gistfile1.rb

module ActiveRecord
  module Acts
    module TaggableOn
      module SingletonMethods
        def find_options_for_tag_counts(options = {})
          options.assert_valid_keys :start_at, :end_at, :conditions, :at_least, :at_most, :order, :limit, :on, :id
  
          scope = scope(:find)
          start_at = sanitize_sql(["#{Tagging.table_name}.created_at >= ?", options.delete(:start_at)]) if options[:start_at]
          end_at = sanitize_sql(["#{Tagging.table_name}.created_at <= ?", options.delete(:end_at)]) if options[:end_at]

          taggable_type = sanitize_sql(["#{Tagging.table_name}.taggable_type = ?", base_class.name])
          taggable_id = sanitize_sql(["#{Tagging.table_name}.taggable_id = ?", options.delete(:id)]) if options[:id]
  
          conditions = [
            taggable_type,
            taggable_id,
            options[:conditions],
            start_at,
            end_at
          ]

          conditions = conditions.compact.join(' AND ')
          conditions = merge_conditions(conditions, scope[:conditions]) if scope

          joins = ["LEFT OUTER JOIN #{Tagging.table_name} ON #{Tag.table_name}.id = #{Tagging.table_name}.tag_id"]
          joins << sanitize_sql(["AND #{Tagging.table_name}.context = ?",options.delete(:on).to_s]) unless options[:on].nil?
          joins << "LEFT OUTER JOIN #{table_name} ON #{table_name}.#{primary_key} = #{Tagging.table_name}.taggable_id"
          joins << scope[:joins] if scope && scope[:joins]

          at_least  = sanitize_sql(['COUNT(*) >= ?', options.delete(:at_least)]) if options[:at_least]
          at_most   = sanitize_sql(['COUNT(*) <= ?', options.delete(:at_most)]) if options[:at_most]
          having    = [at_least, at_most].compact.join(' AND ')
          group_by  = "#{Tag.table_name}.id, #{Tag.table_name}.name HAVING COUNT(*) > 0"
          group_by << " AND #{having}" unless having.blank?

          limit = options.delete(:limit)

          { :select     => "#{Tag.table_name}.id, #{Tag.table_name}.name, COUNT(*) AS count", 
            :joins      => joins.join(" "),
            :conditions => conditions,
            :group      => group_by,
            :limit      => limit
          }
        end
      end
    end
  end
end