discourse/plugins/discourse-ai/lib/utils/search.rb

# frozen_string_literal: true

module DiscourseAi
  module Utils
    class Search
      # arbitrary but we need something safe here
      MAX_RESULTS_LIMIT = 200

      def self.perform_search(
        search_query: nil,
        category: nil,
        user: nil,
        order: nil,
        max_posts: nil,
        tags: nil,
        before: nil,
        after: nil,
        status: nil,
        hyde: true,
        max_results: 20,
        current_user: nil,
        result_style: :compact
      )
        max_results = max_results.to_i
        raise ArgumentError, "max_results must be a positive integer" if max_results <= 0
        max_results = MAX_RESULTS_LIMIT if max_results > MAX_RESULTS_LIMIT

        search_terms = []

        search_terms << search_query.strip if search_query.present?
        search_terms << "category:#{category}" if category.present?
        search_terms << "user:#{user}" if user.present?
        search_terms << "order:#{order}" if order.present?
        search_terms << "max_posts:#{max_posts}" if max_posts.present?
        search_terms << "tags:#{tags}" if tags.present?
        search_terms << "before:#{before}" if before.present?
        search_terms << "after:#{after}" if after.present?
        search_terms << "status:#{status}" if status.present?

        guardian = Guardian.new(current_user)

        search_string = search_terms.join(" ").to_s

        begin
          results = ::Search.execute(search_string, search_type: :full_page, guardian: guardian)
        rescue Discourse::InvalidAccess => e
          return(
            {
              args: {
                search_query:,
                category:,
                user:,
                order:,
                max_posts:,
                tags:,
                before:,
                after:,
                status:,
                max_results:,
              }.compact,
              rows: [],
              instruction: I18n.t("invalid_access"),
              error: e.message,
            }
          )
        end

        results_limit = max_results

        should_try_semantic_search =
          SiteSetting.ai_embeddings_enabled && SiteSetting.ai_embeddings_semantic_search_enabled &&
            search_query.present?

        max_semantic_results = max_results / 4
        results_limit = results_limit - max_semantic_results if should_try_semantic_search

        posts = results&.posts || []
        posts = posts[0..results_limit.to_i - 1]

        if should_try_semantic_search
          semantic_search = DiscourseAi::Embeddings::SemanticSearch.new(guardian)
          topic_ids = Set.new(posts.map(&:topic_id))

          search = ::Search.new(search_string, guardian: guardian)

          semantic_results = nil
          begin
            semantic_results = semantic_search.search_for_topics(search.term, hyde: hyde)
          rescue => e
            Discourse.warn_exception(e, message: "Semantic search failed")
          end

          if semantic_results
            semantic_results = search.apply_filters(semantic_results)

            semantic_results.each do |post|
              next if topic_ids.include?(post.topic_id)

              topic_ids << post.topic_id
              posts << post

              break if posts.length >= max_results
            end
          end
        end

        # Construct search_args hash for consistent return format
        search_args = {
          search_query:,
          category:,
          user:,
          order:,
          max_posts:,
          tags:,
          before:,
          after:,
          status:,
          max_results:,
        }.compact

        if posts.blank?
          { args: search_args, rows: [], instruction: "nothing was found, expand your search" }
        else
          hidden_tags = DiscourseTagging.hidden_tag_names if SiteSetting.tagging_enabled
          format_results(posts, args: search_args, result_style: result_style) do |post|
            format_row(topic: post.topic, post:, hidden_tags:)
          end
        end
      end

      def self.format_row(topic:, post: nil, hidden_tags: nil)
        row = {
          title: topic.title,
          # this is deliberate, we don't want to repeat https://example.com/ in every result, but we need subfolder
          url: post ? post.relative_url : topic.relative_url,
          username: post ? post.user&.username : topic.user&.username,
          excerpt: post ? post.excerpt : topic.excerpt,
          created: post ? post.created_at : topic.created_at,
          category: category_breadcrumb(topic.category),
          likes: post ? post.like_count : topic.like_count,
          topic_views: topic.views,
          topic_likes: topic.like_count,
          # deliberate - we don't want the number of "replies" in the Discourse sense, this is total number or replies to topic
          topic_replies: topic.posts_count - 1,
        }

        if SiteSetting.tagging_enabled
          hidden_tags ||= DiscourseTagging.hidden_tag_names
          tag_names = visible_tag_names(topic.tags, hidden_tags)
          row[:tags] = tag_names if tag_names
        end

        row
      end

      def self.category_breadcrumb(category)
        [category&.parent_category&.name, category&.name].compact.join(" > ")
      end

      def self.visible_tag_names(tags, hidden_tags)
        return nil unless SiteSetting.tagging_enabled && tags.present?
        visible = tags.map(&:name) - hidden_tags
        visible.presence&.join(", ")
      end

      def self.format_results(rows, args: nil, result_style:)
        rows = rows&.map { |row| yield row } if block_given?
        column_names = nil

        if result_style == :compact
          index = -1
          column_indexes = {}

          rows =
            rows&.map do |data|
              new_row = []
              data.each do |key, value|
                found_index = column_indexes[key.to_s] ||= (index += 1)
                new_row[found_index] = value
              end
              new_row
            end
          column_names = column_indexes.keys
        end

        result = { rows: rows }
        result[:column_names] = column_names if column_names
        result[:args] = args if args
        result
      end
    end
  end
end