
#
# spyne - Copyright (C) Spyne contributors.
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301
#

"""The ``spyne.model.complex`` module contains
:class:`spyne.model.complex.ComplexBase` class and its helper objects and
subclasses. These are mainly container classes for other simple or
complex objects -- they don't carry any data by themselves.
"""

from __future__ import print_function

import logging
logger = logging.getLogger(__name__)

import decimal
import traceback

from copy import copy
from weakref import WeakKeyDictionary
from collections import deque, OrderedDict
from inspect import isclass
from itertools import chain

from spyne import const
from spyne.const.xml import PREFMAP

from spyne.model import Point, Unicode, PushBase, ModelBase
from spyne.model._base import PSSM_VALUES, apply_pssm
from spyne.model.primitive import NATIVE_MAP

from spyne.util import six, memoize, memoize_id, sanitize_args, \
    memoize_ignore_none
from spyne.util.color import YEL
from spyne.util.meta import Prepareable
from spyne.util.odict import odict
from spyne.util.six import add_metaclass, with_metaclass, string_types

# FIXME: for backwards compatibility, to be removed in Spyne 3
# noinspection PyUnresolvedReferences
from spyne.model import json, jsonb, xml, msgpack, table


def _get_flat_type_info(cls, retval):
    assert isinstance(retval, TypeInfo)
    parent = getattr(cls, '__extends__', None)
    if not (parent is None):
        _get_flat_type_info(parent, retval)
    retval.update(cls._type_info)
    retval.alt.update(cls._type_info_alt)  # FIXME: move to cls._type_info.alt
    retval.attrs.update({k: v for (k, v) in cls._type_info.items()
                                                if issubclass(v, XmlAttribute)})
    return retval


class TypeInfo(odict):
    def __init__(self, *args, **kwargs):
        super(TypeInfo, self).__init__(*args, **kwargs)

        self.attributes = {}
        self.alt = OrderedDict()
        self.attrs = OrderedDict()

    def __setitem__(self, key, val):
        assert isinstance(key, string_types)
        super(TypeInfo, self).__setitem__(key, val)


class _SimpleTypeInfoElement(object):
    __slots__ = ['path', 'parent', 'type', 'is_array', 'can_be_empty']

    def __init__(self, path, parent, type_, is_array, can_be_empty):
        self.path = path
        self.parent = parent
        self.type = type_
        self.is_array = is_array
        self.can_be_empty = can_be_empty

    def __repr__(self):
        return "SimpleTypeInfoElement(path=%r, parent=%r, type=%r, is_array=%r)" \
                            % (self.path, self.parent, self.type, self.is_array)


class XmlModifier(ModelBase):
    def __new__(cls, type, ns=None):
        retval = cls.customize()
        retval.type = type
        retval.Attributes = type.Attributes
        retval._ns = ns
        if type.__type_name__ is ModelBase.Empty:
            retval.__type_name__ = ModelBase.Empty
        return retval

    @staticmethod
    def resolve_namespace(cls, default_ns, tags=None):
        cls.type.resolve_namespace(cls.type, default_ns, tags)

        cls.__namespace__ = cls._ns

        if cls.__namespace__ is None:
            cls.__namespace__ = cls.type.get_namespace()

        if cls.__namespace__ in PREFMAP:
            cls.__namespace__ = default_ns

    @classmethod
    def _fill_empty_type_name(cls, parent_ns, parent_tn, k):
        cls.__namespace__ = parent_ns
        tn = "%s_%s%s" % (parent_tn, k, const.TYPE_SUFFIX)

        child_v = cls.type
        child_v.__type_name__ = tn

        cls._type_info = TypeInfo({tn: child_v})
        cls.__type_name__ = '%s%s%s' % (const.ARRAY_PREFIX, tn,
                                                         const.ARRAY_SUFFIX)

        extends = child_v.__extends__
        while extends is not None and extends.get_type_name() is cls.Empty:
            extends._fill_empty_type_name(parent_ns, parent_tn,
                                                    k + const.PARENT_SUFFIX)
            extends = extends.__extends__


class XmlData(XmlModifier):
    """Items which are marshalled as data of the parent element."""

    @classmethod
    def marshall(cls, prot, name, value, parent_elt):
        if value is not None:
            if len(parent_elt) == 0:
                parent_elt.text = prot.to_bytes(cls.type, value)
            else:
                parent_elt[-1].tail = prot.to_bytes(cls.type, value)

    @classmethod
    def get_type_name(cls):
        return cls.type.get_type_name()

    @classmethod
    def get_type_name_ns(cls, interface):
        return cls.type.get_type_name_ns(interface)

    @classmethod
    def get_namespace(cls):
        return cls.type.get_namespace()

    @classmethod
    def get_element_name(cls):
        return cls.type.get_element_name()

    @classmethod
    def get_element_name_ns(cls, interface):
        return cls.type.get_element_name_ns(interface)


class XmlAttribute(XmlModifier):
    """Items which are marshalled as attributes of the parent element."""

    def __new__(cls, type_, use=None, ns=None):
        retval = super(XmlAttribute, cls).__new__(cls, type_, ns)
        retval._use = use
        if retval.type.Attributes.min_occurs > 0 and retval._use is None:
            retval._use = 'required'
        return retval


class XmlAttributeRef(XmlAttribute):
    """Reference to an Xml attribute."""

    def __init__(self, ref, use=None):
        self._ref = ref
        self._use = use

    def describe(self, name, element, app):
        element.set('ref', self._ref)
        if self._use:
            element.set('use', self._use)


class SelfReference(object):
    """Use this as a placeholder type in classes that contain themselves. See
    :func:`spyne.test.model.test_complex.TestComplexModel.test_self_reference`.
    """
    customize_args = []
    customize_kwargs = {}
    __orig__ = None

    def __init__(self):
        raise NotImplementedError()

