Вот теперь точно все работает и все сделано (надеюсь)

LawFirm/LawFirm/FormShopSell.cs

@@ -66,10 +66,9 @@ namespace LawFirmView
             try
             {
                 var operationResult = _logicS.SellDocument(
-                    new DocumentSearchModel
+                    new DocumentBindingModel
                     {
-                        Id = Convert.ToInt32(comboBoxDocument.SelectedValue),
-                        DocumentName = comboBoxDocument.Text
+                        Id = Convert.ToInt32(comboBoxDocument.SelectedValue)
                     },
                     Convert.ToInt32(textBoxCount.Text)
                 );

LawFirm/LawFirmBusinessLogic/BusinessLogics/OrderLogic.cs

@@ -17,11 +17,16 @@ namespace LawFirmBusinessLogic.BusinessLogics
     {
         private readonly ILogger _logger;
         private readonly IOrderStorage _orderStorage;
+        private readonly IShopLogic _shopLogic;
+        private readonly IDocumentStorage _documentStorage;
 
-        public OrderLogic(ILogger<OrderLogic> logger, IOrderStorage orderStorage)
+
+        public OrderLogic(ILogger<OrderLogic> logger, IOrderStorage orderStorage, IShopLogic shopLogic, IDocumentStorage documentStorage)
         {
             _logger = logger;
             _orderStorage = orderStorage;
+            _shopLogic = shopLogic;
+            _documentStorage = documentStorage;
         }
 
         public bool CreateOrder(OrderBindingModel model)
@@ -73,6 +78,22 @@ namespace LawFirmBusinessLogic.BusinessLogics
                 _logger.LogWarning("Status update to " + newStatus.ToString() +" operation failed. Order status incorrect.");
                 return false;
             }
+
+            if (newStatus == OrderStatus.Готов)
+            {
+                var document = _documentStorage.GetElement(new DocumentSearchModel() { Id = model.DocumentId});
+                if (document == null)
+                {
+                    _logger.LogWarning("Status update to " + newStatus.ToString() + " operation failed. Document not found.");
+                    return false;
+                }
+                if (_shopLogic.CheckThenSupplyMany(document, model.Count) == false)
+                {
+                    _logger.LogWarning("Status update to " + newStatus.ToString() + " operation failed. Shop supply error.");
+                    return false;
+                }
+            }
+
             model.Status = newStatus;
             if (model.Status == OrderStatus.Выдан) model.DateImplement = DateTime.Now;
             if (_orderStorage.Update(model) == null)

LawFirm/LawFirmBusinessLogic/BusinessLogics/ShopLogic.cs

@@ -116,8 +116,68 @@ namespace LawFirmBusinessLogic.BusinessLogics
             }
             return true;
         }
+        public bool CheckThenSupplyMany(IDocumentModel document, int count)
+        {
+            if (count <= 0)
+            {
+                _logger.LogWarning("Check then supply operation error. Document count < 0.");
+                return false;
+            }
 
-        public bool SellDocument(DocumentSearchModel document, int count)
+            int freeSpace = 0;
+            foreach(var shop in _shopStorage.GetFullList())
+            {
+                freeSpace += shop.MaxCountDocuments;
+                foreach (var doc in shop.ShopDocuments)
+                {
+                    freeSpace -= doc.Value.Item2;
+                }
+            }
+
+            if (freeSpace - count < 0) 
+            {
+                _logger.LogWarning("Check then supply operation error. There's no place for new docs in shops.");
+                return false;
+            }
+
+            foreach (var shop in _shopStorage.GetFullList())
+            {
+                freeSpace = shop.MaxCountDocuments;
+                foreach (var doc in shop.ShopDocuments)
+                {
+                    freeSpace -= doc.Value.Item2;
+                }
+                if (freeSpace == 0)
+                {
+                    continue;
+                }
+                if (freeSpace - count >= 0)
+                {
+                    if (SupplyDocuments(new() { Id = shop.Id}, document, count)) count = 0;
+                    else
+                    {
+                        _logger.LogWarning("Supply error");
+                        return false;
+                    }
+                }
+                if (freeSpace - count < 0)
+                {
+                    if (SupplyDocuments(new() { Id = shop.Id }, document, freeSpace)) count-= freeSpace;
+                    else
+                    {
+                        _logger.LogWarning("Supply error");
+                        return false;
+                    }
+                }
+                if (count <= 0)
+                {
+                    return true;
+                }
+            }
+            return false;
+        }
+
+        public bool SellDocument(IDocumentModel document, int count)
         {;
             return _shopStorage.SellDocument(document, count);
         }

