names = self.method_urls[method]
        for regexp, name in regexp_and_names.items():
            match = re.match(regexp, request_uri)
            self.uri_match = match
            if match:
                return name
        return None

    def _get_action(self):
        action = self.querystring.get("Action", [""])[0]
        if not action:  # Some services use a header for the action
            # Headers are case-insensitive. Probably a better way to do this.
            match = self.headers.get("x-amz-target") or self.headers.get("X-Amz-Target")
            if match:
                action = match.split(".")[-1]
        # get action from method and uri
        if not action:
            return self._get_action_from_method_and_request_uri(self.method, self.path)
        return action

    def call_action(self):
        headers = self.response_headers

        try:
            self._authenticate_and_authorize_normal_action()
        except HTTPException as http_error:
            response = http_error.description, dict(status=http_error.code)
            return self._send_response(headers, response)

        action = camelcase_to_underscores(self._get_action())
        method_names = method_names_from_class(self.__class__)
        if action in method_names:
            method = getattr(self, action)
            try:
                response = method()
            except HTTPException as http_error:
                response = http_error.description, dict(status=http_error.code)

            if isinstance(response, six.string_types):
                return 200, headers, response
            else:
                return self._send_response(headers, response)

        if not action:
            return 404, headers, ""

        raise NotImplementedError(
            "The {0} action has not been implemented".format(action)
        )

    @staticmethod
    def _send_response(headers, response):
        if len(response) == 2:
            body, new_headers = response
        else:
            status, new_headers, body = response
        status = new_headers.get("status", 200)
        headers.update(new_headers)
        # Cast status to string
        if "status" in headers:
            headers["status"] = str(headers["status"])
        return status, headers, body

    def _get_param(self, param_name, if_none=None):
        val = self.querystring.get(param_name)
        if val is not None:
            return val[0]

        # try to get json body parameter
        if self.body is not None:
            try:
                return json.loads(self.body)[param_name]
            except ValueError:
                pass
            except KeyError:
                pass
        # try to get path parameter
        if self.uri_match:
            try:
                return self.uri_match.group(param_name)
            except IndexError:
                # do nothing if param is not found
                pass
        return if_none

    def _get_int_param(self, param_name, if_none=None):
        val = self._get_param(param_name)
        if val is not None:
            return int(val)
        return if_none

    def _get_bool_param(self, param_name, if_none=None):
        val = self._get_param(param_name)
        if val is not None:
            if val.lower() == "true":
                return True
            elif val.lower() == "false":
                return False
        return if_none

    def _get_multi_param_helper(self, param_prefix):
        value_dict = dict()
        tracked_prefixes = set()  # prefixes which have already been processed

        def is_tracked(name_param):
            for prefix_loop in tracked_prefixes:
                if name_param.startswith(prefix_loop):
                    return True
            return False

        for name, value in self.querystring.items():
            if is_tracked(name) or not name.startswith(param_prefix):
                continue

            if len(name) > len(param_prefix) and not name[
                len(param_prefix) :
            ].startswith("."):
                continue

            match = (
                self.param_list_regex.search(name[len(param_prefix) :])
                if len(name) > len(param_prefix)
                else None
            )
            if match:
                prefix = param_prefix + match.group(1)
                value = self._get_multi_param(prefix)
                tracked_prefixes.add(prefix)
                name = prefix
                value_dict[name] = value
            else:
                value_dict[name] = value[0]

        if not value_dict:
            return None

        if len(value_dict) > 1:
            # strip off period prefix
            value_dict = {
                name[len(param_prefix) + 1 :]: value
                for name, value in value_dict.items()
            }
        else:
            value_dict = list(value_dict.values())[0]

        return value_dict

    def _get_multi_param(self, param_prefix):
        """
        Given a querystring of ?LaunchConfigurationNames.member.1=my-test-1&LaunchConfigurationNames.member.2=my-test-2
        this will return ['my-test-1', 'my-test-2']
        """
        if param_prefix.endswith("."):
            prefix = param_prefix
        else:
            prefix = param_prefix + "."
        values = []
        index = 1
        while True:
            value_dict = self._get_multi_param_helper(prefix + str(index))
            if not value_dict and value_dict != "":
                break

