# Copyright 2014 Amazon.com, Inc. or its affiliates. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License"). You
# may not use this file except in compliance with the License. A copy of
# the License is located at
#
# http://aws.amazon.com/apache2.0/
#
# or in the "license" file accompanying this file. This file is
# distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF
# ANY KIND, either express or implied. See the License for the specific
# language governing permissions and limitations under the License.
"""Protocol input serializes.

This module contains classes that implement input serialization
for the various AWS protocol types.

These classes essentially take user input, a model object that
represents what the expected input should look like, and it returns
a dictionary that contains the various parts of a request.  A few
high level design decisions:


* Each protocol type maps to a separate class, all inherit from
  ``Serializer``.
* The return value for ``serialize_to_request`` (the main entry
  point) returns a dictionary that represents a request.  This
  will have keys like ``url_path``, ``query_string``, etc.  This
  is done so that it's a) easy to test and b) not tied to a
  particular HTTP library.  See the ``serialize_to_request`` docstring
  for more details.

Unicode
-------

The input to the serializers should be text (str/unicode), not bytes,
with the exception of blob types.  Those are assumed to be binary,
and if a str/unicode type is passed in, it will be encoded as utf-8.
"""
import re
import base64
from xml.etree import ElementTree
import calendar

from botocore.compat import six

from botocore.compat import json, formatdate
from botocore.utils import parse_to_aware_datetime
from botocore.utils import percent_encode
from botocore import validate


# From the spec, the default timestamp format if not specified is iso8601.
DEFAULT_TIMESTAMP_FORMAT = 'iso8601'
ISO8601 = '%Y-%m-%dT%H:%M:%SZ'
# Same as ISO8601, but with microsecond precision.
ISO8601_MICRO = '%Y-%m-%dT%H:%M:%S.%fZ'


def create_serializer(protocol_name, include_validation=True):
    # TODO: Unknown protocols.
    serializer = SERIALIZERS[protocol_name]()
    if include_validation:
        validator = validate.ParamValidator()
        serializer = validate.ParamValidationDecorator(validator, serializer)
    return serializer


class Serializer(object):
    DEFAULT_METHOD = 'POST'
    # Clients can change this to a different MutableMapping
    # (i.e OrderedDict) if they want.  This is used in the
    # compliance test to match the hash ordering used in the
    # tests.
    MAP_TYPE = dict
    DEFAULT_ENCODING = 'utf-8'

    def serialize_to_request(self, parameters, operation_model):
        """Serialize parameters into an HTTP request.

        This method takes user provided parameters and a shape
        model and serializes the parameters to an HTTP request.
        More specifically, this method returns information about
        parts of the HTTP request, it does not enforce a particular
        interface or standard for an HTTP request.  It instead returns
        a dictionary of:

            * 'url_path'
            * 'query_string'
            * 'headers'
            * 'body'
            * 'method'

        It is then up to consumers to decide how to map this to a Request
        object of their HTTP library of choice.  Below is an example
        return value::

            {'body': {'Action': 'OperationName',
                      'Bar': 'val2',
                      'Foo': 'val1',
                      'Version': '2014-01-01'},
             'headers': {},
             'method': 'POST',
             'query_string': '',
             'url_path': '/'}

        :param parameters: The dictionary input parameters for the
            operation (i.e the user input).
        :param operation_model: The OperationModel object that describes
            the operation.
        """
        raise NotImplementedError("serialize_to_request")

    def _create_default_request(self):
        # Creates a boilerplate default request dict that subclasses
        # can use as a starting point.
        serialized = {
            'url_path': '/',
            'query_string': '',
            'method': self.DEFAULT_METHOD,
            'headers': {},
            # An empty body is represented as an empty byte string.
            'body': b''
        }
        return serialized

