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, 118 insertions, 0 deletions

diff --git a/libs/installer_fomod_plus/installer/lib/Logger.h b/libs/installer_fomod_plus/installer/lib/Logger.h
new file mode 100644
index 0000000..fdeb1f0
--- /dev/null
+++ b/libs/installer_fomod_plus/installer/lib/Logger.h
@@ -0,0 +1,118 @@
+#pragma once
+#include <fstream>
+#include <iostream>
+#include <mutex>
+#include <regex>
+
+
+// Log levels
+enum LogLevel {
+    DEBUG = 0,
+    INFO = 1,
+    WARN = 2,
+    ERR = 3
+};
+
+// Convert LogLevel to string
+inline const char* logLevelToString(const LogLevel level) {
+    switch (level) {
+    case DEBUG: return "DEBUG";
+    case INFO:  return "INFO";
+    case WARN:  return "WARN";
+    case ERR:   return "ERROR";
+    default:    return "UNKNOWN";
+    }
+}
+
+
+class Logger {
+public:
+    static Logger& getInstance()
+    {
+        static Logger instance;
+        return instance;
+    }
+
+    void setLogFilePath(const std::string& filePath)
+    {
+        std::lock_guard lock(mMutex);
+        if (mLogFile.is_open()) {
+            mLogFile.close();
+        }
+        mLogFile.open(filePath, std::ios::out);
+        // std::ios::app is an option for appending but dont wanna grow it forever.
+    }
+
+    void setDebugMode(bool debug)
+    {
+        std::lock_guard lock(mMutex);
+        mDebugMode = debug;
+    }
+
+    void logMessage(const LogLevel level, const std::string& message)
+    {
+
+#if defined(__GNUC__) || defined(__clang__)
+                std::string functionName = __PRETTY_FUNCTION__;
+#elif defined(_MSC_VER)
+        std::string functionName = __FUNCSIG__;
+#else
+                std::string functionName = "UnknownFunction";
+#endif
+
+        std::regex classNameRegex(R"((\w+)::\w+\()");
+        std::smatch match;
+        std::string className = "UnknownClass";
+
+        if (std::regex_search(functionName, match, classNameRegex) && match.size() > 1) {
+            className = match.str(1);
+        }
+
+        std::lock_guard lock(mMutex);
+        
+        auto writeLog = [&](std::ostream& stream) {
+            switch (level) {
+            case DEBUG:
+                stream << "[DEBUG] " << message << std::endl;
+                break;
+            case INFO:
+                stream << "[INFO] " << message << std::endl;
+                break;
+            case WARN:
+                stream << "[WARN] " << message << std::endl;
+                break;
+            case ERR:
+                stream << "[ERROR] " << message << std::endl;
+                break;
+            }
+        };
+
+        if (mLogFile.is_open()) {
+            writeLog(mLogFile);
+        }
+        
+        writeLog(std::cout);
+    }
+
+    Logger& operator=(const Logger&) = delete;
+
+private:
+    Logger() = default;
+
+    ~Logger()
+    {
+        if (mLogFile.is_open()) {
+            mLogFile.close();
+        }
+    }
+
+    Logger(const Logger&) = delete;
+
+    std::ofstream mLogFile;
+    std::mutex mMutex;
+#if !defined(NDEBUG) || defined(CMAKE_BUILD_TYPE_RELWITHDEBINFO)
+    bool mDebugMode = true;   // Auto-enable in debug/RelWithDebInfo builds
+#else
+    bool mDebugMode = false;  // Disable in release builds
+#endif
+};
\ No newline at end of file