Qualified Andela Ruby

20210520175831_create_albums.rb

class CreateAlbums < ActiveRecord::Migration[6.1]
  def change
    create_table "albums", force: :cascade do |t|
      t.string "title"
      t.string "performer"
      t.integer "cost"
      t.datetime "created_at", null: false
      t.datetime "updated_at", null: false
      t.datetime "last_purchased_at"
      t.integer "last_purchased_by"
    end
  end
end

album.rb

class Album < ApplicationRecord
  has_many :purchases
  
  # Validates presence of title, performer, and cost
  validates :title, :performer, :cost, presence: true
  
  # Validates cost is a positive integer
  validates :cost, numericality: { only_integer: true, greater_than: 0 }
end

purchase.rb

class Purchase < ApplicationRecord
  belongs_to :album
  belongs_to :user
  
  validates :album_id, :user_id, presence: true
  
  after_create :update_album_purchase_info, :increment_user_total_purchases

  private

  def update_album_purchase_info
    album.update(last_purchased_at: Time.current, last_purchased_by: user.id)
  end
  
  def increment_user_total_purchases
    user.increment!(:total_purchases)
  end
end

user.rb

class User < ActiveRecord::Base
  has_many :purchases
  
  validates :name, presence: true
end