feat(settings): add method that saves settings to file

engine/include/cubos/engine/settings/settings.hpp

@@ -101,6 +101,9 @@ namespace cubos::engine
         /// @param settingsToMerge Settings to be merged to this instance.
         void merge(const Settings& settingsToMerge);
 
+        /// @brief Saves settings as json to path specified in the settings.path value.
+        bool save();
+
         /// @return Underlying `std::unordered_map` with the settings.
         const std::unordered_map<std::string, std::string>& getValues() const;
 

engine/samples/settings/main.cpp

@@ -14,6 +14,14 @@ int main(int argc, char** argv)
 
     cubos.startupSystem("print setting value").after(settingsTag).call([](Settings& settings) {
         CUBOS_INFO("{}", settings.getString("greeting", "Hello!"));
+        settings.save();
+    });
+
+    cubos.startupSystem("print number setting value").after(settingsTag).call([](Settings& settings) {
+        CUBOS_INFO("{}", settings.getInteger("number", 1));
+        CUBOS_INFO("{}", settings.getDouble("double", 1e-07));
+        CUBOS_INFO("{}", settings.getBool("boolean", false));
+        settings.save();
     });
 
     cubos.run();

engine/src/settings/settings.cpp

@@ -1,7 +1,16 @@
+#include <nlohmann/json.hpp>
+
+#include <cubos/core/data/fs/file_system.hpp>
+#include <cubos/core/data/fs/standard_archive.hpp>
 #include <cubos/core/ecs/reflection.hpp>
 
 #include <cubos/engine/settings/settings.hpp>
 
+using cubos::core::data::File;
+using cubos::core::data::FileSystem;
+using cubos::core::data::StandardArchive;
+using cubos::core::memory::Stream;
+
 using namespace cubos::engine;
 
 CUBOS_REFLECT_IMPL(Settings)
@@ -96,6 +105,46 @@ void Settings::merge(const Settings& settingsToMerge)
     }
 }
 
+static inline void saveSettingsAsJson(const Settings& settings, Stream& stream)
+{
+    auto json = nlohmann::json();
+    for (const auto& value : settings.getValues())
+    {
+        char* pEnd;
+        strtod(value.second.c_str(), &pEnd);
+        // Store as string if second value is not number nor boolean
+        if (pEnd != value.second.c_str() + value.second.length() && (value.second != "true" && value.second != "false"))
+        {
+            json[value.first] = value.second;
+        }
+        else
+        {
+            json[value.first] = nlohmann::json::parse(value.second);
+        }
+    }
+    stream.print(json.dump(2));
+}
+
+bool Settings::save()
+{
+    // If the settings file is not mounted, mount it.
+    if (FileSystem::find("/settings.json") == nullptr)
+    {
+        const std::string& path = getString("settings.path", "settings.json");
+        // Mount the real settings file as `/settings.json`.
+        if (!FileSystem::mount("/settings.json",
+                               std::make_unique<StandardArchive>(path, false /*isDirectory*/, false /*readOnly*/)))
+        {
+            // CUBOS_ERROR("Couldn't mount the settings file at {}", path);
+            return false;
+        }
+    }
+
+    auto stream = FileSystem::open("/settings.json", File::OpenMode::Write);
+    saveSettingsAsJson(*this, *stream);
+    return true;
+}
+
 const std::unordered_map<std::string, std::string>& Settings::getValues() const
 {
     return mValues;