1 files changed, 119 insertions, 1 deletions

diff --git a/py_modules/lsfg_vk/dll_detection.py b/py_modules/lsfg_vk/dll_detection.py
index f1dace9..e547405 100644
--- a/py_modules/lsfg_vk/dll_detection.py
+++ b/py_modules/lsfg_vk/dll_detection.py
@@ -3,8 +3,9 @@ DLL detection service for Lossless Scaling.
 """
 
 import os
+import re
 from pathlib import Path
-from typing import Dict, Any
+from typing import Dict, Any, List
 
 from .base_service import BaseService
 from .constants import (
@@ -20,6 +21,12 @@ class DllDetectionService(BaseService):
     def check_lossless_scaling_dll(self) -> DllDetectionResponse:
         """Check if Lossless Scaling DLL is available at the expected paths
         
+        Search order:
+        1. LSFG_DLL_PATH environment variable
+        2. XDG_DATA_HOME Steam directory
+        3. HOME/.local/share Steam directory  
+        4. All Steam library folders (including SD cards)
+        
         Returns:
             DllDetectionResponse with detection status and path information
         """
@@ -39,6 +46,11 @@ class DllDetectionService(BaseService):
             if home_path:
                 return home_path
             
+            # Check all Steam library folders (including SD cards)
+            steam_libraries_path = self._check_steam_library_folders()
+            if steam_libraries_path:
+                return steam_libraries_path
+            
             # DLL not found in any expected location
             return {
                 "detected": False,
@@ -118,3 +130,109 @@ class DllDetectionService(BaseService):
                     "error": None
                 }
         return None
+
+    def _check_steam_library_folders(self) -> DllDetectionResponse | None:
+        """Check all Steam library folders for Lossless Scaling DLL
+        
+        This method parses Steam's libraryfolders.vdf file to find all
+        Steam library locations and checks each one for the DLL.
+        
+        Returns:
+            DllDetectionResponse if found, None otherwise
+        """
+        steam_libraries = self._get_steam_library_paths()
+        
+        for library_path in steam_libraries:
+            dll_path = Path(library_path) / STEAM_COMMON_PATH / LOSSLESS_DLL_NAME
+            if dll_path.exists():
+                self.log.info(f"Found DLL in Steam library: {dll_path}")
+                return {
+                    "detected": True,
+                    "path": str(dll_path),
+                    "source": f"Steam library folder: {library_path}",
+                    "message": None,
+                    "error": None
+                }
+        
+        return None
+    
+    def _get_steam_library_paths(self) -> List[str]:
+        """Get all Steam library folder paths from libraryfolders.vdf
+        
+        Returns:
+            List of Steam library folder paths
+        """
+        library_paths = []
+        
+        # Try different possible Steam installation locations
+        steam_paths = []
+        
+        # XDG_DATA_HOME path
+        data_dir = os.getenv(ENV_XDG_DATA_HOME)
+        if data_dir and data_dir.strip():
+            steam_paths.append(Path(data_dir.strip()) / "Steam")
+        
+        # HOME/.local/share path (most common on Steam Deck)
+        home_dir = os.getenv(ENV_HOME)
+        if home_dir and home_dir.strip():
+            steam_paths.append(Path(home_dir.strip()) / ".local" / "share" / "Steam")
+        
+        for steam_path in steam_paths:
+            if steam_path.exists():
+                # Add the main Steam directory as a library
+                library_paths.append(str(steam_path))
+                
+                # Parse libraryfolders.vdf for additional libraries
+                vdf_path = steam_path / "steamapps" / "libraryfolders.vdf"
+                if vdf_path.exists():
+                    try:
+                        additional_paths = self._parse_library_folders_vdf(vdf_path)
+                        library_paths.extend(additional_paths)
+                    except Exception as e:
+                        self.log.warning(f"Failed to parse {vdf_path}: {str(e)}")
+        
+        # Remove duplicates while preserving order
+        seen = set()
+        unique_paths = []
+        for path in library_paths:
+            if path not in seen:
+                seen.add(path)
+                unique_paths.append(path)
+        
+        self.log.info(f"Found {len(unique_paths)} Steam library paths: {unique_paths}")
+        return unique_paths
+    
+    def _parse_library_folders_vdf(self, vdf_path: Path) -> List[str]:
+        """Parse Steam's libraryfolders.vdf file to extract library paths
+        
+        Args:
+            vdf_path: Path to the libraryfolders.vdf file
+            
+        Returns:
+            List of additional Steam library folder paths
+        """
+        library_paths = []
+        
+        try:
+            with open(vdf_path, 'r', encoding='utf-8', errors='ignore') as f:
+                content = f.read()
+            
+            # Look for "path" entries in the VDF file
+            # The format is typically: "path"		"/path/to/library"
+            path_pattern = r'"path"\s*"([^"]+)"'
+            matches = re.findall(path_pattern, content, re.IGNORECASE)
+            
+            for path_match in matches:
+                # Convert Windows paths to Unix paths if needed
+                path = path_match.replace('\\\\', '/').replace('\\', '/')
+                library_path = Path(path)
+                
+                # Verify the library folder exists and has a steamapps directory
+                if library_path.exists() and (library_path / "steamapps").exists():
+                    library_paths.append(str(library_path))
+                    self.log.info(f"Found additional Steam library: {library_path}")
+        
+        except Exception as e:
+            self.log.error(f"Error parsing libraryfolders.vdf: {str(e)}")
+        
+        return library_paths