            values.append(value_dict)
            index += 1

        return values

    def _get_dict_param(self, param_prefix):
        """
        Given a parameter dict of
        {
            'Instances.SlaveInstanceType': ['m1.small'],
            'Instances.InstanceCount': ['1']
        }

        returns
        {
            "slave_instance_type": "m1.small",
            "instance_count": "1",
        }
        """
        params = {}
        for key, value in self.querystring.items():
            if key.startswith(param_prefix):
                params[camelcase_to_underscores(key.replace(param_prefix, ""))] = value[
                    0
                ]
        return params

    def _get_params(self):
        """
        Given a querystring of
        {
            'Action': ['CreatRule'],
            'Conditions.member.1.Field': ['http-header'],
            'Conditions.member.1.HttpHeaderConfig.HttpHeaderName': ['User-Agent'],
            'Conditions.member.1.HttpHeaderConfig.Values.member.1': ['curl'],
            'Actions.member.1.FixedResponseConfig.StatusCode': ['200'],
            'Actions.member.1.FixedResponseConfig.ContentType': ['text/plain'],
            'Actions.member.1.Type': ['fixed-response']
        }

        returns
        {
            'Action': 'CreatRule',
            'Conditions': [
                {
                    'Field': 'http-header',
                    'HttpHeaderConfig': {
                        'HttpHeaderName': 'User-Agent',
                        'Values': ['curl']
                    }
                }
            ],
            'Actions': [
                {
                    'Type': 'fixed-response',
                    'FixedResponseConfig': {
                        'StatusCode': '200',
                        'ContentType': 'text/plain'
                    }
                }
            ]
        }
        """
        params = {}
        for k, v in sorted(self.querystring.items()):
            self._parse_param(k, v[0], params)
        return params

    def _parse_param(self, key, value, params):
        keylist = key.split(".")
        obj = params
        for i, key in enumerate(keylist[:-1]):
            if key in obj:
                # step into
                parent = obj
                obj = obj[key]
            else:
                if key == "member":
                    if not isinstance(obj, list):
                        # initialize list
                        # reset parent
                        obj = []
                        parent[keylist[i - 1]] = obj
                elif key.isdigit():
                    index = int(key) - 1
                    if len(obj) <= index:
                        # initialize list element
                        obj.insert(index, {})
                    # step into
                    parent = obj
                    obj = obj[index]
                else:
                    # initialize dict
                    obj[key] = {}
                    # step into
                    parent = obj
                    obj = obj[key]
        if isinstance(obj, list):
            obj.append(value)
        else:
            obj[keylist[-1]] = value

    def _get_list_prefix(self, param_prefix):
        """
        Given a query dict like
        {
            'Steps.member.1.Name': ['example1'],
            'Steps.member.1.ActionOnFailure': ['TERMINATE_JOB_FLOW'],
            'Steps.member.1.HadoopJarStep.Jar': ['streaming1.jar'],
            'Steps.member.2.Name': ['example2'],
            'Steps.member.2.ActionOnFailure': ['TERMINATE_JOB_FLOW'],
            'Steps.member.2.HadoopJarStep.Jar': ['streaming2.jar'],
        }

        returns
        [{
            'name': u'example1',
            'action_on_failure': u'TERMINATE_JOB_FLOW',
            'hadoop_jar_step._jar': u'streaming1.jar',
        }, {
            'name': u'example2',
            'action_on_failure': u'TERMINATE_JOB_FLOW',
            'hadoop_jar_step._jar': u'streaming2.jar',
        }]
        """
        results = []
        param_index = 1
        while True:
            index_prefix = "{0}.{1}.".format(param_prefix, param_index)
            new_items = {}
            for key, value in self.querystring.items():
                if key.startswith(index_prefix):
                    new_items[
                        camelcase_to_underscores(key.replace(index_prefix, ""))
                    ] = value[0]
            if not new_items:
                break
            results.append(new_items)
            param_index += 1
        return results

