muMLE/framework/conformance.py

from services.bottom.V0 import Bottom
from services import od
from services.primitives.actioncode_type import ActionCode
from uuid import UUID
from state.base import State
from typing import Dict, Tuple, Set, Any, List
from pprint import pprint

from api.cd import CDAPI
from api.od import ODAPI

import functools


# based on https://stackoverflow.com/a/39381428
# Parses and executes a block of Python code, and returns the eval result of the last statement
import ast
def exec_then_eval(code, _globals, _locals):
    block = ast.parse(code, mode='exec')
    # assumes last node is an expression
    last = ast.Expression(block.body.pop().value)
    exec(compile(block, '<string>', mode='exec'), _globals, _locals)
    return eval(compile(last, '<string>', mode='eval'), _globals, _locals)

def render_conformance_check_result(error_list):
    if len(error_list) == 0:
        return "CONFORM"
    else:
        joined = '\n  '.join(error_list)
        return f"NOT CONFORM, {len(error_list)} errors: \n  {joined}"


class Conformance:
    def __init__(self, state: State, model: UUID, type_model: UUID, constraint_check_subtypes=True):
        self.state = state
        self.bottom = Bottom(state)
        type_model_id = state.read_dict(state.read_root(), "SCD")
        self.scd_model = UUID(state.read_value(type_model_id))
        self.model = model
        self.type_model = type_model
        self.constraint_check_subtypes = constraint_check_subtypes # for a class-level constraint, also check the constraint on the subtypes of that class? In other words, are constraints inherited.
        self.type_mapping: Dict[str, str] = {}
        self.model_names = {
            # map model elements to their names to prevent iterating too much
            self.bottom.read_outgoing_elements(self.model, e)[0]: e
            for e in self.bottom.read_keys(self.model)
        }
        self.type_model_names = {
            # map type model elements to their names to prevent iterating too much
            self.bottom.read_outgoing_elements(self.type_model, e)[0]
                : e for e in self.bottom.read_keys(self.type_model)
        }
        self.sub_types: Dict[str, Set[str]] = {
            k: set() for k in self.bottom.read_keys(self.type_model)
        }
        self.primitive_values: Dict[UUID, Any] = {}
        self.abstract_types: List[str] = []
        self.multiplicities: Dict[str, Tuple] = {}
        self.source_multiplicities: Dict[str, Tuple] = {}
        self.target_multiplicities: Dict[str, Tuple] = {}
        self.structures = {}
        self.matches = {}
        self.candidates = {}

        self.odapi = ODAPI(state, model, type_model)

    def check_nominal(self, *, log=False):
        """
        Perform a nominal conformance check

        Args:
            log: boolean indicating whether to log errors

        Returns:
            Boolean indicating whether the check has passed
        """
        errors = []
        errors += self.check_typing()
        errors += self.check_link_typing()
        errors += self.check_multiplicities()
        errors += self.check_constraints()
        return errors

    # def check_structural(self, *, build_morphisms=True, log=False):
    #     """
    #     Perform a structural conformance check

    #     Args:
    #         build_morphisms: boolean indicating whether to create morpishm links
    #         log: boolean indicating whether to log errors

    #     Returns:
    #         Boolean indicating whether the check has passed
    #     """
    #     try:
    #         self.precompute_structures()
    #         self.match_structures()
    #         if build_morphisms:
    #             self.build_morphisms()
    #             self.check_nominal(log=log)
    #         return True
    #     except RuntimeError as e:
    #         if log:
    #             print(e)
    #         return False

    def read_attribute(self, element: UUID, attr_name: str):
        """
        Read an attribute value attached to an element

        Args:
            element: UUID of the element
            attr_name: name of the attribute to read

