Discounts feature

[cyri113]

Use Cases:

1. Frequency: Depending on the frequency selected, a discount should be applied
2. Coupon: When a valid coupon is entered, the discount should be applied
3. Product: When a product is selected, any associated Discounts should be applied
4. User: When a given user is ordering, any associated Discounts should be applied

Rules:

• Maximum 1 Frequency Discount is allowed per order

Models:

• Discount:

  • name
  • description
  • coupon
  • discount_type (:fixed, :percentage)
  • amount
  • category (:frequency, :coupon, :association)
  • Item (polymorphic)

• DiscountItem:

  • Discount
  • Cart

Frequency

@weekly = Discount.create(name: 'Weekly', description: 'A professional will clean once a week', discount_type: :percentage, amount: 0.3, category: :frequency)
@weekly.update_attributes(locale: :de, name: 'Wöchentlich', description: 'Ein Profi wird einmal wöchentlich reinigen')
@2weeks = Discount.create(name: 'Every 2 Weeks', description: 'A professional will clean every 2 weeks', discount_type: :percentage, amount: 0.3, category: :frequency)
@2weeks.update_attributes(locale: :de, name: 'Alle 2 Wochen', description: 'Ein Profi wird alle 2 Wochen reinigen')

[cyri113]

Models:

class Cart
  has_many :discount_items, dependent: :destroy
  has_many :discounts, through: :discount_items

  def total_discount
    total_discount = discounts.sum(&total_discount)
    total_discount = total_price if discount > total_price
    total_discount
  end

end

class Discount
  has_many :discount_items
  has_many :carts, through: :discount_items

  before_destroy :ensure_not_referenced_by_any_discount_item

  private

  # ensure that there are not discount items referencing this product
  def ensure_not_referenced_by_any_discount_item
    unless discount_items.empty?
      errors.add(:base, 'Discount Items present')
      throw :abort
    end
  end
end

class DiscountItem
  belongs_to :discount
  belongs_to :cart
  def total_discount
    total_discount = discount.amount
    total_discount = discount.amount * cart.total_price if discount.discount_type == :percentage
    total_discount
  end

end

[cyri113]

Tests

• Maximum 1 frequency Discount is allowed per Cart
• Duplicate discounts are not allowed
• New frequency Discount should overwrite old one

[cyri113]

Future:

• One time versus recurring discounts
• Discounts associated with Users or Products