fix package layout for Decky runtime modulessafe-patch-refactor

7 files changed, 1790 insertions, 0 deletions

diff --git a/py_modules/services/__init__.py b/py_modules/services/__init__.py
new file mode 100644
index 0000000..737c993
--- /dev/null
+++ b/py_modules/services/__init__.py
@@ -0,0 +1 @@
+"""Focused services for Decky Framegen."""
diff --git a/py_modules/services/assets.py b/py_modules/services/assets.py
new file mode 100644
index 0000000..69f71ba
--- /dev/null
+++ b/py_modules/services/assets.py
@@ -0,0 +1,184 @@
+"""Static asset metadata and patch file inventories."""
+
+OPTISCALER_ARCHIVE_ASSET = {
+    "name": "Optiscaler_0.9.4-final.20260718._MM.7z",
+    "sha256": "575cb4df866116093df75af607e37fd70e10f5163e0f23fd5c804142e80ef0ad",
+    "version": "0.9.4-final.20260718",
+}
+
+FSR4_INT8_ASSET = {
+    "name": "amd_fidelityfx_upscaler_dx12.dll",
+    "sha256": "c7720bc16bede334f59a1a32cd22edbcbbb159685ed5240e61350a5fb0bc8a94",
+    "version": "4.0.2c",
+}
+
+FSR4_OFFICIAL_411_ASSET = {
+    "name": "amdxcffx64.dll",
+    "sha256": "a2b136b6affd35a49b141a936be935f7d5ddc8d8f9b8c9afbe62ff9ddb2538a0",
+    "version": "4.1.1-official",
+}
+
+FSR4_VALVE_411_ASSET = {
+    "name": "amdxcffx64_valve_2.3.0.2913.dll",
+    "sha256": "4e7dc37aebea3a90e3d3cc43e24cb2b54176b2535315f20dbe63b3b7cfc56b1e",
+    "version": "4.1.1-valve-2.3.0.2913",
+}
+
+AMDXC64_RDNA2_ASSET = {
+    "name": "amdxc64.dll",
+    "sha256": "a0a0af61d475e30a70966b3459f3793df772faf8f26ae3261d10554ff592cbd5",
+    "version": "8.18.10.0474",
+}
+
+OPTISCALER_PRE10_ASSET = {
+    "name": "OptiScaler_0.10.0-pre1.20260622_135940.dll",
+    "sha256": "b374b19081cc066365d0c6da4808d768e16469b0cbdfc478b6e95999947d5364",
+    "version": "0.10.0-pre1.20260622_135940",
+}
+
+OPTIPATCHER_ASSET = {
+    "name": "OptiPatcher_rolling.asi",
+    "sha256": "88b9e1be3559737cd205fdf5f2c8550cf1923fb1def4c603e5bf03c3e84131b1",
+    "version": "rolling",
+}
+
+FSR4_UPSCALER_FILENAME = "amd_fidelityfx_upscaler_dx12.dll"
+FSR4_DRIVER_OVERRIDE_FILENAME = "amdxcffx64.dll"
+INSTALL_MANIFEST_FILENAME = "install-manifest.json"
+VERSION_FILENAME = "version.txt"
+DEFAULT_FSR4_VARIANT = "rdna23-int8"
+DEFAULT_FRAMEGEN_BACKEND = "auto"
+FRAMEGEN_BACKENDS = {
+    "auto": "OptiScaler automatic selection",
+    "nukems": "Nukem's DLSSG → FSR3",
+}
+
+FSR4_VARIANTS = {
+    "rdna23-int8": {
+        "label": "4.0.2c / RDNA2-3 compatibility",
+        "dir_name": "fsr4-rdna2-3",
+        "sha256": "c7720bc16bede334f59a1a32cd22edbcbbb159685ed5240e61350a5fb0bc8a94",
+        "source_asset_name": FSR4_INT8_ASSET["name"],
+        "source_version": FSR4_INT8_ASSET["version"],
+        "uses_archive_native": False,
+        "extra_files": [],
+    },
+    "rdna4-native": {
+        "label": "4.1.1 SDK / RDNA3 dGPU + RDNA4",
+        "dir_name": "fsr4-rdna4",
+        "sha256": "d0dcccc74a43c44ba435b7a369b456e0970d8a4464e4bd683119b374f2c9fb46",
+        "source_asset_name": OPTISCALER_ARCHIVE_ASSET["name"],
+        "source_version": OPTISCALER_ARCHIVE_ASSET["version"],
+        "uses_archive_native": True,
+        "extra_files": [],
+    },
+    "rdna34-official-411": {
+        "label": "4.1.1 driver override / RDNA3-4",
+        "dir_name": "fsr4-rdna3-4-official-411",
+        "sha256": "d0dcccc74a43c44ba435b7a369b456e0970d8a4464e4bd683119b374f2c9fb46",
+        "source_asset_name": OPTISCALER_ARCHIVE_ASSET["name"],
+        "source_version": OPTISCALER_ARCHIVE_ASSET["version"],
+        "uses_archive_native": True,
+        "extra_files": [
+            {
+                "name": FSR4_DRIVER_OVERRIDE_FILENAME,
+                "sha256": FSR4_OFFICIAL_411_ASSET["sha256"],
+                "source_asset_name": FSR4_OFFICIAL_411_ASSET["name"],
+                "source_version": FSR4_OFFICIAL_411_ASSET["version"],
+            }
+        ],
+        "config_overrides": {},
+    },
+    "rdna2-valve-411-pre10": {
+        "label": "4.1.1 Valve RDNA2 compatibility",
+        "dir_name": "fsr4-rdna2-valve-411-pre10",
+        "sha256": "d0dcccc74a43c44ba435b7a369b456e0970d8a4464e4bd683119b374f2c9fb46",
+        "source_asset_name": OPTISCALER_ARCHIVE_ASSET["name"],
+        "source_version": OPTISCALER_ARCHIVE_ASSET["version"],
+        "uses_archive_native": True,
+        "injector": {
+            "name": "OptiScaler.dll",
+            "sha256": OPTISCALER_PRE10_ASSET["sha256"],
+            "source_asset_name": OPTISCALER_PRE10_ASSET["name"],
+            "source_version": OPTISCALER_PRE10_ASSET["version"],
+        },
+        "extra_files": [
+            {
+                "name": FSR4_DRIVER_OVERRIDE_FILENAME,
+                "sha256": FSR4_VALVE_411_ASSET["sha256"],
+                "source_asset_name": FSR4_VALVE_411_ASSET["name"],
+                "source_version": FSR4_VALVE_411_ASSET["version"],
+            },
+            {
+                "name": "amdxc64.dll",
+                "sha256": AMDXC64_RDNA2_ASSET["sha256"],
+                "source_asset_name": AMDXC64_RDNA2_ASSET["name"],
+                "source_version": AMDXC64_RDNA2_ASSET["version"],
+            },
+        ],
+        "config_overrides": {
+            "FSR.Fsr4ForceModel": "2",
+            "Plugins.LoadCustomAmdxc64OnRdna2": "true",
+        },
+    },
+}
+
+VARIANT_EXTRA_FILENAMES = sorted(
+    {
+        extra_file["name"]
+        for variant in FSR4_VARIANTS.values()
+        for extra_file in variant.get("extra_files", [])
+    }
+)
+
+PROXY_DLL_BACKUPS = [
+    "dxgi.dll",
+    "winmm.dll",
+    "dbghelp.dll",
+    "version.dll",
+    "wininet.dll",
+    "winhttp.dll",
+    "OptiScaler.asi",
+]
+VALID_DLL_NAMES = set(PROXY_DLL_BACKUPS)
+
+INJECTOR_FILENAMES = [
+    *PROXY_DLL_BACKUPS,
+    "nvngx.dll",
+    "_nvngx.dll",
+    "nvngx-wrapper.dll",
+    "dlss-enabler.dll",
+    "OptiScaler.dll",
+]
+
+ORIGINAL_DLL_BACKUPS = [
+    "d3dcompiler_47.dll",
+    "amd_fidelityfx_dx12.dll",
+    "amd_fidelityfx_framegeneration_dx12.dll",
+    FSR4_UPSCALER_FILENAME,
+    FSR4_DRIVER_OVERRIDE_FILENAME,
+    "amdxc64.dll",
+    "amd_fidelityfx_vk.dll",
+]
+
+RESTORABLE_BACKUP_FILES = [
+    *PROXY_DLL_BACKUPS,
+    *ORIGINAL_DLL_BACKUPS,
+]
+
+SUPPORT_FILES = [
+    "libxess.dll",
+    "libxess_dx11.dll",
+    "libxess_fg.dll",
+    "libxell.dll",
+    "amd_fidelityfx_dx12.dll",
+    "amd_fidelityfx_framegeneration_dx12.dll",
+    "amd_fidelityfx_vk.dll",
+    "dlssg_to_fsr3_amd_is_better.dll",
+    "fakenvapi.dll",
+    "fakenvapi.ini",
+]
+
+MARKER_FILENAME = "FRAMEGEN_PATCH"
+MANIFEST_SCHEMA_VERSION = 2
+BACKUP_DIRECTORY_NAME = ".framegen-backups"
diff --git a/py_modules/services/bundle.py b/py_modules/services/bundle.py
new file mode 100644
index 0000000..a6ef9e4
--- /dev/null
+++ b/py_modules/services/bundle.py
@@ -0,0 +1,522 @@
+"""Management of the shared OptiScaler bundle in ``~/fgmod``."""
