FIX[BE}: really fixed duplicate SO number

internal/database/migrations/20251210044651_create_so_number_sequence.down.sql

@@ -0,0 +1,3 @@
+-- Drop function and sequence for sales order numbers
+DROP FUNCTION IF EXISTS generate_so_number();
+DROP SEQUENCE IF EXISTS so_number_seq;

internal/database/migrations/20251210044651_create_so_number_sequence.up.sql

@@ -0,0 +1,12 @@
+-- Create sequence for sales order numbers
+CREATE SEQUENCE so_number_seq START WITH 1 INCREMENT BY 1;
+
+CREATE OR REPLACE FUNCTION generate_so_number()
+RETURNS VARCHAR AS $$
+DECLARE
+    next_val INTEGER;
+BEGIN
+    next_val := nextval('so_number_seq');
+    RETURN 'SO-' || LPAD(next_val::TEXT, 5, '0');
+END;
+$$ LANGUAGE plpgsql;

internal/modules/marketing/repositories/salesorder.repository.go

@@ -3,14 +3,10 @@ package repository
 import (
 	"context"
 	"fmt"
-	"strconv"
-	"strings"
 
 	"gitlab.com/mbugroup/lti-api.git/internal/common/repository"
 	entity "gitlab.com/mbugroup/lti-api.git/internal/entities"
-	"gitlab.com/mbugroup/lti-api.git/internal/utils"
 	"gorm.io/gorm"
-	"gorm.io/gorm/clause"
 )
 
 type MarketingRepository interface {
@@ -43,82 +39,19 @@ func (r *MarketingRepositoryImpl) GetNextSequence(ctx context.Context) (uint, er
 }
 
 func (r *MarketingRepositoryImpl) NextSoNumber(ctx context.Context, tx *gorm.DB) (string, error) {
-	return r.generateSequentialNumber(ctx, tx, "so_number", utils.MarketingSoNumberPrefix, utils.MarketingNumberPadding)
-}
-
-func parseNumericSuffix(value, prefix string) (int, bool) {
-	if !strings.HasPrefix(value, prefix) {
-		return 0, false
-	}
-	suffix := strings.TrimPrefix(value, prefix)
-	if suffix == "" {
-		return 0, false
-	}
-	trimmed := strings.TrimLeft(suffix, "0")
-	if trimmed == "" {
-		trimmed = "0"
-	}
-	number, err := strconv.Atoi(trimmed)
-	if err != nil {
-		return 0, false
-	}
-	return number, true
-}
-
-func (r *MarketingRepositoryImpl) numberExists(ctx context.Context, db *gorm.DB, column, value string) (bool, error) {
-	var count int64
-	if err := db.WithContext(ctx).
-		Model(&entity.Marketing{}).
-		Where(fmt.Sprintf("%s = ?", column), value).
-		Where("deleted_at IS NULL").
-		Count(&count).Error; err != nil {
-		return false, err
-	}
-	return count > 0, nil
-}
-
-func (r *MarketingRepositoryImpl) generateSequentialNumber(ctx context.Context, tx *gorm.DB, column, prefix string, padding int) (string, error) {
-
 	db := tx
 	if db == nil {
 		db = r.DB()
 	}
 
-	var values []string
+	var soNumber string
 	err := db.WithContext(ctx).
-		Model(&entity.Marketing{}).
-		Where(fmt.Sprintf("%s LIKE ?", column), prefix+"%").
-		Where("deleted_at IS NULL").
-		Select(column).
-		Order(fmt.Sprintf("%s DESC", column)).
-		Limit(20).
-		Clauses(clause.Locking{Strength: "UPDATE"}).
-		Pluck(column, &values).Error
+		Raw("SELECT generate_so_number()").
+		Scan(&soNumber).Error
+
 	if err != nil {
-		return "", err
+		return "", fmt.Errorf("failed to generate SO number: %w", err)
 	}
 
-	next := 1
-	for _, value := range values {
-		if number, ok := parseNumericSuffix(value, prefix); ok {
-			next = number + 1
-			break
-		}
-	}
-
-	const maxAttempts = 20
-	for attempt := 0; attempt < maxAttempts; attempt++ {
-		candidate := fmt.Sprintf("%s%0*d", prefix, padding, next)
-		exists, err := r.numberExists(ctx, db, column, candidate)
-		if err != nil {
-			return "", err
-		}
-		if !exists {
-			return candidate, nil
-		}
-		next++
-	}
-
-	return "", fmt.Errorf("unable to generate unique %s", column)
-
+	return soNumber, nil
 }