from uuid import UUID
from state.base import State
from services.bottom.V0 import Bottom
from services.primitives.integer_type import Integer
from services.primitives.string_type import String
from services.primitives.boolean_type import Boolean
from services.primitives.actioncode_type import ActionCode
from api.cd import CDAPI
from typing import Optional

def get_slot_link_name(obj_name: str, attr_name: str):
    return f"{obj_name}_{attr_name}"

# Object Diagrams service

class OD:

    def __init__(self, type_model: UUID, model: UUID, state: State):
        """
        Implements services for the object diagrams LTM.
        Implementation is done in terms of services provided by LTM-bottom.

            Args:
                type_model: The SCD-conforming class diagram that contains the types of this object diagram
                model: UUID of the (OD) model to manipulate
        """
        self.scd_model = UUID(state.read_value(state.read_dict(state.read_root(), "SCD")))
        self.type_model = type_model
        self.model = model
        self.bottom = Bottom(state)
        self.cd = CDAPI(self.bottom.state, self.type_model)


    def create_object(self, name: str, class_name: str):
        class_nodes = self.bottom.read_outgoing_elements(self.type_model, class_name)
        if len(class_nodes) == 0:
            raise Exception(f"Cannot create object: No such class '{class_name}'")
        class_node = class_nodes[0]
        abstract_nodes = self.bottom.read_outgoing_elements(self.type_model, f"{class_name}.abstract")
        try:
            return self._create_object(name, class_node)
        except Exception as e:
            e.add_note("Class: " + class_name)
            raise

    def _create_object(self, name: str, class_node: UUID):
        # Look at our `type_model` as if it's an object diagram:
        mm_od = OD(
            get_scd_mm(self.bottom), # the type model of our type model
            self.type_model,
            self.bottom.state)

        slot = mm_od.get_slot(class_node, "abstract")
        if slot != None:
            is_abstract, _ = read_primitive_value(self.bottom, slot, self.scd_model)
            if is_abstract:
                raise Exception("Cannot instantiate abstract class!")

        object_node = self.bottom.create_node()
        self.bottom.create_edge(self.model, object_node, name) # attach to model
        self.bottom.create_edge(object_node, class_node, "Morphism") # typed-by link
        return object_node

    def get_class_of_object(self, object_name: str):
        object_node, = self.bottom.read_outgoing_elements(self.model, object_name) # get the object
        return self._get_class_of_object(object_node)


    def _get_class_of_object(self, object_node: UUID):
        type_el, = self.bottom.read_outgoing_elements(object_node, "Morphism")
        for key in self.bottom.read_keys(self.type_model):
            type_el2, = self.bottom.read_outgoing_elements(self.type_model, key)
            if type_el == type_el2:
                return key

    def create_slot(self, attr_name: str, object_name: str, target_name: str):
        class_name = self.get_class_of_object(object_name)
        attr_link_name = self.get_attr_link_name(class_name, attr_name)
        if attr_link_name == None:
            raise Exception(f"Failed to get link name for attribute '{attr_name}' of object '{object_name}'")
        # An attribute-link is indistinguishable from an ordinary link:
        slot_link_name = get_slot_link_name(object_name, attr_name)
        slot_id = self.create_link(slot_link_name,
            attr_link_name, object_name, target_name)
        return slot_id

    def get_slot(self, object_node: UUID, attr_name: str):
        edge = self.get_slot_link(object_node, attr_name)
        slot_ref = self.bottom.read_edge_target(edge)
        return slot_ref

    def get_slot_link(self, object_node: UUID, attr_name: str):
        # I really don't like how complex and inefficient it is to read an attribute of an object...
        class_name = self._get_class_of_object(object_node)
        attr_link_name = self.get_attr_link_name(class_name, attr_name)
        if attr_link_name == None:
            raise Exception(f"Type '{class_name}' has no attribute '{attr_name}'")
        type_edge, = self.bottom.read_outgoing_elements(self.type_model, attr_link_name)
        for outgoing_edge in self.bottom.read_outgoing_edges(object_node):
            if type_edge in self.bottom.read_outgoing_elements(outgoing_edge, "Morphism"):
                return outgoing_edge