+
+import os
+import shutil
+import subprocess
+from datetime import datetime, timezone
+from pathlib import Path
+from typing import Callable
+
+from . import config
+from .assets import (
+    DEFAULT_FRAMEGEN_BACKEND,
+    DEFAULT_FSR4_VARIANT,
+    FRAMEGEN_BACKENDS,
+    FSR4_DRIVER_OVERRIDE_FILENAME,
+    FSR4_VARIANTS,
+    FSR4_UPSCALER_FILENAME,
+    INSTALL_MANIFEST_FILENAME,
+    MANIFEST_SCHEMA_VERSION,
+    OPTIPATCHER_ASSET,
+    OPTISCALER_ARCHIVE_ASSET,
+    OPTISCALER_PRE10_ASSET,
+    AMDXC64_RDNA2_ASSET,
+    FSR4_INT8_ASSET,
+    FSR4_OFFICIAL_411_ASSET,
+    FSR4_VALVE_411_ASSET,
+    VERSION_FILENAME,
+)
+from .files import file_sha256, read_json, write_json
+
+
+Logger = Callable[[str], None]
+
+
+class BundleManager:
+    def __init__(self, home: Path, plugin_dir: Path, logger: Logger):
+        self.home = home
+        self.plugin_dir = plugin_dir
+        self.logger = logger
+
+    @property
+    def fgmod_path(self) -> Path:
+        return self.home / "fgmod"
+
+    def _log(self, message: str) -> None:
+        self.logger(f"[Framegen] {message}")
+
+    def _create_renamed_copies(self, source_file: Path, renames_dir: Path) -> bool:
+        try:
+            if not source_file.exists():
+                self._log(f"Source file {source_file} does not exist")
+                return False
+            renames_dir.mkdir(parents=True, exist_ok=True)
+            for filename in ("dxgi.dll", "winmm.dll", "dbghelp.dll", "version.dll", "wininet.dll", "winhttp.dll", "OptiScaler.asi"):
+                shutil.copy2(source_file, renames_dir / filename)
+            return True
+        except OSError as exc:
+            self._log(f"Failed to create renamed copies: {exc}")
+            return False
+
+    def _copy_launcher_scripts(self, assets_dir: Path, extract_path: Path) -> bool:
+        try:
+            scripts = {
+                "fgmod.sh": "fgmod",
+                "fgmod-uninstaller.sh": "fgmod-uninstaller.sh",
+                "update-optiscaler-config.py": "update-optiscaler-config.py",
+            }
+            for source_name, destination_name in scripts.items():
+                source = assets_dir / source_name
+                if not source.exists():
+                    continue
+                destination = extract_path / destination_name
+                shutil.copy2(source, destination)
+                destination.chmod(0o755)
+            return True
+        except OSError as exc:
+            self._log(f"Failed to copy launcher scripts: {exc}")
+            return False
+
+    def _extract_archive(self, archive_path: Path, output_dir: Path) -> None:
+        output_dir.mkdir(parents=True, exist_ok=True)
+        environment = os.environ.copy()
+        environment["LD_LIBRARY_PATH"] = ""
+        result = subprocess.run(
+            ["7z", "x", "-y", "-o" + str(output_dir), str(archive_path)],
+            capture_output=True,
+            text=True,
+            check=False,
+            env=environment,
+        )
+        if result.returncode != 0:
+            raise RuntimeError(result.stderr or result.stdout or f"Failed to extract {archive_path.name}")
+
+    def _verify(self, path: Path, expected_sha256: str, description: str) -> str:
+        actual = file_sha256(path)
+        if actual.lower() != expected_sha256.lower():
+            raise RuntimeError(f"{description} hash mismatch: expected {expected_sha256}, got {actual}")
+        return actual
+
+    def _manifest_path(self) -> Path:
+        return self.fgmod_path / INSTALL_MANIFEST_FILENAME
+
+    def load_manifest(self) -> dict:
+        return read_json(self._manifest_path())
+
+    @staticmethod
+    def normalize_variant(value: str | None) -> str:
+        return value if value in FSR4_VARIANTS else DEFAULT_FSR4_VARIANT
+
+    @staticmethod
+    def normalize_backend(value: str | None) -> str:
+        return value if value in FRAMEGEN_BACKENDS else DEFAULT_FRAMEGEN_BACKEND
+
+    def selected_variant(self, requested: str | None = None) -> str:
+        if requested in FSR4_VARIANTS:
+            return requested
+        installed = self.load_manifest().get("selected_default_variant")
+        return self.normalize_variant(installed)
+
+    def selected_backend(self, requested: str | None = None) -> str:
+        if requested in FRAMEGEN_BACKENDS:
+            return requested
+        manifest_backend = self.load_manifest().get("framegen_backend")
+        if manifest_backend in FRAMEGEN_BACKENDS:
+            return manifest_backend
+        return self.normalize_backend(config.detect_backend(self.fgmod_path / "OptiScaler.ini"))
+
+    def variant_info(self, variant: str | None) -> dict:
+        return FSR4_VARIANTS[self.normalize_variant(variant)]
+
+    def variant_dir(self, variant: str | None) -> Path:
+        return self.fgmod_path / self.variant_info(variant)["dir_name"]
+
+    def variant_path(self, variant: str | None) -> Path:
+        return self.variant_dir(variant) / FSR4_UPSCALER_FILENAME
+
+    def variant_extra_files(self, variant: str | None) -> list[dict]:
+        return list(self.variant_info(variant).get("extra_files") or [])
+
+    def variant_extra_path(self, variant: str | None, filename: str) -> Path:
+        return self.variant_dir(variant) / filename
+
+    def variant_injector_info(self, variant: str | None) -> dict | None:
+        injector = self.variant_info(variant).get("injector")
+        return injector if isinstance(injector, dict) else None
+
+    def variant_injector_path(self, variant: str | None) -> Path | None:
+        injector = self.variant_injector_info(variant)
+        return self.variant_dir(variant) / injector["name"] if injector else None
+
+    def variant_proxy_path(self, variant: str | None, dll_name: str) -> Path | None:
+        if not self.variant_injector_info(variant):
+            return None
+        return self.variant_dir(variant) / "renames" / dll_name
+
+    def variant_config_overrides(self, variant: str | None) -> dict:
+        overrides = self.variant_info(variant).get("config_overrides") or {}
+        return dict(overrides) if isinstance(overrides, dict) else {}
+
+    def fgmod_version(self) -> str | None:
+        manifest = self.load_manifest()
+        optiscaler = manifest.get("optiscaler")
+        if isinstance(optiscaler, dict) and optiscaler.get("version"):
+            return str(optiscaler["version"])
+        try:
+            version = (self.fgmod_path / VERSION_FILENAME).read_text(encoding="utf-8").strip()
+            return version or None
+        except OSError:
+            return None
+
+    def managed_support_candidates(self, filename: str) -> list[Path]:
+        candidates = [self.fgmod_path / filename]
+        if filename == FSR4_UPSCALER_FILENAME:
+            candidates = [self.fgmod_path / filename] + [self.variant_path(variant) for variant in FSR4_VARIANTS]
+        else:
+            for variant in FSR4_VARIANTS:
+                if any(extra.get("name") == filename for extra in self.variant_extra_files(variant)):
+                    candidates.append(self.variant_extra_path(variant, filename))
+        unique: list[Path] = []
+        seen: set[str] = set()
+        for candidate in candidates:
+            if str(candidate) not in seen:
+                unique.append(candidate)
+                seen.add(str(candidate))
+        return unique
+
+    def is_managed_support_file(self, path: Path) -> bool:
+        return path.exists() and any(
+            candidate.is_file() and file_sha256(path) == file_sha256(candidate)
+            for candidate in self.managed_support_candidates(path.name)
+        )
+
+    def _sync_variant_root_extra_files(self, variant: str) -> None:
+        selected = {extra["name"]: extra for extra in self.variant_extra_files(variant)}
+        all_extra_names = {
+            extra["name"]
+            for item in FSR4_VARIANTS.values()
+            for extra in item.get("extra_files", [])
+        }
+        for filename in all_extra_names:
+            root_path = self.fgmod_path / filename
+            if filename not in selected:
+                if root_path.exists():
+                    root_path.unlink()
+                continue
+            source = self.variant_extra_path(variant, filename)
+            if not source.exists():
+                raise FileNotFoundError(f"Prepared FSR4 variant extra file missing: {source}")
+            shutil.copy2(source, root_path)
+
+    def activate_variant(self, variant: str | None) -> str:
+        variant_id = self.normalize_variant(variant)
+        source = self.variant_path(variant_id)
+        if not source.exists():
+            raise FileNotFoundError(f"Prepared FSR4 variant missing: {source}")
+        shutil.copy2(source, self.fgmod_path / FSR4_UPSCALER_FILENAME)
+        self._sync_variant_root_extra_files(variant_id)
+        return variant_id
+
+    def detect_variant(self, directory: Path, upscaler_sha256: str | None) -> str | None:
+        if not upscaler_sha256:
+            return None
+        normalized = upscaler_sha256.lower()
+        for variant_id, variant in FSR4_VARIANTS.items():
+            if str(variant.get("sha256", "")).lower() != normalized:
+                continue
+            if all(
+                (directory / extra["name"]).exists()
+                and file_sha256(directory / extra["name"]).lower() == extra["sha256"].lower()
+                for extra in variant.get("extra_files", [])
+            ):
+                return variant_id
+        return None
+
+    def extract_static_optiscaler(
+        self,
+        selected_default_variant: str = DEFAULT_FSR4_VARIANT,
+        framegen_backend: str = DEFAULT_FRAMEGEN_BACKEND,
+    ) -> dict:
+        """Prepare the shared bundle; replacement remains intentionally non-atomic for compatibility."""