    @classmethod
    def customize(cls, *args, **kwargs):
        args = list(chain(args, cls.customize_args))
        kwargs = dict(chain(kwargs.items(), cls.customize_kwargs.items()))
        if cls.__orig__ is None:
            cls.__orig__ = cls

        return type("SelfReference", (cls,), {
            'customize_args': args,
            'customize_kwargs': kwargs,
        })


def _get_spyne_type(cls_name, k, v):
    try:
        v = NATIVE_MAP.get(v, v)
    except TypeError:
        return

    try:
        subc = issubclass(v, ModelBase) or issubclass(v, SelfReference)
    except:
        subc = False

    if subc:
        if issubclass(v, Array) and len(v._type_info) != 1:
            raise Exception("Invalid Array definition in %s.%s."% (cls_name, k))
        elif issubclass(v, Point) and v.Attributes.dim is None:
            raise Exception("Please specify the number of dimensions")
        return v


def _join_args(x, y):
    if x is None:
        return y
    if y is None:
        return x

    xa, xk = sanitize_args(x)
    ya, yk = sanitize_args(y)

    xk = dict(xk)
    xk.update(yk)

    return xa + ya, xk


def _gen_attrs(cls_bases, cls_dict):
    attrs = cls_dict.get('Attributes', None)
    if attrs is None:
        for b in cls_bases:
            if hasattr(b, 'Attributes'):
                class Attributes(b.Attributes):
                    pass
                attrs = cls_dict['Attributes'] = Attributes
                break
        else:
            raise Exception("No ModelBase subclass in bases? Huh?")

    return attrs


def _get_type_info(cls, cls_name, cls_bases, cls_dict, attrs):
    base_type_info = TypeInfo()
    mixin = TypeInfo()
    extends = cls_dict.get('__extends__', None)

    # user did not specify explicit base class so let's try to derive it from
    # the actual class hierarchy
    if extends is None:
        # we don't want origs end up as base classes
        orig = cls_dict.get("__orig__", None)
        if orig is None:
            orig = getattr(cls, '__orig__', None)

        if orig is not None:
            bases = orig.__bases__
            logger.debug("Got bases for %s from orig: %r", cls_name, bases)
        else:
            bases = cls_bases
            logger.debug("Got bases for %s from meta: %r", cls_name, bases)

        for b in bases:
            base_types = getattr(b, "_type_info", None)

            # we don't care about non-ComplexModel bases
            if base_types is None:
                continue

            # mixins are simple
            if getattr(b, '__mixin__', False) == True:
                logger.debug("Adding fields from mixin %r to '%s'", b, cls_name)
                mixin.update(b.get_flat_type_info(b))

                if '__mixin__' not in cls_dict:
                    cls_dict['__mixin__'] = False

                continue

            if not (extends in (None, b)):
                raise Exception("Spyne objects do not support multiple "
                    "inheritance. Use mixins if you need to reuse "
                    "fields from multiple classes.")

            if len(base_types) > 0 and issubclass(b, ModelBase):
                extends = cls_dict["__extends__"] = b
                assert extends.__orig__ is None, "You can't inherit from a " \
                    "customized class. You should first get your class " \
                    "hierarchy right, then start customizing classes."

                b.get_subclasses.memo.clear()
                logger.debug("Registering %r as base of '%s'", b, cls_name)

    if not ('_type_info' in cls_dict):
        cls_dict['_type_info'] = _type_info = TypeInfo()
        _type_info.update(base_type_info)

        class_fields = []
        for k, v in cls_dict.items():
            if k.startswith('_'):
                continue

            if isinstance(v, tuple) and len(v) == 1 and \
                                 _get_spyne_type(cls_name, k, v[0]) is not None:
                logger.warning(YEL("There seems to be a stray comma in the"
                                   "definition of '%s.%s'.", cls_name, k))

            v = _get_spyne_type(cls_name, k, v)

            if v is None:
                continue

            class_fields.append((k, v))

        _type_info.update(class_fields)

    else:
        _type_info = cls_dict['_type_info']

        if not isinstance(_type_info, TypeInfo):
            _type_info = cls_dict['_type_info'] = TypeInfo(_type_info)

    for k, v in reversed(mixin.items()):
        _type_info.insert(0, (k, v))

    return _type_info


class _MethodsDict(dict):
    def __init__(self, *args, **kwargs):
        super(_MethodsDict, self).__init__(*args, **kwargs)

        self._processed = False


def _gen_methods(cls, cls_dict):
    methods = _MethodsDict()
    for k, v in cls_dict.items():
        if not k.startswith('_') and hasattr(v, '_is_rpc'):
            logger.debug("Registering %s as member method for %r", k, cls)
            assert cls is not None

            # generate method descriptor from information in the decorator
            descriptor = v(_default_function_name=k, _self_ref_replacement=cls)

            # strip the decorator and put the original function in the class
            setattr(cls, k, descriptor.function)

            # modify the descriptor with user-supplied class
            if cls.Attributes.method_config_do is not None:
                descriptor = cls.Attributes.method_config_do(descriptor)

            methods[k] = descriptor

    return methods


def _get_ordered_attributes(cls_name, cls_dict, attrs):
    if not isinstance(cls_dict, odict):
        # FIXME: Maybe add a warning here?
        return cls_dict

    SUPPORTED_ORDERS = ('random', 'declared')
    if (attrs.declare_order is not None and
            not attrs.declare_order in SUPPORTED_ORDERS):

        msg = "The declare_order attribute value %r is invalid in %s"
        raise Exception(msg % (attrs.declare_order, cls_name))

    declare_order = attrs.declare_order or const.DEFAULT_DECLARE_ORDER
    if declare_order is None or declare_order == 'random':
        # support old behaviour
        cls_dict = dict(cls_dict)

    return cls_dict


def _sanitize_sqlalchemy_parameters(cls_dict, attrs):
    table_name = cls_dict.get('__tablename__', None)
    if attrs.table_name is None:
        attrs.table_name = table_name

