text: # -*- coding: utf-8 -*-
  # Copyright: See the LICENSE file.
  
  from __future__ import unicode_literals
  
  import itertools
  import logging
  
  from . import enums
  from . import compat
  from . import errors
  from . import utils
  
  
  logger = logging.getLogger('factory.generate')
  
  
  class BaseDeclaration(utils.OrderedBase):
      """A factory declaration.
  
      Declarations mark an attribute as needing lazy evaluation.
      This allows them to refer to attributes defined by other BaseDeclarations
      in the same factory.
      """
  
      def evaluate(self, instance, step, extra):
          """Evaluate this declaration.
  
          Args:
              instance (builder.Resolver): The object holding currently computed
                  attributes
              step: a factory.builder.BuildStep
              extra (dict): additional, call-time added kwargs
                  for the step.
          """
          raise NotImplementedError('This is an abstract method')
  
  
  class OrderedDeclaration(BaseDeclaration):
      """Compatibility"""
  
      # FIXME(rbarrois)
  
  
  class LazyFunction(BaseDeclaration):
      """Simplest BaseDeclaration computed by calling the given function.
  
      Attributes:
          function (function): a function without arguments and
              returning the computed value.
      """
  
      def __init__(self, function, *args, **kwargs):
          super(LazyFunction, self).__init__(*args, **kwargs)
          self.function = function
  
      def evaluate(self, instance, step, extra):
          logger.debug("LazyFunction: Evaluating %s on %s", utils.log_repr(self.function), utils.log_repr(step))
          return self.function()
  
  
  class LazyAttribute(BaseDeclaration):
      """Specific BaseDeclaration computed using a lambda.
  
      Attributes:
          function (function): a function, expecting the current LazyStub and
              returning the computed value.
      """
  
      def __init__(self, function, *args, **kwargs):
          super(LazyAttribute, self).__init__(*args, **kwargs)
          self.function = function
  
      def evaluate(self, instance, step, extra):
          logger.debug("LazyAttribute: Evaluating %s on %s", utils.log_repr(self.function), utils.log_repr(instance))
          return self.function(instance)
  
  
  class _UNSPECIFIED(object):
      pass
  
  
  def deepgetattr(obj, name, default=_UNSPECIFIED):
      """Try to retrieve the given attribute of an object, digging on '.'.
  
      This is an extended getattr, digging deeper if '.' is found.
  
      Args:
          obj (object): the object of which an attribute should be read
          name (str): the name of an attribute to look up.
          default (object): the default value to use if the attribute wasn't found
  
      Returns:
          the attribute pointed to by 'name', splitting on '.'.
  
      Raises:
          AttributeError: if obj has no 'name' attribute.
      """
      try:
          if '.' in name:
              attr, subname = name.split('.', 1)
              return deepgetattr(getattr(obj, attr), subname, default)
          else:
              return getattr(obj, name)
      except AttributeError:
          if default is _UNSPECIFIED:
              raise
          else:
              return default
  
  
  class SelfAttribute(BaseDeclaration):
      """Specific BaseDeclaration copying values from other fields.
  
      If the field name starts with two dots or more, the lookup will be anchored
      in the related 'parent'.
  
      Attributes:
          depth (int): the number of steps to go up in the containers chain
          attribute_name (str): the name of the attribute to copy.
          default (object): the default value to use if the attribute doesn't
              exist.
      """
  
      def __init__(self, attribute_name, default=_UNSPECIFIED, *args, **kwargs):
          super(SelfAttribute, self).__init__(*args, **kwargs)
          depth = len(attribute_name) - len(attribute_name.lstrip('.'))
          attribute_name = attribute_name[depth:]
  
          self.depth = depth
          self.attribute_name = attribute_name
          self.default = default
  
      def evaluate(self, instance, step, extra):
          if self.depth > 1:
              # Fetching from a parent
              target = step.chain[self.depth - 1]
          else:
              target = instance
  
          logger.debug("SelfAttribute: Picking attribute %r on %s", self.attribute_name, utils.log_repr(target))
          return deepgetattr(target, self.attribute_name, self.default)
  
      def __repr__(self):
          return '<%s(%r, default=%r)>' % (
              self.__class__.__name__,
              self.attribute_name,
              self.default,
          )
  
  
  class Iterator(BaseDeclaration):
      """Fill this value using the values returned by an iterator.
  
