GeneralHelpers used in Span6 (and other projects) as Mixin for most ActiveRecord models

general_helpers.rb

# To extend AR models with general instance and class methods that are needed through the Span6 project
# Simply call the class method #general_helpers in the AR model

module S6
  module GeneralHelpers
    def self.included(base)
      base.extend ClassMethods
    end

    module ClassMethods

      def humanize_money(*args)
        args.each do |field_name|
          # dynamically create getter and setter wrappers around field_name
          self.class_eval %{
          def #{field_name}_in_dollars
            #{field_name}.to_f / 100.00 unless #{field_name}.blank?
          end
          def #{field_name}_in_dollars=(new_val)
            return self.#{field_name} = nil if new_val.blank?
            self.#{field_name} = (new_val.gsub('$', '').to_f * 100.00).round
            new_val
          end
          def humanized_#{field_name}_in_dollars
            unless #{field_name}.blank?
              "$\#\{sprintf("%0.02f", #{field_name}_in_dollars)\}"
            end
          end
          }
        end
      end


      def general_helpers
        scope :recent_first, order("#{quoted_table_name}.created_at DESC")
        scope :oldest_first, order("#{quoted_table_name}.created_at ASC")
        scope :recently_updated_first, order("#{quoted_table_name}.updated_at DESC")
        scope :random, order("RANDOM()")
        scope :date_between, lambda { |field, from, to| where("#{quoted_table_name}.#{field.to_s} between ? and ?", from, to) }
        scope :created_between, lambda { |from, to| date_between(:created_at, from, to) }
        scope :grouped_by_date_for_field, lambda { |date_field, group_field|
          # Account for timezone offset since times in DB are stored as UTC and the way we are querying here doesn't leverage AR capability of auto-converting the time to UTC
          interval = Time.zone.now.utc_offset / 60 / 60
          interval = if interval < 0
            " - interval '#{interval.abs} hours'"
          elsif interval > 0
            " + interval '#{interval} hours'"
          else
            ""
          end
          select("date_trunc('day', #{quoted_table_name}.#{date_field}#{interval}) as \"date\", #{group_field}").
            group("\"date\"").
            order("\"date\"")
        }
        scope :count_by_date_for, lambda { |date_field| grouped_by_date_for_field(date_field, "COUNT(1) as num_entries") }
      end
    end

  end
end