    _cls_table = cls_dict.get('__table__', None)
    if attrs.sqla_table is None:
        attrs.sqla_table = _cls_table

    metadata = cls_dict.get('__metadata__', None)
    if attrs.sqla_metadata is None:
        attrs.sqla_metadata = metadata

    margs = cls_dict.get('__mapper_args__', None)
    attrs.sqla_mapper_args = _join_args(attrs.sqla_mapper_args, margs)

    targs = cls_dict.get('__table_args__', None)
    attrs.sqla_table_args = _join_args(attrs.sqla_table_args, targs)


def _sanitize_type_info(cls_name, _type_info, _type_info_alt):
    """Make sure _type_info contents are sane"""

    for k, v in _type_info.items():
        if not isinstance(k, six.string_types):
            raise ValueError("Invalid class key", k)

        if not isclass(v):
            raise ValueError(v)

        if issubclass(v, SelfReference):
            continue

        elif not issubclass(v, ModelBase):
            v = _get_spyne_type(cls_name, k, v)
            if v is None:
                raise ValueError( (cls_name, k, v) )
            _type_info[k] = v

        elif issubclass(v, Array) and len(v._type_info) != 1:
            raise Exception("Invalid Array definition in %s.%s." %
                                                        (cls_name, k))
        sub_ns = v.Attributes.sub_ns
        sub_name = v.Attributes.sub_name

        if sub_ns is None and sub_name is None:
            pass

        elif sub_ns is not None and sub_name is not None:
            key = "{%s}%s" % (sub_ns, sub_name)
            if key in _type_info:
                raise Exception("%r is already defined: %r" %
                                                         (key, _type_info[key]))
            _type_info_alt[key] = v, k

        elif sub_ns is None:
            key = sub_name
            if sub_ns in _type_info:
                raise Exception("%r is already defined: %r" %
                                                         (key, _type_info[key]))
            _type_info_alt[key] = v, k

        elif sub_name is None:
            key = "{%s}%s" % (sub_ns, k)
            if key in _type_info:
                raise Exception("%r is already defined: %r" %
                                                         (key, _type_info[key]))
            _type_info_alt[key] = v, k


D_EXC = dict(exc=True)


def _process_child_attrs(cls, retval, kwargs):
    child_attrs = copy(kwargs.get('child_attrs', None))
    child_attrs_all = kwargs.get('child_attrs_all', None)
    child_attrs_noexc = copy(kwargs.get('child_attrs_noexc', None))

    # add exc=False to child_attrs_noexc
    if child_attrs_noexc is not None:
        # if there is _noexc, make sure that child_attrs_all is also used to
        # exclude exclude everything else first
        if child_attrs_all is None:
            child_attrs_all = D_EXC

        else:
            if 'exc' in child_attrs_all and child_attrs_all['exc'] != D_EXC:
                logger.warning("Overriding child_attrs_all['exc'] to True "
                                                                  "for %r", cls)

            child_attrs_all.update(D_EXC)

        # update child_attrs_noexc with exc=False
        for k, v in child_attrs_noexc.items():
            if 'exc' in v:
                logger.warning("Overriding 'exc' for %s.%s from "
                         "child_attrs_noexc with False", cls.get_type_name(), k)

            v['exc'] = False

        # update child_attrs with data from child_attrs_noexc
        if child_attrs is None:
            child_attrs = child_attrs_noexc

        else:
            # update with child_attrs_noexc with exc=False
            if child_attrs is None:
                child_attrs = dict()

            for k, v in child_attrs_noexc.items():
                if k in child_attrs:
                    logger.warning("Overriding child_attrs for %s.%s from "
                                    "child_attrs_noexc", cls.get_type_name(), k)

                child_attrs[k] = v

    if child_attrs_all is not None:
        ti = retval._type_info
        logger.debug("processing child_attrs_all for %r", cls)
        for k, v in ti.items():
            logger.debug("  child_attrs_all set %r=%r", k, child_attrs_all)
            ti[k] = ti[k].customize(**child_attrs_all)

        if retval.__extends__ is not None:
            retval.__extends__ = retval.__extends__.customize(
                                                child_attrs_all=child_attrs_all)

        retval.Attributes._delayed_child_attrs_all = child_attrs_all

    if child_attrs is not None:
        ti = retval._type_info
        logger.debug("processing child_attrs for %r", cls)
        for k, v in list(child_attrs.items()):
            if k in ti:
                logger.debug("  child_attr set %r=%r", k, v)
                ti[k] = ti[k].customize(**v)
                del child_attrs[k]

        base_fti = {}
        if retval.__extends__ is not None:
            retval.__extends__ = retval.__extends__.customize(
                                                        child_attrs=child_attrs)
            base_fti = retval.__extends__.get_flat_type_info(retval.__extends__)

        for k, v in child_attrs.items():
            if k not in base_fti:
                logger.debug("  child_attr delayed %r=%r", k, v)
                retval.Attributes._delayed_child_attrs[k] = v


def recust_selfref(selfref, cls):
    if len(selfref.customize_args) > 0 or len(selfref.customize_kwargs) > 0:
        logger.debug("Replace self reference with %r with *%r and **%r",
                          cls, selfref.customize_args, selfref.customize_kwargs)
        return cls.customize(*selfref.customize_args,
                                                     **selfref.customize_kwargs)
    logger.debug("Replace self reference with %r", cls)
    return cls


def _set_member_default(inst, key, cls, attr):
    def_val = attr.default
    def_fac = attr.default_factory

    if def_fac is None and def_val is None:
        return False

    if def_fac is not None:
        if six.PY2 and hasattr(def_fac, 'im_func'):
            # unbound-method error workaround. huh.
            def_fac = def_fac.im_func

        dval = def_fac()

        # should not check for read-only for default values
        setattr(inst, key, dval)

        return True

    if def_val is not None:
        # should not check for read-only for default values
        setattr(inst, key, def_val)

        return True

    assert False, "Invalid application state"


def _is_sqla_array(cls, attr):
    # inner object is complex
    ret1 = issubclass(cls, Array) and \
                              hasattr(cls.get_inner_type(), '_sa_class_manager')

    # inner object is primitive
    ret2 = issubclass(cls, Array) and attr.store_as is not None

    # object is a bare array
    ret3 = attr.max_occurs > 1 and hasattr(cls, '_sa_class_manager')

    return ret1 or ret2 or ret3


def _init_member(inst, key, cls, attr):
    cls_getattr_ret = getattr(inst.__class__, key, None)

    if isinstance(cls_getattr_ret, property) and cls_getattr_ret.fset is None:
        return  # we skip read-only properties

    if _set_member_default(inst, key, cls, attr):
       return

    # sqlalchemy objects do their own init.
    if _is_sqla_array(cls, attr):
        # except the attributes that sqlalchemy doesn't know about
        if attr.exc_db:
            setattr(inst, key, None)

        elif attr.store_as is None:
            setattr(inst, key, None)

        return

    # sqlalchemy objects do their own init.
    if hasattr(inst.__class__, '_sa_class_manager'):
        # except the attributes that sqlalchemy doesn't know about
        if attr.exc_db:
            setattr(inst, key, None)

        elif issubclass(cls, ComplexModelBase) and attr.store_as is None:
            setattr(inst, key, None)

        return

    setattr(inst, key, None)


class ComplexModelMeta(with_metaclass(Prepareable, type(ModelBase))):
    """This metaclass sets ``_type_info``, ``__type_name__`` and ``__extends__``
    which are going to be used for (de)serialization and schema generation.
    """

    def __new__(cls, cls_name, cls_bases, cls_dict):
        """This function initializes the class and registers attributes."""