LawFirm/LawFirmContracts/BusinessLogicContracts/IShopLogic.cs

@@ -18,7 +18,7 @@ namespace LawFirmContracts.BusinessLogicContracts
         bool Update(ShopBindingModel model);
         bool Delete(ShopBindingModel model);
         bool SupplyDocuments(ShopSearchModel model, IDocumentModel document, int count);
-
-        bool SellDocument(DocumentSearchModel document, int count);
+        bool SellDocument(IDocumentModel document, int count);
+        bool CheckThenSupplyMany(IDocumentModel document, int count);
     }
 }

LawFirm/LawFirmContracts/StorageContracts/IShopStorage.cs

@@ -1,6 +1,7 @@
 using LawFirmContracts.BindingModels;
 using LawFirmContracts.SearchModels;
 using LawFirmContracts.ViewModels;
+using LawFirmDataModels.Models;
 using System;
 using System.Collections.Generic;
 using System.Linq;
@@ -17,6 +18,6 @@ namespace LawFirmContracts.StorageContracts
         ShopViewModel? Insert(ShopBindingModel model);
         ShopViewModel? Update(ShopBindingModel model);
         ShopViewModel? Delete(ShopBindingModel model);
-        bool SellDocument(DocumentSearchModel model, int count);
+        bool SellDocument(IDocumentModel model, int count);
     }
 }

LawFirm/LawFirmFileImplement/Implements/ShopStorage.cs

@@ -2,6 +2,7 @@
 using LawFirmContracts.SearchModels;
 using LawFirmContracts.StorageContracts;
 using LawFirmContracts.ViewModels;
+using LawFirmDataModels.Models;
 using LawFirmFileImplement.Models;
 using System;
 using System.Collections.Generic;
@@ -80,9 +81,9 @@ namespace LawFirmFileImplement.Implements
             return shop.GetViewModel;
         }
 
-        public bool SellDocument(DocumentSearchModel model, int count)
+        public bool SellDocument(IDocumentModel model, int count)
         {
-            var document = source.Documents.FirstOrDefault(x => model.Id.HasValue && x.Id == model.Id);
+            var document = source.Documents.FirstOrDefault(x => x.Id == model.Id);
 
             var countStore = count;
 
@@ -142,7 +143,9 @@ namespace LawFirmFileImplement.Implements
                             MaxCountDocuments = shop.MaxCountDocuments,
                             ShopDocuments = documents
                         });
+                        source.SaveShops();
                         return true;
+
                     }
                 }
 
@@ -155,6 +158,7 @@ namespace LawFirmFileImplement.Implements
                     MaxCountDocuments = shop.MaxCountDocuments,
                     ShopDocuments = documents
                 });
+                source.SaveShops();
             }
 
             if (count > 0)

LawFirm/LawFirmListImplements/Implements/ShopStorage.cs

@@ -2,6 +2,7 @@
 using LawFirmContracts.SearchModels;
 using LawFirmContracts.StorageContracts;
 using LawFirmContracts.ViewModels;
+using LawFirmDataModels.Models;
 using LawFirmListImplements.Models;
 using System;
 using System.Collections.Generic;
@@ -116,7 +117,7 @@ namespace LawFirmListImplements.Implements
             return null;
         }
 
-        public bool SellDocument(DocumentSearchModel model, int count)
+        public bool SellDocument(IDocumentModel model, int count)
         {
             throw new NotImplementedException();
         }