      Warning: the iterator should not end !
  
      Attributes:
          iterator (iterable): the iterator whose value should be used.
          getter (callable or None): a function to parse returned values
      """
  
      def __init__(self, iterator, cycle=True, getter=None):
          super(Iterator, self).__init__()
          self.getter = getter
          self.iterator = None
  
          if cycle:
              self.iterator_builder = lambda: utils.ResetableIterator(itertools.cycle(iterator))
          else:
              self.iterator_builder = lambda: utils.ResetableIterator(iterator)
  
      def evaluate(self, instance, step, extra):
          # Begin unrolling as late as possible.
          # This helps with ResetableIterator(MyModel.objects.all())
          if self.iterator is None:
              self.iterator = self.iterator_builder()
  
          logger.debug("Iterator: Fetching next value from %s", utils.log_repr(self.iterator))
          value = next(iter(self.iterator))
          if self.getter is None:
              return value
          return self.getter(value)
  
      def reset(self):
          """Reset the internal iterator."""
          self.iterator.reset()
  
  
  class Sequence(BaseDeclaration):
      """Specific BaseDeclaration to use for 'sequenced' fields.
  
      These fields are typically used to generate increasing unique values.
  
      Attributes:
          function (function): A function, expecting the current sequence counter
              and returning the computed value.
          type (function): A function converting an integer into the expected kind
              of counter for the 'function' attribute.
      """
      def __init__(self, function, type=int):
          super(Sequence, self).__init__()
          self.function = function
          self.type = type
  
      def evaluate(self, instance, step, extra):
          logger.debug("Sequence: Computing next value of %r for seq=%s", self.function, step.sequence)
          return self.function(self.type(step.sequence))
  
  
  class LazyAttributeSequence(Sequence):
      """Composite of a LazyAttribute and a Sequence.
  
      Attributes:
          function (function): A function, expecting the current LazyStub and the
              current sequence counter.
          type (function): A function converting an integer into the expected kind
              of counter for the 'function' attribute.
      """
      def evaluate(self, instance, step, extra):
          logger.debug(
              "LazyAttributeSequence: Computing next value of %r for seq=%s, obj=%s",
              self.function, step.sequence, utils.log_repr(instance))
          return self.function(instance, self.type(step.sequence))
  
  
  class ContainerAttribute(BaseDeclaration):
      """Variant of LazyAttribute, also receives the containers of the object.
  
      Attributes:
          function (function): A function, expecting the current LazyStub and the
              (optional) object having a subfactory containing this attribute.
          strict (bool): Whether evaluating should fail when the containers are
              not passed in (i.e used outside a SubFactory).
      """
      def __init__(self, function, strict=True, *args, **kwargs):
          super(ContainerAttribute, self).__init__(*args, **kwargs)
          self.function = function
          self.strict = strict
  
      def evaluate(self, instance, step, extra):
          """Evaluate the current ContainerAttribute.
  
          Args:
              obj (LazyStub): a lazy stub of the object being constructed, if
                  needed.
              containers (list of LazyStub): a list of lazy stubs of factories
                  being evaluated in a chain, each item being a future field of
                  next one.
          """
          # Strip the current instance from the chain
          chain = step.chain[1:]
          if self.strict and not chain:
              raise TypeError(
                  "A ContainerAttribute in 'strict' mode can only be used "
                  "within a SubFactory.")
  
          return self.function(instance, chain)
  
  
  class ParameteredAttribute(BaseDeclaration):
      """Base class for attributes expecting parameters.
  