        Returns:
            The value of hte attribute, if no attribute with given name is found, returns None
        """
        if element in self.type_model_names:
            # type model element
            element_name = self.type_model_names[element]
            model = self.type_model
        else:
            # model element
            element_name = self.model_names[element]
            model = self.model
        try:
            attr_elem, = self.bottom.read_outgoing_elements(model, f"{element_name}.{attr_name}")
            return self.primitive_values.get(attr_elem, self.bottom.read_value(UUID(self.bottom.read_value(attr_elem))))
        except ValueError:
            return None

    def precompute_sub_types(self):
        """
        Creates an internal representation of sub-type hierarchies that is
        more easily queryable that the state graph
        """
        # collect inheritance link instances
        inh_element, = self.bottom.read_outgoing_elements(self.scd_model, "Inheritance")
        inh_links = []
        for tm_element, tm_name in self.type_model_names.items():
            morphisms = self.bottom.read_outgoing_elements(tm_element, "Morphism")
            if inh_element in morphisms:
                # we have an instance of an inheritance link
                inh_links.append(tm_element)

        # for each inheritance link we add the parent and child to the sub types map
        for link in inh_links:
            tm_source = self.bottom.read_edge_source(link)
            tm_target = self.bottom.read_edge_target(link)
            parent_name = self.type_model_names[tm_target]
            child_name = self.type_model_names[tm_source]
            self.sub_types[parent_name].add(child_name)

        # iteratively expand the sub type hierarchies in the sub types map
        stop = False
        while not stop:
            stop = True
            for child_name, child_children in self.sub_types.items():
                for parent_name, parent_children in self.sub_types.items():
                    if child_name in parent_children:
                        original_size = len(parent_children)
                        parent_children.update(child_children)
                        if len(parent_children) != original_size:
                            stop = False

    def deref_primitive_values(self):
        """
        Prefetch the values stored in referenced primitive type models
        """
        ref_element, = self.bottom.read_outgoing_elements(self.scd_model, "ModelRef")
        string_element, = self.bottom.read_outgoing_elements(self.scd_model, "String")
        boolean_element, = self.bottom.read_outgoing_elements(self.scd_model, "Boolean")
        integer_element, = self.bottom.read_outgoing_elements(self.scd_model, "Integer")
        t_deref = []
        t_refs = []
        for tm_element, tm_name in self.type_model_names.items():
            morphisms = self.bottom.read_outgoing_elements(tm_element, "Morphism")
            if ref_element in morphisms:
                t_refs.append(self.type_model_names[tm_element])
            elif string_element in morphisms:
                t_deref.append(tm_element)
            elif boolean_element in morphisms:
                t_deref.append(tm_element)
            elif integer_element in morphisms:
                t_deref.append(tm_element)

        for elem in t_deref:
            primitive_model = UUID(self.bottom.read_value(elem))
            primitive_value_node, = self.bottom.read_outgoing_elements(primitive_model)
            primitive_value = self.bottom.read_value(primitive_value_node)
            self.primitive_values[elem] = primitive_value

        for m_name, tm_name in self.type_mapping.items():
            if tm_name in t_refs:
                # dereference
                m_element, = self.bottom.read_outgoing_elements(self.model, m_name)
                primitive_model = UUID(self.bottom.read_value(m_element))
                try:
                    primitive_value_node, = self.bottom.read_outgoing_elements(primitive_model)
                    primitive_value = self.bottom.read_value(primitive_value_node)
                    self.primitive_values[m_element] = primitive_value
                except ValueError:
                    pass  # multiple elements in model indicate that we're not dealing with a primitive

    def precompute_multiplicities(self):
        """
        Creates an internal representation of type multiplicities that is
        more easily queryable that the state graph
        """
        for tm_element, tm_name in self.type_model_names.items():
            # class abstract flags and multiplicities
            abstract = self.read_attribute(tm_element, "abstract")
            lc = self.read_attribute(tm_element, "lower_cardinality")
            uc = self.read_attribute(tm_element, "upper_cardinality")
            if abstract:
                self.abstract_types.append(tm_name)
            if lc or uc:
                mult = (
                    lc if lc != None else float("-inf"),
                    uc if uc != None else float("inf")
                )
                self.multiplicities[tm_name] = mult
            # multiplicities for associations
            slc = self.read_attribute(tm_element, "source_lower_cardinality")
            suc = self.read_attribute(tm_element, "source_upper_cardinality")
            if slc or suc:
                mult = (
                    # slc if slc != None else float("-inf"),
                    slc if slc != None else 0,
                    suc if suc != None else float("inf")
                )
                self.source_multiplicities[tm_name] = mult
            tlc = self.read_attribute(tm_element, "target_lower_cardinality")
            tuc = self.read_attribute(tm_element, "target_upper_cardinality")
            if tlc or tuc:
                mult = (
                    # tlc if tlc != None else float("-inf"),
                    tlc if tlc != None else 0,
                    tuc if tuc != None else float("inf")
                )
                self.target_multiplicities[tm_name] = mult
            # optional for attribute links
            opt = self.read_attribute(tm_element, "optional")
            if opt != None:
                self.source_multiplicities[tm_name] = (0, float('inf'))
                self.target_multiplicities[tm_name] = (0 if opt else 1, 1)

