fix: also detect renamed files (#38)

This is needed because some Software, i.e. Chrome, downloads a file to the desired directory with a name like "XXX.csv.crdownload"
and renames it to "XXX.csv" after the download was finished. The service did not detect such actions before

Closes #33

src/CsvProc9000.Tests/BackgroundServices/CsvFileWatcherBackgroundServiceTests.cs

@@ -79,6 +79,7 @@ public void Dispose_Disposes_FileSystemWatcher()
             sut.Dispose();
 
             fileSystemWatcher.VerifyRemove(watcher => watcher.Created -= It.IsAny<FileSystemEventHandler>());
+            fileSystemWatcher.VerifyRemove(watcher => watcher.Renamed -= It.IsAny<RenamedEventHandler>());
         }
 
         [Fact]
@@ -119,6 +120,44 @@ public void Add_Created_Files_To_Pool()
                     job.TargetFile == fileInfoMock.Object)), Times.Once);
         }
 
+        [Fact]
+        public void Not_Add_Renamed_Files_To_Pool_When_Wrong_Change_Type()
+        {
+            var (context, fileSystemWatcher) = CreateContext();
+            _ = context.Build();
+
+            fileSystemWatcher
+                .Raise(watcher => watcher.Renamed += null,
+                    new RenamedEventArgs(WatcherChangeTypes.Deleted, "something", "some name", "some old name"));
+
+            context
+                .For<IJobPool>()
+                .Verify(pool => pool.Add(It.IsAny<IJob>()), Times.Never);
+        }
+
+        [Fact]
+        public void Add_Renamed_Files_To_Pool()
+        {
+            var (context, fileSystemWatcher) = CreateContext();
+            _ = context.Build();
+
+            var fileInfoMock = new Mock<IFileInfo>();
+
+            context
+                .For<IFileSystem>()
+                .Setup(fileSystem => fileSystem.FileInfo.FromFileName(It.IsAny<string>()))
+                .Returns(fileInfoMock.Object);
+
+            fileSystemWatcher
+                .Raise(watcher => watcher.Renamed += null,
+                    new RenamedEventArgs(WatcherChangeTypes.All, "something", "some file", "some old name"));
+
+            context
+                .For<IJobPool>()
+                .Verify(pool => pool.Add(It.Is<CsvProcessJob>(job =>
+                    job.TargetFile == fileInfoMock.Object)), Times.Once);
+        }
+
         private static (ArrangeContext<CsvFileWatcherBackgroundService>, Mock<IFileSystemWatcher>) CreateContext()
         {
             var options = new CsvProcessorOptions();

src/CsvProc9000/BackgroundServices/CsvFileWatcherBackgroundService.cs

@@ -36,6 +36,7 @@ public CsvFileWatcherBackgroundService(
             _fileSystemWatcher.Filter = "*.csv";
 
             _fileSystemWatcher.Created += OnFileCreated;
+            _fileSystemWatcher.Renamed += OnFileRenamed;
         }
 
         protected override Task ExecuteAsync(CancellationToken stoppingToken)
@@ -60,6 +61,7 @@ public override void Dispose()
             base.Dispose();
 
             _fileSystemWatcher.Created -= OnFileCreated;
+            _fileSystemWatcher.Renamed -= OnFileRenamed;
             _fileSystemWatcher.Dispose();
         }
 
@@ -68,11 +70,24 @@ private void OnFileCreated(object sender, FileSystemEventArgs eventArgs)
             if (!eventArgs.ChangeType.HasFlag(WatcherChangeTypes.Created)) return;
 
             _logger.LogDebug("FileWatcher: File Created: {File}", eventArgs.FullPath);
+            AddJobForFile(eventArgs.FullPath);
+        }
 
-            var file = _fileSystem.FileInfo.FromFileName(eventArgs.FullPath);
+        private void OnFileRenamed(object sender, RenamedEventArgs eventArgs)
+        {
+            if (!eventArgs.ChangeType.HasFlag(WatcherChangeTypes.Renamed)) return;
+
+            _logger.LogDebug("FileWatcher: File Renamed: from {OldFile} to {File}", 
+                eventArgs.OldFullPath, eventArgs.FullPath);
+            AddJobForFile(eventArgs.FullPath);
+        }
+
+        private void AddJobForFile(string filePath)
+        {
+            var file = _fileSystem.FileInfo.FromFileName(filePath);
             var job = new CsvProcessJob(file);
 
-            _logger.LogDebug("FileWatcher: Added CsvProcessJob #{JobId}", job.Id);
+            _logger.LogDebug("FileWatcher: Added CsvProcessJob #{JobId} for {File}", job.Id, filePath);
 
             _jobPool.Add(job);
         }