New: App health displayed in UI

src/NzbDrone.Core/HealthCheck/Checks/DroneFactoryCheck.cs

@@ -0,0 +1,50 @@
+using System;
+using System.IO;
+using NzbDrone.Common;
+using NzbDrone.Common.Disk;
+using NzbDrone.Core.Configuration;
+
+namespace NzbDrone.Core.HealthCheck.Checks
+{
+    public class DroneFactoryCheck : IProvideHealthCheck
+    {
+        private readonly IConfigService _configService;
+        private readonly IDiskProvider _diskProvider;
+
+        public DroneFactoryCheck(IConfigService configService, IDiskProvider diskProvider)
+        {
+            _configService = configService;
+            _diskProvider = diskProvider;
+        }
+
+        public HealthCheck Check()
+        {
+            var droneFactoryFolder = _configService.DownloadedEpisodesFolder;
+
+            if (droneFactoryFolder.IsNullOrWhiteSpace())
+            {
+                return new HealthCheck(HealthCheckResultType.Warning, "Drone factory folder is not configured");
+            }
+
+            if (!_diskProvider.FolderExists(droneFactoryFolder))
+            {
+                return new HealthCheck(HealthCheckResultType.Error, "Drone factory folder does not exist");
+            }
+            
+            try
+            {
+                var testPath = Path.Combine(droneFactoryFolder, "drone_test.txt");
+                _diskProvider.WriteAllText(testPath, DateTime.Now.ToString());
+                _diskProvider.DeleteFile(testPath);
+            }
+            catch (Exception)
+            {
+                return new HealthCheck(HealthCheckResultType.Error, "Unable to write to drone factory folder");
+            }
+
+            //Todo: Unable to import one or more files/folders from
+
+            return null;
+        }
+    }
+}