+        try:
+            selected_default_variant = self.normalize_variant(selected_default_variant)
+            framegen_backend = self.normalize_backend(framegen_backend)
+            bin_path = self.plugin_dir / "bin"
+            assets_dir = self.plugin_dir / "assets"
+            if not bin_path.exists():
+                return {"status": "error", "message": f"Bin directory not found: {bin_path}"}
+
+            asset_sources = {
+                "archive": (bin_path / OPTISCALER_ARCHIVE_ASSET["name"], OPTISCALER_ARCHIVE_ASSET),
+                "int8": (bin_path / FSR4_INT8_ASSET["name"], FSR4_INT8_ASSET),
+                "official": (bin_path / FSR4_OFFICIAL_411_ASSET["name"], FSR4_OFFICIAL_411_ASSET),
+                "valve": (bin_path / FSR4_VALVE_411_ASSET["name"], FSR4_VALVE_411_ASSET),
+                "amdxc64": (bin_path / AMDXC64_RDNA2_ASSET["name"], AMDXC64_RDNA2_ASSET),
+                "pre10": (bin_path / OPTISCALER_PRE10_ASSET["name"], OPTISCALER_PRE10_ASSET),
+                "optipatcher": (bin_path / OPTIPATCHER_ASSET["name"], OPTIPATCHER_ASSET),
+            }
+            for path, asset in asset_sources.values():
+                if not path.exists():
+                    return {"status": "error", "message": f"Required bundled asset missing: {asset['name']}"}
+                self._verify(path, asset["sha256"], asset["name"])
+
+            if self.fgmod_path.exists():
+                shutil.rmtree(self.fgmod_path)
+            self.fgmod_path.mkdir(parents=True, exist_ok=True)
+            self._extract_archive(asset_sources["archive"][0], self.fgmod_path)
+
+            source = self.fgmod_path / "OptiScaler.dll"
+            if not self._create_renamed_copies(source, self.fgmod_path / "renames"):
+                return {"status": "error", "message": "Failed to prepare renamed OptiScaler proxies."}
+            if not self._copy_launcher_scripts(assets_dir, self.fgmod_path):
+                return {"status": "error", "message": "Failed to copy launcher scripts."}
+
+            plugins_dir = self.fgmod_path / "plugins"
+            plugins_dir.mkdir(parents=True, exist_ok=True)
+            optipatcher_dst = plugins_dir / "OptiPatcher.asi"
+            shutil.copy2(asset_sources["optipatcher"][0], optipatcher_dst)
+            optipatcher_sha256 = self._verify(optipatcher_dst, OPTIPATCHER_ASSET["sha256"], "Prepared OptiPatcher plugin")
+
+            ini_file = self.fgmod_path / "OptiScaler.ini"
+            config.configure(ini_file, framegen_backend, logger=self.logger)
+
+            native_root = self.fgmod_path / FSR4_UPSCALER_FILENAME
+            native_sha256 = self._verify(native_root, FSR4_VARIANTS["rdna4-native"]["sha256"], "Archive-native FSR4 upscaler")
+            for variant_id in ("rdna4-native", "rdna34-official-411", "rdna2-valve-411-pre10"):
+                variant_dir = self.variant_dir(variant_id)
+                variant_dir.mkdir(parents=True, exist_ok=True)
+                prepared = variant_dir / FSR4_UPSCALER_FILENAME
+                shutil.copy2(native_root, prepared)
+                self._verify(prepared, FSR4_VARIANTS[variant_id]["sha256"], f"Prepared {variant_id} FSR4 upscaler")
+
+            official_dir = self.variant_dir("rdna34-official-411")
+            shutil.copy2(asset_sources["official"][0], official_dir / FSR4_DRIVER_OVERRIDE_FILENAME)
+            self._verify(official_dir / FSR4_DRIVER_OVERRIDE_FILENAME, FSR4_OFFICIAL_411_ASSET["sha256"], "Prepared official driver override")
+
+            valve_dir = self.variant_dir("rdna2-valve-411-pre10")
+            shutil.copy2(asset_sources["valve"][0], valve_dir / FSR4_DRIVER_OVERRIDE_FILENAME)
+            shutil.copy2(asset_sources["amdxc64"][0], valve_dir / "amdxc64.dll")
+            shutil.copy2(asset_sources["pre10"][0], valve_dir / "OptiScaler.dll")
+            self._verify(valve_dir / FSR4_DRIVER_OVERRIDE_FILENAME, FSR4_VALVE_411_ASSET["sha256"], "Prepared Valve driver override")
+            self._verify(valve_dir / "amdxc64.dll", AMDXC64_RDNA2_ASSET["sha256"], "Prepared RDNA2 driver override")
+            self._verify(valve_dir / "OptiScaler.dll", OPTISCALER_PRE10_ASSET["sha256"], "Prepared pre10 OptiScaler injector")
+            if not self._create_renamed_copies(valve_dir / "OptiScaler.dll", valve_dir / "renames"):
+                return {"status": "error", "message": "Failed to prepare renamed pre10 OptiScaler proxies."}
+
+            int8_dir = self.variant_dir("rdna23-int8")
+            int8_dir.mkdir(parents=True, exist_ok=True)
+            shutil.copy2(asset_sources["int8"][0], int8_dir / FSR4_UPSCALER_FILENAME)
+            self._verify(int8_dir / FSR4_UPSCALER_FILENAME, FSR4_INT8_ASSET["sha256"], "Prepared RDNA2-3 FSR4 upscaler")
+
+            selected_default_variant = self.activate_variant(selected_default_variant)
+            active_sha256 = file_sha256(self.fgmod_path / FSR4_UPSCALER_FILENAME)
+            (self.fgmod_path / VERSION_FILENAME).write_text(OPTISCALER_ARCHIVE_ASSET["version"], encoding="utf-8")
+            manifest = self._build_manifest(
+                selected_default_variant,
+                framegen_backend,
+                native_sha256,
+                optipatcher_sha256,
+                active_sha256,
+            )
+            write_json(self._manifest_path(), manifest)
+            return {
+                "status": "success",
+                "message": f"Successfully extracted OptiScaler {OPTISCALER_ARCHIVE_ASSET['version']} to ~/fgmod",
+                "version": OPTISCALER_ARCHIVE_ASSET["version"],
+                "selected_default_variant": selected_default_variant,
+                "selected_default_variant_label": FSR4_VARIANTS[selected_default_variant]["label"],
+                "framegen_backend": framegen_backend,
+                "framegen_backend_label": FRAMEGEN_BACKENDS[framegen_backend],
+            }
+        except Exception as exc:
+            self._log(f"Extract failed: {exc}")
+            return {"status": "error", "message": f"Extract failed: {exc}"}
+
+    def _build_manifest(
+        self,
+        selected_variant: str,
+        framegen_backend: str,
+        native_sha256: str,
+        optipatcher_sha256: str,
+        active_sha256: str,
+    ) -> dict:
+        variants = {}
+        for variant_id, variant in FSR4_VARIANTS.items():
+            injector = variant.get("injector")
+            injector_manifest = None
+            if isinstance(injector, dict):
+                injector_manifest = {
+                    key: injector[key]
+                    for key in ("name", "sha256", "source_asset_name", "source_version")
+                }
+                injector_manifest["path"] = str(Path(variant["dir_name"]) / injector["name"])
+            variants[variant_id] = {
+                "label": variant["label"],
+                "dir_name": variant["dir_name"],
+                "path": str(Path(variant["dir_name"]) / FSR4_UPSCALER_FILENAME),
+                "sha256": variant["sha256"],
+                "source_asset_name": variant["source_asset_name"],
+                "source_version": variant["source_version"],
+                "uses_archive_native": bool(variant["uses_archive_native"]),
+                "injector": injector_manifest,
+                "config_overrides": dict(variant.get("config_overrides") or {}),
+                "extra_files": [
+                    {
+                        **{key: extra[key] for key in ("name", "sha256", "source_asset_name", "source_version")},
+                        "path": str(Path(variant["dir_name"]) / extra["name"]),
+                    }
+                    for extra in variant.get("extra_files", [])
+                ],
+            }
+        return {
+            "schema_version": MANIFEST_SCHEMA_VERSION,
+            "installed_at": datetime.now(timezone.utc).isoformat(),
+            "optiscaler": {
+                "asset_name": OPTISCALER_ARCHIVE_ASSET["name"],
+                "version": OPTISCALER_ARCHIVE_ASSET["version"],
