from modelverse_kernel.primitives import PrimitiveFinished

def reverseKeyLookup(a, b, **remainder):
    edges = yield [("RO", [a])]
    expanded_edges = yield [("RE", [i]) for i in edges]
    for i, edge in enumerate(expanded_edges):
        if b == edge[1]:
            # Found our edge: edges[i]
            outgoing = yield [("RO", [edges[i]])]
            result = yield [("RE", [outgoing[0]])]
            raise PrimitiveFinished(result[1])

    result = yield [("CNV", ["(unknown: %s)" % b])]
    raise PrimitiveFinished(result)

def read_attribute(a, b, c, **remainder):
    #TODO this can be optimized even further...
    model_dict, b_val, type_mapping = \
                    yield [("RD", [a, "model"]),
                           ("RV", [b]),
                           ("RD", [a, "type_mapping"]),
                           ]
    model_instance, edges = \
                    yield [("RD", [model_dict, b]),
                           ("RO", [a]),
                           ]
    edge_types =    yield [("RDN", [type_mapping, i]) for i in edges]
    type_edge_val = yield [("RE", [i]) for i in edge_types]

    src_nodes = set([i[0] for i in type_edge_val])

    found_edges =   yield [("RDE", [i, b_val]) for i in src_nodes]

    if len(src_nodes) == 1:
        found_edges = [found_edges]

    for e1 in found_edges:
        if e1 is not None:
            # Found an edge!
            for i, e2 in enumerate(edge_types):
                if e1 == e2:
                    # The instance of this edge is the one we want!
                    edge = edges[i]
                    edge_val = yield [("RE", [edge])]
                    result = edge_val[1]
                    raise PrimitiveFinished(result)
    else:
        result = yield [("RR", [])]
        raise PrimitiveFinished(result)

    raise Exception("Error in reading edge!")

def precompute_cardinalities(a, **remainder):
    result =        yield [("CN", [])]

    # Read out all edges from the metamodel
    model_dict =    yield [("RD", [a, "model"])]
    type_mapping =  yield [("RD", [a, "type_mapping"])]
    elems =         yield [("RO", [model_dict])]
    elems =         yield [("RE", [i]) for i in elems]
    elems = [i[1] for i in elems]
    edges =         yield [("RE", [i]) for i in elems]
    elems = [elems[i] for i, edge_val in enumerate(edges) if edge_val is not None]
    # Now we have all edges in the metamodel

    # Read out the type of the Association defining all cardinalities
    metamodel =     yield [("RD", [a, "metamodel"])]
    metamodel_dict= yield [("RD", [metamodel, "model"])]
    assoc =         yield [("RD", [metamodel_dict, "Association"])]
    slc, suc, tlc, tuc = \
                    yield [("RDE", [assoc, "source_lower_cardinality"]),
                           ("RDE", [assoc, "source_upper_cardinality"]),
                           ("RDE", [assoc, "target_lower_cardinality"]),
                           ("RDE", [assoc, "target_upper_cardinality"]),
                          ]

    # All that we now have to do is find, for each edge, whether or not it has an edge typed by any of these links!
    # Just find all links typed by these links!
    types =         yield [("RDN", [type_mapping, i]) for i in elems]

    cardinalities = {}
    for i, edge_type in enumerate(types):
        if edge_type == slc:
            t = "slc"
        elif edge_type == suc:
            t = "suc"
        elif edge_type == tlc:
            t = "tlc"
        elif edge_type == tuc:
            t = "tuc"
        else:
            continue
        
        # Found a link, so add it
        source, destination = yield [("RE", [elems[i]])]
        # The edge gives the "source" the cardinality found in "destination"
        cardinalities.setdefault(source, {})[t] = destination

    # Now we have to translate the "cardinalities" Python dictionary to a Modelverse dictionary
    nodes = yield [("CN", []) for i in cardinalities]
    yield [("CD", [result, i, node]) for i, node in zip(cardinalities, nodes)]
    l = list(cardinalities)
    values = yield [("RD", [result, i]) for i in l]

    for i, value in enumerate(values):
        cards = cardinalities[l[i]]
        yield [("CD", [value, card_type, cards[card_type]]) for card_type in cards]

    raise PrimitiveFinished(result)