drhenner/ror_ecommerce

# == Class Deal
#
#  The deal model is basically a "buy X get y percent free" or "buy X get y dollars off"
#
#  In the scenario "buy X get y percent free", X is buy_quantity and y is get_percentage.
#  The way it works get_percentage is multiplied by the lowest costing item that "qualifies" for the deal.
#
#  NOTE: "qualifies" =>  a product qualifies if is of the correct product_type_id.  If
#        the product_type_id doesn't match it will not qualify.  so you might have three pants
#        but also one belt.  the belt and the pants will not be the same product_type_id.

#  In the scenario "buy X get y dollars off", X is buy_quantity and y is get_amount.
#  The way it works get_amount is the number of cents reduced from the order total.
#  Again the NOTE above about "qualifies" still is in effect

# == Schema Information
#
# Table name: deals
#
#  id              :integer          not null, primary key
#  buy_quantity    :integer          not null
#  get_percentage  :integer
#  deal_type_id    :integer          not null
#  product_type_id :integer          not null
#  get_amount      :integer
#  deleted_at      :datetime
#  created_at      :datetime         not null
#  updated_at      :datetime         not null
#

class Deal < ApplicationRecord

  validates :buy_quantity,            presence: true
  validates :get_percentage,          presence: true, :if => :get_amount_is_blank?
  validates :product_type_id,         presence: true
  validates :get_amount,              presence: true, :if => :get_percentage_is_blank?
  #validates :description,             presence: true, length: {:maximum => 255}

  belongs_to :deal_type
  belongs_to :product_type

  def self.best_qualifing_deal(order)
    product_type_and_amount_hash = order.number_of_a_given_product_type.sort_by{|v| v.last.size }.reverse # sort the hashes by the number of items for that product type
    deal_time = order.completed_at || order.deal_time || Time.zone.now # Deal.best_qualifing_deal(ooo)
    Hash[product_type_and_amount_hash].each_pair do |product_type_id, product_type_prices|
      deal_amount = qualifing_deal(product_type_id, product_type_prices, deal_time)
      return deal_amount.round_at(2) if deal_amount
    end
    0.0
  end
  def self.qualifing_deal(product_type_id, product_type_prices, at)
    deal = self.for_x_number_purchased(product_type_prices.size).
    for_product_type_id(product_type_id).existed_at(at).active_at(at).
    order('deals.get_percentage DESC').first
    deal ? deal.final_deal_amount(product_type_prices) : false
  end

  def self.for_x_number_purchased(num)
    where(['deals.buy_quantity <= ?', num])
  end

  def self.active_at(at)
    where(['deals.deleted_at >= ? OR deals.deleted_at IS NULL', at])
  end

  def self.existed_at(at)
    where(['deals.created_at <= ?', at])
  end

  def self.for_product_type_id(product_type_id)
    where(['deals.product_type_id IN (?)', product_type_id])
  end

  def final_deal_amount(product_type_prices)
    if get_amount && get_amount > 0.0
      get_amount.to_f / 100.0
    else
      ((product_type_prices.sort.reverse[0..(buy_quantity - 1)].min) * get_percentage).to_f / 100.0
    end
  end

  private
    def get_percentage_is_blank?
      get_percentage.blank?
    end
    def get_amount_is_blank?
      get_amount.blank?
    end
end