    def get_type(self, element: UUID):
        """
        Retrieve the type of an element (wrt. current type model)
        """
        morphisms = self.bottom.read_outgoing_elements(element, "Morphism")
        tm_element, = [m for m in morphisms if m in self.type_model_names.keys()]
        return tm_element

    def check_typing(self):
        """
        for each element of model check whether a morphism
        link exists to some element of type_model
        """
        errors = []
        ref_element, = self.bottom.read_outgoing_elements(self.scd_model, "ModelRef")
        model_names = self.bottom.read_keys(self.model)
        for m_name in model_names:
            m_element, = self.bottom.read_outgoing_elements(self.model, m_name)
            try:
                tm_element = self.get_type(m_element)
                tm_name = self.type_model_names[tm_element]
                self.type_mapping[m_name] = tm_name
                if ref_element in self.bottom.read_outgoing_elements(tm_element, "Morphism"):
                    sub_m = UUID(self.bottom.read_value(m_element))
                    sub_tm = UUID(self.bottom.read_value(tm_element))
                    nested_errors = Conformance(self.state, sub_m, sub_tm).check_nominal()
                    errors += [f"In ModelRef ({m_name}):" + err for err in nested_errors]
            except ValueError as e:
                import traceback
                traceback.format_exc(e)
                # no or too many morphism links found
                errors.append(f"Incorrectly typed element: {m_name}")
        return errors

    def check_link_typing(self):
        """
        for each link, check whether its source and target are of a valid type
        """
        errors = []
        self.precompute_sub_types()
        for m_name, tm_name in self.type_mapping.items():
            m_element, = self.bottom.read_outgoing_elements(self.model, m_name)
            m_source = self.bottom.read_edge_source(m_element)
            m_target = self.bottom.read_edge_target(m_element)
            if m_source == None or m_target == None:
                # element is not a link
                continue
            tm_element, = self.bottom.read_outgoing_elements(self.type_model, tm_name)
            tm_source = self.bottom.read_edge_source(tm_element)
            tm_target = self.bottom.read_edge_target(tm_element)
            # check if source is typed correctly
            source_name = self.model_names[m_source]
            source_type_actual = self.type_mapping[source_name]
            source_type_expected = self.type_model_names[tm_source]
            if source_type_actual != source_type_expected:
                if source_type_actual not in self.sub_types[source_type_expected]:
                    errors.append(f"Invalid source type {source_type_actual} for element {m_name}")
            # check if target is typed correctly
            target_name = self.model_names[m_target]
            target_type_actual = self.type_mapping[target_name]
            target_type_expected = self.type_model_names[tm_target]
            if target_type_actual != target_type_expected:
                if target_type_actual not in self.sub_types[target_type_expected]:
                    errors.append(f"Invalid target type {target_type_actual} for element {m_name}")
        return errors

