from evennia.prototypes import spawner
from evennia.utils import inherits_from
from evennia.utils.search import search_object


def create_exit(exit_prototype, location, direction):
    x = location.db.x
    y = location.db.y
    if direction == "north":
        x -= 1
    if direction == "south":
        x += 1
    if direction == "west":
        y -= 1
    if direction == "east":
        y += 1

    destination_id = location.db.zone.ndb.map[x][y]["room_id"]
    if destination_id == -1:
        return False

    destinations = search_object(destination_id, exact=True)
    if not destinations:
        raise Exception("create_exit: cannot find room {}".format(destination_id))
    destination = destinations[0]

    # check if exists a room in the selected direction
    exits = search_object(direction, candidates=location.exits)
    if exits:
        exit_obj = exits[0]
        exit_obj.delete()

    exit_obj, *rest = spawner.spawn(exit_prototype)
    exit_obj.location = location
    exit_obj.destination = destination
    exit_obj.aliases.add(direction)

    if inherits_from(exit_obj, "typeclasses.exits.BaseDoor"):
        # a door - create its counterpart
        return_exit, *rest = spawner.spawn(exit_prototype)
        return_exit.location = destination
        return_exit.destination = location
        return_exit.aliases.add(direction)

        exit_obj.db.return_exit = return_exit
        return_exit.db.return_exit = exit_obj

    return exit_obj