+                "sha256": OPTISCALER_ARCHIVE_ASSET["sha256"],
+                "native_upscaler_sha256": native_sha256,
+            },
+            "optipatcher": {
+                "asset_name": OPTIPATCHER_ASSET["name"],
+                "version": OPTIPATCHER_ASSET["version"],
+                "sha256": optipatcher_sha256,
+                "target_path": "plugins/OptiPatcher.asi",
+            },
+            "fsr4_variants": variants,
+            "selected_default_variant": selected_variant,
+            "framegen_backend": framegen_backend,
+            "framegen_backend_label": FRAMEGEN_BACKENDS[framegen_backend],
+            "active_root_upscaler": {
+                "path": FSR4_UPSCALER_FILENAME,
+                "sha256": active_sha256,
+                "variant": selected_variant,
+            },
+        }
+
+    def run_install(self, selected_variant: str, framegen_backend: str) -> dict:
+        selected_variant = self.normalize_variant(selected_variant)
+        framegen_backend = self.normalize_backend(framegen_backend)
+        result = self.extract_static_optiscaler(selected_variant, framegen_backend)
+        if result["status"] != "success":
+            return {"status": "error", "message": f"OptiScaler extraction failed: {result.get('message', 'Unknown error')}"}
+        return {
+            "status": "success",
+            "output": f"Successfully installed OptiScaler {result.get('version', OPTISCALER_ARCHIVE_ASSET['version'])} with {result.get('selected_default_variant_label', FSR4_VARIANTS[selected_variant]['label'])}.",
+            "version": result.get("version", OPTISCALER_ARCHIVE_ASSET["version"]),
+            "selected_default_variant": result.get("selected_default_variant", selected_variant),
+            "selected_default_variant_label": result.get("selected_default_variant_label", FSR4_VARIANTS[selected_variant]["label"]),
+            "framegen_backend": result.get("framegen_backend", framegen_backend),
+            "framegen_backend_label": result.get("framegen_backend_label", FRAMEGEN_BACKENDS[framegen_backend]),
+        }
+
+    def uninstall(self) -> dict:
+        try:
+            if not self.fgmod_path.exists():
+                return {"status": "success", "output": "No fgmod directory found to remove"}
+            shutil.rmtree(self.fgmod_path)
+            return {"status": "success", "output": "Successfully removed fgmod directory"}
+        except OSError as exc:
+            self._log(f"Uninstall error: {exc}")
+            return {"status": "error", "message": f"Uninstall failed: {exc}", "output": str(exc)}
+
+    def set_default_variant(self, selected_variant: str) -> dict:
+        try:
+            if not self.fgmod_path.exists():
+                return {"status": "error", "message": "OptiScaler bundle not installed. Run Install first."}
+            manifest = self.load_manifest()
+            if not manifest:
+                return {"status": "error", "message": "Install manifest missing. Reinstall OptiScaler."}
+            selected_variant = self.activate_variant(selected_variant)
+            active_sha256 = file_sha256(self.fgmod_path / FSR4_UPSCALER_FILENAME)
+            manifest["selected_default_variant"] = selected_variant
+            manifest["active_root_upscaler"] = {
+                "path": FSR4_UPSCALER_FILENAME,
+                "sha256": active_sha256,
+                "variant": selected_variant,
+            }
+            manifest["updated_at"] = datetime.now(timezone.utc).isoformat()
+            write_json(self._manifest_path(), manifest)
+            return {
+                "status": "success",
+                "output": f"Default FSR4 runtime switched to {FSR4_VARIANTS[selected_variant]['label']}.",
+                "version": self.fgmod_version(),
+                "selected_default_variant": selected_variant,
+                "selected_default_variant_label": FSR4_VARIANTS[selected_variant]["label"],
+            }
+        except Exception as exc:
+            self._log(f"Failed to switch default FSR4 runtime: {exc}")
+            return {"status": "error", "message": f"Failed to switch default FSR4 runtime: {exc}"}
+
+    def set_framegen_backend(self, framegen_backend: str) -> dict:
+        try:
+            if not self.fgmod_path.exists():
+                return {"status": "error", "message": "OptiScaler bundle not installed. Run Install first."}
+            backend = self.normalize_backend(framegen_backend)
+            manifest = self.load_manifest()
+            if not manifest:
+                return {"status": "error", "message": "Install manifest missing. Reinstall OptiScaler."}
+            ini_file = self.fgmod_path / "OptiScaler.ini"
+            if not config.configure(ini_file, backend, logger=self.logger):
+                return {"status": "error", "message": "Could not update the shared OptiScaler.ini."}
+            manifest["framegen_backend"] = backend
+            manifest["framegen_backend_label"] = FRAMEGEN_BACKENDS[backend]
+            manifest["updated_at"] = datetime.now(timezone.utc).isoformat()
+            write_json(self._manifest_path(), manifest)
+            return {
+                "status": "success",
+                "framegen_backend": backend,
+                "framegen_backend_label": FRAMEGEN_BACKENDS[backend],
+                "output": f"Frame generation backend set to {FRAMEGEN_BACKENDS[backend]}.",
+            }
+        except Exception as exc:
+            self._log(f"Failed to set frame generation backend: {exc}")
+            return {"status": "error", "message": f"Failed to set frame generation backend: {exc}"}
+
+    def check(self) -> dict:
+        required_files = [
+            "OptiScaler.dll",
+            "OptiScaler.ini",
+            "dlssg_to_fsr3_amd_is_better.dll",
+            "fakenvapi.dll",
+            "fakenvapi.ini",
+            "amd_fidelityfx_dx12.dll",
+            "amd_fidelityfx_framegeneration_dx12.dll",
+            FSR4_UPSCALER_FILENAME,
+            "amd_fidelityfx_vk.dll",
+            "libxess.dll",
+            "libxess_dx11.dll",
+            "libxess_fg.dll",
+            "libxell.dll",
+            "fgmod",
+            "fgmod-uninstaller.sh",
+            "update-optiscaler-config.py",
+            INSTALL_MANIFEST_FILENAME,
+        ]
+        if not self.fgmod_path.exists() or any(not (self.fgmod_path / filename).exists() for filename in required_files):
+            return {"exists": False}
+        plugins_dir = self.fgmod_path / "plugins"
+        if not (plugins_dir / "OptiPatcher.asi").exists():
+            return {"exists": False}
+        for variant_id, variant in FSR4_VARIANTS.items():
+            variant_dir = self.variant_dir(variant_id)
+            if not (variant_dir / FSR4_UPSCALER_FILENAME).exists():
+                return {"exists": False}
+            injector = variant.get("injector")
+            if isinstance(injector, dict) and not (variant_dir / injector.get("name", "OptiScaler.dll")).exists():
+                return {"exists": False}
+            for extra in variant.get("extra_files", []):
+                if not (variant_dir / extra["name"]).exists():
+                    return {"exists": False}
+        manifest = self.load_manifest()
+        variant = self.selected_variant()
+        backend = self.selected_backend()
+        return {
+            "exists": True,
+            "version": self.fgmod_version(),
+            "selected_fsr4_variant": variant,
+            "selected_fsr4_variant_label": FSR4_VARIANTS[variant]["label"],
+            "framegen_backend": backend,
+            "framegen_backend_label": FRAMEGEN_BACKENDS[backend],
+            "install_manifest_present": bool(manifest),
+        }
diff --git a/py_modules/services/config.py b/py_modules/services/config.py
new file mode 100644
index 0000000..87476cc
--- /dev/null
+++ b/py_modules/services/config.py
@@ -0,0 +1,175 @@
+"""OptiScaler configuration migration and default handling."""
