Add FUSE external mapping support, BG3/Oblivion Remastered fixes, fomod-plus and NaK integration

FUSE VFS now deploys non-data-dir mod mappings (Paks, OBSE, UE4SS, etc.)
via real symlinks and injects file-level data-dir mappings (plugins.txt,
loadorder.txt) into the VFS tree. Fixes game launches for Oblivion
Remastered (Root Builder path resolution, script extender support) and
BG3 (Wine prefix documents directory, file mapper symlinks on Linux).

Vendors mo2-fomod-plus plugin and NaK crate for FOMOD installer and
game finder/runtime support.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

1 files changed, 154 insertions, 0 deletions

diff --git a/libs/installer_fomod_plus/installer/ui/FomodViewModel.h b/libs/installer_fomod_plus/installer/ui/FomodViewModel.h
new file mode 100644
index 0000000..f0ce070
--- /dev/null
+++ b/libs/installer_fomod_plus/installer/ui/FomodViewModel.h
@@ -0,0 +1,154 @@
+#pragma once
+
+#include <imoinfo.h>
+#include <string>
+
+#include "lib/ConditionTester.h"
+#include "lib/FlagMap.h"
+#include "lib/FileInstaller.h"
+#include "lib/ViewModels.h"
+#include "xml/FomodInfoFile.h"
+
+/*
+--------------------------------------------------------------------------------
+                                Info
+--------------------------------------------------------------------------------
+*/
+class InfoViewModel {
+public:
+    explicit InfoViewModel(const std::unique_ptr<FomodInfoFile>& infoFile)
+    {
+        if (infoFile) {
+            // Copy the necessary members from FomodInfoFile to InfoViewModel
+            mName    = infoFile->getName();
+            mVersion = infoFile->getVersion();
+            mAuthor  = infoFile->getAuthor();
+            mWebsite = infoFile->getWebsite();
+        }
+    }
+
+    // Accessor methods
+    [[nodiscard]] std::string getName() const { return mName; }
+    [[nodiscard]] std::string getVersion() const { return mVersion; }
+    [[nodiscard]] std::string getAuthor() const { return mAuthor; }
+    [[nodiscard]] std::string getWebsite() const { return mWebsite; }
+
+private:
+    std::string mName;
+    std::string mVersion;
+    std::string mAuthor;
+    std::string mWebsite;
+};
+
+/*
+--------------------------------------------------------------------------------
+                               View Model
+--------------------------------------------------------------------------------
+*/
+class FomodViewModel {
+public:
+    FomodViewModel(
+        MOBase::IOrganizer* organizer,
+        std::unique_ptr<ModuleConfiguration> fomodFile,
+        std::unique_ptr<FomodInfoFile> infoFile);
+
+    static std::shared_ptr<FomodViewModel> create(
+        MOBase::IOrganizer* organizer,
+        std::unique_ptr<ModuleConfiguration> fomodFile,
+        std::unique_ptr<FomodInfoFile> infoFile);
+
+    void forEachGroup(const std::function<void(GroupRef)>& callback) const;
+
+    void forEachPlugin(const std::function<void(GroupRef, PluginRef)>& callback) const;
+
+    void forEachFuturePlugin(int fromStepIndex, const std::function<void(GroupRef, PluginRef)>& callback) const;
+
+    void selectFromJson(nlohmann::json json) const;
+
+    void resetToDefaults();
+
+    [[nodiscard]] std::shared_ptr<PluginViewModel> getFirstPluginForActiveStep() const;
+
+    // Steps
+    [[nodiscard]] shared_ptr_list<StepViewModel> getSteps() const { return mSteps; }
+    [[nodiscard]] StepRef getActiveStep() const { return mActiveStep; }
+    [[nodiscard]] int getCurrentStepIndex() const { return mCurrentStepIndex; }
+    [[deprecated]] void setCurrentStepIndex(const int index) { mCurrentStepIndex = index; }
+
+    void updateVisibleSteps() const;
+
+    void rebuildConditionFlagsForStep(int stepIndex) const;
+
+    void preinstall(const std::shared_ptr<MOBase::IFileTree>& tree, const QString& fomodPath);
+
+    std::shared_ptr<FileInstaller> getFileInstaller() { return mFileInstaller; }
+
+    std::string getDisplayImage() const;
+
+    // Plugins
+    [[nodiscard]] PluginRef getActivePlugin() const { return mActivePlugin; }
+
+    // Info
+    [[nodiscard]] std::shared_ptr<InfoViewModel> getInfoViewModel() const { return mInfoViewModel; }
+
+    // Interactions
+    void stepBack();
+
+    void stepForward();
+
+    bool isLastVisibleStep() const;
+
+    bool isFirstVisibleStep() const;
+
+    bool togglePlugin(const GroupRef, const PluginRef, bool selected) const;
+
+    bool ctrlTogglePlugin(const GroupRef, const PluginRef, bool selected) const;
+
+    void setActivePlugin(const PluginRef plugin) const { mActivePlugin = plugin; }
+
+    static void markManuallySet(PluginRef plugin);
+
+private:
+    Logger& log                    = Logger::getInstance();
+    MOBase::IOrganizer* mOrganizer = nullptr;
+    std::unique_ptr<ModuleConfiguration> mFomodFile;
+    std::unique_ptr<FomodInfoFile> mInfoFile;
+    std::shared_ptr<FlagMap> mFlags{ nullptr };
+    ConditionTester mConditionTester;
+    std::shared_ptr<InfoViewModel> mInfoViewModel;
+    std::vector<std::shared_ptr<StepViewModel> > mSteps;
+    mutable std::shared_ptr<PluginViewModel> mActivePlugin{ nullptr };
+    mutable std::shared_ptr<StepViewModel> mActiveStep{ nullptr };
+    mutable std::vector<int> mVisibleStepIndices;
+    std::shared_ptr<FileInstaller> mFileInstaller{ nullptr };
+    bool mInitialized{ false };
+
+    void createStepViewModels();
+
+    void setFlagForPluginState(const std::shared_ptr<PluginViewModel>& plugin) const;
+
+    static void createNonePluginForGroup(const std::shared_ptr<GroupViewModel>& group);
+
+    void processPlugin(const std::shared_ptr<GroupViewModel>& group,
+        const std::shared_ptr<PluginViewModel>& plugin) const;
+
+    void enforceRadioGroupConstraints(const std::shared_ptr<GroupViewModel>& group) const;
+
+    void enforceSelectAllConstraint(const std::shared_ptr<GroupViewModel>& groupViewModel) const;
+
+    void enforceSelectAtLeastOneConstraint(const std::shared_ptr<GroupViewModel>& group) const;
+
+    void enforceGroupConstraints() const;
+
+    void processPluginConditions(int fromStepIndex) const;
+
+    // Indices
+    int mCurrentStepIndex{ 0 };
+
+    void logMessage(const LogLevel level, const std::string& message) const
+    {
+        log.logMessage(level, "[VIEWMODEL] " + message);
+    }
+
+    std::string toString() const;
+};