        attrs = _gen_attrs(cls_bases, cls_dict)
        assert issubclass(attrs, ComplexModelBase.Attributes), \
                   ("%r must be a ComplexModelBase.Attributes subclass" % attrs)

        cls_dict = _get_ordered_attributes(cls_name, cls_dict, attrs)

        type_name = cls_dict.get("__type_name__", None)
        if type_name is None:
            cls_dict["__type_name__"] = cls_name

        _type_info = _get_type_info(cls, cls_name, cls_bases, cls_dict, attrs)

        # used for sub_name and sub_ns
        _type_info_alt = cls_dict['_type_info_alt'] = TypeInfo()
        for b in cls_bases:
            if hasattr(b, '_type_info_alt'):
                _type_info_alt.update(b._type_info_alt)

        _sanitize_type_info(cls_name, _type_info, _type_info_alt)
        _sanitize_sqlalchemy_parameters(cls_dict, attrs)

        return super(ComplexModelMeta, cls).__new__(cls,
                                                  cls_name, cls_bases, cls_dict)

    def __init__(self, cls_name, cls_bases, cls_dict):
        type_info = self._type_info

        extends = self.__extends__
        if extends is not None and self.__orig__ is None:
            eattr = extends.Attributes
            if eattr._subclasses is None:
                eattr._subclasses = []
            eattr._subclasses.append(self)
            if self.Attributes._subclasses is eattr._subclasses:
                self.Attributes._subclasses = None

        # sanitize fields
        for k, v in type_info.items():
            # replace bare SelfRerefence
            if issubclass(v, SelfReference):
                self._replace_field(k, recust_selfref(v, self))

            # cache XmlData for easier access
            elif issubclass(v, XmlData):
                if self.Attributes._xml_tag_body_as is None:
                    self.Attributes._xml_tag_body_as = [(k, v)]
                else:
                    self.Attributes._xml_tag_body_as.append((k, v))

            # replace SelfRerefence in arrays
            elif issubclass(v, Array):
                v2, = v._type_info.values()
                while issubclass(v2, Array):
                    v = v2
                    v2, = v2._type_info.values()

                if issubclass(v2, SelfReference):
                    v._set_serializer(recust_selfref(v2, self))

        # apply field order
        # FIXME: Implement this better
        new_type_info = []
        for k, v in self._type_info.items():
            if v.Attributes.order == None:
                new_type_info.append(k)

        for k, v in self._type_info.items():
            if v.Attributes.order is not None:
                new_type_info.insert(v.Attributes.order, k)

        assert len(self._type_info) == len(new_type_info)
        self._type_info.keys()[:] = new_type_info

        # install checkers for validation on assignment
        for k, v in self._type_info.items():
            if not v.Attributes.validate_on_assignment:
                continue

            def _get_prop(self):
                return self.__dict__[k]

            def _set_prop(self, val):
                if not (val is None or isinstance(val, v.Value)):
                    raise ValueError("Invalid value %r, "
                                 "should be an instance of %r" % (val, v.Value))

                self.__dict__[k] = val

            setattr(self, k, property(_get_prop, _set_prop))

        # process member rpc methods
        methods = _gen_methods(self, cls_dict)
        if len(methods) > 0:
            self.Attributes.methods = methods

        # finalize sql table mapping
        tn = self.Attributes.table_name
        meta = self.Attributes.sqla_metadata
        t = self.Attributes.sqla_table

        # For spyne objects reflecting an existing db table
        if tn is None:
            if t is not None:
                self.Attributes.sqla_metadata = t.metadata
                from spyne.store.relational import gen_spyne_info

                gen_spyne_info(self)

        # For spyne objects being converted to a sqlalchemy table
        elif meta is not None and (tn is not None or t is not None) and \
                                                       len(self._type_info) > 0:
            from spyne.store.relational import gen_sqla_info

            gen_sqla_info(self, cls_bases)

        super(ComplexModelMeta, self).__init__(cls_name, cls_bases, cls_dict)

    #
    # We record the order fields are defined into ordered dict, so we can
    # declare them in the same order in the WSDL.
    #
    # For Python 3 __prepare__ works out of the box, see PEP 3115.
    # But we use `Preparable` metaclass for both Python 2 and Python 3 to
    # support six.add_metaclass decorator
    #
    @classmethod
    def __prepare__(mcs, name, bases, **kwds):
        return odict()


_is_array = lambda v: issubclass(v, Array) or (v.Attributes.max_occurs > 1)


class ComplexModelBase(ModelBase):
    """If you want to make a better class type, this is what you should inherit
    from.
    """

    __mixin__ = False

    class Attributes(ModelBase.Attributes):
        """ComplexModel-specific attributes"""

        store_as = None
        """Method for serializing to persistent storage. One of %r. It makes
        sense to specify this only when this object is a child of another
        ComplexModel subclass.""" % (PSSM_VALUES,)

        sqla_metadata = None
        """None or :class:`sqlalchemy.MetaData` instance."""

        sqla_table_args = None
        """A dict that will be passed to :class:`sqlalchemy.schema.Table`
        constructor as ``**kwargs``.
        """

        sqla_mapper_args = None
        """A dict that will be passed to :func:`sqlalchemy.orm.mapper`
        constructor as. ``**kwargs``.
        """

        sqla_table = None
        """The sqlalchemy table object"""

        sqla_mapper = None
        """The sqlalchemy mapper object"""

        validate_freq = True
        """When ``False``, soft validation ignores missing mandatory attributes.
        """

        child_attrs = None
        """Customize child attributes in one go. It's a dict of dicts. This is
        ignored unless used via explicit customization."""

        child_attrs_all = None
        """Customize all child attributes. It's a dict. This is ignored unless
        used via explicit customization. `child_attrs` always take precedence.
        """

        declare_order = None
        """The order fields of the :class:``ComplexModel`` are to be declared
        in the SOAP WSDL. If this is left as None or explicitly set to
        ``'random'`` declares then the fields appear in whatever order the
        Python's hash map implementation seems fit in the WSDL. This randomised
        order can change every time the program is run. This is what Spyne <2.11
        did if you didn't set _type_info as an explicit sequence (e.g. using a
        list, odict, etc.). It means that clients who are manually complied or
        generated from the WSDL will likely need to be recompiled every time it
        changes. The string ``name`` means the field names are alphabetically
        sorted in the WSDL declaration.  The string ``declared`` means in the
        order the field type was declared in Python 2, and the order the
        field was declared in Python 3.

