Enhance dashboard repository and service with caching and aggregation improvements

- Introduced caching mechanisms for summary and statistics in the dashboard service, improving performance by reducing redundant data retrieval.
- Refactored the Summary method to utilize MongoDB aggregation for more efficient data processing and retrieval.
- Added synchronization features using singleflight to prevent duplicate processing of requests for cached data.
- Updated the repository to include a cachedScrapedTendersScope method, enhancing the efficiency of scraped document statistics retrieval.

This update significantly optimizes the dashboard's performance and data handling capabilities, ensuring faster response times and reduced load on the database.

internal/dashboard/statistics_repository.go

@@ -16,6 +16,10 @@ import (
 
 const noticesCollectionName = "notices"
 
+// scrapedScopeCacheTTL avoids listing every MinIO object on each statistics request while
+// keeping counts aligned with the tender panel (MinIO is the source of truth for scraped docs).
+const scrapedScopeCacheTTL = 5 * time.Minute
+
 // scrapedTendersScope is the resolved Mongo filter for tenders with scraped documents.
 // zero is set when MinIO reports no procedure folders; callers must return zero without querying.
 type scrapedTendersScope struct {
@@ -28,7 +32,8 @@ func (r *repository) Statistics(ctx context.Context, days int, startUnix int64)
 	endDay := time.Date(now.Year(), now.Month(), now.Day(), 0, 0, 0, 0, time.UTC)
 	startDay := endDay.AddDate(0, 0, -(days - 1))
 
-	scrapedScope, err := r.resolveScrapedTendersScope(ctx)
+	// Resolve scraped-document scope from MinIO (cached); falls back to Mongo flags on error.
+	scrapedScope, err := r.cachedScrapedTendersScope(ctx)
 	if err != nil {
 		return nil, err
 	}
@@ -187,6 +192,58 @@ func (r *repository) totalScrapedTenders(ctx context.Context, scope scrapedTende
 	return r.ormRepo.Count(ctx, scope.match)
 }
 
+func mongoScrapedTendersScope() scrapedTendersScope {
+	return scrapedTendersScope{
+		match: bson.M{
+			"processing_metadata.documents_scraped": true,
+			"scraped_documents":                   bson.M{"$exists": true, "$ne": bson.A{}},
+		},
+	}
+}
+
+func (r *repository) cachedScrapedTendersScope(ctx context.Context) (scrapedTendersScope, error) {
+	now := time.Now()
+
+	r.scrapedScopeMu.Lock()
+	if r.scrapedScopeCached && now.Before(r.scrapedScopeExpiry) {
+		scope := r.scrapedScope
+		r.scrapedScopeMu.Unlock()
+		return scope, nil
+	}
+	r.scrapedScopeMu.Unlock()
+
+	v, err, _ := r.scrapedScopeGroup.Do("scraped-scope", func() (interface{}, error) {
+		r.scrapedScopeMu.Lock()
+		if r.scrapedScopeCached && time.Now().Before(r.scrapedScopeExpiry) {
+			scope := r.scrapedScope
+			r.scrapedScopeMu.Unlock()
+			return scope, nil
+		}
+		r.scrapedScopeMu.Unlock()
+
+		scope, resolveErr := r.resolveScrapedTendersScope(ctx)
+		if resolveErr != nil {
+			r.logger.Warn("MinIO scraped scope unavailable, using Mongo fallback for dashboard statistics", map[string]interface{}{
+				"error": resolveErr.Error(),
+			})
+			return mongoScrapedTendersScope(), nil
+		}
+
+		r.scrapedScopeMu.Lock()
+		r.scrapedScope = scope
+		r.scrapedScopeExpiry = time.Now().Add(scrapedScopeCacheTTL)
+		r.scrapedScopeCached = true
+		r.scrapedScopeMu.Unlock()
+
+		return scope, nil
+	})
+	if err != nil {
+		return scrapedTendersScope{}, err
+	}
+
+	return v.(scrapedTendersScope), nil
+}
+
 func (r *repository) resolveScrapedTendersScope(ctx context.Context) (scrapedTendersScope, error) {
 	folderIDs, err := r.scrapedDocumentsFolderIDs(ctx)
 	if err != nil {