    def _get_map_prefix(self, param_prefix, key_end=".key", value_end=".value"):
        results = {}
        param_index = 1
        while 1:
            index_prefix = "{0}.{1}.".format(param_prefix, param_index)

            k, v = None, None
            for key, value in self.querystring.items():
                if key.startswith(index_prefix):
                    if key.endswith(key_end):
                        k = value[0]
                    elif key.endswith(value_end):
                        v = value[0]

            if not (k and v):
                break

            results[k] = v
            param_index += 1

        return results

    def _parse_tag_specification(self, param_prefix):
        tags = self._get_list_prefix(param_prefix)

        results = defaultdict(dict)
        for tag in tags:
            resource_type = tag.pop("resource_type")

            param_index = 1
            while True:
                key_name = "tag.{0}._key".format(param_index)
                value_name = "tag.{0}._value".format(param_index)

                try:
                    results[resource_type][tag[key_name]] = tag[value_name]
                except KeyError:
                    break
                param_index += 1

        return results

    def _get_object_map(self, prefix, name="Name", value="Value"):
        """
        Given a query dict like
        {
            Prefix.1.Name: [u'event'],
            Prefix.1.Value.StringValue: [u'order_cancelled'],
            Prefix.1.Value.DataType: [u'String'],
            Prefix.2.Name: [u'store'],
            Prefix.2.Value.StringValue: [u'example_corp'],
            Prefix.2.Value.DataType [u'String'],
        }

        returns
        {
            'event': {
                'DataType': 'String',
                'StringValue': 'example_corp'
            },
            'store': {
                'DataType': 'String',
                'StringValue': 'order_cancelled'
            }
        }
        """
        object_map = {}
        index = 1
        while True:
            # Loop through looking for keys representing object name
            name_key = "{0}.{1}.{2}".format(prefix, index, name)
            obj_name = self.querystring.get(name_key)
            if not obj_name:
                # Found all keys
                break

            obj = {}
            value_key_prefix = "{0}.{1}.{2}.".format(prefix, index, value)
            for k, v in self.querystring.items():
                if k.startswith(value_key_prefix):
                    _, value_key = k.split(value_key_prefix, 1)
                    obj[value_key] = v[0]

            object_map[obj_name[0]] = obj

            index += 1

        return object_map

    @property
    def request_json(self):
        return "JSON" in self.querystring.get("ContentType", [])

    def is_not_dryrun(self, action):
        if "true" in self.querystring.get("DryRun", ["false"]):
            message = (
                "An error occurred (DryRunOperation) when calling the %s operation: Request would have succeeded, but DryRun flag is set"
                % action
            )
            raise DryRunClientError(error_type="DryRunOperation", message=message)
        return True


class MotoAPIResponse(BaseResponse):
    def reset_response(self, request, full_url, headers):
        if request.method == "POST":
            from .models import moto_api_backend

            moto_api_backend.reset()
            return 200, {}, json.dumps({"status": "ok"})
        return 400, {}, json.dumps({"Error": "Need to POST to reset Moto"})

    def reset_auth_response(self, request, full_url, headers):
        if request.method == "POST":
            previous_initial_no_auth_action_count = (
                settings.INITIAL_NO_AUTH_ACTION_COUNT
            )
            settings.INITIAL_NO_AUTH_ACTION_COUNT = float(request.data.decode())
            ActionAuthenticatorMixin.request_count = 0
            return (
                200,
                {},
                json.dumps(
                    {
                        "status": "ok",
                        "PREVIOUS_INITIAL_NO_AUTH_ACTION_COUNT": str(
                            previous_initial_no_auth_action_count
                        ),
                    }
                ),
            )
        return 400, {}, json.dumps({"Error": "Need to POST to reset Moto Auth"})

    def model_data(self, request, full_url, headers):
        from moto.core.models import model_data

        results = {}
        for service in sorted(model_data):
            models = model_data[service]
            results[service] = {}
            for name in sorted(models):
                model = models[name]
                results[service][name] = []
                for instance in model.instances:
                    inst_result = {}
                    for attr in dir(instance):
                        if not attr.startswith("_"):
                            try:
                                json.dumps(getattr(instance, attr))
                            except TypeError:
                                pass
                            else:
                                inst_result[attr] = getattr(instance, attr)
                    results[service][name].append(inst_result)
        return 200, {"Content-Type": "application/javascript"}, json.dumps(results)

    def dashboard(self, request, full_url, headers):
        from flask import render_template

        return render_template("dashboard.html")


class _RecursiveDictRef(object):
    """Store a recursive reference to dict."""

