Cracking the Code Interview 7.2 (OOP)

call_center.rb

# Imagine you have a call center with three levels of employees: fresher, technical lead (TL), 
# product manager (PM). There can be multiple employees, but only one TL or PM
# An incoming telephone call must be allocated to a fresher who is free. If a fresher
# can’t handle the call, he or she must escalate the call to technical lead. If the TL is
# not free or not able to handle it, then the call should be escalated to PM. Design the
# classes and data structures for this problem. Implement a method getCallHandler().

class CallHandler
  attr_reader :product_manager, :tech_lead, :freshers, :calls

  def initialize(args={})
    @product_manager = args[:product_manager]
    @tech_lead       = args[:tech_lead]
    @freshers        = args[:freshers]
    @calls           = []
  end

  def get_call_handler
    employees_by_rank.each do |emp|
      return emp if emp.free?
    end
  end

  def employees_by_rank
    [freshers, tech_lead, product_manager].flatten
  end

  def route_incoming(call)
    employee = get_call_handler
    if employee
      employee.status = :busy
      call.employee   = employee      
    else
      calls << call
    end
  end
end

class Employee
  attr_reader :name, :title
  attr_accessor :status

  def initialize(name, title)
    @name         = name
    @title        = title
    @status       = :free
  end

  def free?
    status == :free
  end
end

class Call
  attr_accessor :employee

  def initialize(caller, message)
    @caller  = caller
    @message = message
  end
end


### Example 

employee1 = Employee.new('John', 'Product Manager')
employee2 = Employee.new('Jim', 'Tech Lead')
employee3 = Employee.new('James', 'Fresher')
employee4 = Employee.new('Joe', 'Fresher')

call_center = CallHandler.new(
                product_manager:  employee1,
                tech_lead:        employee2,
                freshers:         [employee3, employee4] )

call1 = Call.new("Mr T", "My WoW account isn't working.")
call2 = Call.new("Mr Kim", "Issue with login...")

call_center.route_incoming(call1)
call_center.route_incoming(call2)


call_center.employees_by_rank.each do |emp|
  puts "#{emp.name}: #{emp.status}"
end