# -*- coding: utf-8 -*-

from lodel.context import LodelContext
LodelContext.expose_modules(globals(), {
    'lodel.leapi.datahandlers.base_classes': ['Reference', 'MultipleRef',
        'SingleRef'],
    'lodel.logger': 'logger',
    'lodel.exceptions': ['LodelException', 'LodelExceptions',
        'LodelFatalError', 'DataNoneValid', 'FieldValidationError']})

class Link(SingleRef):
    pass


##@brief Child class of MultipleRef where references are represented in the form of a python list
class List(MultipleRef):

    ##@brief instanciates a list reference
    # @param max_length int
    # @param kwargs
    #   - allowed_classes list | None : list of allowed em classes if None no restriction
    #   - internal bool

    def __init__(self, max_length = None, **kwargs):
        super().__init__(**kwargs)

    @classmethod
    def empty(cls):
        return list()

    ##@brief Check and cast value in appropriate type
    #@param value *
    #@throw FieldValidationError if value is unappropriate or can not be cast 
    #@return value
    def _check_data_value(self, value):
        value = super()._check_data_value(value)
        try:
            return list(value)
        except Exception as e:
            raise FieldValidationError("Given iterable is not castable in \
a list : %s" % e)
        return value

##@brief Child class of MultipleRef where references are represented in the form of a python set
class Set(MultipleRef):

    ##@brief instanciates a set reference
    # @param kwargs : named arguments
    #   - allowed_classes list | None : list of allowed em classes if None no restriction
    #   - internal bool : if False, the field is not internal
    def __init__(self, **kwargs):
        super().__init__(**kwargs)

    @classmethod
    def empty(cls):
        return set()

    ##@brief Check and cast value in appropriate type
    #@param value *
    #@throw FieldValidationError if value is unappropriate or can not be cast 
    #@return value
    def _check_data_value(self, value):
        value = super()._check_data_value(value)
        try:
            return set(value)
        except Exception as e:
            raise FieldValidationError("Given iterable is not castable in \
a set : %s" % e)
    
##@brief Child class of MultipleRef where references are represented in the form of a python dict
class Map(MultipleRef):

    ##@brief instanciates a dict reference
    # @param kwargs : named arguments
    #   - allowed_classes list | None : list of allowed em classes if None no restriction
    #   - internal bool : if False, the field is not internal
    def __init__(self, **kwargs):
        super().__init__(**kwargs)

    @classmethod
    def empty(cls):
        return dict()

    ##@brief Check and cast value in appropriate type
    #@param value *
    #@throw FieldValidationError if value is unappropriate or can not be cast 
    #@return value
    def _check_data_value(self, value):
        value = super()._check_data_value(value)
        if not isinstance(value, dict):
            raise FieldValidationError("Values for dict fields should be dict")
        return value

##@brief This Reference class is designed to handler hierarchy with some constraint
class Hierarch(MultipleRef):
    
    directly_editable = False
    ##@brief Instanciate a data handler handling hierarchical relation with constraints
    # @param back_reference tuple : Here it is mandatory to have a back ref (like a parent field)
    # @param max_depth int | None :  limit of depth
    # @param max_childs int | Nine : maximum number of childs by nodes
    def __init__(self, back_reference, max_depth = None, max_childs = None, **kwargs):
        super().__init__(   back_reference = back_reference,
                            max_depth = max_depth,
                            max_childs = max_childs,
                            **kwargs)

    @classmethod
    def empty(cls):
        return tuple()

    ##@brief Check and cast value in appropriate type
    #@param value *
    #@throw FieldValidationError if value is unappropriate or can not be cast 
    #@return value
    def _check_data_value(self, value):
        value = super()._check_data_value(value)
        if  not (isinstance(value, list) or isinstance(value, str)):
            raise FieldValidationError(
                "List or string expected for a set field")
        return value