    def get_slots(self, object_node):
        attrlink_node = get_scd_mm_attributelink_node(self.bottom)
        slots = []
        outgoing_links = self.bottom.read_outgoing_edges(object_node)
        for l in outgoing_links:
            for type_of_link in self.bottom.read_outgoing_elements(l, "Morphism"):
                for type_of_type_of_link in self.bottom.read_outgoing_elements(type_of_link, "Morphism"):
                    if type_of_type_of_link == attrlink_node:
                        # hooray, we have a slot
                        attr_name = get_attr_name(self.bottom, type_of_link)
                        slots.append((attr_name, l))
        return slots

    def read_slot(self, slot_id):
        tgt = self.bottom.read_edge_target(slot_id)
        return read_primitive_value(self.bottom, tgt, self.type_model)

    def create_integer_value(self, name: str, value: int):
        from services.primitives.integer_type import Integer
        int_node = self.bottom.create_node()
        integer_t = Integer(int_node, self.bottom.state)
        integer_t.create(value)
        # name = 'int'+str(value) # name of the ref to the created integer
        # By convention, the type model must have a ModelRef named "Integer"
        return self.create_model_ref(name, "Integer", int_node)

    def create_boolean_value(self, name: str, value: bool):
        from services.primitives.boolean_type import Boolean
        bool_node = self.bottom.create_node()
        bool_service = Boolean(bool_node, self.bottom.state)
        bool_service.create(value)
        return self.create_model_ref(name, "Boolean", bool_node)

    def create_string_value(self, name: str, value: str):
        from services.primitives.string_type import String
        string_node = self.bottom.create_node()
        string_t = String(string_node, self.bottom.state)
        string_t.create(value)
        return self.create_model_ref(name, "String", string_node)

    def create_actioncode_value(self, name: str, value: str):
        from services.primitives.actioncode_type import ActionCode
        actioncode_node = self.bottom.create_node()
        actioncode_t = ActionCode(actioncode_node, self.bottom.state)
        actioncode_t.create(value)
        return self.create_model_ref(name, "ActionCode", actioncode_node)

    # Identical to the same SCD method:
    def create_model_ref(self, name: str, type_name: str, model: UUID):
        # create element + morphism links
        element_node = self.bottom.create_node(str(model))  # create element node
        self.bottom.create_edge(self.model, element_node, name)  # attach to model
        type_node, = self.bottom.read_outgoing_elements(self.type_model, type_name)  # retrieve type
        self.bottom.create_edge(element_node, type_node, "Morphism")  # create morphism link
        # print('model ref:', name, type_name, element_node, model)
        return element_node

    # The edge connecting an object to the value of a slot must be named `{object_name}_{attr_name}`
    def get_attr_link_name(self, class_name, attr_name):
        return self.cd.get_attr_link_name(class_name, attr_name)

    def create_link(self, link_name: Optional[str], assoc_name: str, src_obj_name: str, tgt_obj_name: str):
        src_obj_nodes = self.bottom.read_outgoing_elements(self.model, src_obj_name)
        if len(src_obj_nodes) == 0:
            raise Exception(f"Cannot create link '{link_name}' ({assoc_name}): source object '{src_obj_name}' not found")
        src_obj_node = src_obj_nodes[0]
        tgt_obj_nodes = self.bottom.read_outgoing_elements(self.model, tgt_obj_name)
        if len(tgt_obj_nodes) == 0:
            raise Exception(f"Cannot create link '{link_name}' ({assoc_name}): target object '{tgt_obj_name}' not found")
        tgt_obj_node = tgt_obj_nodes[0]

        # generate a unique name for the link
        if link_name == None:
            i = 0;
            while True:
                link_name = f"{assoc_name}{i}"
                if len(self.bottom.read_outgoing_elements(self.model, link_name)) == 0:
                    break
                i += 1

        type_edges = self.bottom.read_outgoing_elements(self.type_model, assoc_name)
        if len(type_edges) == 0:
            raise Exception(f"No such attribute/association: {assoc_name}")
        type_edge = type_edges[0]
        link_id = self._create_link(link_name, type_edge, src_obj_node, tgt_obj_node)
        return link_id

