#!/usr/bin/python3

from Person import *

class MITPerson(Person):

    nextIdNum = 0 # next ID number to assign

    def __init__(self, name):
        Person.__init__(self, name)      # Initialize person's attributes
        self.idNum = MITPerson.nextIdNum # MITPerson global attribute: unique ID
        MITPerson.nextIdNum += 1

    def getIdNum(self):
        return self.idNum

    # Sorting MIT people uses their ID number, not name
    def __lt__(self, other):
        return self.idNum < other.idNum

    def speak(self, utterance):
        return (self.name + " says: " + utterance)

class Student(MITPerson):
    pass

class UG(Student):
    def __init__(self, name, classYear):
        MITPerson.__init__(self, name)
        self.year = classYear

    def getClass(self):
        return self.year

    def speak(self, utterance):
        return MITPerson.speak(self, " Yo Bro: " + utterance)

class Grad(Student):
    pass

class TransferStudent(Student):
    pass



# By creating a new 'blank' class Student, and making all UG, Grad and
# TransferStudent classes inherit from it, we clean up the class inheritance a
# bit, so, in the function below, we can simply us Student class, to check if an
# object belongs to that class, instead of the old version (commented out below,
# for historical perspective)
def isStudent(obj):
#    return isinstance(obj, UG) or isinstance(obj, Grad)
    return isinstance(obj, Student)

class Professor(MITPerson):
    def __init__(self, name, department):
        MITPerson__init__(self, name)
        self.department = department

    def speak(self, utterance):
        new = "In course " + self.department + " we say "
        return MITPerson.speak(self, new + utterance)

    def lecture(self, topic):
        return self.speak('it is obvious that ' + topic)

m1 = MITPerson("Mark Zuckeberg")
m2 = MITPerson("Bill Gates")
m3 = MITPerson("Carlos Maiolino")
p1 = Person("Drew Houston")


s1 = UG("Matt Damon", 2017)
s2 = Grad("Leonardo di Caprio")
# Remember, comparison is done by using __lt__ method, which takes the instance
# itself + another instance. When using the MITPerson instance, the __lt__
# method uses the idNum attribute, which, an instance of Person class will not
# have. But, using an instance of Person class, the __lt__ method, uses the
# LastName, which, since MITPerson is a subclass of Person class, it also
# contains a lastName attribute

## print(p1 < m3) # Comparison works
## print(m3 < p1) # Comparison does not work (Attribute error)