+
+import re
+from pathlib import Path
+from typing import Callable
+
+
+Logger = Callable[[str], None]
+
+
+def _split_override_key(raw_key: str) -> tuple[str | None, str]:
+    key = str(raw_key).strip()
+    if "." in key:
+        section, section_key = key.split(".", 1)
+        section = section.strip()
+        section_key = section_key.strip()
+        if section and section_key:
+            return section, section_key
+    return None, key
+
+
+def apply_overrides(ini_file: Path, overrides: dict, logger: Logger | None = None) -> bool:
+    """Upsert INI keys without disturbing unrelated game configuration."""
+    if not overrides:
+        return True
+    try:
+        content = ini_file.read_text(encoding="utf-8", errors="replace")
+        newline = "\r\n" if "\r\n" in content else "\n"
+        lines = content.splitlines(keepends=True)
+        section_pattern = re.compile(r"^\s*\[(?P<section>[^\]]+)\]\s*$")
+
+        def ensure_trailing_newline() -> None:
+            if lines and not lines[-1].endswith(("\n", "\r")):
+                lines[-1] += newline
+
+        def upsert(section: str | None, key: str, value: str) -> None:
+            replacement = f"{key}={value}"
+            key_pattern = re.compile(rf"^(\s*{re.escape(key)}\s*)=.*$")
+
+            if section is None:
+                for index, line in enumerate(lines):
+                    if key_pattern.match(line):
+                        ending = "\r\n" if line.endswith("\r\n") else ("\n" if line.endswith("\n") else newline)
+                        lines[index] = f"{replacement}{ending}"
+                        return
+                ensure_trailing_newline()
+                lines.append(f"{replacement}{newline}")
+                return
+
+            in_section = False
+            insert_at = None
+            for index, line in enumerate(lines):
+                match = section_pattern.match(line.strip())
+                if match:
+                    if in_section:
+                        insert_at = index
+                        break
+                    if match.group("section") == section:
+                        in_section = True
+                        continue
+                if in_section and key_pattern.match(line):
+                    ending = "\r\n" if line.endswith("\r\n") else ("\n" if line.endswith("\n") else newline)
+                    lines[index] = f"{replacement}{ending}"
+                    return
+
+            if in_section:
+                if insert_at is None:
+                    ensure_trailing_newline()
+                    insert_at = len(lines)
+                lines.insert(insert_at, f"{replacement}{newline}")
+                return
+
+            ensure_trailing_newline()
+            if lines and lines[-1].strip():
+                lines.append(newline)
+            lines.extend((f"[{section}]{newline}", f"{replacement}{newline}"))
+
+        for raw_key, raw_value in overrides.items():
+            section, key = _split_override_key(str(raw_key))
+            if key:
+                upsert(section, key, str(raw_value).strip())
+        ini_file.write_text("".join(lines), encoding="utf-8")
+        return True
+    except Exception as exc:
+        if logger:
+            logger(f"Failed to apply OptiScaler.ini overrides to {ini_file}: {exc}")
+        return False
+
+
+def migrate(ini_file: Path, logger: Logger | None = None) -> bool:
+    """Migrate the pre-0.9 ``FGType`` setting to split input/output keys."""
+    try:
+        if not ini_file.exists():
+            return False
+        content = ini_file.read_text(encoding="utf-8", errors="replace")
+        match = re.search(r"^FGType\s*=\s*(\S+)", content, re.MULTILINE)
+        if not match:
+            return True
+
+        value = match.group(1)
+        if re.search(r"^FGInput\s*=", content, re.MULTILINE):
+            updated = re.sub(r"^FGType\s*=\s*\S+\n?", "", content, flags=re.MULTILINE)
+            message = f"Removed stale FGType from {ini_file}"
+        else:
+            updated = re.sub(
+                r"^FGType\s*=\s*\S+",
+                f"FGInput={value}\nFGOutput={value}",
+                content,
+                flags=re.MULTILINE,
+            )
+            message = f"Migrated FGType={value} in {ini_file}"
+        if updated != content:
+            ini_file.write_text(updated, encoding="utf-8")
+            if logger:
+                logger(message)
+        return True
+    except Exception as exc:
+        if logger:
+            logger(f"Failed to migrate OptiScaler.ini: {exc}")
+        return False
+
+
+def disable_hq_font_auto(ini_file: Path, logger: Logger | None = None) -> bool:
+    """Avoid the HQ font auto mode, which is unreliable under Proton."""
+    try:
+        if not ini_file.exists():
+            return False
+        content = ini_file.read_text(encoding="utf-8", errors="replace")
+        updated = re.sub(r"UseHQFont\s*=\s*auto", "UseHQFont=false", content)
+        if updated != content:
+            ini_file.write_text(updated, encoding="utf-8")
+        return True
+    except Exception as exc:
+        if logger:
+            logger(f"Failed to update HQ font setting in {ini_file}: {exc}")
+        return False
+
+
+def configure(
+    ini_file: Path,
+    framegen_backend: str,
+    variant_overrides: dict | None = None,
+    logger: Logger | None = None,
+) -> bool:
+    """Apply safe defaults and the selected frame-generation backend."""
+    if not ini_file.exists():
+        return False
+    backend = framegen_backend if framegen_backend in {"auto", "nukems"} else "auto"
+    overrides = {
+        "FGInput": backend,
+        "FGOutput": backend,
+        "Fsr4Update": "true",
+        "LoadAsiPlugins": "true",
+    }
+    if variant_overrides:
+        overrides.update(variant_overrides)
+    migrated = migrate(ini_file, logger)
+    hq_updated = disable_hq_font_auto(ini_file, logger)
+    configured = apply_overrides(ini_file, overrides, logger)
+    return migrated and hq_updated and configured
+
+
+def detect_backend(ini_file: Path) -> str:
+    """Return the configured backend when both FG keys agree."""
+    try:
+        content = ini_file.read_text(encoding="utf-8", errors="replace")
+    except OSError:
+        return "auto"
+    values = [
+        match.group(1).strip().lower()
+        for match in re.finditer(r"^FG(?:Input|Output)\s*=\s*(\S+)", content, re.MULTILINE)
+    ]
+    if values and all(value == "nukems" for value in values):
+        return "nukems"
+    return "auto"
diff --git a/py_modules/services/files.py b/py_modules/services/files.py
new file mode 100644
index 0000000..d8571ba
--- /dev/null
+++ b/py_modules/services/files.py
@@ -0,0 +1,36 @@
+"""Small filesystem helpers shared by service modules."""
