Remove inventory, delete transactions

InventoryTraker.Web/Controllers/TransactionController.cs

@@ -2,9 +2,7 @@
 using System.Collections.Generic;
 using System.Linq;
 using System.Web.Mvc;
-using AutoMapper;
 using AutoMapper.QueryableExtensions;
-using InventoryTraker.Web.ActionResults;
 using InventoryTraker.Web.Core;
 using InventoryTraker.Web.Data;
 using InventoryTraker.Web.Models;
@@ -35,7 +33,7 @@ namespace InventoryTraker.Web.Controllers
 			return BetterJson(viewModels);
 		}
 
-		public JsonResult GetTransactions(int? pageNumber, int? pageSize, int? inventoryId)
+		public JsonResult Get(int? pageNumber, int? pageSize, int? inventoryId)
 		{
 			IQueryable<Transaction> query =
 				_context.Transactions
@@ -56,5 +54,38 @@ namespace InventoryTraker.Web.Controllers
 						.ToArray();
 			return BetterJson(new { totalItems, transactions });
 		}
+
+		public JsonResult Delete(int transactionId)
+		{
+			var transaction = _context.Transactions.Find(transactionId);
+
+			if (transaction == null)
+				return GetErrorListJson("Transaction not found");
+
+			var inventory = transaction.Inventory;
+			var inventoryId = inventory.Id;
+
+			var inventoryTransactionsMostRecent =
+				inventory
+					.Transactions.OrderByDescending(t => t.TransactionDate)
+					.First() == transaction;
+			
+			if (!inventoryTransactionsMostRecent)
+				return GetErrorListJson("Delete permitted only when transaction is the most recent");
+
+			// roll back that transaction
+			inventory.Quantity -= transaction.AddedQuantity;
+			inventory.Quantity += transaction.RemovedQuantity;
+
+			inventory.Transactions.Remove(transaction);
+			_context.Transactions.Remove(transaction);
+
+			if (!inventory.Transactions.Any())
+				_context.Inventories.Remove(inventory);
+
+			_context.SaveChanges();
+
+			return BetterJson(new { inventoryId});
+		}
 	}
 }