from abc import ABCMeta, abstractmethod from collections import deque from enum import Enum class Rank(Enum): OPERATOR = 0 SUPERVISOR = 1 DIRECTOR = 2 class Employee(metaclass=ABCMeta): def __init__(self, employee_id, name, rank, call_center): self.employee_id = employee_id self.name = name self.rank = rank self.call = None self.call_center = call_center def take_call(self, call): """Assume the employee will always successfully take the call.""" self.call = call self.call.employee = self self.call.state = CallState.IN_PROGRESS def complete_call(self): self.call.state = CallState.COMPLETE self.call_center.notify_call_completed(self.call) @abstractmethod def escalate_call(self): pass def _escalate_call(self): self.call.state = CallState.READY call = self.call self.call = None self.call_center.notify_call_escalated(call) class Operator(Employee): def __init__(self, employee_id, name): super(Operator, self).__init__(employee_id, name, Rank.OPERATOR) def escalate_call(self): self.call.level = Rank.SUPERVISOR self._escalate_call() class Supervisor(Employee): def __init__(self, employee_id, name): super(Operator, self).__init__(employee_id, name, Rank.SUPERVISOR) def escalate_call(self): self.call.level = Rank.DIRECTOR self._escalate_call() class Director(Employee): def __init__(self, employee_id, name): super(Operator, self).__init__(employee_id, name, Rank.DIRECTOR) def escalate_call(self): raise NotImplemented('Directors must be able to handle any call') class CallState(Enum): READY = 0 IN_PROGRESS = 1 COMPLETE = 2 class Call(object): def __init__(self, rank): self.state = CallState.READY self.rank = rank self.employee = None class CallCenter(object): def __init__(self, operators, supervisors, directors): self.operators = operators self.supervisors = supervisors self.directors = directors self.queued_calls = deque() def dispatch_call(self, call): if call.rank not in (Rank.OPERATOR, Rank.SUPERVISOR, Rank.DIRECTOR): raise ValueError('Invalid call rank: {}'.format(call.rank)) employee = None if call.rank == Rank.OPERATOR: employee = self._dispatch_call(call, self.operators) if call.rank == Rank.SUPERVISOR or employee is None: employee = self._dispatch_call(call, self.supervisors) if call.rank == Rank.DIRECTOR or employee is None: employee = self._dispatch_call(call, self.directors) if employee is None: self.queued_calls.append(call) def _dispatch_call(self, call, employees): for employee in employees: if employee.call is None: employee.take_call(call) return employee return None def notify_call_escalated(self, call): # ... def notify_call_completed(self, call): # ... def dispatch_queued_call_to_newly_freed_employee(self, call, employee): # ...