+
+import filecmp
+import hashlib
+import json
+from pathlib import Path
+
+
+def file_sha256(path: Path) -> str:
+    digest = hashlib.sha256()
+    with path.open("rb") as stream:
+        for chunk in iter(lambda: stream.read(1024 * 1024), b""):
+            digest.update(chunk)
+    return digest.hexdigest()
+
+
+def files_match(file_a: Path, file_b: Path) -> bool:
+    try:
+        return file_a.is_file() and file_b.is_file() and filecmp.cmp(file_a, file_b, shallow=False)
+    except OSError:
+        return False
+
+
+def read_json(path: Path) -> dict:
+    try:
+        with path.open("r", encoding="utf-8") as stream:
+            payload = json.load(stream)
+        return payload if isinstance(payload, dict) else {}
+    except (OSError, ValueError, TypeError):
+        return {}
+
+
+def write_json(path: Path, payload: dict) -> None:
+    path.parent.mkdir(parents=True, exist_ok=True)
+    with path.open("w", encoding="utf-8") as stream:
+        json.dump(payload, stream, indent=2)
diff --git a/py_modules/services/patcher.py b/py_modules/services/patcher.py
new file mode 100644
index 0000000..59d08f1
--- /dev/null
+++ b/py_modules/services/patcher.py
@@ -0,0 +1,685 @@
+"""Patch ownership, safe cleanup, and Steam-game operations."""
+
+import os
+import shutil
+from datetime import datetime, timezone
+from pathlib import Path
+from typing import Callable
+
+from . import config
+from .assets import (
+    BACKUP_DIRECTORY_NAME,
+    FRAMEGEN_BACKENDS,
+    FSR4_UPSCALER_FILENAME,
+    INJECTOR_FILENAMES,
+    MARKER_FILENAME,
+    MANIFEST_SCHEMA_VERSION,
+    RESTORABLE_BACKUP_FILES,
+    SUPPORT_FILES,
+    VALID_DLL_NAMES,
+    VARIANT_EXTRA_FILENAMES,
+)
+from .bundle import BundleManager
+from .files import file_sha256, files_match, read_json, write_json
+from .steam import SteamLibrary
+
+
+Logger = Callable[[str], None]
+
+
+class PatchManager:
+    def __init__(self, home: Path, bundle: BundleManager, steam: SteamLibrary, logger: Logger):
+        self.home = home
+        self.bundle = bundle
+        self.steam = steam
+        self.logger = logger
+
+    def _log(self, message: str) -> None:
+        self.logger(f"[Framegen] {message}")
+
+    @staticmethod
+    def _relative_path(root: Path, path: Path) -> str:
+        return path.resolve().relative_to(root.resolve()).as_posix()
+
+    def _safe_path(self, root: Path, value: str | Path) -> Path:
+        candidate = Path(value)
+        if candidate.is_absolute():
+            resolved = candidate.resolve()
+        else:
+            resolved = (root / candidate).resolve()
+        try:
+            resolved.relative_to(root.resolve())
+        except ValueError as exc:
+            raise ValueError(f"Path escapes patch directory: {value}") from exc
+        return resolved
+
+    def _read_marker(self, marker_path: Path) -> dict:
+        return read_json(marker_path)
+
+    def _find_marker(self, install_root: Path, appid: str | None = None) -> Path | None:
+        if not install_root.exists():
+            return None
+        try:
+            markers = sorted(path for path in install_root.rglob(MARKER_FILENAME) if path.is_file())
+        except OSError:
+            return None
+        for marker in markers:
+            metadata = self._read_marker(marker)
+            if appid is None or str(metadata.get("appid")) == str(appid):
+                return marker
+        return None
+
+    def _marker_target(self, marker_path: Path, metadata: dict) -> Path:
+        target_value = metadata.get("target_relative") or metadata.get("target_dir") or str(marker_path.parent)
+        target = self._safe_path(marker_path.parent, target_value)
+        if not target.is_dir():
+            raise FileNotFoundError(f"Patch target directory does not exist: {target}")
+        return target
+
+    def _bundle_source_for_proxy(self, variant: str, dll_name: str) -> Path:
+        candidates = [
+            self.bundle.variant_proxy_path(variant, dll_name),
+            self.bundle.variant_injector_path(variant),
+            self.bundle.fgmod_path / "renames" / dll_name,
+            self.bundle.fgmod_path / "OptiScaler.dll",
+        ]
+        for candidate in candidates:
+            if candidate and candidate.exists():
+                return candidate
+        raise FileNotFoundError(f"No injector source found for {dll_name}")
+
+    def _copy_plan(self, target_dir: Path, variant: str) -> list[tuple[str, Path]]:
+        plan: list[tuple[str, Path]] = []
+        # The proxy is the only file selected by the user; all other files are bundle-owned.
+        plan.append(("__proxy__", self._bundle_source_for_proxy(variant, "dxgi.dll")))
+        for filename in SUPPORT_FILES:
+            source = self.bundle.fgmod_path / filename
+            if source.is_file():
+                plan.append((filename, source))
+        upscaler = self.bundle.variant_path(variant)
+        if upscaler.is_file():
+            plan.append((FSR4_UPSCALER_FILENAME, upscaler))
+        for extra in self.bundle.variant_extra_files(variant):
+            source = self.bundle.variant_extra_path(variant, extra["name"])
+            if source.is_file():
+                plan.append((extra["name"], source))
+
+        for source_root, relative_root in (
+            (self.bundle.fgmod_path / "plugins", Path("plugins")),
+            (self.bundle.fgmod_path / "D3D12_Optiscaler", Path("D3D12_Optiscaler")),
+        ):
+            if not source_root.is_dir():
+                continue
+            for source in sorted(path for path in source_root.rglob("*") if path.is_file()):
+                plan.append(((relative_root / source.relative_to(source_root)).as_posix(), source))
+        return plan
+
+    def _backup_destination(self, target_dir: Path, relative: str, source: Path, force: bool = False) -> str | None:
+        destination = self._safe_path(target_dir, relative)
+        if not destination.exists():
+            return None
+        if destination.is_dir():
+            raise IsADirectoryError(f"Patch destination is a directory: {destination}")
+        if not force and files_match(destination, source):
+            return None
+
+        if relative in RESTORABLE_BACKUP_FILES:
+            legacy_backup = destination.with_name(destination.name + ".b")
+            if not legacy_backup.exists():
+                shutil.copy2(destination, legacy_backup)
+            elif not files_match(legacy_backup, destination):
+                raise RuntimeError(f"Refusing to overwrite an existing backup: {legacy_backup}")
+            return self._relative_path(target_dir, legacy_backup)
+
+        backup = target_dir / BACKUP_DIRECTORY_NAME / relative
+        backup.parent.mkdir(parents=True, exist_ok=True)
+        if backup.exists():
+            if not files_match(backup, destination):
+                raise RuntimeError(f"Refusing to overwrite an existing backup: {backup}")
+        else:
+            shutil.copy2(destination, backup)
+        return self._relative_path(target_dir, backup)
+
+    def _cleanup_empty_directories(self, target_dir: Path, managed_files: list[str]) -> None:
+        directories = sorted(
+            {self._safe_path(target_dir, path).parent for path in managed_files},
+            key=lambda path: len(path.parts),
+            reverse=True,
+        )
+        for directory in directories:
+            if directory == target_dir:
+                continue
+            try:
+                directory.rmdir()
+            except OSError:
+                pass
+        backup_dir = target_dir / BACKUP_DIRECTORY_NAME
+        try:
+            backup_dir.rmdir()
+        except OSError:
+            pass
+
+    def _rollback(
+        self,
+        target_dir: Path,
+        managed: list[dict],
+        backups: list[dict],
+    ) -> None:
+        for entry in reversed(managed):
+            try:
+                path = self._safe_path(target_dir, entry["path"])
+                backup = next((item["backup"] for item in backups if item["path"] == entry["path"]), None)
+                if backup:
+                    backup_path = self._safe_path(target_dir, backup)
+                    if backup_path.exists():
+                        if path.exists():
+                            path.unlink()
+                        shutil.move(backup_path, path)
+                elif path.exists() and entry.get("sha256") == file_sha256(path):
+                    path.unlink()
+            except (OSError, ValueError):
+                continue
+        self._cleanup_empty_directories(target_dir, [entry["path"] for entry in managed])
+
+    def _patch_directory(
+        self,
+        target_dir: Path,
+        dll_name: str,
+        variant: str,
+        framegen_backend: str,
+        *,
+        appid: str,
+        game_name: str,
+        original_launch_options: str,
+        previous_variant: str | None = None,
+    ) -> dict:
+        if dll_name not in VALID_DLL_NAMES:
+            return {"status": "error", "message": f"Invalid proxy DLL name: {dll_name}"}
+        if not self.bundle.fgmod_path.exists() or not (self.bundle.fgmod_path / "OptiScaler.dll").exists():
+            return {"status": "error", "message": "OptiScaler bundle not installed. Run Install first."}
+
+        variant = self.bundle.selected_variant(variant)
+        framegen_backend = self.bundle.selected_backend(framegen_backend)
+        previous_marker = target_dir / MARKER_FILENAME
+        if previous_marker.exists():
+            return {"status": "error", "message": f"Patch marker already exists in {target_dir}; clean it up before patching."}
+        variant_overrides = self.bundle.variant_config_overrides(variant)
+        if previous_variant == "rdna2-valve-411-pre10" and variant != previous_variant:
+            variant_overrides.setdefault("FSR.Fsr4ForceModel", "auto")
+            variant_overrides.setdefault("Plugins.LoadCustomAmdxc64OnRdna2", "false")
+
+        managed: list[dict] = []
+        backups: list[dict] = []
+        try:
+            plan = self._copy_plan(target_dir, variant)
+            proxy_source = self._bundle_source_for_proxy(variant, dll_name)
+            plan[0] = (dll_name, proxy_source)
+            config_path = target_dir / "OptiScaler.ini"
+            if config_path.exists():
+                plan.append(("OptiScaler.ini", config_path))
+            elif (self.bundle.fgmod_path / "OptiScaler.ini").exists():
+                plan.append(("OptiScaler.ini", self.bundle.fgmod_path / "OptiScaler.ini"))
+
+            for relative, source in plan:
+                destination = self._safe_path(target_dir, relative)
+                if not source.is_file():
+                    continue
+                backup = self._backup_destination(
+                    target_dir,
+                    relative,
+                    source,
+                    # Preserve every pre-existing destination. Identical bytes do
+                    # not prove that a file belongs to this plugin.
