class Predicate(ndb.Model):
    name = ndb.StringProperty()
    parameters = ndb.JsonProperty()

class State(ndb.Model):
    predicates = ndb.StructuredProperty(Predicate, repeated=True)

class Action(ndb.Model):
    name = ndb.StringProperty()
    parameters = ndb.StringProperty(repeated=True)
    preconditions = ndb.StructuredProperty(Predicate, repeated=True)
    predicatesToAdd = ndb.StructuredProperty(Predicate, repeated=True)
    predicatesToDel = ndb.StructuredProperty(Predicate, repeated=True)

class Plan(ndb.Model):
    plan = ndb.StructuredProperty(Predicate, repeated=True)

class Problem(ndb.Model):
    initialState = ndb.StructuredProperty(Predicate)
    goalState = ndb.StructuredProperty(Predicate)
    actions = ndb.StructuredProperty(Action, repeated=True)