      Attributes:
          defaults (dict): Default values for the parameters.
              May be overridden by call-time parameters.
  
      Class attributes:
          CONTAINERS_FIELD (str): name of the field, if any, where container
              information (e.g for SubFactory) should be stored. If empty,
              containers data isn't merged into generate() parameters.
      """
  
      CONTAINERS_FIELD = '__containers'
  
      # Whether to add the current object to the stack of containers
      EXTEND_CONTAINERS = False
  
      def __init__(self, **kwargs):
          super(ParameteredAttribute, self).__init__()
          self.defaults = kwargs
  
      def _prepare_containers(self, obj, containers=()):
          if self.EXTEND_CONTAINERS:
              return (obj,) + tuple(containers)
  
          return containers
  
      def evaluate(self, instance, step, extra):
          """Evaluate the current definition and fill its attributes.
  
          Uses attributes definition in the following order:
          - values defined when defining the ParameteredAttribute
          - additional values defined when instantiating the containing factory
  
          Args:
              instance (builder.Resolver): The object holding currently computed
                  attributes
              step: a factory.builder.BuildStep
              extra (dict): additional, call-time added kwargs
                  for the step.
          """
          defaults = dict(self.defaults)
          if extra:
              defaults.update(extra)
  
          return self.generate(step, defaults)
  
      def generate(self, step, params):
          """Actually generate the related attribute.
  
          Args:
              sequence (int): the current sequence number
              obj (LazyStub): the object being constructed
              create (bool): whether the calling factory was in 'create' or
                  'build' mode
              params (dict): parameters inherited from init and evaluation-time
                  overrides.
  
          Returns:
              Computed value for the current declaration.
          """
          raise NotImplementedError()
  
  
  class _FactoryWrapper(object):
      """Handle a 'factory' arg.
  
      Such args can be either a Factory subclass, or a fully qualified import
      path for that subclass (e.g 'myapp.factories.MyFactory').
      """
      def __init__(self, factory_or_path):
          self.factory = None
          self.module = self.name = ''
          if isinstance(factory_or_path, type):
              self.factory = factory_or_path
          else:
              if not (compat.is_string(factory_or_path) and '.' in factory_or_path):
                  raise ValueError(
                      "A factory= argument must receive either a class "
                      "or the fully qualified path to a Factory subclass; got "
                      "%r instead." % factory_or_path)
              self.module, self.name = factory_or_path.rsplit('.', 1)
  
      def get(self):
          if self.factory is None:
              self.factory = utils.import_object(
                  self.module,
                  self.name,
              )
          return self.factory
  
      def __repr__(self):
          if self.factory is None:
              return '<_FactoryImport: %s.%s>' % (self.module, self.name)
          else:
              return '<_FactoryImport: %s>' % self.factory.__class__
  
  
  class SubFactory(ParameteredAttribute):
      """Base class for attributes based upon a sub-factory.
  
      Attributes:
          defaults (dict): Overrides to the defaults defined in the wrapped
              factory
          factory (base.Factory): the wrapped factory
      """
  
      EXTEND_CONTAINERS = True
      FORCE_SEQUENCE = False
  
      def __init__(self, factory, **kwargs):
          super(SubFactory, self).__init__(**kwargs)
          self.factory_wrapper = _FactoryWrapper(factory)
  
      def get_factory(self):
          """Retrieve the wrapped factory.Factory subclass."""
          return self.factory_wrapper.get()
  
      def generate(self, step, params):
          """Evaluate the current definition and fill its attributes.
  
          Args:
              step: a factory.builder.BuildStep
              params (dict): additional, call-time added kwargs
                  for the step.
          """
          subfactory = self.get_factory()
          logger.debug(
              "SubFactory: Instantiating %s.%s(%s), create=%r",
              subfactory.__module__, subfactory.__name__,
              utils.log_pprint(kwargs=params),
              step,
          )
          force_sequence = step.sequence if self.FORCE_SEQUENCE else None
          return step.recurse(subfactory, params, force_sequence=force_sequence)
  
  
  class Dict(SubFactory):
      """Fill a dict with usual declarations."""
  