    # used for attribute-links and association-links
    def _create_link(self, link_name: str, type_edge: UUID, src_obj_node: UUID, tgt_obj_node: UUID):
        # print('create_link', link_name, type_edge, src_obj_node, tgt_obj_node)
        if not isinstance(src_obj_node, UUID):
            raise Exception("Expected source object to be UUID")
        if not isinstance(tgt_obj_node, UUID):
            raise Exception("Expected target object to be UUID")
        # the link itself is unlabeled:
        link_edge = self.bottom.create_edge(src_obj_node, tgt_obj_node)
        if link_edge == None:
            # Why does the above call silently fail??????
            raise Exception("Could not create link")
        # it is only in the context of the model, that the link has a name:
        self.bottom.create_edge(self.model, link_edge, link_name) # add to model
        self.bottom.create_edge(link_edge, type_edge, "Morphism")
        return link_edge

    def get_objects(self, class_node):
        return get_typed_by(self.bottom, self.model, class_node)

    def get_all_objects(self):
        scd_mm = get_scd_mm(self.bottom)
        class_node = get_scd_mm_class_node(self.bottom)
        all_classes = OD(scd_mm, self.type_model, self.bottom.state).get_objects(class_node)
        result = {}
        for class_name, class_node in all_classes.items():
            objects = self.get_objects(class_node)
            result[class_name] = objects
        return result

    def get_all_links(self):
        scd_mm = get_scd_mm(self.bottom)
        assoc_node = get_scd_mm_assoc_node(self.bottom)
        all_classes = OD(scd_mm, self.type_model, self.bottom.state).get_objects(assoc_node)
        result = {}
        for assoc_name, assoc_node in all_classes.items():
            links = self.get_objects(assoc_node)
            m = {}
            for link_name, link_edge in links.items():
                src_node = self.bottom.read_edge_source(link_edge)
                tgt_node = self.bottom.read_edge_target(link_edge)
                src_name = get_object_name(self.bottom, self.model, src_node)
                tgt_name = get_object_name(self.bottom, self.model, tgt_node)
                m[link_name] = (link_edge, src_name, tgt_name)
            result[assoc_name] = m
        return result

    def get_object_name(self, obj: UUID):
        for key in self.bottom.read_keys(self.model):
            for el in self.bottom.read_outgoing_elements(self.model, key):
                if el == obj:
                    return key

def get_types(bottom: Bottom, obj: UUID):
    return bottom.read_outgoing_elements(obj, "Morphism")

def get_type(bottom: Bottom, obj: UUID):
    types = get_types(bottom, obj)
    if len(types) == 1:
        return types[0]
    elif len(types) > 1:
        raise Exception(f"Expected at most one type. Instead got {len(types)}.")

def is_typed_by(bottom, el: UUID, typ: UUID):
    for typed_by in get_types(bottom, el):
        if typed_by == typ:
            return True
    return False

def get_typed_by(bottom, model, type_node: UUID):
    name_to_instance = {}
    for key in bottom.read_keys(model):
        els = bottom.read_outgoing_elements(model, key)
        if len(els) > 1:
            raise Exception(f"Assertion failed: Model contains more than one object named '{key}'!")
        element = els[0]
        element_types = bottom.read_outgoing_elements(element, "Morphism")
        if type_node in element_types:
            name_to_instance[key] = element
    # mapping from instance name to UUID
    return name_to_instance

def get_scd_mm(bottom):
    scd_metamodel_id = bottom.state.read_dict(bottom.state.read_root(), "SCD")
    scd_metamodel = UUID(bottom.state.read_value(scd_metamodel_id))
    return scd_metamodel    

def get_scd_mm_class_node(bottom: Bottom):
    return get_scd_mm_node(bottom, "Class")

def get_scd_mm_attributelink_node(bottom: Bottom):
    return get_scd_mm_node(bottom, "AttributeLink")

def get_scd_mm_attributelink_name_node(bottom: Bottom):
    return get_scd_mm_node(bottom, "AttributeLink_name")

def get_scd_mm_assoc_node(bottom: Bottom):
    return get_scd_mm_node(bottom, "Association")

def get_scd_mm_modelref_node(bottom: Bottom):
    return get_scd_mm_node(bottom, "ModelRef")

def get_scd_mm_actioncode_node(bottom: Bottom):
    return get_scd_mm_node(bottom, "ActionCode")

def get_scd_mm_node(bottom: Bottom, node_name: str):
    scd_metamodel = get_scd_mm(bottom)
    node, = bottom.read_outgoing_elements(scd_metamodel, node_name)
    return node