        In order to get declared field order in Python 2, the
        :class:`spyne.util.meta.Preparable` class inspects the frame stack in
        order to locate the class definition, re-parses it to get declaration
        order from the AST and uses that information to order elements.

        It's a horrible hack that we tested to work with CPython 2.6 through 3.3
        and PyPy. It breaks in Nuitka as Nuitka does away with code objects.
        Other platforms were not tested.

        It's not recommended to use set this to ``'declared'`` in Python 2
        unless you're sure you fully understand the consequences.
        """

        parent_variant = None
        """FIXME: document me yo."""

        methods = None
        """A dict of member RPC methods (typically marked with @mrpc)."""

        method_config_do = None
        """When not None, it's a callable that accepts a ``@mrpc`` method
        descriptor and returns a modified version."""

        not_wrapped = None
        """When True, serializes to non-wrapped object, overriding the protocol
        flag."""

        wrapped = None
        """When True, serializes to a wrapped object, overriding the protocol
        flag. When a str/bytes/unicode value, uses that value as key wrapper
        object name."""

        _variants = None
        _xml_tag_body_as = None
        _delayed_child_attrs = None
        _delayed_child_attrs_all = None
        _subclasses = None

    def __init__(self, *args, **kwargs):
        cls = self.__class__
        cls_attr = cls.Attributes
        fti = cls.get_flat_type_info(cls)

        if cls.__orig__ is not None:
            logger.warning("%r(0x%X) seems to be a customized class. It is not "
                    "supposed to be instantiated. You have been warned.",
                                                                   cls, id(cls))
            logger.debug(traceback.format_stack())

        if cls_attr._xml_tag_body_as is not None:
            for arg, (xtba_key, xtba_type) in \
                                           zip(args, cls_attr._xml_tag_body_as):

                if xtba_key is not None and len(args) == 1:
                    attr = xtba_type.Attributes
                    _init_member(self, xtba_key, xtba_type, attr)
                    self._safe_set(xtba_key, arg, xtba_type,
                                                           xtba_type.Attributes)
                elif len(args) > 0:
                    raise TypeError(
                                "Positional argument is only for ComplexModels "
                                "with XmlData field. You must use keyword "
                                "arguments in any other case.")

        for k, v in fti.items():
            attr = v.Attributes
            if not k in self.__dict__:
                _init_member(self, k, v, attr)

            if k in kwargs:
                self._safe_set(k, kwargs[k], v, attr)

    def __len__(self):
        return len(self._type_info)

    def __getitem__(self, i):
        if isinstance(i, slice):
            retval = []
            for key in self._type_info.keys()[i]:
                retval.append(getattr(self, key, None))

        else:
            retval = getattr(self, self._type_info.keys()[i], None)

        return retval

    def __repr__(self):
        return "%s(%s)" % (self.get_type_name(), ', '.join(
               ['%s=%r' % (k, self.__dict__.get(k))
                    for k in self.__class__.get_flat_type_info(self.__class__)
                    if self.__dict__.get(k, None) is not None]))

    def _safe_set(self, key, value, t, attrs):
        if attrs.read_only:
            return False

        try:
            setattr(self, key, value)
        except AttributeError as e:
            logger.exception(e)
            raise AttributeError("can't set %r attribute %s to %r" %
                                                   (self.__class__, key, value))

        return True

    @classmethod
    def get_identifiers(cls):
        for k, v in cls.get_flat_type_info(cls).items():
            if getattr(v.Attributes, 'primary_key', None):
                yield k, v

    @classmethod
    def get_primary_keys(cls):
        return cls.get_identifiers()

    def as_dict(self):
        """Represent object as dict.

        Null values are omitted from dict representation to support optional
        not nullable attributes.
        """

        return dict((
            (k, getattr(self, k)) for k in self.get_flat_type_info(self.__class__)
            if getattr(self, k) is not None
        ))

    @classmethod
    def get_serialization_instance(cls, value):
        """Returns the native object corresponding to the serialized form passed
        in the ``value`` argument.

        :param value: This argument can be:
            * A list or tuple of native types aligned with cls._type_info.
            * A dict of native types.
            * The native type itself.

            If the value type is not a ``list``, ``tuple`` or ``dict``, the
            value is returned untouched.
        """

        # if the instance is a list, convert it to a cls instance.
        # this is only useful when deserializing method arguments for a client
        # request which is the only time when the member order is not arbitrary
        # (as the members are declared and passed around as sequences of
        # arguments, unlike dictionaries in a regular class definition).
        if isinstance(value, list) or isinstance(value, tuple):
            keys = cls.get_flat_type_info(cls).keys()

            if not len(value) <= len(keys):
                logger.error("\n\tcls: %r" "\n\tvalue: %r" "\n\tkeys: %r",
                                                               cls, value, keys)
                raise ValueError("Impossible sequence to instance conversion")

            cls_orig = cls
            if cls.__orig__ is not None:
                cls_orig = cls.__orig__

            try:
                inst = cls_orig()

            except Exception as e:
                logger.error("Error instantiating %r: %r", cls_orig, e)
                raise

            for i in range(len(value)):
                setattr(inst, keys[i], value[i])

        elif isinstance(value, dict):
            cls_orig = cls
            if cls.__orig__ is not None:
                cls_orig = cls.__orig__
            inst = cls_orig()

            for k in cls.get_flat_type_info(cls):
                setattr(inst, k, value.get(k, None))

        else:
            inst = value

        return inst

    @classmethod
    def get_deserialization_instance(cls, ctx):
        """Get an empty native type so that the deserialization logic can set
        its attributes.
        """
        if cls.__orig__ is None:
            return cls()
        return cls.__orig__()

    @classmethod
    @memoize_id
    def get_subclasses(cls):
        retval = []
        subca = cls.Attributes._subclasses
        if subca is not None:
            retval.extend(subca)
            for subc in subca:
                retval.extend(subc.get_subclasses())
        return retval

    @staticmethod
    @memoize_ignore_none
    def get_flat_type_info(cls):
        """Returns a _type_info dict that includes members from all base
        classes.