      FORCE_SEQUENCE = True
  
      def __init__(self, params, dict_factory='factory.DictFactory'):
          super(Dict, self).__init__(dict_factory, **dict(params))
  
  
  class List(SubFactory):
      """Fill a list with standard declarations."""
  
      FORCE_SEQUENCE = True
  
      def __init__(self, params, list_factory='factory.ListFactory'):
          params = dict((str(i), v) for i, v in enumerate(params))
          super(List, self).__init__(list_factory, **params)
  
  
  # Parameters
  # ==========
  
  
  class Skip(object):
      def __bool__(self):
          return False
  
      # Py2 compatibility
      __nonzero__ = __bool__
  
  
  SKIP = Skip()
  
  
  class Maybe(BaseDeclaration):
      def __init__(self, decider, yes_declaration=SKIP, no_declaration=SKIP):
          self.decider = decider
          self.yes = yes_declaration
          self.no = no_declaration
  
      def evaluate(self, instance, step, extra):
          if isinstance(self.decider, BaseDeclaration):
              choice = self.decider.evaluate(instance=instance, step=step, extra={})
          else:
              choice = getattr(instance, self.decider, None)
          target = self.yes if choice else self.no
  
          if isinstance(target, BaseDeclaration):
              return target.evaluate(
                  instance=instance,
                  step=step,
                  extra=extra,
              )
          else:
              # Flat value
              return target
  
      def __repr__(self):
          return 'Maybe(%r, yes=%r, no=%r)' % (self.decider, self.yes, self.no)
  
  
  class Parameter(utils.OrderedBase):
      """A complex parameter, to be used in a Factory.Params section.
  
      Must implement:
      - A "compute" function, performing the actual declaration override
      - Optionally, a get_revdeps() function (to compute other parameters it may alter)
      """
  
      def as_declarations(self, field_name, declarations):
          """Compute the overrides for this parameter.
  
          Args:
          - field_name (str): the field this parameter is installed at
          - declarations (dict): the global factory declarations
  
          Returns:
              dict: the declarations to override
          """
          raise NotImplementedError()
  
      def get_revdeps(self, parameters):
          """Retrieve the list of other parameters modified by this one."""
          return []
  
  
  class SimpleParameter(Parameter):
      def __init__(self, value):
          self.value = value
  
      def as_declarations(self, field_name, declarations):
          return {
              field_name: self.value,
          }
  
      @classmethod
      def wrap(cls, value):
          if not isinstance(value, Parameter):
              return cls(value)
          return value
  
  
  class Trait(Parameter):
      """The simplest complex parameter, it enables a bunch of new declarations based on a boolean flag."""
      def __init__(self, **overrides):
          super(Trait, self).__init__()
          self.overrides = overrides
  
      def as_declarations(self, field_name, declarations):
          overrides = {}
          for maybe_field, new_value in self.overrides.items():
              overrides[maybe_field] = Maybe(
                  decider=SelfAttribute(
                      '%s.%s' % (
                          '.' * maybe_field.count(enums.SPLITTER),
                          field_name,
                      ),
                      default=False,
                  ),
                  yes_declaration=new_value,
                  no_declaration=declarations.get(maybe_field, SKIP),
              )
          return overrides
  
      def get_revdeps(self, parameters):
          """This might alter fields it's injecting."""
          return [param for param in parameters if param in self.overrides]
  
      def __repr__(self):
          return '%s(%s)' % (
              self.__class__.__name__,
              ', '.join('%s=%r' % t for t in self.overrides.items())
          )
  
  
  # Post-generation
  # ===============
  
  
  class PostGenerationDeclaration(utils.OrderedBase):
      """Declarations to be called once the model object has been generated."""
  
      def call(self, instance, step, context):  # pragma: no cover
          """Call this hook; no return value is expected.
  
