Ruby - Object-oriented Store example - ruby

Question

I am starting my studies with Ruby and OO and I have received a test to do about OO.
It is a store scenario where I have to create the classes, methods, calls ...
For now I have create the class Payment and Product classes (Physical, Membership, Digital)
class Payment
attr_reader :authorization_number, :amount, :invoice, :order, :payment_method, :paid_at, :shipping
def initialize(attributes = {})
#authorization_number, #amount = attributes.values_at(:authorization_number, :amount)
#invoice, #order = attributes.values_at(:invoice, :order)
#payment_method = attributes.values_at(:payment_method)
#shipping.extend Shipping
end
def pay(paid_at = Time.now)
#amount = order.total_amount
#authorization_number = Time.now.to_i
#invoice = Invoice.new(order.get_address, order.get_address, order)
#paid_at = paid_at
order.close(#paid_at)
extend
def paid?
!paid_at.nil?
end
def prepare_shipping(order)
???
end
end
class Product
attr_reader :name, :description, :type
def initialize(name, description, type)
#name = name
#description = description
#type = type
end
end
class Digital < Product
include DigitalProduct
def initialize(name, description, type)
super(name, description, type)
end
def matches?(query)
query=="digital"
end
end
class Physical < Product
def initialize(name, description, type)
super(name, description, type)
end
def matches?(query)
query=="physical"
end
end
class Membership < Product
attr_reader :membership_status
include DigitalProduct
def initialize(name, description, type)
super(name, description, type)
end
def matches?(query)
query=="membership"
end
def activate_membership()
#membership_status = true;
end
end
Here is my problem:
1.If the product is physical I have to generate a shipping label.
1.1 If its a book I have to notify that this product doesn't have taxes.
2.If the product is membership I have to activate the signature and notify via email the buyer.
If the product is digital I have to send a email for the buyer and give $10 discount in this product.
I am doing pretty good, but now I would like your opinion to know what is the best way following OO techniques (SOLID) to create the points above.
ps: I tried to create but my solution was really poor with many ifs.
I think there is a better way to do it with
I have other classes if you need more info tell me please.
Sorry about my poor english.
I have developed this solution, I think it is good ... maybe you can give me a feedback about it.
So to solve the problem about shipping and discount rules I created 2 modules Shipping and Discount
module Discount
def prepare_discount(order)
total_discount = 0
order.get_items.each do |item|
total_discount += item.product.discount
end
return total_discount
end
def discount
if matches?("physical")
return discount_for_physical_product
elsif matches?("digital")
return discount_for_digital_product
elsif matches?("membership")
return discount_for_membership_product
elsif matches?("default")
return discount_for_default_product
end
end
def discount_for_physical_product
price_discount_for_physical_product = 0
return price_discount_for_physical_product
end
def discount_for_digital_product
price_discount_for_digital_product = 10.00
return price_discount_for_digital_product
end
def discount_for_default_product
price_discount_for_digital_product = 10.00
return price_discount_for_digital_product
end
def discount_for_membership_product
price_discount_for_membership_product = 0
return price_discount_for_membership_product
end
end
module Shipping
def prepare_shipping(order)
order.get_items.each do |item|
item.product.shipping
end
end
def shipping
if matches?("physical")
shipping_for_physical_product
elsif matches?("digital")
shipping_for_digital_product
elsif matches?("membership")
shipping_for_membership_product
elsif matches?("default")
shipping_for_default_product
end
end
def shipping_for_physical_product
case #type
when :book
create_shipping_label
notify_buyer_product_without_taxes
else
create_shipping_label
end
end
def shipping_for_digital_product
notify_buyer_via_email
end
def shipping_for_membership_product
notify_buyer_via_email
activate_membership
end
def shipping_for_default_product
create_shipping_label
notify_buyer_via_email
end
def create_shipping_label
puts "Creating shipping label ..."
end
def notify_buyer_product_without_taxes
puts "Product exempt from taxes, as provided in the Constitution Art. 150, VI, d."
end
def notify_buyer_via_email
puts "Sending email ..."
end
end
This way Product and Order can extend both modules and implement the logic.