diff -r 37f936073cac -r e1ced2523cad src/documentmanager.h
--- a/src/documentmanager.h	Sun Oct 24 11:33:32 2021 +0300
+++ b/src/documentmanager.h	Tue Nov 02 15:43:57 2021 +0200
@@ -26,34 +26,52 @@
 public:
 	enum OpenType
 	{
+		/**
+		  * Document was opened manually by the user
+		  */
 		ManuallyOpened,
+		/**
+		  * Document was opened automatically in order to resolve subfile references
+		  */
 		AutomaticallyOpened,
 	};
     DocumentManager(QObject* parent = nullptr);
-	QString newModel();
-	Model* findModelByName(const QString& name);
-	QString openModel(const QString& path, QTextStream& errorStream, const OpenType openType);
+	ModelId newModel();
+	Model* findDependencyByName(const ModelId modelId, const QString& name);
+	Model* getModelById(ModelId modelId);
+	std::optional<ModelId> openModel(const QString& path, QTextStream& errorStream, const OpenType openType);
 	QString makeNewModelName();
-	void loadDependenciesForModel(const QString& modelName,
+	void loadDependenciesForAllModels(const LibraryManager &libraries, QTextStream &errorStream);
+	void loadDependenciesForModel(const ModelId modelId,
 		const QString& path,
 		const LibraryManager& libraries,
 		QTextStream& errorStream);
-	void closeDocument(const QString& name);
+	void closeDocument(const ModelId modelId);
+	const QString* modelPath(ModelId modelId) const;
+	void setModelPath(
+			const ModelId modelId,
+			const QString& newPath,
+			const LibraryManager &libraries,
+			QTextStream &errorStream);
+	bool saveModel(const ModelId modelId, QTextStream& errors);
+	std::optional<ModelId> findIdForModel(const Model* model) const;
 private:
-	void collectReferences(QSet<QString> &referenced, const QString& name, const Model* model);
 	struct ModelInfo
 	{
 		std::unique_ptr<Model> model;
+		QString path;
 		OpenType opentype;
+		std::map<QString, ModelId> dependencies = {};
 	};
+	struct LoadDepedenciesBag;
+	int modelIdCounter = 0;
 	int untitledNameCounter = 0;
-	std::map<QString, ModelInfo> openModels;
-	void loadDependenciesForModel(const QString& modelName,
-		const QString& path,
-		const LibraryManager& libraries,
-		QStringList& missing,
-		QStringList& processed,
-		QTextStream& errorStream);
+	std::map<ModelId, ModelInfo> openModels;
+	void loadDependenciesForModel(const ModelId modelId, const QString& path, LoadDepedenciesBag& bag);
+	void collectReferences(QSet<QString> &referenced, const QString& name, const Model* model);
+	void updateDependencies(ModelInfo* model);
+	void prune();
+	bool isReferencedByAnything(const ModelId modelId) const;
 };
 
 QString pathToName(const QFileInfo& path);