module ActiveRecord
  module Acts #:nodoc:
    module MuckCoupon #:nodoc:
      def self.included(base)
        base.extend(ClassMethods)
      end

      module ClassMethods

        def acts_as_muck_coupon(options = {})
          validates_presence_of :code, :amount, :percent, :uses
          validates_uniqueness_of :code

          has_many :orders, :through => :coupons_orders
          belongs_to :user # coupons can be attached to users for referral codes
          belongs_to :coupon_type

          validate :validate_discount

          named_scope :by_newest, :order => 'created_at DESC'
          named_scope :active, :conditions => 'coupons.expires_at > Now() AND coupons.uses <= use_limit'

          named_scope :referrals, lambda { { :conditions => ["coupon_type_id = ? ", CouponType.user_referral] } }
          named_scope :default, lambda { { :conditions => ["coupon_type_id = ? ", CouponType.default] } }                                                                                                                                            

          include ActiveRecord::Acts::MuckCoupon::InstanceMethods
          extend ActiveRecord::Acts::MuckCoupon::SingletonMethods
        end
      
      end

      # class methods
      module SingletonMethods
        def random_code
          coupon_length = 14 # will generate a code 15 chars long
          letters = ['B', 'C', 'D', 'F', 'H', 'J', 'K', 'L', 'M', 'N', 'P', 'Q', 'R', 'S', 'T', 'V', 'W', 'X', 'Y', 'Z']
          numbers = [2, 3, 4, 7, 9]
          promo_set = letters | numbers # combine arrays
          begin
            promo_code = promo_set.sort_by{rand}[0..coupon_length].to_s # randomize array and take the first 15 elements and make them a string
          end until !self.active_code?(promo_code)
          promo_code
        end

        # Checks the database to ensure the specified code is not taken
        def active_code?(code)
          Coupon.find_by_code(code)
        end

        def check_referrals(coupon_codes)
          # Check to see if the discount code is associated with another user  ie person one invites person two
          # and so both people get a free month of storage.
          users = []
          coupon_codes.each do |code|
            coupon = Coupon.find_by_code(code)
            coupon.give_referral_benefit if coupon
          end
        end

        # Calculate total discount for a given array of coupon codes.
        # amount:         amount in cents to calculate discount for
        # discount_codes: a string coupon code or array of coupon codes
        def calculate_total_discount(amount, discount_codes)
          coupon_amount = 0
          coupon_override = false
          coupons = []
          if discount_codes
            discount_codes = [discount_codes] unless discount_codes.is_a?(Array)
            discount_codes.each do |discount_code|
              coupon = Coupon.find_by_code(discount_code)
              if coupon
                coupon_amount = coupon.calculate_discount(amount)
                coupon.redeem
                coupons << coupon
              end
              if amount - coupon_amount == 0
                coupon_override = true
              end
            end
          end
          [coupons, coupon_amount, coupon_override]
        end
      end

      # All the methods available to a record that has had <tt>acts_as_muck_billing_information</tt> specified.
      module InstanceMethods
      
        def give_referral_benefit
          raise MuckCommerce::Exceptions::CouponError, "Implement the 'give_referral_benefit' method in coupon.rb."
        end
        
        def validate_discount
          if self.percent.blank? && self.amount.blank? 
            errors.add_to_base('Please enter a value for either the coupon amount or percent')
            false
          else
            true
          end
        end
  
        def calculate_discount(amount)
    
          coupon_amount = 0
    
          if self.invalid?
            raise MuckCommerce::Exceptions::CouponError, 'The coupon you entered has expired or is no longer valid'
          else
            if self.amount > 0
              coupon_amount = self.amount
            elsif self.percent > 0
              coupon_amount = amount * (0.01 * self.percent)
            end
          end
    
          coupon_amount = 0 if coupon_amount < 0    
          coupon_amount
        end
  
        def redeem
          self.update_attribute(:uses, self.uses + 1)
        end
  
        def invalid?
          expired? || overused?
        end
  
        def expired?
          self.expires_at? && self.expires_at < Time.now
        end
  
        def overused?
          (self.uses >= self.use_limit) && !self.unlimited
        end
      end
    
    end
    
  end
  
end