          Args:
              obj (object): the newly generated object
              create (bool): whether the object was 'built' or 'created'
              context: a builder.PostGenerationContext containing values
                  extracted from the containing factory's declaration
          """
          raise NotImplementedError()
  
  
  class PostGeneration(PostGenerationDeclaration):
      """Calls a given function once the object has been generated."""
      def __init__(self, function):
          super(PostGeneration, self).__init__()
          self.function = function
  
      def call(self, instance, step, context):
          logger.debug(
              "PostGeneration: Calling %s.%s(%s)",
              self.function.__module__,
              self.function.__name__,
              utils.log_pprint(
                  (instance, step),
                  context._asdict(),
              ),
          )
          create = step.builder.strategy == enums.CREATE_STRATEGY
          return self.function(
              instance, create, context.value, **context.extra)
  
  
  class RelatedFactory(PostGenerationDeclaration):
      """Calls a factory once the object has been generated.
  
      Attributes:
          factory (Factory): the factory to call
          defaults (dict): extra declarations for calling the related factory
          name (str): the name to use to refer to the generated object when
              calling the related factory
      """
  
      def __init__(self, factory, factory_related_name='', **defaults):
          super(RelatedFactory, self).__init__()
  
          self.name = factory_related_name
          self.defaults = defaults
          self.factory_wrapper = _FactoryWrapper(factory)
  
      def get_factory(self):
          """Retrieve the wrapped factory.Factory subclass."""
          return self.factory_wrapper.get()
  
      def call(self, instance, step, context):
          factory = self.get_factory()
  
          if context.value_provided:
              # The user passed in a custom value
              logger.debug(
                  "RelatedFactory: Using provided %s instead of generating %s.%s.",
                  utils.log_repr(context.value),
                  factory.__module__, factory.__name__,
              )
              return context.value
  
          passed_kwargs = dict(self.defaults)
          passed_kwargs.update(context.extra)
          if self.name:
              passed_kwargs[self.name] = instance
  
          logger.debug(
              "RelatedFactory: Generating %s.%s(%s)",
              factory.__module__,
              factory.__name__,
              utils.log_pprint((step,), passed_kwargs),
          )
          return step.recurse(factory, passed_kwargs)
  
  
  class NotProvided:
      pass
  
  
  class PostGenerationMethodCall(PostGenerationDeclaration):
      """Calls a method of the generated object.
  
      Attributes:
          method_name (str): the method to call
          method_args (list): arguments to pass to the method
          method_kwargs (dict): keyword arguments to pass to the method
  
      Example:
          class UserFactory(factory.Factory):
              ...
              password = factory.PostGenerationMethodCall('set_pass', password='')
      """
      def __init__(self, method_name, *args, **kwargs):
          super(PostGenerationMethodCall, self).__init__()
          if len(args) > 1:
              raise errors.InvalidDeclarationError(
                  "A PostGenerationMethodCall can only handle 1 positional argument; "
                  "please provide other parameters through keyword arguments."
              )
          self.method_name = method_name
          self.method_arg = args[0] if args else NotProvided
          self.method_kwargs = kwargs
  
      def call(self, instance, step, context):
          if not context.value_provided:
              if self.method_arg is NotProvided:
                  args = tuple()
              else:
                  args = tuple([self.method_arg])
          else:
              args = tuple([context.value])
  
          kwargs = dict(self.method_kwargs)
          kwargs.update(context.extra)
          method = getattr(instance, self.method_name)
          logger.debug(
              "PostGenerationMethodCall: Calling %s.%s(%s)",
              utils.log_repr(instance),
              self.method_name,
              utils.log_pprint(args, kwargs),
          )
          return method(*args, **kwargs)
  