Refactoring acts-as-taggable-on SQL queries to be more readable

01-before.rb

      def tagged_with(tags, options = {})
        tag_list = ActsAsTaggableOn::Taggable::TagList.from(tags)

        joins = []
        conditions = []

        context = options.delete(:on)
        context_condition = context.blank? ? "" : sanitize_sql(["AND #{acts_as_taggable_on_tagging_model.table_name}.context = ?", context.to_s])

        if options.delete(:exclude)
          tags_conditions = tag_list.map { |t| sanitize_sql(["#{acts_as_taggable_on_tag_model.table_name}.name #{ActsAsTaggableOn.like_operator} ?", t]) }.join(" OR ")
          conditions << "#{table_name}.#{primary_key} NOT IN (SELECT #{acts_as_taggable_on_tagging_model.table_name}.taggable_id FROM #{acts_as_taggable_on_tagging_model.table_name} JOIN #{acts_as_taggable_on_tag_model.table_name} ON #{acts_as_taggable_on_tagging_model.table_name}.tag_id = #{acts_as_taggable_on_tag_model.table_name}.id AND (#{tags_conditions}) WHERE #{acts_as_taggable_on_tagging_model.table_name}.taggable_type = #{quote_value(base_class.name)} #{context_condition})"

        elsif options.delete(:any)
          tags_conditions = tag_list.map { |t| sanitize_sql(["#{acts_as_taggable_on_tag_model.table_name}.name #{ActsAsTaggableOn.like_operator} ?", t]) }.join(" OR ")
          conditions << "#{table_name}.#{primary_key} IN (SELECT #{acts_as_taggable_on_tagging_model.table_name}.taggable_id FROM #{acts_as_taggable_on_tagging_model.table_name} JOIN #{acts_as_taggable_on_tag_model.table_name} ON #{acts_as_taggable_on_tagging_model.table_name}.tag_id = #{acts_as_taggable_on_tag_model.table_name}.id AND (#{tags_conditions}) WHERE #{acts_as_taggable_on_tagging_model.table_name}.taggable_type = #{quote_value(base_class.name)} #{context_condition})"

        elsif tag_list.empty? && options(:match_all)
          conditions << "#{table_name}.#{primary_key} NOT IN (SELECT #{acts_as_taggable_on_tagging_model.table_name}.taggable_id FROM #{acts_as_taggable_on_tagging_model.table_name} WHERE #{acts_as_taggable_on_tagging_model.table_name}.taggable_type = #{quote_value(base_class.name)} #{context_condition})"

      end

02-after.rb

      def tagged_with(tags, options = {})
        tag_list = ActsAsTaggableOn::Taggable::TagList.from(tags)

        joins = []
        conditions = []

        context = options.delete(:on)
        context_condition = context.blank? ? "" : sanitize_sql(["AND #{acts_as_taggable_on_tagging_model.table_name}.context = ?", context.to_s])

        if options.delete(:exclude)
          tags_conditions = tag_list.map { |t| sanitize_sql(["#{acts_as_taggable_on_tag_model.table_name}.name #{ActsAsTaggableOn.like_operator} ?", t]) }.join(" OR ")
          conditions << <<-SQL
#{table_name}.#{primary_key} NOT IN (
  SELECT #{acts_as_taggable_on_tagging_model.table_name}.taggable_id
  FROM #{acts_as_taggable_on_tagging_model.table_name}
  JOIN #{acts_as_taggable_on_tag_model.table_name}
  ON #{acts_as_taggable_on_tagging_model.table_name}.tag_id = #{acts_as_taggable_on_tag_model.table_name}.id
  AND (#{tags_conditions})
  WHERE #{acts_as_taggable_on_tagging_model.table_name}.taggable_type = #{quote_value(base_class.name)} #{context_condition}
)
SQL

        elsif options.delete(:any)
          tags_conditions = tag_list.map { |t| sanitize_sql(["#{acts_as_taggable_on_tag_model.table_name}.name #{ActsAsTaggableOn.like_operator} ?", t]) }.join(" OR ")
          conditions << <<-SQL
#{table_name}.#{primary_key} IN (
  SELECT #{acts_as_taggable_on_tagging_model.table_name}.taggable_id
  FROM #{acts_as_taggable_on_tagging_model.table_name}
  JOIN #{acts_as_taggable_on_tag_model.table_name}
  ON #{acts_as_taggable_on_tagging_model.table_name}.tag_id = #{acts_as_taggable_on_tag_model.table_name}.id
  AND (#{tags_conditions})
  WHERE #{acts_as_taggable_on_tagging_model.table_name}.taggable_type = #{quote_value(base_class.name)}
  #{context_condition}
)
SQL

        elsif tag_list.empty? && options(:match_all)
          conditions << <<-SQL
#{table_name}.#{primary_key} NOT IN (
  SELECT #{acts_as_taggable_on_tagging_model.table_name}.taggable_id
  FROM #{acts_as_taggable_on_tagging_model.table_name}
  WHERE #{acts_as_taggable_on_tagging_model.table_name}.taggable_type = #{quote_value(base_class.name)}
  #{context_condition}
)
SQL

      end