compute variations stats from sent instead of delivered

Author: pierre-b

internal/domain/broadcast.go

@@ -805,12 +805,12 @@ func (r *GetTestResultsRequest) FromURLParams(values url.Values) error {
 type VariationResult struct {
 	TemplateID   string  `json:"template_id"`
 	TemplateName string  `json:"template_name"`
-	Recipients   int     `json:"recipients"`
-	Delivered    int     `json:"delivered"`
+	Recipients   int     `json:"recipients"` // Total sent emails (used as denominator for rate calculations)
+	Delivered    int     `json:"delivered"`  // Total delivered emails (ESP-dependent, may not be available)
 	Opens        int     `json:"opens"`
 	Clicks       int     `json:"clicks"`
-	OpenRate     float64 `json:"open_rate"`
-	ClickRate    float64 `json:"click_rate"`
+	OpenRate     float64 `json:"open_rate"`  // Opens / Recipients
+	ClickRate    float64 `json:"click_rate"` // Clicks / Recipients
 }
 
 // TestResultsResponse represents the response for A/B test results

internal/service/broadcast_service.go

@@ -966,15 +966,15 @@ func (s *BroadcastService) GetTestResults(ctx context.Context, workspaceID, broa
 		// Calculate rates (avoid division by zero)
 		openRate := 0.0
 		clickRate := 0.0
-		if stats.TotalDelivered > 0 {
-			openRate = float64(stats.TotalOpened) / float64(stats.TotalDelivered)
-			clickRate = float64(stats.TotalClicked) / float64(stats.TotalDelivered)
+		if stats.TotalSent > 0 {
+			openRate = float64(stats.TotalOpened) / float64(stats.TotalSent)
+			clickRate = float64(stats.TotalClicked) / float64(stats.TotalSent)
 		}
 
 		variationResults[variation.TemplateID] = &domain.VariationResult{
 			TemplateID:   variation.TemplateID,
 			TemplateName: "Template " + variation.TemplateID, // Could fetch actual template name
-			Recipients:   stats.TotalSent,
+			Recipients:   stats.TotalSent,                    // Use sent as recipients to match rate calculation denominator
 			Delivered:    stats.TotalDelivered,
 			Opens:        stats.TotalOpened,
 			Clicks:       stats.TotalClicked,