    def check_multiplicities(self):
        """
        Check whether multiplicities for all types are respected
        """
        self.deref_primitive_values()
        self.precompute_multiplicities()
        errors = []
        for tm_name in self.type_model_names.values():
            # abstract classes
            if tm_name in self.abstract_types:
                type_count = list(self.type_mapping.values()).count(tm_name)
                if type_count > 0:
                    errors.append(f"Invalid instantiation of abstract class: {tm_name}")
            # class multiplicities
            if tm_name in self.multiplicities:
                lc, uc = self.multiplicities[tm_name]
                type_count = list(self.type_mapping.values()).count(tm_name)
                for sub_type in self.sub_types[tm_name]:
                    type_count += list(self.type_mapping.values()).count(sub_type)
                if type_count < lc or type_count > uc:
                    errors.append(f"Cardinality of type exceeds valid multiplicity range: {tm_name} ({type_count})")
            # association source multiplicities
            if tm_name in self.source_multiplicities:
                tm_element, = self.bottom.read_outgoing_elements(self.type_model, tm_name)
                tm_tgt_element = self.bottom.read_edge_target(tm_element)
                tm_tgt_name = self.type_model_names[tm_tgt_element]
                lc, uc = self.source_multiplicities[tm_name]
                for tgt_obj_name, t in self.type_mapping.items():
                    if t == tm_tgt_name or t in self.sub_types[tm_tgt_name]:
                        count = 0
                        tgt_obj_node, = self.bottom.read_outgoing_elements(self.model, tgt_obj_name)
                        incoming = self.bottom.read_incoming_edges(tgt_obj_node)
                        for i in incoming:
                            try:
                                if self.type_mapping[self.model_names[i]] == tm_name:
                                    count += 1
                            except KeyError:
                                pass  # for elements not part of model, e.g. morphism links
                        if count < lc or count > uc:
                            errors.append(f"Source cardinality of type {tm_name} ({count}) out of bounds ({lc}..{uc}) in {tgt_obj_name}.")

            # association target multiplicities
            if tm_name in self.target_multiplicities:
                tm_element, = self.bottom.read_outgoing_elements(self.type_model, tm_name)
                # tm_target_element = self.bottom.read_edge_target(tm_element)
                tm_src_element = self.bottom.read_edge_source(tm_element)
                tm_src_name = self.type_model_names[tm_src_element]
                lc, uc = self.target_multiplicities[tm_name]
                # print("checking assoc", tm_name, "source", tm_src_name)
                # print("subtypes of", tm_src_name, self.sub_types[tm_src_name])
                for src_obj_name, t in self.type_mapping.items():
                    if t == tm_src_name or t in self.sub_types[tm_src_name]:
                        # print("got obj", src_obj_name, "of type", t)
                        count = 0
                        src_obj_node, = self.bottom.read_outgoing_elements(self.model, src_obj_name)
                        # outgoing = self.bottom.read_incoming_edges(src_obj_node)
                        outgoing = self.bottom.read_outgoing_edges(src_obj_node)
                        for o in outgoing:
                            try:
                                if self.type_mapping[self.model_names[o]] == tm_name:
                                    # print("have an outgoing edge", self.model_names[o], self.type_mapping[self.model_names[o]], "---> increase counter")
                                    count += 1
                            except KeyError:
                                pass  # for elements not part of model, e.g. morphism links
                        if count < lc or count > uc:
                            errors.append(f"Target cardinality of type {tm_name} ({count}) out of bounds ({lc}..{uc}) in {src_obj_name}.")
                        # else:
                            # print(f"OK: Target cardinality of type {tm_name} ({count}) within bounds ({lc}..{uc}) in {src_obj_name}.")
        return errors

    def evaluate_constraint(self, code, **kwargs):
        """
        Evaluate constraint code (Python code)
        """

        funcs = {
            'read_value': self.state.read_value,
            'get_value': self.odapi.get_value,
            'get_target': self.odapi.get_target,
            'get_source': self.odapi.get_source,
            'get_slot': self.odapi.get_slot,
            'get_slot_value': self.odapi.get_slot_value,
            'get_all_instances': self.odapi.get_all_instances,
            'get_name': self.odapi.get_name,
            'get_type_name': self.odapi.get_type_name,
            'get_outgoing': self.odapi.get_outgoing,
            'get_incoming': self.odapi.get_incoming,
        }
        # print("evaluating constraint ...", code)
        loc = {**kwargs, }
        result = exec_then_eval(
            code,
            {'__builtins__': {'isinstance': isinstance, 'print': print,
                              'int': int, 'float': float, 'bool': bool, 'str': str, 'tuple': tuple, 'len': len, 'set': set, 'dict': dict},
                **funcs
             },  # globals
             loc # locals
        )
        # print('result =', result)
        return result

