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

import importlib

import EditorialModel
from EditorialModel.model import Model
from EditorialModel.fieldtypes.generic import GenericFieldType

## @brief This class is designed to generated the leobject API given an EditorialModel.model
# @note Contains only static methods
#
# The name is not good but i've no other ideas for the moment
class LeFactory(object):
    
    output_file = 'dyn.py'

    def __init__(LeFactory):raise NotImplementedError("Not designed (yet?) to be implemented")

    ## @brief Return a LeObject child class given its name
    # @return a python class or False
    @staticmethod
    def leobj_from_name(name):
        mod = importlib.import_module('leobject.'+LeFactory.output_file.split('.')[-1])
        try:
            res = getattr(mod, name)
        except AttributeError:
            return False
        return res

    ## @brief Convert an EmType or EmClass name in a python class name
    # @param name str : The name
    # @return name.title()
    @staticmethod
    def name2classname(name):
        if not isinstance(name, str):
            raise AttributeError("Argument name should be a str and not a %s"%type(name))
        return name.title()

    ## @brief Return a call to a FieldType constructor given an EmField
    # @param emfield EmField : An EmField
    # @return a string representing the python code to instanciate a EmFieldType
    @staticmethod
    def fieldtype_construct_from_field(emfield):    
        return '%s.EmFieldType(**%s)'%(
            GenericFieldType.module_name(emfield.fieldtype),
            repr(emfield._fieldtype_args),
        )

    ## @brief Given a Model and an EmClass instances generate python code for corresponding LeClass
    # @param model Model : A Model instance
    # @param emclass EmClass : An EmClass instance from model
    # @return A string representing the python code for the corresponding LeClass child class
    @staticmethod
    def emclass_pycode(model, emclass):
        cls_fields = dict()
        cls_linked_types = list()
        for field in emclass.fields():
            cls_fields[field.name] = LeFactory.fieldtype_construct_from_field(field)
            fti = field.fieldtype_instance()
            if fti.name == 'rel2type':
                #relationnal field/fieldtype
                cls_linked_types.append(LeFactory.name2classname(model.component(fti.rel_to_type_id).name))
        cls_fieldgroup = dict()
        for fieldgroup in emclass.fieldgroups():
            cls_fieldgroup[fieldgroup.name] = list()
            for field in fieldgroup.fields():
                cls_fieldgroup[fieldgroup.name].append(field.name)
        
        return """
#Initialisation of {name} class attributes
{name}._fieldtypes = {ftypes}
{name}._linked_types = {ltypes}
{name}._fieldgroups = {fgroups}
""".format(
    name = LeFactory.name2classname(emclass.name),
    ftypes = "{"+(','.join([ '\n\t%s:%s'%(repr(f),v) for f,v in cls_fields.items()]))+"\n}",
    ltypes = "{"+(','.join(cls_linked_types))+'}',
    fgroups = repr(cls_fieldgroup)
)

    ## @brief Given a Model and an EmType instances generate python code for corresponding LeType
    # @param model Model : A Model instance
    # @param emtype EmType : An EmType instance from model
    # @return A string representing the python code for the corresponding LeType child class
    @staticmethod
    def emtype_pycode(model, emtype):
        type_fields = list()
        type_superiors = list()
        for field in emtype.fields():
            type_fields.append(field.name)

        for nat, sup_l in emtype.superiors().items():
            type_superiors.append('%s:[%s]'%(
                repr(nat),
                ','.join([ LeFactory.name2classname(sup.name) for sup in sup_l])
            ))

        return """
#Initialisation of {name} class attributes
{name}._fields = {fields}
{name}._superiors = {dsups}
{name}._leclass = {leclass}
""".format(
    name = LeFactory.name2classname(emtype.name),
    fields = repr(type_fields),
    dsups = '{'+(','.join(type_superiors))+'}',
    leclass = LeFactory.name2classname(emtype.em_class.name)
)

    ## @brief Generate python code containing the LeObject API
    # @param backend_cls Backend : A model backend class
    # @param backend_args dict : A dict representing arguments for backend_cls instanciation
    # @param datasource_cls Datasource : A datasource class
    # @param datasource_args dict : A dict representing arguments for datasource_cls instanciation
    # @return A string representing python code
    @staticmethod
    def generate_python(backend_cls, backend_args, datasource_cls, datasource_args):
        model = Model(backend=backend_cls(**backend_args))

        result = ""
        #result += "#-*- coding: utf-8 -*-\n"
        #Putting import directives in result
        result += """

from EditorialModel.model import Model
from leobject.leobject import _LeObject
from leobject.leclass import LeClass
from leobject.letype import LeType
import EditorialModel.fieldtypes
"""

        result += """
import %s
import %s
"""%(backend_cls.__module__, datasource_cls.__module__)

        #Generating the code for LeObject class
        backend_constructor = '%s.%s(**%s)'%(backend_cls.__module__, backend_cls.__name__, repr(backend_args))
        leobj_me_uid = dict()
        for comp in model.components('EmType') + model.components('EmClass'):
            leobj_me_uid[comp.uid] = LeFactory.name2classname(comp.name)

        result += """
## @brief _LeObject concret clas
# @see leobject::leobject::_LeObject
class LeObject(_LeObject):
    _model = Model(backend=%s)
    _datasource = %s(**%s)
    _me_uid = %s

"""%(backend_constructor, datasource_cls.__module__+'.'+datasource_cls.__name__, repr(datasource_args), repr(leobj_me_uid))
        
        emclass_l = model.components(EditorialModel.classes.EmClass)
        emtype_l = model.components(EditorialModel.types.EmType)

        #LeClass child classes definition
        for emclass in emclass_l:
           result += """
## @brief EmClass {name} LeClass child class
# @see leobject::leclass::LeClass
class {name}(LeObject,LeClass):
    _class_id = {uid}
""".format(
    name = LeFactory.name2classname(emclass.name),
    uid = emclass.uid
)
        #LeType child classes definition
        for emtype in emtype_l:
           result += """
## @brief EmType {name} LeType child class
# @see leobject::letype::LeType
class {name}({leclass},LeType):
    _type_id = {uid}
""".format(
    name = LeFactory.name2classname(emtype.name),
    leclass = LeFactory.name2classname(emtype.em_class.name),
    uid = emtype.uid
)
            
        #Set attributes of created LeClass and LeType child classes
        for emclass in emclass_l:
            result += LeFactory.emclass_pycode(model, emclass)
        for emtype in emtype_l:
            result += LeFactory.emtype_pycode(model, emtype)

        #Populating LeObject._me_uid dict for a rapid fetch of LeType and LeClass given an EM uid
        result += """
## @brief Dict for getting LeClass and LeType child classes given an EM uid
LeObject._me_uid = %s
"""%repr({ comp.uid:LeFactory.name2classname(comp.name) for comp in emclass_l + emtype_l })
            
        return result