        It's called a "flat" dict because it flattens all members from the
        inheritance hierarchy into one dict.
        """
        return _get_flat_type_info(cls, TypeInfo())

    @classmethod
    def get_orig(cls):
        return cls.__orig__ or cls

    @staticmethod
    def get_simple_type_info(cls, hier_delim="."):
        """Returns a _type_info dict that includes members from all base classes
        and whose types are only primitives. It will prefix field names in
        non-top-level complex objects with field name of its parent.

        For example, given hier_delim='.'; the following hierarchy: ::

            {'some_object': [{'some_string': ['abc']}]}

        would be transformed to: ::

            {'some_object.some_string': ['abc']}

        :param hier_delim: String that will be used as delimiter between field
            names. Default is ``'.'``.
        """
        return ComplexModelBase.get_simple_type_info_with_prot(
                                                     cls, hier_delim=hier_delim)

    @staticmethod
    @memoize
    def get_simple_type_info_with_prot(cls, prot=None, hier_delim="."):
        """See :func:ComplexModelBase.get_simple_type_info"""
        fti = cls.get_flat_type_info(cls)

        retval = TypeInfo()
        tags = set()

        queue = deque()
        if prot is None:
            for k, v in fti.items():
                sub_name = k

                queue.append((
                    (k,),
                    v,
                    (sub_name,),
                    (_is_array(v),),
                    cls,
                ))

        else:
            for k, v in fti.items():
                cls_attrs = prot.get_cls_attrs(v)
                sub_name = cls_attrs.sub_name
                if sub_name is None:
                    sub_name = k

                queue.append((
                    (k,),
                    v,
                    (sub_name,),
                    (_is_array(v),),
                    cls,
                ))

        tags.add(cls)

        while len(queue) > 0:
            keys, v, prefix, is_array, parent = queue.popleft()
            k = keys[-1]
            if issubclass(v, Array) and v.Attributes.max_occurs == 1:
                v, = v._type_info.values()

            key = hier_delim.join(prefix)
            if issubclass(v, ComplexModelBase):
                retval[key] = _SimpleTypeInfoElement(
                    path=keys,
                    parent=parent,
                    type_=v,
                    is_array=tuple(is_array),
                    can_be_empty=True,
                )

                if not (v in tags):
                    tags.add(v)
                    if prot is None:
                        for k2, v2 in v.get_flat_type_info(v).items():
                            sub_name = k2
                            queue.append((
                                keys + (k2,),
                                v2,
                                prefix + (sub_name,),
                                is_array + (_is_array(v),),
                                v
                            ))

                    else:
                        for k2, v2 in v.get_flat_type_info(v).items():
                            cls_attrs = prot.get_cls_attrs(v2)
                            sub_name = cls_attrs.sub_name
                            if sub_name is None:
                                sub_name = k2

                            queue.append((
                                keys + (k2,),
                                v2,
                                prefix + (sub_name,),
                                is_array + (_is_array(v),),
                                v,
                            ))

            else:
                value = retval.get(key, None)

                if value is not None:
                    raise ValueError("%r.%s conflicts with %r" %
                                                       (cls, k, value.path))

                retval[key] = _SimpleTypeInfoElement(
                    path=keys,
                    parent=parent,
                    type_=v,
                    is_array=tuple(is_array),
                    can_be_empty=False,
                )

        return retval

    @staticmethod
    def resolve_namespace(cls, default_ns, tags=None):
        if tags is None:
            tags = set()
        elif cls in tags:
            return False

        if not ModelBase.resolve_namespace(cls, default_ns, tags):
            return False

        for k, v in cls._type_info.items():
            if v is None:
                continue

            if v.__type_name__ is ModelBase.Empty:
                v._fill_empty_type_name(cls.get_namespace(),
                                                         cls.get_type_name(), k)

            v.resolve_namespace(v, default_ns, tags)

        if cls._force_own_namespace is not None:
            for c in cls._force_own_namespace:
                c.__namespace__ = cls.get_namespace()
                ComplexModel.resolve_namespace(c, cls.get_namespace(), tags)

        assert not (cls.__namespace__ is ModelBase.Empty)
        assert not (cls.__type_name__ is ModelBase.Empty)

        return True

    @staticmethod
    def produce(namespace, type_name, members):
        """Lets you create a class programmatically."""

        return ComplexModelMeta(type_name, (ComplexModel,), odict({
            '__namespace__': namespace,
            '__type_name__': type_name,
            '_type_info': TypeInfo(members),
        }))

    @classmethod
    def customize(cls, **kwargs):
        """Duplicates cls and overwrites the values in ``cls.Attributes`` with
        ``**kwargs`` and returns the new class.

        Because each class is registered as a variant of the original (__orig__)
        class, using this function to generate classes dynamically on-the-fly
        could cause memory leaks. You have been warned.
        """

        store_as = apply_pssm(kwargs.get('store_as', None))
        if store_as is not None:
            kwargs['store_as'] = store_as

        cls_name, cls_bases, cls_dict = cls._s_customize(**kwargs)
        cls_dict['__module__'] = cls.__module__
        if '__extends__' not in cls_dict:
            cls_dict['__extends__'] = cls.__extends__

        retval = type(cls_name, cls_bases, cls_dict)
        retval._type_info = TypeInfo(cls._type_info)
        retval.__type_name__ = cls.__type_name__
        retval.__namespace__ = cls.__namespace__
        retval.Attributes.parent_variant = cls

        dca = retval.Attributes._delayed_child_attrs
        if retval.Attributes._delayed_child_attrs is None:
            retval.Attributes._delayed_child_attrs = {}
        else:
            retval.Attributes._delayed_child_attrs = dict(dca.items())

        tn = kwargs.get("type_name", None)
        if tn is not None:
            retval.__type_name__ = tn

        ns = kwargs.get("namespace", None)
        if ns is not None:
            retval.__namespace__ = ns

        if cls is not ComplexModel:
            cls._process_variants(retval)

