fix: manage stock

backend/gestion/db/db_basket.go

@@ -46,14 +46,18 @@ func (d *Database) GetAllProductsInBasket(username string) ([]models.Panier, err
 func (d *Database) DecrementAndAddToBasket(username string, productID int, quantity float64) (*models.Panier, error) {
 	var basket models.Panier
 	err := d.GDB.Transaction(func(tx *gorm.DB) error {
-		result := tx.Exec(`UPDATE products SET stock = stock - ? WHERE id = ? AND stock >= ?`,
-			quantity, productID, quantity)
+		var currentStock float64
+		if err := tx.Raw(`SELECT stock FROM products WHERE id = ? FOR UPDATE`, productID).Scan(&currentStock).Error; err != nil {
+			return fmt.Errorf("erreur lecture stock: %w", err)
+		}
+		if currentStock < quantity {
+			return fmt.Errorf("stock insuffisant")
+		}
+
+		result := tx.Exec(`UPDATE products SET stock = stock - ? WHERE id = ?`, quantity, productID)
 		if result.Error != nil {
 			return fmt.Errorf("erreur stock: %w", result.Error)
 		}
-		if result.RowsAffected == 0 {
-			return fmt.Errorf("stock insuffisant")
-		}
 
 		var priceResult struct {
 			Price float64 `gorm:"column:price"`
@@ -100,7 +104,7 @@ func (d *Database) DeleteProductFromBasket(basketID int) error {
 			ProductID int     `gorm:"column:product_id"`
 			Quantity  float64 `gorm:"column:quantity"`
 		}
-		if err := tx.Raw(`SELECT product_id, quantity FROM baskets WHERE id = ?`, basketID).Scan(&item).Error; err != nil {
+		if err := tx.Raw(`SELECT product_id, quantity FROM baskets WHERE id = ? FOR UPDATE`, basketID).Scan(&item).Error; err != nil {
 			return fmt.Errorf("produit non trouvé dans le panier")
 		}
 		if item.ProductID == 0 {
@@ -126,6 +130,17 @@ func (d *Database) DeleteProductFromBasket(basketID int) error {
 // ClearBasket vide complètement le panier d'un utilisateur et restitue les stocks.
 func (d *Database) ClearBasket(username string) error {
 	return d.GDB.Transaction(func(tx *gorm.DB) error {
+		var items []struct {
+			ProductID int     `gorm:"column:product_id"`
+			Quantity  float64 `gorm:"column:quantity"`
+		}
+		if err := tx.Raw(`SELECT product_id, quantity FROM baskets WHERE username = ? FOR UPDATE`, username).Scan(&items).Error; err != nil {
+			return fmt.Errorf("erreur lecture panier: %w", err)
+		}
+		if len(items) == 0 {
+			return nil
+		}
+
 		if err := tx.Exec(`
 			UPDATE products p
 			SET stock = stock + b.quantity
@@ -157,6 +172,36 @@ func (d *Database) GetBasketItemOwner(basketID int) (string, error) {
 	return username, nil
 }
 
+// GetUnavailableBasketItems retourne les noms des produits du panier dont tous les prix ont été désactivés.
+func (d *Database) GetUnavailableBasketItems(username string) ([]string, error) {
+	var names []string
+	err := d.GDB.Raw(`
+		SELECT DISTINCT p.name
+		FROM baskets b
+		INNER JOIN products p ON b.product_id = p.id
+		WHERE b.username = ?
+		  AND NOT EXISTS (
+		      SELECT 1 FROM product_prices pp
+		      WHERE pp.product_id = b.product_id
+		        AND pp.quantity <= b.quantity
+		        AND pp.active_price = true
+		  )`, username).Scan(&names).Error
+	if err != nil {
+		return nil, fmt.Errorf("erreur vérification disponibilité: %w", err)
+	}
+	return names, nil
+}
+
+// GetReservedQuantityInBaskets retourne la somme des quantités d'un produit dans tous les paniers actifs.
+func (d *Database) GetReservedQuantityInBaskets(productID int) (float64, error) {
+	var total float64
+	err := d.GDB.Raw(`SELECT COALESCE(SUM(quantity), 0) FROM baskets WHERE product_id = ?`, productID).Scan(&total).Error
+	if err != nil {
+		return 0, fmt.Errorf("erreur lecture réservations panier: %w", err)
+	}
+	return total, nil
+}
+
 func (d *Database) GetBasketItems(username string) ([]map[string]any, error) {
 	var items []map[string]any
 	if err := d.GDB.Raw(`SELECT product_id, quantity::float8 as quantity, price::float8 as price FROM baskets WHERE username = ?`,