def get_scd_mm_class_uppercard_node(bottom: Bottom):
    return get_scd_mm_node(bottom, "Class_upper_cardinality")
def get_scd_mm_class_lowercard_node(bottom: Bottom):
    return get_scd_mm_node(bottom, "Class_lower_cardinality")

def get_scd_mm_assoc_src_uppercard_node(bottom: Bottom):
    return get_scd_mm_node(bottom, "Association_source_upper_cardinality")
def get_scd_mm_assoc_src_lowercard_node(bottom: Bottom):
    return get_scd_mm_node(bottom, "Association_source_lower_cardinality")
def get_scd_mm_assoc_tgt_uppercard_node(bottom: Bottom):
    return get_scd_mm_node(bottom, "Association_target_upper_cardinality")
def get_scd_mm_assoc_tgt_lowercard_node(bottom: Bottom):
    return get_scd_mm_node(bottom, "Association_target_lower_cardinality")


def get_object_name(bottom: Bottom, model: UUID, object_node: UUID):
    for key in bottom.read_keys(model):
        for el in bottom.read_outgoing_elements(model, key):
            if el == object_node:
                return key

def get_type2(bottom: Bottom, mm: UUID, object_node: UUID):
    type_node, = bottom.read_outgoing_elements(object_node, "Morphism")
    return type_node, get_object_name(bottom, mm, type_node)

def find_outgoing_typed_by(bottom, src: UUID, type_node: UUID):
    edges = []
    for outgoing_edge in bottom.read_outgoing_edges(src):
        for typedBy in bottom.read_outgoing_elements(outgoing_edge, "Morphism"):
            if typedBy == type_node:
                edges.append(outgoing_edge)
                break
    return edges

def find_incoming_typed_by(bottom, tgt: UUID, type_node: UUID):
    edges = []
    for incoming_edge in bottom.read_incoming_edges(tgt):
        for typedBy in bottom.read_outgoing_elements(incoming_edge, "Morphism"):
            if typedBy == type_node:
                edges.append(incoming_edge)
                break
    return edges

def navigate_modelref(bottom, node: UUID):
    uuid = bottom.read_value(node)
    return UUID(uuid)

def find_cardinality(bottom, class_node: UUID, type_node: UUID):
    upper_card_edges = find_outgoing_typed_by(bottom, class_node, type_node)
    if len(upper_card_edges) == 1:
        ref = bottom.read_edge_target(upper_card_edges[0])
        integer, = bottom.read_outgoing_elements(
            navigate_modelref(bottom, ref),
            "integer")
        # finally, the value we're looking for:
        return bottom.read_value(integer)

def get_attributes(bottom, class_node: UUID):
    attr_link_node = get_scd_mm_attributelink_node(bottom)
    attr_edges = find_outgoing_typed_by(bottom, class_node, attr_link_node)
    result = []
    for attr_edge in attr_edges:
        attr_name = get_attr_name(bottom, attr_edge)
        result.append((attr_name, attr_edge))
    return result

def get_attr_name(bottom, attr_edge: UUID):
    attr_link_name_node = get_scd_mm_attributelink_name_node(bottom)
    name_edge, = find_outgoing_typed_by(bottom, attr_edge, attr_link_name_node)
    if name_edge == None:
        raise Exception("Expected attribute to have a name...")
    ref_name = bottom.read_edge_target(name_edge)
    string, = bottom.read_outgoing_elements(
        navigate_modelref(bottom, ref_name),
        "string")
    return bottom.read_value(string)

# We need the meta-model (`mm`) to find out how to read the `modelref`
def read_primitive_value(bottom, modelref: UUID, mm: UUID):
    typ = get_type(bottom, modelref)
    if not is_typed_by(bottom, typ, get_scd_mm_modelref_node(bottom)):
        raise Exception("Assertion failed: argument must be typed by ModelRef", typ)
    referred_model = UUID(bottom.read_value(modelref))
    typ_name = get_object_name(bottom, model=mm, object_node=typ)
    if typ_name == "Integer":
        return Integer(referred_model, bottom.state).read(), typ_name
    elif typ_name == "String":
        return String(referred_model, bottom.state).read(), typ_name
    elif typ_name == "Boolean":
        return Boolean(referred_model, bottom.state).read(), typ_name
    elif typ_name == "ActionCode":
        return ActionCode(referred_model, bottom.state).read(), typ_name
    else:
        raise Exception("Unimplemented type:", typ_name)