    def check_constraints(self):
        """
        Check whether all constraints defined for a model are respected
        """
        errors = []

        def get_code(tm_name):
            constraints = self.bottom.read_outgoing_elements(self.type_model, f"{tm_name}.constraint")
            if len(constraints) == 1:
                constraint = constraints[0]
                code = ActionCode(UUID(self.bottom.read_value(constraint)), self.bottom.state).read()
                return code

        def check_result(result, description):
            if not isinstance(result, bool):
                raise Exception(f"{description} evaluation result is not boolean! Instead got {result}")
            if not result:
                errors.append(f"{description} not satisfied.")

        # local constraints
        for type_name in self.bottom.read_keys(self.type_model):
            code = get_code(type_name)
            if code != None:
                instances = self.odapi.get_all_instances(type_name, include_subtypes=self.constraint_check_subtypes)
                for obj_name, obj_id in instances:
                    description = f"Local constraint of \"{type_name}\" in \"{obj_name}\""
                    # print(description)
                    result = self.evaluate_constraint(code, this=obj_id)
                    check_result(result, description)

        # global constraints
        glob_constraints = []
        # find global constraints...
        glob_constraint_type, = self.bottom.read_outgoing_elements(self.scd_model, "GlobalConstraint")
        for tm_name in self.bottom.read_keys(self.type_model):
            tm_node, = self.bottom.read_outgoing_elements(self.type_model, tm_name)
            # print(key,  node)
            for type_of_node in self.bottom.read_outgoing_elements(tm_node, "Morphism"):
                if type_of_node == glob_constraint_type:
                    # node is GlobalConstraint
                    glob_constraints.append(tm_name)
        # evaluate them (each constraint once)
        for tm_name in glob_constraints:
            code = get_code(tm_name)
            if code != None:
                result = self.evaluate_constraint(code, model=self.model)
                description = f"Global constraint \"{tm_name}\""
                check_result(result, description)
        return errors

