Refactor recommendation response handling and enhance enrichment logic

- Removed the `buildRecommendedTenderResponsesParallel` method and replaced it with `buildRecommendedTenderListResponses`, simplifying the response building process.
- Introduced `enrichRecommendedTenderResponsesParallel` to handle enrichment of tender responses in parallel, improving performance.
- Updated the `Recommend` method to utilize the new enrichment logic, ensuring timely and efficient processing of recommendations.
- Cleaned up unused functions and imports in `recommendation_page_cache.go` and `recommendation_response.go`, enhancing code clarity and maintainability.

This update streamlines the recommendation response handling and improves the overall efficiency of the tender recommendation service.

internal/tender/recommendation_page_cache.go

@@ -8,9 +8,6 @@ import (
 	"time"
 
 	"github.com/redis/go-redis/v9"
-	"go.mongodb.org/mongo-driver/v2/bson"
-	"golang.org/x/sync/errgroup"
-
 	"tm/internal/company"
 	"tm/pkg/response"
 )
@@ -92,7 +89,7 @@ func (s *tenderService) buildRecommendedTendersPageCache(ctx context.Context, co
 		return nil
 	}
 
-	responses := s.buildRecommendedTenderResponsesParallel(ctx, items, language)
+	responses := s.buildRecommendedTenderListResponses(items, language)
 	page := cachedRecommendedTendersPage{
 		BuiltAt:   time.Now().Unix(),
 		CompanyID: companyID,
@@ -204,54 +201,6 @@ func (s *tenderService) buildAllRankedRecommendations(
 	return out, nil
 }
 
-func (s *tenderService) buildRecommendedTenderResponsesParallel(
-	ctx context.Context,
-	items []rankedRecommendedTender,
-	language string,
-) []TenderResponse {
-	if len(items) == 0 {
-		return nil
-	}
-
-	out := make([]TenderResponse, len(items))
-	if len(items) == 1 {
-		out[0] = s.buildRecommendedTenderResponse(
-			ctx, items[0].tender, items[0].rank, items[0].analysis, items[0].tenderRef, language,
-			newRecommendationTranslationCache(),
-		)
-		return out
-	}
-
-	translationCache := newRecommendationTranslationCache()
-	group, groupCtx := errgroup.WithContext(ctx)
-	group.SetLimit(recommendationPageCacheConcurrency)
-
-	for i := range items {
-		i := i
-		item := items[i]
-		group.Go(func() error {
-			out[i] = s.buildRecommendedTenderResponse(
-				groupCtx, item.tender, item.rank, item.analysis, item.tenderRef, language, translationCache,
-			)
-			return nil
-		})
-	}
-
-	if err := group.Wait(); err != nil {
-		s.logger.Warn("Parallel recommendation page cache build degraded to sequential", map[string]interface{}{
-			"error": err.Error(),
-			"count": len(items),
-		})
-		for i, item := range items {
-			out[i] = s.buildRecommendedTenderResponse(
-				ctx, item.tender, item.rank, item.analysis, item.tenderRef, language, translationCache,
-			)
-		}
-	}
-
-	return out
-}
-
 func (s *tenderService) recommendFromPageCache(
 	ctx context.Context,
 	companyID string,
@@ -292,8 +241,11 @@ func (s *tenderService) recommendFromPageCache(
 		end = len(filtered)
 	}
 
+	paged := append([]TenderResponse(nil), filtered[start:end]...)
+	paged = s.enrichRecommendedTenderResponsesParallel(ctx, paged, lang)
+
 	return &SearchResponse{
-		Tenders:  append([]TenderResponse(nil), filtered[start:end]...),
+		Tenders:  paged,
 		Metadata: pagination.ListMeta(total, "", end < len(filtered), start),
 	}, true
 }
@@ -376,21 +328,6 @@ func filterCachedRecommendedTenders(
 	return out
 }
 
-func tenderFromRecommendationResponse(item TenderResponse) Tender {
-	var tender Tender
-	if id, err := bson.ObjectIDFromHex(strings.TrimSpace(item.ID)); err == nil {
-		tender.ID = id
-	}
-	tender.ContractFolderID = item.ContractFolderID
-	tender.NoticePublicationID = item.NoticePublicationID
-	tender.RelatedNoticePublicationIDs = append([]string(nil), item.RelatedNoticePublicationIDs...)
-	tender.Status = item.Status
-	tender.PublicationDate = item.PublicationDate
-	tender.SubmissionDeadline = item.SubmissionDeadline
-	tender.TenderDeadline = item.TenderDeadline
-	return tender
-}
-
 // RecommendedTendersPageCacheKeyPrefix is shared with company invalidation logic.
 const RecommendedTendersPageCacheKeyPrefix = recommendedTendersPageCacheKeyPrefix