From 5929e13dca43a991ab13a9ec700fe570ce94e7de Mon Sep 17 00:00:00 2001
From: Simon G <simon.gockner@gmail.com>
Date: Fri, 13 Nov 2020 17:00:27 +0100
Subject: [PATCH] - handle Keys

---
 GBase/GBaseTable.cs | 40 ++++++++++++++++++++++++++++++++++++----
 1 file changed, 36 insertions(+), 4 deletions(-)

diff --git a/GBase/GBaseTable.cs b/GBase/GBaseTable.cs
index 4a20a1a..6571f69 100644
--- a/GBase/GBaseTable.cs
+++ b/GBase/GBaseTable.cs
@@ -10,6 +10,7 @@ using System.Threading;
 using System.Threading.Tasks;
 using GBase.Api;
 using GBase.Attributes;
+using GBase.Exceptions;
 using GBase.Factories;
 using GBase.FileHandling.Factories;
 using GBase.Helpers;
@@ -66,6 +67,18 @@ namespace GBase
         /// </summary>
         public List<T> Entries { get; }
 
+        private int CurrentLastKey
+        {
+            get
+            {
+                T lastEntry = Entries.LastOrDefault();
+                if (lastEntry == null)
+                    return -1;
+
+                return lastEntry.Key;
+            }
+        } 
+
 
         /// <summary>
         /// Initialize this <see cref="IGBase"/>
@@ -83,11 +96,13 @@ namespace GBase
             //TODO: Init columns list depending on GBaseColumnAttributes set for this GBaseTable
             foreach (var property in type.GetProperties())
             {
-                GBaseColumnAttribute gBaseColumnAttribute = property.GetCustomAttribute<GBaseColumnAttribute>();
+                GBaseColumnAttribute gBaseColumnAttribute = property.GetCustomAttribute<GBaseColumnAttribute>() ??
+                                                            property.GetAttributeFromInheritedInterfaces<GBaseColumnAttribute>();
+
                 if (gBaseColumnAttribute == null)
                     continue;
 
-                IGBaseColumn gBaseColumn = _gBaseColumnFactory.Create(property.Name, property.PropertyType);
+                IGBaseColumn gBaseColumn = _gBaseColumnFactory.Create(property.Name, property.PropertyType, gBaseColumnAttribute.IsKey);
                 AddColumn(gBaseColumn);
             }
             
@@ -102,7 +117,7 @@ namespace GBase
                     T entry = new T();
                     
                     List<object> parameters = new List<object>();
-                    foreach (var column in Columns)
+                    foreach (var column in Columns.Where(c => !c.IsKey))
                     {
                         using IPoolItem<IDataHandler> dataHandlerItem = await _dataHandlerPool.RequestDataHandler(this, false, cancellationToken);
                         
@@ -112,8 +127,18 @@ namespace GBase
                             typeof(T), column.Type,
                             file.File, column.Name, cancellationToken));
                     }
+
+                    IGBaseColumn keyColumn = Columns.FirstOrDefault(c => c.IsKey);
+                    if (keyColumn == null)
+                        throw new MissingKeyColumnException<T>();
+
+                    GBaseKey key = new GBaseKey();
+                    using (IPoolItem<IDataHandler> dataHandlerItem = await _dataHandlerPool.RequestDataHandler(this, false, cancellationToken))
+                    {
+                        key.Key = await dataHandlerItem.Use().GetValue<T, int>(file.File, keyColumn.Name, cancellationToken);
+                    }
                     
-                    entry.Initialize(parameters);
+                    entry.Initialize(key, parameters);
 
                     file.Entry = entry;
                     Entries.Add(entry);
@@ -158,6 +183,13 @@ namespace GBase
         /// <returns>True if successful, false if not</returns>
         public async Task<bool> AddEntry(T entry, CancellationToken cancellationToken)
         {
+            entry.Key ??= new GBaseKey();
+            
+            if (entry.Key != -1)
+                throw new InvalidKeyException("Key of entry is already set. Make sure it is -1 when initializing.");
+            
+            entry.Key.Key = CurrentLastKey + 1; //set next possible key
+            
             Entries.Add(entry);
 
             using IGBaseFile file = _fileHandler.CreateEntryFile(entry, this);