module Returnly
  module Services
    class CreateReimbursement
      attr_accessor :reimbursement

      delegate :return_items, to: :reimbursement

      def initialize(reimbursement)
        @reimbursement = reimbursement
      end

      def perform!
        reimbursement.save!
        reimbursement.update!(total: calculated_total)
        performer.perform(reimbursement)

        if unpaid_amount_within_tolerance?
          reimbursement.reimbursed!
          Spree::Reimbursement.reimbursement_success_hooks.each { |h| h.call reimbursement }
          send_reimbursement_email
        else
          reimbursement.errored!
          Spree::Reimbursement.reimbursement_failure_hooks.each { |h| h.call reimbursement }
          raise incomplete_error_class, Spree.t('validation.unpaid_amount_not_zero', amount: unpaid_amount)
        end
      end

      private

      def incomplete_error_class
        Spree::Reimbursement::IncompleteReimbursementError
      end

      def reimbursement_models
        Spree::Reimbursement.reimbursement_models
      end

      def paid_amount
        reimbursement_models.sum do |model|
          model.total_amount_reimbursed_for(reimbursement)
        end
      end

      def unpaid_amount
        reimbursement.total - paid_amount
      end

      def calculated_total
        return_items.to_a.sum(&:total).to_d.round(2, :down)
      end

      def performer
        Spree::Reimbursement.reimbursement_performer
      end

      def send_reimbursement_email
        Spree::ReimbursementMailer.reimbursement_email(reimbursement.id).deliver_later
      end

      def unpaid_amount_within_tolerance?
        reimbursement_count = reimbursement_models.count do |model|
          model.total_amount_reimbursed_for(reimbursement) > 0
        end

        leniency = if reimbursement_count > 0
                     (reimbursement_count - 1) * 0.01.to_d
                   else
                     0
                   end
        unpaid_amount.abs.between?(0, leniency)
      end
    end
  end
end