    def __init__(self):
        self.key = None
        self.dic = {}

    def __repr__(self):
        return "{!r}".format(self.dic)

    def __getattr__(self, key):
        return self.dic.__getattr__(key)

    def __getitem__(self, key):
        return self.dic.__getitem__(key)

    def set_reference(self, key, dic):
        """Set the RecursiveDictRef object to keep reference to dict object
        (dic) at the key.

        """
        self.key = key
        self.dic = dic


class AWSServiceSpec(object):
    """Parse data model from botocore. This is used to recover type info
    for fields in AWS API XML response.

    """

    def __init__(self, path):
        # Importing pkg_resources takes ~60ms; keep it local
        from pkg_resources import resource_filename  # noqa

        self.path = resource_filename("botocore", path)
        with io.open(self.path, "r", encoding="utf-8") as f:
            spec = json.load(f)
        self.metadata = spec["metadata"]
        self.operations = spec["operations"]
        self.shapes = spec["shapes"]

    def input_spec(self, operation):
        try:
            op = self.operations[operation]
        except KeyError:
            raise ValueError("Invalid operation: {}".format(operation))
        if "input" not in op:
            return {}
        shape = self.shapes[op["input"]["shape"]]
        return self._expand(shape)

    def output_spec(self, operation):
        """Produce a JSON with a valid API response syntax for operation, but
        with type information. Each node represented by a key has the
        value containing field type, e.g.,

          output_spec["SomeBooleanNode"] => {"type": "boolean"}

        """
        try:
            op = self.operations[operation]
        except KeyError:
            raise ValueError("Invalid operation: {}".format(operation))
        if "output" not in op:
            return {}
        shape = self.shapes[op["output"]["shape"]]
        return self._expand(shape)

    def _expand(self, shape):
        def expand(dic, seen=None):
            seen = seen or {}
            if dic["type"] == "structure":
                nodes = {}
                for k, v in dic["members"].items():
                    seen_till_here = dict(seen)
                    if k in seen_till_here:
                        nodes[k] = seen_till_here[k]
                        continue
                    seen_till_here[k] = _RecursiveDictRef()
                    nodes[k] = expand(self.shapes[v["shape"]], seen_till_here)
                    seen_till_here[k].set_reference(k, nodes[k])
                nodes["type"] = "structure"
                return nodes

            elif dic["type"] == "list":
                seen_till_here = dict(seen)
                shape = dic["member"]["shape"]
                if shape in seen_till_here:
                    return seen_till_here[shape]
                seen_till_here[shape] = _RecursiveDictRef()
                expanded = expand(self.shapes[shape], seen_till_here)
                seen_till_here[shape].set_reference(shape, expanded)
                return {"type": "list", "member": expanded}

            elif dic["type"] == "map":
                seen_till_here = dict(seen)
                node = {"type": "map"}

                if "shape" in dic["key"]:
                    shape = dic["key"]["shape"]
                    seen_till_here[shape] = _RecursiveDictRef()
                    node["key"] = expand(self.shapes[shape], seen_till_here)
                    seen_till_here[shape].set_reference(shape, node["key"])
                else:
                    node["key"] = dic["key"]["type"]

                if "shape" in dic["value"]:
                    shape = dic["value"]["shape"]
                    seen_till_here[shape] = _RecursiveDictRef()
                    node["value"] = expand(self.shapes[shape], seen_till_here)
                    seen_till_here[shape].set_reference(shape, node["value"])
                else:
                    node["value"] = dic["value"]["type"]

                return node

            else:
                return {"type": dic["type"]}

        return expand(shape)


