module MakeTaggable::Taggable::TaggedWithQuery
  class AllTagsQuery < QueryBase
    def build
      taggable_model.joins(each_tag_in_list)
        .group(by_taggable)
        .having(tags_that_matches_count)
        .order(order_conditions)
        .readonly(false)
    end

    private

    def each_tag_in_list
      arel_join = taggable_arel_table

      tag_list.each do |tag|
        tagging_alias = tagging_arel_table.alias(tagging_alias(tag))
        arel_join = arel_join
          .join(tagging_alias)
          .on(on_conditions(tag, tagging_alias))
      end

      if options[:match_all].present?
        arel_join = arel_join
          .join(tagging_arel_table, Arel::Nodes::OuterJoin)
          .on(
            match_all_on_conditions
          )
      end

      arel_join.join_sources
    end

    def on_conditions(tag, tagging_alias)
      on_condition = tagging_alias[:taggable_id].eq(taggable_arel_table[taggable_model.primary_key])
        .and(tagging_alias[:taggable_type].eq(taggable_model.base_class.name))
        .and(
          tagging_alias[:tag_id].in(
            tag_arel_table.project(tag_arel_table[:id]).where(tag_match_type(tag))
          )
        )

      if options[:start_at].present?
        on_condition = on_condition.and(tagging_alias[:created_at].gteq(options[:start_at]))
      end

      if options[:end_at].present?
        on_condition = on_condition.and(tagging_alias[:created_at].lteq(options[:end_at]))
      end

      if options[:on].present?
        on_condition = on_condition.and(tagging_alias[:context].eq(options[:on]))
      end

      if (owner = options[:owned_by]).present?
        on_condition = on_condition.and(tagging_alias[:tagger_id].eq(owner.id))
          .and(tagging_alias[:tagger_type].eq(owner.class.base_class.to_s))
      end

      on_condition
    end

    def match_all_on_conditions
      on_condition = tagging_arel_table[:taggable_id].eq(taggable_arel_table[taggable_model.primary_key])
        .and(tagging_arel_table[:taggable_type].eq(taggable_model.base_class.name))

      if options[:start_at].present?
        on_condition = on_condition.and(tagging_arel_table[:created_at].gteq(options[:start_at]))
      end

      if options[:end_at].present?
        on_condition = on_condition.and(tagging_arel_table[:created_at].lteq(options[:end_at]))
      end

      if options[:on].present?
        on_condition = on_condition.and(tagging_arel_table[:context].eq(options[:on]))
      end

      on_condition
    end

    def by_taggable
      return [] unless options[:match_all].present?

      taggable_arel_table[taggable_model.primary_key]
    end

    def tags_that_matches_count
      return [] unless options[:match_all].present?

      taggable_model.find_by_sql(tag_arel_table.project(Arel.star.count).where(tags_match_type).to_sql)

      tagging_arel_table[:taggable_id].count.eq(
        tag_arel_table.project(Arel.star.count).where(tags_match_type)
      )
    end

    def order_conditions
      order_by = []
      order_by << tagging_arel_table.project(tagging_arel_table[Arel.star].count.as("taggings_count")).order("taggings_count DESC").to_sql if options[:order_by_matching_tag_count].present? && options[:match_all].blank?

      order_by << options[:order] if options[:order].present?
      order_by.join(", ")
    end

    def tagging_alias(tag)
      alias_base_name = taggable_model.base_class.name.downcase
      adjust_taggings_alias("#{alias_base_name[0..11]}_taggings_#{MakeTaggable::Utils.sha_prefix(tag)}")
    end
  end
end