Add extraction of Part nested data

SabreTools.Serialization/Internal.cs

@@ -0,0 +1,60 @@
+using System.Collections.Generic;
+using System.Linq;
+using SabreTools.Models.Internal;
+
+namespace SabreTools.Serialization
+{
+    public class Internal
+    {
+        /// <summary>
+        /// Extract nested items from a Part
+        /// </summary>
+        public static DatItem[]? ExtractItems(Part? item)
+        {
+            if (item == null)
+                return null;
+
+            var datItems = new List<DatItem>();
+
+            var features = item.Read<Feature[]>(Part.FeatureKey);
+            if (features != null && features.Any())
+                datItems.AddRange(features);
+
+            var dataAreas = item.Read<DataArea[]>(Part.DataAreaKey);
+            if (dataAreas != null && dataAreas.Any())
+                datItems.AddRange(dataAreas.SelectMany(ExtractItems));
+
+            var diskAreas = item.Read<DiskArea[]>(Part.DiskAreaKey);
+            if (diskAreas != null && diskAreas.Any())
+                datItems.AddRange(diskAreas.SelectMany(ExtractItems));
+
+            var dipSwitches = item.Read<DipSwitch[]>(Part.DipSwitchKey);
+            if (dipSwitches != null && dipSwitches.Any())
+                datItems.AddRange(dipSwitches);
+
+            return datItems.ToArray();
+        }
+
+        /// <summary>
+        /// Extract nested items from a DataArea
+        /// </summary>
+        private static Rom[]? ExtractItems(DataArea? item)
+        {
+            if (item == null)
+                return null;
+
+            return item.Read<Rom[]>(DataArea.RomKey);
+        }
+
+        /// <summary>
+        /// Extract nested items from a DiskArea
+        /// </summary>
+        private static Disk[]? ExtractItems(DiskArea? item)
+        {
+            if (item == null)
+                return null;
+
+            return item.Read<Disk[]>(DiskArea.DiskKey);
+        }
+    }
+}