        _process_child_attrs(cls, retval, kwargs)

        # we could be smarter, but customize is supposed to be called only
        # during daemon initialization, so it's not really necessary.
        ComplexModelBase.get_subclasses.memo.clear()
        ComplexModelBase.get_flat_type_info.memo.clear()
        ComplexModelBase.get_simple_type_info_with_prot.memo.clear()

        return retval

    @classmethod
    def _process_variants(cls, retval):
        orig = getattr(retval, '__orig__', None)
        if orig is not None:
            if orig.Attributes._variants is None:
                orig.Attributes._variants = WeakKeyDictionary()
            orig.Attributes._variants[retval] = True
            # _variants is only for the root class.
            retval.Attributes._variants = None

    @classmethod
    def _append_field_impl(cls, field_name, field_type):
        assert isinstance(field_name, string_types)

        dcaa = cls.Attributes._delayed_child_attrs_all
        if dcaa is not None:
            field_type = field_type.customize(**dcaa)

        dca = cls.Attributes._delayed_child_attrs
        if dca is not None:
            d_cust = dca.get(field_name, None)
            if d_cust is not None:
                field_type = field_type.customize(**d_cust)

        cls._type_info[field_name] = field_type

        ComplexModelBase.get_flat_type_info.memo.clear()
        ComplexModelBase.get_simple_type_info_with_prot.memo.clear()

    @classmethod
    def _append_to_variants(cls, field_name, field_type):
        if cls.Attributes._variants is not None:
            for c in cls.Attributes._variants:
                c.append_field(field_name, field_type)

    @classmethod
    def append_field(cls, field_name, field_type):
        cls._append_field_impl(field_name, field_type)
        cls._append_to_variants(field_name, field_type)

    @classmethod
    def _insert_to_variants(cls, index, field_name, field_type):
        if cls.Attributes._variants is not None:
            for c in cls.Attributes._variants:
                c.insert_field(index, field_name, field_type)

    @classmethod
    def _insert_field_impl(cls, index, field_name, field_type):
        assert isinstance(index, int)
        assert isinstance(field_name, string_types)

        dcaa = cls.Attributes._delayed_child_attrs_all
        if dcaa is not None:
            field_type = field_type.customize(**dcaa)

        dca = cls.Attributes._delayed_child_attrs
        if dca is not None:
            if field_name in dca:
                d_cust = dca.pop(field_name)
                field_type = field_type.customize(**d_cust)

        cls._type_info.insert(index, (field_name, field_type))

        ComplexModelBase.get_flat_type_info.memo.clear()
        ComplexModelBase.get_simple_type_info_with_prot.memo.clear()

    @classmethod
    def insert_field(cls, index, field_name, field_type):
        cls._insert_field_impl(index, field_name, field_type)
        cls._insert_to_variants(index, field_name, field_type)

    @classmethod
    def _replace_in_variants(cls, field_name, field_type):
        if cls.Attributes._variants is not None:
            for c in cls.Attributes._variants:
                c._replace_field(field_name, field_type)

    @classmethod
    def _replace_field_impl(cls, field_name, field_type):
        assert isinstance(field_name, string_types)

        cls._type_info[field_name] = field_type

        ComplexModelBase.get_flat_type_info.memo.clear()
        ComplexModelBase.get_simple_type_info_with_prot.memo.clear()

    @classmethod
    def _replace_field(cls, field_name, field_type):
        cls._replace_field_impl(field_name, field_type)
        cls._replace_in_variants(field_name, field_type)

    @classmethod
    def store_as(cls, what):
        return cls.customize(store_as=what)

    @classmethod
    def novalidate_freq(cls):
        return cls.customize(validate_freq=False)

    @classmethod
    def init_from(cls, other, **kwargs):
        retval = (cls if cls.__orig__ is None else cls.__orig__)()

        for k, v in cls.get_flat_type_info(cls).items():
            try:
                if k in kwargs:
                    retval._safe_set(k, kwargs[k], v, v.Attributes)

                elif hasattr(other, k):
                    retval._safe_set(k, getattr(other, k), v, v.Attributes)

            except AttributeError as e:
                logger.warning("Error setting %s: %r", k, e)

        return retval

    @classmethod
    def __respawn__(cls, ctx=None, filters=None):
        if ctx is not None and ctx.in_object is not None and \
                                                         len(ctx.in_object) > 0:
            retval = next(iter(ctx.in_object))
            if retval is not None:
                return retval

        if ctx.descriptor.default_on_null:
            return cls.get_deserialization_instance(ctx)


@add_metaclass(ComplexModelMeta)
class ComplexModel(ComplexModelBase):
    """The general complexType factory. The __call__ method of this class will
    return instances, contrary to primivites where the same call will result in
    customized duplicates of the original class definition.
    Those who'd like to customize the class should use the customize method.
    (see :class:``spyne.model.ModelBase``).
    """


@add_metaclass(ComplexModelMeta)
class Array(ComplexModelBase):
    """This class generates a ComplexModel child that has one attribute that has
    the same name as the serialized class. It's contained in a Python list.
    """

    class Attributes(ComplexModelBase.Attributes):
        _wrapper = True

    def __new__(cls, serializer, member_name=None, wrapped=True, **kwargs):
        if not wrapped:
            if serializer.Attributes.max_occurs == 1:
                kwargs['max_occurs'] = 'unbounded'

            return serializer.customize(**kwargs)

        retval = cls.customize(**kwargs)

