From 7f813d2eb140d61baee1a345cd113630bb631f0a Mon Sep 17 00:00:00 2001
From: MihailRis <mexaruc@gmail.com>
Date: Wed, 29 Jul 2026 23:06:02 +0300
Subject: [PATCH] add app.start_background_instance (test)

---
 src/devtools/Project.hpp                |  2 ++
 src/engine/Engine.cpp                   |  1 +
 src/logic/scripting/lua/libs/libapp.cpp | 25 ++++++++++++++++++++++++-
 3 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/src/devtools/Project.hpp b/src/devtools/Project.hpp
index daeac7ca0..4906b9373 100644
--- a/src/devtools/Project.hpp
+++ b/src/devtools/Project.hpp
@@ -1,6 +1,7 @@
 #pragma once
 
 #include "interfaces/Serializable.hpp"
+#include "io/path.hpp"
 
 #include <set>
 #include <string>
@@ -21,6 +22,7 @@ struct Permissions {
 struct Project : Serializable {
     std::string name;
     std::string title;
+    io::path path;
     std::vector<std::string> basePacks;
     Permissions permissions;
 
diff --git a/src/engine/Engine.cpp b/src/engine/Engine.cpp
index 10f8cee6d..55ed9fec0 100644
--- a/src/engine/Engine.cpp
+++ b/src/engine/Engine.cpp
@@ -380,6 +380,7 @@ void Engine::loadAssets() {
 void Engine::loadProject() {
     io::path projectFile = "project:project.toml";
     project = std::make_unique<Project>();
+    project->path = "project:";
     project->deserialize(io::read_object(projectFile));
     logger.info() << "loaded project " << util::quote(project->name);
 }
diff --git a/src/logic/scripting/lua/libs/libapp.cpp b/src/logic/scripting/lua/libs/libapp.cpp
index 12758c724..771567fd4 100644
--- a/src/logic/scripting/lua/libs/libapp.cpp
+++ b/src/logic/scripting/lua/libs/libapp.cpp
@@ -366,11 +366,33 @@ static int l_start_debug_instance(lua::State* L) {
     platform::new_engine_instance(
         std::move(args),
         outputPath.empty() ? "" : io::resolve(std::string(outputPath)),
-        true // debug instance may be detached
+        false
     );
     return lua::pushinteger(L, port);
 }
 
+static int l_start_background_instance(lua::State* L) {
+    auto scriptPath = lua::require_lstring(L, 1);
+    io::path outputPath = "user:background.log"; // TODO:
+    const auto& paths = engine->getPaths();
+
+    std::vector<std::string> args {
+        "--headless",
+        "--res", paths.getResourcesFolder().u8string(),
+        "--dir", paths.getUserFilesFolder().u8string(),
+        "--script", io::resolve(scriptPath).u8string(),
+    };
+    args.emplace_back("--project");
+    args.emplace_back(io::resolve(engine->getProject().path).u8string());
+
+    platform::new_engine_instance(
+        std::move(args),
+        outputPath.empty() ? "" : io::resolve(outputPath),
+        true 
+    );
+    return 0;
+}
+
 const luaL_Reg applib[] = {
     /// content
     {"is_content_loaded", lua::wrap<l_is_content_loaded>},
@@ -403,5 +425,6 @@ const luaL_Reg applib[] = {
     {"get_version", lua::wrap<l_get_version>},
     {"create_memory_device", lua::wrap<l_create_memory_device>},
     {"start_debug_instance", lua::wrap<l_start_debug_instance>},
+    {"start_background_instance", lua::wrap<l_start_background_instance>},
     {nullptr, nullptr}
 };