+                    force=destination.exists(),
+                )
+                if backup:
+                    backups.append({
+                        "path": relative,
+                        "backup": backup,
+                        "sha256": file_sha256(self._safe_path(target_dir, backup)),
+                    })
+                destination.parent.mkdir(parents=True, exist_ok=True)
+                if destination.resolve() != source.resolve():
+                    shutil.copy2(source, destination)
+                managed.append({
+                    "path": relative,
+                    "sha256": file_sha256(destination),
+                    "source_sha256": file_sha256(source),
+                })
+
+            if config_path.exists() and not config.configure(
+                config_path,
+                framegen_backend,
+                variant_overrides=variant_overrides,
+                logger=self.logger,
+            ):
+                raise RuntimeError("Could not update OptiScaler.ini")
+            config_entry = next((entry for entry in managed if entry["path"] == "OptiScaler.ini"), None)
+            if config_entry:
+                config_entry["sha256"] = file_sha256(config_path)
+
+            payload = {
+                "schema_version": MANIFEST_SCHEMA_VERSION,
+                "appid": str(appid),
+                "game_name": game_name,
+                "dll_name": dll_name,
+                "target_dir": str(target_dir),
+                "target_relative": ".",
+                "original_launch_options": original_launch_options,
+                "backed_up_files": [item["path"] for item in backups],
+                "backups": backups,
+                "managed_files": managed,
+                "managed_directories": sorted({str(Path(item["path"]).parent) for item in managed if Path(item["path"]).parent != Path(".")}),
+                "optiscaler_version": self.bundle.fgmod_version(),
+                "fsr4_variant": variant,
+                "fsr4_variant_label": self.bundle.variant_info(variant)["label"],
+                "fsr4_upscaler_sha256": file_sha256(target_dir / FSR4_UPSCALER_FILENAME) if (target_dir / FSR4_UPSCALER_FILENAME).exists() else None,
+                "framegen_backend": framegen_backend,
+                "framegen_backend_label": FRAMEGEN_BACKENDS[framegen_backend],
+                "patched_at": datetime.now(timezone.utc).isoformat(),
+            }
+            # The marker is written last, so an interrupted copy is never advertised as a complete patch.
+            write_json(previous_marker, payload)
+            return {
+                "status": "success",
+                "message": f"OptiScaler files copied to {target_dir} using {self.bundle.variant_info(variant)['label']}",
+                "fsr4_variant": variant,
+                "fsr4_variant_label": self.bundle.variant_info(variant)["label"],
+                "fsr4_upscaler_sha256": payload["fsr4_upscaler_sha256"],
+                "optiscaler_version": payload["optiscaler_version"],
+                "framegen_backend": framegen_backend,
+            }
+        except (OSError, RuntimeError, ValueError) as exc:
+            self._rollback(target_dir, managed, backups)
+            self._log(f"Patch failed for {target_dir}: {exc}")
+            return {"status": "error", "message": f"Patch failed: {exc}"}
+
+    def _managed_entries(self, target_dir: Path, metadata: dict) -> tuple[list[tuple[dict, Path]], list[str]]:
+        entries: list[tuple[dict, Path]] = []
+        errors: list[str] = []
+        for entry in metadata.get("managed_files", []):
+            if not isinstance(entry, dict) or not entry.get("path"):
+                errors.append("Patch marker contains an invalid managed file entry.")
+                continue
+            try:
+                path = self._safe_path(target_dir, entry["path"])
+            except ValueError as exc:
+                errors.append(str(exc))
+                continue
+            expected = str(entry.get("sha256") or "")
+            if not expected:
+                errors.append(f"Patch marker has no hash for {entry['path']}.")
+            elif path.exists() and (not path.is_file() or file_sha256(path).lower() != expected.lower()):
+                errors.append(f"Refusing to remove modified managed file: {path}")
+            entries.append((entry, path))
+        return entries, errors
+
+    def _restore_backups(self, target_dir: Path, metadata: dict) -> list[str]:
+        restored: list[str] = []
+        for item in metadata.get("backups", []):
+            if not isinstance(item, dict) or not item.get("path") or not item.get("backup"):
+                raise ValueError("Patch marker contains an invalid backup entry.")
+            path = self._safe_path(target_dir, item["path"])
+            backup = self._safe_path(target_dir, item["backup"])
+            if not backup.exists():
+                continue
+            if not backup.is_file():
+                raise ValueError(f"Patch backup is not a file: {backup}")
+            expected = str(item.get("sha256") or "")
+            if expected and file_sha256(backup).lower() != expected.lower():
+                raise RuntimeError(f"Refusing to restore a modified backup: {backup}")
+            if path.exists():
+                raise RuntimeError(f"Refusing to overwrite a file while restoring backup: {path}")
+            path.parent.mkdir(parents=True, exist_ok=True)
+            shutil.move(backup, path)
+            restored.append(str(item["path"]))
+
+        # Older releases used ``name.b`` backups and listed only their base names.
+        for raw_name in metadata.get("backed_up_files", []):
+            name = Path(str(raw_name)).name
+            if name not in RESTORABLE_BACKUP_FILES:
+                continue
+            original = self._safe_path(target_dir, name)
+            backup = self._safe_path(target_dir, name + ".b")
+            if backup.exists() and not original.exists():
+                shutil.move(backup, original)
+                restored.append(name)
+        return restored
+
+    def _validate_backups(self, target_dir: Path, metadata: dict) -> None:
+        for item in metadata.get("backups", []):
+            if not isinstance(item, dict) or not item.get("path") or not item.get("backup"):
+                raise ValueError("Patch marker contains an invalid backup entry.")
