Feature #33: Enhanced Device Importing

Dynamic device importing. better input parsing and 5 additional import
fields.

Disco.Services/Devices/Importing/DeviceImportFieldBase.cs

@@ -0,0 +1,44 @@
+using Disco.Data.Repository;
+using Disco.Models.Repository;
+using Disco.Models.Services.Devices.Importing;
+using System;
+using System.Collections.Generic;
+using System.Data;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Disco.Services.Devices.Importing
+{
+    internal abstract class DeviceImportFieldBase : IDeviceImportField
+    {
+        public abstract DeviceImportFieldTypes FieldType { get; }
+
+        public EntityState? FieldAction { get; protected set; }
+
+        public string ErrorMessage { get; protected set; }
+
+        public abstract object RawParsedValue { get; }
+        public abstract string FriendlyValue { get; }
+        public abstract string FriendlyPreviousValue { get; }
+
+        public abstract bool Parse(DiscoDataContext Database, IDeviceImportCache Cache, DeviceImportContext Context, int RecordIndex, string DeviceSerialNumber, Device ExistingDevice, Dictionary<DeviceImportFieldTypes, string> Values, string Value);
+        public abstract bool Apply(DiscoDataContext Database, Device Device);
+
+        public abstract int? GuessHeader(DiscoDataContext Database, DeviceImportContext Context);
+
+        #region Helpers
+        protected bool Error(string Message)
+        {
+            this.ErrorMessage = Message;
+            this.FieldAction = null;
+            return false;
+        }
+        protected bool Success(EntityState Action)
+        {
+            this.FieldAction = Action;
+            return true;
+        }
+        #endregion
+    }
+}