Refactor database layer: convert to DatabaseProvider class with initialization

bin/routes/auth_routes.dart

@@ -0,0 +1,52 @@
+import 'package:shelf/shelf.dart';
+import 'package:shelf_router/shelf_router.dart';
+import 'package:bcrypt/bcrypt.dart';
+import '../database/database_provider.dart';
+import 'dart:convert';
+
+class AuthRoutes {
+  final DatabaseProvider database;
+
+  AuthRoutes(this.database);
+
+  Router get routes {
+    final router = Router();
+    router.post('/login', _login);
+    router.get('/watch', _watch);
+    return router;
+  }
+
+  Future<Response> _login(Request request) async {
+    final body = await request.readAsString();
+    final data = jsonDecode(body);
+
+    final login = data['login'];
+    final password = data['password'];
+
+    final user = await database.findUserByLogin(login);
+
+    if (user == null || !BCrypt.checkpw(password, user.pwdHash)) {
+      return Response(401, body: 'Invalid credentials');
+    }
+
+    return Response(200, body: jsonEncode({'user': user.toMap()}));
+  }
+
+  Future<Response> _watch(Request request) async {
+    final uniqueId = request.url.queryParameters['unique_id'];
+
+    final userId = database.getUserIdByShareId(uniqueId!);
+
+    if (userId == null) {
+      return Response(404, body: 'Share link not found');
+    }
+
+    final position = await database.getLatestPosition(userId);
+
+    if (position == null) {
+      return Response(404, body: 'No position available');
+    }
+
+    return Response(200, body: position.toJson());
+  }
+}