Show notification in case no config changes were made by plugin

src/main/java/de/gebit/plugins/autoconfig/actions/RunAutoconfigAction.java

@@ -1,14 +1,21 @@
 package de.gebit.plugins.autoconfig.actions;
 
 import com.intellij.openapi.actionSystem.AnActionEvent;
+import com.intellij.openapi.fileEditor.FileDocumentManager;
 import com.intellij.openapi.project.DumbAwareAction;
 import com.intellij.openapi.project.Project;
+import com.intellij.openapi.vfs.VirtualFile;
 import de.gebit.plugins.autoconfig.AutoconfigStartup;
 import de.gebit.plugins.autoconfig.ConfigurationLoaderService;
+import de.gebit.plugins.autoconfig.util.Notifications;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.Arrays;
+import java.util.List;
 
 /**
- * Action to apply the projects Autoconfig-Configurations manually
+ * Action to apply the projects Autoconfig-Configurations manually.
  */
 public class RunAutoconfigAction extends DumbAwareAction {
 	@Override
@@ -23,6 +30,31 @@ public void actionPerformed(@NotNull AnActionEvent e) {
 			configurationLoaderService.resetConfigurationCache();
 		}
 
-		new AutoconfigStartup().runAutoconfig(project);
+		// save currently open and unsaved config files
+		saveUnsavedAutoconfigs();
+
+		// perform changes
+		List<String> changedSettings = new AutoconfigStartup().runAutoconfig(project);
+
+		// notify user if no changes were necessary
+		if (changedSettings == null || changedSettings.isEmpty()) {
+			Notifications.showInfo("No settings have been changed.", project);
+		}
+	}
+
+	private void saveUnsavedAutoconfigs() {
+		FileDocumentManager fileDocumentManager = FileDocumentManager.getInstance();
+		Arrays.stream(fileDocumentManager.getUnsavedDocuments())
+				.filter(d -> isAutoconfigFile(fileDocumentManager.getFile(d)))
+				.forEach(fileDocumentManager::saveDocument);
+	}
+
+	private boolean isAutoconfigFile(@Nullable VirtualFile document) {
+		if (document == null) {
+			return false;
+		}
+		String[] components = document.getUrl().split("/");
+		String lastComponent = components[components.length - 1];
+		return lastComponent.startsWith("autoconfig") && lastComponent.endsWith(".yaml");
 	}
 }