    def precompute_structures(self):
        """
        Make an internal representation of type structures such that comparing type structures is easier
        """
        self.precompute_sub_types()
        scd_elements = self.bottom.read_outgoing_elements(self.scd_model)
        # collect types
        class_element, = self.bottom.read_outgoing_elements(self.scd_model, "Class")
        association_element, = self.bottom.read_outgoing_elements(self.scd_model, "Association")
        for tm_element, tm_name in self.type_model_names.items():
            # retrieve elements that tm_element is a morphism of
            morphisms = self.bottom.read_outgoing_elements(tm_element, "Morphism")
            morphism, = [m for m in morphisms if m in scd_elements]
            # check if tm_element is a morphism of AttributeLink
            if class_element == morphism or association_element == morphism:
                self.structures[tm_name] = set()
        # collect type structures
        # retrieve AttributeLink to check whether element is a morphism of AttributeLink
        attr_link_element, = self.bottom.read_outgoing_elements(self.scd_model, "AttributeLink")
        for tm_element, tm_name in self.type_model_names.items():
            # retrieve elements that tm_element is a morphism of
            morphisms = self.bottom.read_outgoing_elements(tm_element, "Morphism")
            morphism, = [m for m in morphisms if m in scd_elements]
            # check if tm_element is a morphism of AttributeLink
            if attr_link_element == morphism:
                # retrieve attributes of attribute link, i.e. 'name' and 'optional'
                attrs = self.bottom.read_outgoing_elements(tm_element)
                name_model_node, = filter(lambda x: self.type_model_names.get(x, "").endswith(".name"), attrs)
                opt_model_node, = filter(lambda x: self.type_model_names.get(x, "").endswith(".optional"), attrs)
                # get attr name value
                name_model = UUID(self.bottom.read_value(name_model_node))
                name_node, = self.bottom.read_outgoing_elements(name_model)
                name = self.bottom.read_value(name_node)
                # get attr opt value
                opt_model = UUID(self.bottom.read_value(opt_model_node))
                opt_node, = self.bottom.read_outgoing_elements(opt_model)
                opt = self.bottom.read_value(opt_node)
                # get attr type name
                source_type_node = self.bottom.read_edge_source(tm_element)
                source_type_name = self.type_model_names[source_type_node]
                target_type_node = self.bottom.read_edge_target(tm_element)
                target_type_name = self.type_model_names[target_type_node]
                # add attribute to the structure of its source type
                # attribute is stored as a (name, optional, type) triple
                self.structures.setdefault(source_type_name, set()).add((name, opt, target_type_name))
        # extend structures of sub types with attrs of super types
        for super_type, sub_types in self.sub_types.items():
            for sub_type in sub_types:
                self.structures.setdefault(sub_type, set()).update(self.structures[super_type])
        # filter out abstract types, as they cannot be instantiated
        # retrieve Class_abstract to check whether element is a morphism of Class_abstract
        class_abs_element, = self.bottom.read_outgoing_elements(self.scd_model, "Class_abstract")
        for tm_element, tm_name in self.type_model_names.items():
            # retrieve elements that tm_element is a morphism of
            morphisms = self.bottom.read_outgoing_elements(tm_element, "Morphism")
            morphism, = [m for m in morphisms if m in scd_elements]
            # check if tm_element is a morphism of Class_abstract
            if class_abs_element == morphism:
                # retrieve 'abstract' attribute value
                target_node = self.bottom.read_edge_target(tm_element)
                abst_model = UUID(self.bottom.read_value(target_node))
                abst_node, = self.bottom.read_outgoing_elements(abst_model)
                is_abstract = self.bottom.read_value(abst_node)
                # retrieve type name
                source_node = self.bottom.read_edge_source(tm_element)
                type_name = self.type_model_names[source_node]
                if is_abstract:
                    self.structures.pop(type_name)

    def match_structures(self):
        """
        Try to match the structure of each element in the instance model to some element in the type model
        """
        ref_element, = self.bottom.read_outgoing_elements(self.scd_model, "ModelRef")
        # matching
        for m_element, m_name in self.model_names.items():
            is_edge = self.bottom.read_edge_source(m_element) != None
            print('element:', m_element, 'name:', m_name, 'is_edge', is_edge)
            for type_name, structure in self.structures.items():
                tm_element, = self.bottom.read_outgoing_elements(self.type_model, type_name)
                type_is_edge = self.bottom.read_edge_source(tm_element) != None
                if is_edge == type_is_edge:
                    print('  type_name:', type_name, 'type_is_edge:', type_is_edge, "structure:", structure)
                    mismatch = False
                    matched = 0
                    for name, optional, attr_type in structure:
                        print('    name:', name, "optional:", optional, "attr_type:", attr_type)
                        try:
                            attr, = self.bottom.read_outgoing_elements(self.model, f"{m_name}.{name}")
                            attr_tm, = self.bottom.read_outgoing_elements(self.type_model, attr_type)
                            # if attribute is a modelref, we need to check whether it
                            # linguistically conforms to the specified type
                            # if its an internally defined attribute, this will be checked by constraints
                            morphisms = self.bottom.read_outgoing_elements(attr_tm, "Morphism")
                            attr_conforms = True
                            if ref_element in morphisms:
                                # check conformance of reference model
                                type_model_uuid = UUID(self.bottom.read_value(attr_tm))
                                model_uuid = UUID(self.bottom.read_value(attr))
                                attr_conforms = Conformance(self.state, model_uuid, type_model_uuid)\
                                    .check_nominal()
                            else:
                                # eval constraints
                                code = self.read_attribute(attr_tm, "constraint")
                                if code != None:
                                    attr_conforms = self.evaluate_constraint(code, this=attr)
                            if attr_conforms:
                                matched += 1
                                print("     attr_conforms -> matched:", matched)
                        except ValueError as e:
                            # attr not found or failed parsing UUID
                            if optional:
                                print("     skipping:", e)
                                continue
                            else:
                                # did not match mandatory attribute
                                print("     breaking:", e)
                                mismatch = True
                                break