    # Some extra utility methods subclasses can use.

    def _timestamp_iso8601(self, value):
        if value.microsecond > 0:
            timestamp_format = ISO8601_MICRO
        else:
            timestamp_format = ISO8601
        return value.strftime(timestamp_format)

    def _timestamp_unixtimestamp(self, value):
        return int(calendar.timegm(value.timetuple()))

    def _timestamp_rfc822(self, value):
        return formatdate(value, usegmt=True)

    def _convert_timestamp_to_str(self, value):
        datetime_obj = parse_to_aware_datetime(value)
        converter = getattr(
            self, '_timestamp_%s' % self.TIMESTAMP_FORMAT.lower())
        final_value = converter(datetime_obj)
        return final_value

    def _get_serialized_name(self, shape, default_name):
        # Returns the serialized name for the shape if it exists.
        # Otherwise it will return the passed in default_name.
        return shape.serialization.get('name', default_name)

    def _get_base64(self, value):
        # Returns the base64-encoded version of value, handling
        # both strings and bytes. The returned value is a string
        # via the default encoding.
        if isinstance(value, six.text_type):
            value = value.encode(self.DEFAULT_ENCODING)
        return base64.b64encode(value).strip().decode(
            self.DEFAULT_ENCODING)


class QuerySerializer(Serializer):

    TIMESTAMP_FORMAT = 'iso8601'

    def serialize_to_request(self, parameters, operation_model):
        shape = operation_model.input_shape
        serialized = self._create_default_request()
        serialized['method'] = operation_model.http.get('method',
                                                        self.DEFAULT_METHOD)
        # The query serializer only deals with body params so
        # that's what we hand off the _serialize_* methods.
        body_params = self.MAP_TYPE()
        body_params['Action'] = operation_model.name
        body_params['Version'] = operation_model.metadata['apiVersion']
        if shape is not None:
            self._serialize(body_params, parameters, shape)
        serialized['body'] = body_params
        return serialized

    def _serialize(self, serialized, value, shape, prefix=''):
        # serialized: The dict that is incrementally added to with the
        #             final serialized parameters.
        # value: The current user input value.
        # shape: The shape object that describes the structure of the
        #        input.
        # prefix: The incrementally built up prefix for the serialized
        #         key (i.e Foo.bar.members.1).
        method = getattr(self, '_serialize_type_%s' % shape.type_name,
                         self._default_serialize)
        method(serialized, value, shape, prefix=prefix)

    def _serialize_type_structure(self, serialized, value, shape, prefix=''):
        members = shape.members
        for key, value in value.items():
            member_shape = members[key]
            member_prefix = self._get_serialized_name(member_shape, key)
            if prefix:
                member_prefix = '%s.%s' % (prefix, member_prefix)
            self._serialize(serialized, value, member_shape, member_prefix)

    def _serialize_type_list(self, serialized, value, shape, prefix=''):
        if not value:
            # The query protocol serializes empty lists.
            serialized[prefix] = ''
            return
        if self._is_shape_flattened(shape):
            list_prefix = prefix
            if shape.member.serialization.get('name'):
                name = self._get_serialized_name(shape.member, default_name='')
                # Replace '.Original' with '.{name}'.
                list_prefix = '.'.join(prefix.split('.')[:-1] + [name])
        else:
            list_name = shape.member.serialization.get('name', 'member')
            list_prefix = '%s.%s' % (prefix, list_name)
        for i, element in enumerate(value, 1):
            element_prefix = '%s.%s' % (list_prefix, i)
            element_shape = shape.member
            self._serialize(serialized, element, element_shape, element_prefix)

    def _serialize_type_map(self, serialized, value, shape, prefix=''):
        if self._is_shape_flattened(shape):
            full_prefix = prefix
        else:
            full_prefix = '%s.entry' % prefix
        template = full_prefix + '.{i}.{suffix}'
        key_shape = shape.key
        value_shape = shape.value
        key_suffix = self._get_serialized_name(key_shape, default_name='key')
        value_suffix = self._get_serialized_name(value_shape, 'value')
        for i, key in enumerate(value, 1):
            key_prefix = template.format(i=i, suffix=key_suffix)
            value_prefix = template.format(i=i, suffix=value_suffix)
            self._serialize(serialized, key, key_shape, key_prefix)
            self._serialize(serialized, value[key], value_shape, value_prefix)

