1 files changed, 120 insertions, 0 deletions
diff --git a/lsfg_vk/dll_detection.py b/lsfg_vk/dll_detection.py
new file mode 100644
index 0000000..f1dace9
--- /dev/null
+++ b/lsfg_vk/dll_detection.py
@@ -0,0 +1,120 @@
+"""
+DLL detection service for Lossless Scaling.
+"""
+
+import os
+from pathlib import Path
+from typing import Dict, Any
+
+from .base_service import BaseService
+from .constants import (
+    ENV_LSFG_DLL_PATH, ENV_XDG_DATA_HOME, ENV_HOME,
+    STEAM_COMMON_PATH, LOSSLESS_DLL_NAME
+)
+from .types import DllDetectionResponse
+
+
+class DllDetectionService(BaseService):
+    """Service for detecting Lossless Scaling DLL"""
+    
+    def check_lossless_scaling_dll(self) -> DllDetectionResponse:
+        """Check if Lossless Scaling DLL is available at the expected paths
+        
+        Returns:
+            DllDetectionResponse with detection status and path information
+        """
+        try:
+            # Check environment variable first
+            dll_path = self._check_env_dll_path()
+            if dll_path:
+                return dll_path
+            
+            # Check XDG_DATA_HOME path
+            xdg_path = self._check_xdg_data_home()
+            if xdg_path:
+                return xdg_path
+            
+            # Check HOME/.local/share path
+            home_path = self._check_home_local_share()
+            if home_path:
+                return home_path
+            
+            # DLL not found in any expected location
+            return {
+                "detected": False,
+                "path": None,
+                "source": None,
+                "message": "Lossless Scaling DLL not found in expected locations",
+                "error": None
+            }
+            
+        except Exception as e:
+            error_msg = f"Error checking Lossless Scaling DLL: {str(e)}"
+            self.log.error(error_msg)
+            return {
+                "detected": False,
+                "path": None,
+                "source": None,
+                "message": None,
+                "error": str(e)
+            }
+    
+    def _check_env_dll_path(self) -> DllDetectionResponse | None:
+        """Check LSFG_DLL_PATH environment variable
+        
+        Returns:
+            DllDetectionResponse if found, None otherwise
+        """
+        dll_path = os.getenv(ENV_LSFG_DLL_PATH)
+        if dll_path and dll_path.strip():
+            dll_path_obj = Path(dll_path.strip())
+            if dll_path_obj.exists():
+                self.log.info(f"Found DLL via {ENV_LSFG_DLL_PATH}: {dll_path_obj}")
+                return {
+                    "detected": True,
+                    "path": str(dll_path_obj),
+                    "source": f"{ENV_LSFG_DLL_PATH} environment variable",
+                    "message": None,
+                    "error": None
+                }
+        return None
+    
+    def _check_xdg_data_home(self) -> DllDetectionResponse | None:
+        """Check XDG_DATA_HOME Steam directory
+        
+        Returns:
+            DllDetectionResponse if found, None otherwise
+        """
+        data_dir = os.getenv(ENV_XDG_DATA_HOME)
+        if data_dir and data_dir.strip():
+            dll_path = Path(data_dir.strip()) / "Steam" / STEAM_COMMON_PATH / LOSSLESS_DLL_NAME
+            if dll_path.exists():
+                self.log.info(f"Found DLL via {ENV_XDG_DATA_HOME}: {dll_path}")
+                return {
+                    "detected": True,
+                    "path": str(dll_path),
+                    "source": f"{ENV_XDG_DATA_HOME} Steam directory",
+                    "message": None,
+                    "error": None
+                }
+        return None
+    
+    def _check_home_local_share(self) -> DllDetectionResponse | None:
+        """Check HOME/.local/share Steam directory
+        
+        Returns:
+            DllDetectionResponse if found, None otherwise
+        """
+        home_dir = os.getenv(ENV_HOME)
+        if home_dir and home_dir.strip():
+            dll_path = Path(home_dir.strip()) / ".local" / "share" / "Steam" / STEAM_COMMON_PATH / LOSSLESS_DLL_NAME
+            if dll_path.exists():
+                self.log.info(f"Found DLL via {ENV_HOME}/.local/share: {dll_path}")
+                return {
+                    "detected": True,
+                    "path": str(dll_path),
+                    "source": f"{ENV_HOME}/.local/share Steam directory",
+                    "message": None,
+                    "error": None
+                }
+        return None