                    print('  matched:', matched, 'len(structure):', len(structure))
                    # if matched == len(structure):
                    if not mismatch:
                        print('  add to candidates:', m_name, type_name)
                        self.candidates.setdefault(m_name, set()).add(type_name)
        # filter out candidates for links based on source and target types
        for m_element, m_name in self.model_names.items():
            is_edge = self.bottom.read_edge_source(m_element) != None
            if is_edge and m_name in self.candidates:
                m_source = self.bottom.read_edge_source(m_element)
                m_target = self.bottom.read_edge_target(m_element)
                print(self.candidates)
                source_candidates = self.candidates[self.model_names[m_source]]
                target_candidates = self.candidates[self.model_names[m_target]]
                remove = set()
                for candidate_name in self.candidates[m_name]:
                    candidate_element, = self.bottom.read_outgoing_elements(self.type_model, candidate_name)
                    candidate_source = self.type_model_names[self.bottom.read_edge_source(candidate_element)]
                    if candidate_source not in source_candidates:
                        if len(source_candidates.intersection(set(self.sub_types[candidate_source]))) == 0:
                            remove.add(candidate_name)
                    candidate_target = self.type_model_names[self.bottom.read_edge_target(candidate_element)]
                    if candidate_target not in target_candidates:
                        if len(target_candidates.intersection(set(self.sub_types[candidate_target]))) == 0:
                            remove.add(candidate_name)
                self.candidates[m_name] = self.candidates[m_name].difference(remove)

    def build_morphisms(self):
        """
        Build the morphisms between an instance and a type model that structurally match
        """
        if not all([len(c) == 1 for c in self.candidates.values()]):
            raise RuntimeError("Cannot build incomplete or ambiguous morphism.")
        mapping = {k: v.pop() for k, v in self.candidates.items()}
        for m_name, tm_name in mapping.items():
            # morphism to class/assoc
            m_element, = self.bottom.read_outgoing_elements(self.model, m_name)
            tm_element, = self.bottom.read_outgoing_elements(self.type_model, tm_name)
            self.bottom.create_edge(m_element, tm_element, "Morphism")
            # morphism for attributes and attribute links
            structure = self.structures[tm_name]
            for attr_name, _, attr_type in structure:
                try:
                    # attribute node
                    attr_element, = self.bottom.read_outgoing_elements(self.model, f"{m_name}.{attr_name}")
                    attr_type_element, = self.bottom.read_outgoing_elements(self.type_model, attr_type)
                    self.bottom.create_edge(attr_element, attr_type_element, "Morphism")
                    # attribute link
                    attr_link_element, = self.bottom.read_outgoing_elements(self.model, f"{m_name}_{attr_name}")
                    attr_link_type_element, = self.bottom.read_outgoing_elements(self.type_model, f"{tm_name}_{attr_name}")
                    self.bottom.create_edge(attr_link_element, attr_link_type_element, "Morphism")
                except ValueError:
                    pass


if __name__ == '__main__':
    from state.devstate import DevState as State
    s = State()
    from bootstrap.scd import bootstrap_scd
    scd = bootstrap_scd(s)
    from bootstrap.pn import bootstrap_pn
    ltm_pn = bootstrap_pn(s, "PN")
    ltm_pn_lola = bootstrap_pn(s, "PNlola")
    from services.pn import PN
    my_pn = s.create_node()
    PNserv = PN(my_pn, s)
    PNserv.create_place("p1", 5)
    PNserv.create_place("p2", 0)
    PNserv.create_transition("t1")
    PNserv.create_p2t("p1", "t1", 1)
    PNserv.create_t2p("t1", "p2", 1)
    
    cf = Conformance(s, my_pn, ltm_pn_lola)
    # cf = Conformance(s, scd, ltm_pn, scd)
    cf.precompute_structures()
    cf.match_structures()
    cf.build_morphisms()
    print(cf.check_nominal())