Реализована логика продажи изделий

ConfectioneryDatabaseImplement/ShopStorage.cs

@@ -107,34 +107,37 @@ namespace ConfectioneryDatabaseImplement
 
         public bool HasNeedPastries(IPastryModel pastry, int needCount)
         {
-            using var context = new ConfectioneryDatabase();
-            var resultCount = context.Shops
-                .Select(shop => shop.Pastries
-                    .FirstOrDefault(x => x.Key == pastry.Id).Value.Item2)
-                .Sum();
-            return resultCount >= needCount;
+            throw new NotImplementedException();
         }
 
         public bool SellPastries(IPastryModel pastry, int needCount)
         {
-            if (!HasNeedPastries(pastry, needCount))
-            {
-                return false;
-            }
             using var context = new ConfectioneryDatabase();
-            foreach (var shop in context.Shops.Where(shop => shop.Pastries.ContainsKey(pastry.Id)))
+            using var transaction = context.Database.BeginTransaction();
+            foreach (var sp in context.ShopPastries.Where(x => x.PastryId == pastry.Id))
             {
-                var tuple = shop.Pastries[pastry.Id];
-                var diff = Math.Min(tuple.Item2, needCount);
-                shop.Pastries[pastry.Id] = (tuple.Item1, tuple.Item2 - diff);
-                
-                needCount -= diff;
-                if (needCount <= 0)
+                var res = Math.Min(needCount, sp.Count);
+                sp.Count -= res;
+                needCount -= res;
+                if (sp.Count == 0) // Изделия больше нет в магазине, значит удаляем его
                 {
-                    return true;
+                    context.ShopPastries.Remove(sp);
+                }
+                if (needCount == 0) // Нельзя коммитить изменения в цикле, что использует контекст, поэтому выходим
+                {
+                    break;
                 }
             }
-            return true;
+            if (needCount == 0)
+            {
+                context.SaveChanges();
+                transaction.Commit();
+            }
+            else
+            {
+                transaction.Rollback();
+            }
+            return needCount == 0;
         }
     }
 }