finalize refactoring & ready for the PR

MalwareMultiScan.Api/Services/ScanResultService.cs

@@ -8,29 +8,41 @@ using MongoDB.Driver.GridFS;
 
 namespace MalwareMultiScan.Api.Services
 {
+    /// <summary>
+    /// Scan results service.
+    /// </summary>
     public class ScanResultService
     {
         private const string CollectionName = "ScanResults";
+
         private readonly GridFSBucket _bucket;
-
         private readonly IMongoCollection<ScanResult> _collection;
-
         private readonly ScanBackendService _scanBackendService;
 
+        /// <summary>
+        /// Create scan result service.
+        /// </summary>
+        /// <param name="db">Mongo database.</param>
+        /// <param name="scanBackendService">Scan backend service.</param>
         public ScanResultService(IMongoDatabase db, ScanBackendService scanBackendService)
         {
             _scanBackendService = scanBackendService;
 
-            _collection = db.GetCollection<ScanResult>(CollectionName);
             _bucket = new GridFSBucket(db);
+            _collection = db.GetCollection<ScanResult>(CollectionName);
         }
 
+        /// <summary>
+        /// Create scan result.
+        /// </summary>
+        /// <returns>Scan result.</returns>
         public async Task<ScanResult> CreateScanResult()
         {
             var scanResult = new ScanResult
             {
-                Results = _scanBackendService.List.ToDictionary(
-                    k => k.Id, v => new ScanResultEntry())
+                Results = _scanBackendService.List
+                    .Where(b => b.Enabled)
+                    .ToDictionary(k => k.Id, v => new ScanResultEntry())
             };
 
             await _collection.InsertOneAsync(scanResult);
@@ -38,6 +50,11 @@ namespace MalwareMultiScan.Api.Services
             return scanResult;
         }
 
+        /// <summary>
+        /// Get scan result.
+        /// </summary>
+        /// <param name="id">Scan result id.</param>
+        /// <returns>Scan result.</returns>
         public async Task<ScanResult> GetScanResult(string id)
         {
             var result = await _collection.FindAsync(
@@ -46,27 +63,44 @@ namespace MalwareMultiScan.Api.Services
             return await result.FirstOrDefaultAsync();
         }
 
+        /// <summary>
+        /// Update scan status for the backend.
+        /// </summary>
+        /// <param name="resultId">Result id.</param>
+        /// <param name="backendId">Backend id.</param>
+        /// <param name="completed">If the scan has been completed.</param>
+        /// <param name="succeeded">If the scan has been succeeded.</param>
+        /// <param name="threats">List of found threats.</param>
         public async Task UpdateScanResultForBackend(string resultId, string backendId,
             bool completed = false, bool succeeded = false, string[] threats = null)
         {
-            var filterScanResult = Builders<ScanResult>.Filter.Where(r => r.Id == resultId);
-
-            var updateScanResult = Builders<ScanResult>.Update.Set(r => r.Results[backendId], new ScanResultEntry
-            {
-                Completed = completed,
-                Succeeded = succeeded,
-                Threats = threats
-            });
-
-            await _collection.UpdateOneAsync(filterScanResult, updateScanResult);
+            await _collection.UpdateOneAsync(
+                Builders<ScanResult>.Filter.Where(r => r.Id == resultId),
+                Builders<ScanResult>.Update.Set(r => r.Results[backendId], new ScanResultEntry
+                {
+                    Completed = completed,
+                    Succeeded = succeeded,
+                    Threats = threats ?? new string[] { }
+                }));
         }
 
+        /// <summary>
+        /// Queue URL scan.
+        /// </summary>
+        /// <param name="result">Scan result instance.</param>
+        /// <param name="fileUrl">File URL.</param>
         public async Task QueueUrlScan(ScanResult result, string fileUrl)
         {
-            foreach (var backend in _scanBackendService.List)
+            foreach (var backend in _scanBackendService.List.Where(b => b.Enabled))
                 await _scanBackendService.QueueUrlScan(result, backend, fileUrl);
         }
 
+        /// <summary>
+        /// Store file.
+        /// </summary>
+        /// <param name="fileName">File name.</param>
+        /// <param name="fileStream">File stream.</param>
+        /// <returns>Stored file id.</returns>
         public async Task<string> StoreFile(string fileName, Stream fileStream)
         {
             var objectId = await _bucket.UploadFromStreamAsync(
@@ -75,6 +109,11 @@ namespace MalwareMultiScan.Api.Services
             return objectId.ToString();
         }
 
+        /// <summary>
+        /// Obtain stored file stream.
+        /// </summary>
+        /// <param name="id">File id.</param>
+        /// <returns>File seekable stream.</returns>
         public async Task<Stream> ObtainFile(string id)
         {
             if (!ObjectId.TryParse(id, out var objectId))