    def _serialize_type_blob(self, serialized, value, shape, prefix=''):
        # Blob args must be base64 encoded.
        serialized[prefix] = self._get_base64(value)

    def _serialize_type_timestamp(self, serialized, value, shape, prefix=''):
        serialized[prefix] = self._convert_timestamp_to_str(value)

    def _serialize_type_boolean(self, serialized, value, shape, prefix=''):
        if value:
            serialized[prefix] = 'true'
        else:
            serialized[prefix] = 'false'

    def _default_serialize(self, serialized, value, shape, prefix=''):
        serialized[prefix] = value

    def _is_shape_flattened(self, shape):
        return shape.serialization.get('flattened')


class EC2Serializer(QuerySerializer):
    """EC2 specific customizations to the query protocol serializers.

    The EC2 model is almost, but not exactly, similar to the query protocol
    serializer.  This class encapsulates those differences.  The model
    will have be marked with a ``protocol`` of ``ec2``, so you don't need
    to worry about wiring this class up correctly.

    """

    def _get_serialized_name(self, shape, default_name):
        # Returns the serialized name for the shape if it exists.
        # Otherwise it will return the passed in default_name.
        if 'queryName' in shape.serialization:
            return shape.serialization['queryName']
        elif 'name' in shape.serialization:
            # A locationName is always capitalized
            # on input for the ec2 protocol.
            name = shape.serialization['name']
            return name[0].upper() + name[1:]
        else:
            return default_name

    def _serialize_type_list(self, serialized, value, shape, prefix=''):
        for i, element in enumerate(value, 1):
            element_prefix = '%s.%s' % (prefix, i)
            element_shape = shape.member
            self._serialize(serialized, element, element_shape, element_prefix)


class JSONSerializer(Serializer):
    TIMESTAMP_FORMAT = 'unixtimestamp'

    def serialize_to_request(self, parameters, operation_model):
        target = '%s.%s' % (operation_model.metadata['targetPrefix'],
                            operation_model.name)
        json_version = operation_model.metadata['jsonVersion']
        serialized = self._create_default_request()
        serialized['method'] = operation_model.http.get('method',
                                                        self.DEFAULT_METHOD)
        serialized['headers'] = {
            'X-Amz-Target': target,
            'Content-Type': 'application/x-amz-json-%s' % json_version,
        }
        body = {}
        input_shape = operation_model.input_shape
        if input_shape is not None:
            self._serialize(body, parameters, input_shape)
        serialized['body'] = json.dumps(body).encode(self.DEFAULT_ENCODING)
        return serialized

    def _serialize(self, serialized, value, shape, key=None):
        method = getattr(self, '_serialize_type_%s' % shape.type_name,
                         self._default_serialize)
        method(serialized, value, shape, key)

    def _serialize_type_structure(self, serialized, value, shape, key):
        if key is not None:
            # If a key is provided, this is a result of a recursive
            # call so we need to add a new child dict as the value
            # of the passed in serialized dict.  We'll then add
            # all the structure members as key/vals in the new serialized
            # dictionary we just created.
            new_serialized = self.MAP_TYPE()
            serialized[key] = new_serialized
            serialized = new_serialized
        members = shape.members
        for member_key, member_value in value.items():
            member_shape = members[member_key]
            if 'name' in member_shape.serialization:
                member_key = member_shape.serialization['name']
            self._serialize(serialized, member_value, member_shape, member_key)

    def _serialize_type_map(self, serialized, value, shape, key):
        map_obj = self.MAP_TYPE()
        serialized[key] = map_obj
        for sub_key, sub_value in value.items():
            self._serialize(map_obj, sub_value, shape.value, sub_key)

    def _serialize_type_list(self, serialized, value, shape, key):
        list_obj = []
        serialized[key] = list_obj
        for list_item in value:
            wrapper = {}
            # The JSON list serialization is the only case where we aren't
            # setting a key on a dict.  We handle this by using
            # a __current__ key on a wrapper dict to serialize each