def to_str(value, spec):
    vtype = spec["type"]
    if vtype == "boolean":
        return "true" if value else "false"
    elif vtype == "integer":
        return str(value)
    elif vtype == "float":
        return str(value)
    elif vtype == "double":
        return str(value)
    elif vtype == "timestamp":
        return (
            datetime.datetime.utcfromtimestamp(value)
            .replace(tzinfo=pytz.utc)
            .isoformat()
        )
    elif vtype == "string":
        return str(value)
    elif value is None:
        return "null"
    else:
        raise TypeError("Unknown type {}".format(vtype))


def from_str(value, spec):
    vtype = spec["type"]
    if vtype == "boolean":
        return True if value == "true" else False
    elif vtype == "integer":
        return int(value)
    elif vtype == "float":
        return float(value)
    elif vtype == "double":
        return float(value)
    elif vtype == "timestamp":
        return value
    elif vtype == "string":
        return value
    raise TypeError("Unknown type {}".format(vtype))


def flatten_json_request_body(prefix, dict_body, spec):
    """Convert a JSON request body into query params."""
    if len(spec) == 1 and "type" in spec:
        return {prefix: to_str(dict_body, spec)}

    flat = {}
    for key, value in dict_body.items():
        node_type = spec[key]["type"]
        if node_type == "list":
            for idx, v in enumerate(value, 1):
                pref = key + ".member." + str(idx)
                flat.update(flatten_json_request_body(pref, v, spec[key]["member"]))
        elif node_type == "map":
            for idx, (k, v) in enumerate(value.items(), 1):
                pref = key + ".entry." + str(idx)
                flat.update(
                    flatten_json_request_body(pref + ".key", k, spec[key]["key"])
                )
                flat.update(
                    flatten_json_request_body(pref + ".value", v, spec[key]["value"])
                )
        else:
            flat.update(flatten_json_request_body(key, value, spec[key]))

    if prefix:
        prefix = prefix + "."
    return dict((prefix + k, v) for k, v in flat.items())


def xml_to_json_response(service_spec, operation, xml, result_node=None):
    """Convert rendered XML response to JSON for use with boto3."""

    def transform(value, spec):
        """Apply transformations to make the output JSON comply with the
        expected form. This function applies:

          (1) Type cast to nodes with "type" property (e.g., 'true' to
              True). XML field values are all in text so this step is
              necessary to convert it to valid JSON objects.

          (2) Squashes "member" nodes to lists.

        """
        if len(spec) == 1:
            return from_str(value, spec)

        od = OrderedDict()
        for k, v in value.items():
            if k.startswith("@"):
                continue

            if k not in spec:
                # this can happen when with an older version of
                # botocore for which the node in XML template is not
                # defined in service spec.
                log.warning("Field %s is not defined by the botocore version in use", k)
                continue

            if spec[k]["type"] == "list":
                if v is None:
                    od[k] = []
                elif len(spec[k]["member"]) == 1:
                    if isinstance(v["member"], list):
                        od[k] = transform(v["member"], spec[k]["member"])
                    else:
                        od[k] = [transform(v["member"], spec[k]["member"])]
                elif isinstance(v["member"], list):
                    od[k] = [transform(o, spec[k]["member"]) for o in v["member"]]
                elif isinstance(v["member"], OrderedDict):
                    od[k] = [transform(v["member"], spec[k]["member"])]
                else:
                    raise ValueError("Malformatted input")
            elif spec[k]["type"] == "map":
                if v is None:
                    od[k] = {}
                else:
                    items = (
                        [v["entry"]] if not isinstance(v["entry"], list) else v["entry"]
                    )
                    for item in items:
                        key = from_str(item["key"], spec[k]["key"])
                        val = from_str(item["value"], spec[k]["value"])
                        if k not in od:
                            od[k] = {}
                        od[k][key] = val
            else:
                if v is None:
                    od[k] = None
                else:
                    od[k] = transform(v, spec[k])
        return od

    dic = xmltodict.parse(xml)
    output_spec = service_spec.output_spec(operation)
    try:
        for k in result_node or (operation + "Response", operation + "Result"):
            dic = dic[k]
    except KeyError:
        return None
    else:
        return transform(dic, output_spec)
    return None
