refactor user repo with helpers. better api validation etc.

backend-dart/lib/domain/data/database.dart

@@ -0,0 +1,6 @@
+import 'package:backend_dart/domain/data/user_data_source.dart';
+
+abstract class IDatabase {
+  UserDataSource get users;
+  Future<void> close();
+}

backend-dart/lib/domain/data/project_data_source.dart

@@ -0,0 +1,34 @@
+import 'package:backend_dart/domain/entities/project.dart';
+
+/// Interface for managing project data interactions.
+abstract class ProjectDataSource {
+  /// Creates a new project in the data source.
+  ///
+  /// Throws an error if the creation fails.
+  Future<void> createProject(NewProject project);
+
+  /// Retrieves a project by its unique ID.
+  ///
+  /// Returns `null` if no project is found.
+  Future<Project?> findProjectById(String id);
+
+  /// Retrieves all projects associated with a specific user.
+  ///
+  /// Returns an empty list if no projects are found.
+  Future<List<Project>> findProjectsByUserId(String userId);
+
+  /// Updates an existing project in the data source.
+  ///
+  /// Throws an error if the update fails.
+  Future<void> updateProject(ProjectUpdate project);
+
+  /// Deletes a project by its unique ID.
+  ///
+  /// Throws an error if the deletion fails.
+  Future<void> deleteProject(String id);
+
+  /// Retrieves all projects in the data source.
+  ///
+  /// Returns an empty list if no projects exist.
+  Future<List<Project>> findAllProjects();
+}

backend-dart/lib/domain/data/user_data_source.dart

@@ -1,18 +1,19 @@
+import 'package:backend_dart/domain/entities/user.dart';
 import 'package:backend_dart/domain/interface/error.dart';
 import 'package:fpdart/fpdart.dart';
 
-abstract class UserDataSource<T> {
-  TaskEither<IError, T> create(T user);
+abstract class UserDataSource {
+  TaskEither<IError, User> create(UserCreate user);
 
-  TaskEither<IError, T> findByEmail(String email);
+  TaskEither<IError, User> findByEmail(String email);
 
-  TaskEither<IError, T> findById(String id);
+  TaskEither<IError, User> findById(String id);
 
-  TaskEither<IError, T> update(T user);
+  TaskEither<IError, User> update(UserUpdate user);
 
   TaskEither<IError, void> delete(String id);
 
-  TaskEither<IError, List<T>> findAll();
+  TaskEither<IError, List<User>> findAll();
 
-  TaskEither<IError,String> generateId();
+  TaskEither<IError, String> generateId();
 }