        _serializer = _get_spyne_type(cls.__name__, '__serializer__', serializer)
        if _serializer is None:
            raise ValueError("serializer=%r is not a valid spyne type" % serializer)

        if issubclass(_serializer, SelfReference):
             # hack to make sure the array passes ComplexModel sanity checks
             # that are there to prevent empty arrays.
            retval._type_info = {'_bogus': _serializer}
        else:
            retval._set_serializer(_serializer, member_name)

        tn = kwargs.get("type_name", None)
        if tn is not None:
            retval.__type_name__ = tn

        return retval

    @classmethod
    def _fill_empty_type_name(cls, parent_ns, parent_tn, k):
        cls.__namespace__ = parent_ns
        tn = "%s_%s%s" % (parent_tn, k, const.TYPE_SUFFIX)

        child_v, = cls._type_info.values()
        child_v.__type_name__ = tn

        cls._type_info = TypeInfo({tn: child_v})
        cls.__type_name__ = '%s%s%s' % (const.ARRAY_PREFIX, tn,
                                                             const.ARRAY_SUFFIX)

        extends = child_v.__extends__
        while extends is not None and extends.get_type_name() is cls.Empty:
            extends._fill_empty_type_name(parent_ns, parent_tn,
                                                    k + const.PARENT_SUFFIX)
            extends = extends.__extends__

    @classmethod
    def customize(cls, **kwargs):
        serializer_attrs = kwargs.get('serializer_attrs', None)
        if serializer_attrs is None:
            return super(Array, cls).customize(**kwargs)

        del kwargs['serializer_attrs']

        logger.debug('Pass serializer attrs %r', serializer_attrs)

        serializer, = cls._type_info.values()
        return cls(serializer.customize(**serializer_attrs)).customize(**kwargs)

    @classmethod
    def _set_serializer(cls, serializer, member_name=None):
        if serializer.get_type_name() is ModelBase.Empty:  # A customized class
            member_name = "OhNoes"
            # mark array type name as "to be resolved later".
            cls.__type_name__ = ModelBase.Empty

        else:
            if member_name is None:
                member_name = serializer.get_type_name()

            cls.__type_name__ = '%s%s%s' % (const.ARRAY_PREFIX,
                                                serializer.get_type_name(),
                                                             const.ARRAY_SUFFIX)

        # hack to default to unbounded arrays when the user didn't specify
        # max_occurs.
        if serializer.Attributes.max_occurs == 1:
            serializer = serializer.customize(max_occurs=decimal.Decimal('inf'))

        assert isinstance(member_name, string_types), member_name
        cls._type_info = TypeInfo({member_name: serializer})

    # the array belongs to its child's namespace, it doesn't have its own
    # namespace.
    @staticmethod
    def resolve_namespace(cls, default_ns, tags=None):
        (serializer,) = cls._type_info.values()

        serializer.resolve_namespace(serializer, default_ns, tags)

        if cls.__namespace__ is None:
            cls.__namespace__ = serializer.get_namespace()

        if cls.__namespace__ in PREFMAP:
            cls.__namespace__ = default_ns

        return ComplexModel.resolve_namespace(cls, default_ns, tags)

    @classmethod
    def get_serialization_instance(cls, value):
        inst = ComplexModel.__new__(Array)

        (member_name,) = cls._type_info.keys()
        setattr(inst, member_name, value)

        return inst

    @classmethod
    def get_deserialization_instance(cls, ctx):
        return []

    @classmethod
    def get_inner_type(cls):
        return next(iter(cls._type_info.values()))


class Iterable(Array):
    """This class generates a ``ComplexModel`` child that has one attribute that
    has the same name as the serialized class. It's contained in a Python
    iterable. The distinction with the ``Array`` is made in the protocol
    implementation, this is just a marker.

    Whenever you return a generator instead of a list, you should use this type
    as this suggests the intermediate machinery to NEVER actually try to iterate
    over the value. An ``Array`` could be iterated over for e.g. logging
    purposes.
    """

    class Attributes(Array.Attributes):
        logged = False

    class Push(PushBase):
        """The push interface to the `Iterable`.

        Anything append()'ed to a `Push` instance is serialized and written to
        outgoing stream immediately.

        When using Twisted, Push callbacks are called from the reactor thread if
        the instantiation is done in a reactor thread. Otherwise, callbacks are
        called by `deferToThread`. Make sure to avoid relying on thread-local
        stuff as `deferToThread` is not guaranteed to restore original thread
        context.
        """
        pass


def TTableModelBase():
    from spyne.store.relational import add_column

    class TableModelBase(ComplexModelBase):
        @classmethod
        def append_field(cls, field_name, field_type):
            cls._append_field_impl(field_name, field_type)
            # There could have been changes to field_type in ComplexModel so we
            # should not use field_type directly from above
            if cls.__table__ is not None:
                add_column(cls, field_name, cls._type_info[field_name])
            cls._append_to_variants(field_name, field_type)

        @classmethod
        def replace_field(cls, field_name, field_type):
            raise NotImplementedError()

        @classmethod
        def insert_field(cls, index, field_name, field_type):
            cls._insert_field_impl(index, field_name, field_type)
            # There could have been changes to field_type in ComplexModel so we
            # should not use field_type directly from above
            if cls.__table__ is not None:
                add_column(cls, field_name, cls._type_info[field_name])
            cls._insert_to_variants(index, field_name, field_type)

    return TableModelBase


# this has docstring repeated in the documentation at reference/model/complex.rst
def TTableModel(metadata=None, base=None, metaclass=None):
    """A TableModel template that generates a new TableModel class for each
    call. If metadata is not supplied, a new one is instantiated.
    """

    from sqlalchemy import MetaData

    if base is None:
        base = TTableModelBase()
    if metaclass is None:
        metaclass = ComplexModelMeta

    @add_metaclass(metaclass)
    class TableModel(base):
        class Attributes(ComplexModelBase.Attributes):
            sqla_metadata = metadata if metadata is not None else MetaData()

    return TableModel


def Mandatory(cls, **_kwargs):
    """Customizes the given type to be a mandatory one. Has special cases for
    :class:`spyne.model.primitive.Unicode` and
    :class:`spyne.model.complex.Array`\\.
    """

    kwargs = dict(min_occurs=1, nillable=False)
    if cls.get_type_name() is not cls.Empty:
        kwargs['type_name'] = '%s%s%s' % (const.MANDATORY_PREFIX,
                                    cls.get_type_name(), const.MANDATORY_SUFFIX)
    kwargs.update(_kwargs)
    if issubclass(cls, Unicode):
        kwargs.update(dict(min_len=1))

    elif issubclass(cls, Array):
        (k,v), = cls._type_info.items()
        if v.Attributes.min_occurs == 0:
            cls._type_info[k] = Mandatory(v)

    return cls.customize(**kwargs)