+            self._safe_path(target_dir, item["path"])
+            backup = self._safe_path(target_dir, item["backup"])
+            if not backup.exists():
+                continue
+            if not backup.is_file():
+                raise ValueError(f"Patch backup is not a file: {backup}")
+            expected = str(item.get("sha256") or "")
+            if expected and file_sha256(backup).lower() != expected.lower():
+                raise RuntimeError(f"Refusing to restore a modified backup: {backup}")
+
+    def _legacy_owned_paths(self, target_dir: Path, metadata: dict) -> list[Path]:
+        paths: list[Path] = []
+        for entry in metadata.get("managed_files", []):
+            if isinstance(entry, dict) and entry.get("path"):
+                try:
+                    paths.append(self._safe_path(target_dir, entry["path"]))
+                except ValueError:
+                    continue
+
+        variant = self.bundle.normalize_variant(metadata.get("fsr4_variant"))
+        proxy_sources = [
+            self.bundle.fgmod_path / "OptiScaler.dll",
+            self.bundle.fgmod_path / "renames",
+            self.bundle.variant_dir(variant) / "renames",
+        ]
+        for filename in INJECTOR_FILENAMES:
+            target = target_dir / filename
+            if not target.is_file():
+                continue
+            matches_bundle = False
+            for source in proxy_sources:
+                candidate = source if source.is_file() and source.name == filename else source / filename
+                if candidate.is_file() and files_match(target, candidate):
+                    matches_bundle = True
+                    break
+            if matches_bundle:
+                paths.append(target)
+        for filename in SUPPORT_FILES + VARIANT_EXTRA_FILENAMES + [FSR4_UPSCALER_FILENAME]:
+            target = target_dir / filename
+            if target.is_file() and self.bundle.is_managed_support_file(target):
+                paths.append(target)
+        for relative in (Path("plugins/OptiPatcher.asi"),):
+            target = target_dir / relative
+            source = self.bundle.fgmod_path / relative
+            if target.is_file() and source.is_file() and files_match(target, source):
+                paths.append(target)
+        d3d12_source = self.bundle.fgmod_path / "D3D12_Optiscaler"
+        d3d12_target = target_dir / "D3D12_Optiscaler"
+        if d3d12_source.is_dir() and d3d12_target.is_dir():
+            for source in d3d12_source.rglob("*"):
+                if source.is_file():
+                    candidate = d3d12_target / source.relative_to(d3d12_source)
+                    if candidate.is_file() and files_match(candidate, source):
+                        paths.append(candidate)
+        unique: list[Path] = []
+        seen: set[str] = set()
+        for path in paths:
+            if str(path) not in seen:
+                unique.append(path)
+                seen.add(str(path))
+        return unique
+
+    def _unpatch_target(self, target_dir: Path, marker_path: Path | None) -> dict:
+        metadata = self._read_marker(marker_path) if marker_path else {
+            "backed_up_files": [
+                name for name in RESTORABLE_BACKUP_FILES
+                if (target_dir / f"{name}.b").is_file()
+            ],
+        }
+        try:
+            if marker_path and marker_path.exists() and not metadata:
+                return {"status": "error", "message": f"Patch marker is unreadable: {marker_path}"}
+            schema_version = int(metadata.get("schema_version") or 1) if metadata else 1
+            if schema_version >= MANIFEST_SCHEMA_VERSION:
+                entries, errors = self._managed_entries(target_dir, metadata)
+                if errors:
+                    return {"status": "error", "message": " ".join(errors)}
+                self._validate_backups(target_dir, metadata)
+                managed_paths = [path for _, path in entries]
+                for _, path in entries:
+                    if path.exists():
+                        path.unlink()
+                restored = self._restore_backups(target_dir, metadata)
+                self._cleanup_empty_directories(target_dir, [str(path.relative_to(target_dir)) for path in managed_paths])
+            else:
+                owned = self._legacy_owned_paths(target_dir, metadata)
+                entries, errors = self._managed_entries(target_dir, metadata)
+                if errors:
+                    return {"status": "error", "message": " ".join(errors)}
+                owned.extend(path for _, path in entries if path not in owned)
+                for path in owned:
+                    if path.is_file():
+                        path.unlink()
+                restored = self._restore_backups(target_dir, metadata)
+                self._cleanup_empty_directories(target_dir, [str(path.relative_to(target_dir)) for path in owned])
+            if marker_path and marker_path.exists():
+                marker_path.unlink()
+            return {
+                "status": "success",
+                "message": f"OptiScaler files removed from {target_dir}",
+                "restored_files": restored,
+            }
+        except (OSError, RuntimeError, ValueError) as exc:
+            self._log(f"Unpatch failed for {target_dir}: {exc}")
+            return {"status": "error", "message": f"Unpatch failed: {exc}"}
+
+    def resolve_target_directory(self, directory: str) -> Path:
+        target = Path(directory).expanduser()
+        if not target.exists():
+            raise FileNotFoundError(f"Target directory does not exist: {directory}")
+        if not target.is_dir():
+            raise NotADirectoryError(f"Target path is not a directory: {directory}")
+        if not os.access(target, os.W_OK | os.X_OK):
+            raise PermissionError(f"Insufficient permissions for {directory}")
+        return target.resolve()
+
+    def manual_patch_directory(
+        self,
+        directory: str,
+        dll_name: str,
+        fsr4_variant: str,
+        framegen_backend: str | None = None,
+    ) -> dict:
+        try:
+            target = self.resolve_target_directory(directory)
+        except (FileNotFoundError, NotADirectoryError, PermissionError) as exc:
+            return {"status": "error", "message": str(exc)}
+        marker = target / MARKER_FILENAME
+        previous_metadata = self._read_marker(marker) if marker.exists() else {}
+        previous_variant = previous_metadata.get("fsr4_variant")
+        if marker.exists():
+            if str(previous_metadata.get("appid")) not in ("", "manual", "None"):
+                return {"status": "error", "message": "This directory is managed by an AppID patch; unpatch it there first."}
+            cleanup = self._unpatch_target(target, marker)
+            if cleanup["status"] != "success":
+                return cleanup
+        return self._patch_directory(
+            target,
+            dll_name,
+            self.bundle.selected_variant(fsr4_variant),
+            self.bundle.selected_backend(framegen_backend),
+            appid="manual",
+            game_name="Manual patch",
+            original_launch_options="",
+            previous_variant=previous_variant,
+        )
+
+    def manual_unpatch_directory(self, directory: str) -> dict:
+        try:
+            target = self.resolve_target_directory(directory)
+        except (FileNotFoundError, NotADirectoryError, PermissionError) as exc:
+            return {"status": "error", "message": str(exc)}
+        marker = target / MARKER_FILENAME
+        return self._unpatch_target(target, marker if marker.exists() else None)
+
+    def list_installed_games(self) -> dict:
+        try:
+            return {
+                "status": "success",
+                "games": [
+                    {
+                        "appid": str(game["appid"]),
+                        "name": game["name"],
+                        "install_found": Path(game["install_path"]).exists(),
+                    }
+                    for game in self.steam.find_installed_games()
+                ],
+            }
+        except Exception as exc:
+            self._log(str(exc))
+            return {"status": "error", "message": str(exc)}
+
+    def get_game_status(self, appid: str) -> dict:
+        try:
+            game_info = self.steam.game_record(str(appid))
+            if not game_info:
+                return {
+                    "status": "success", "appid": str(appid), "install_found": False, "patched": False,
+                    "dll_name": None, "target_dir": None, "fsr4_variant": None, "fsr4_variant_label": None,
+                    "framegen_backend": None, "message": "Game not found in Steam library.",
+                }
+            install_root = Path(game_info["install_path"])
+            base = {
+                "status": "success", "appid": str(appid), "name": game_info["name"],
+                "install_found": install_root.exists(), "patched": False, "dll_name": None,
+                "target_dir": None, "fsr4_variant": None, "fsr4_variant_label": None,
+                "framegen_backend": None,
+            }
+            if not install_root.exists():
+                return {**base, "message": "Game install directory not found."}
+            marker = self._find_marker(install_root, str(appid))
+            if not marker:
+                return {**base, "message": "Not patched."}
+            metadata = self._read_marker(marker)
+            target_dir = self._marker_target(marker, metadata)
+            dll_name = str(metadata.get("dll_name") or "dxgi.dll")
+            upscaler = target_dir / FSR4_UPSCALER_FILENAME
+            upscaler_sha256 = file_sha256(upscaler) if upscaler.is_file() else None
+            variant = self.bundle.detect_variant(target_dir, upscaler_sha256) or self.bundle.normalize_variant(metadata.get("fsr4_variant"))
+            backend = self.bundle.normalize_backend(metadata.get("framegen_backend") or self.bundle.selected_backend())
+            dll_present = (target_dir / dll_name).is_file()
+            return {
+                **base,
+                "patched": dll_present,
+                "dll_name": dll_name,
+                "target_dir": str(target_dir),
+                "patched_at": metadata.get("patched_at"),
+                "optiscaler_version": metadata.get("optiscaler_version"),
+                "fsr4_variant": variant,
+                "fsr4_variant_label": self.bundle.variant_info(variant)["label"],
+                "fsr4_upscaler_sha256": upscaler_sha256,
+                "framegen_backend": backend,
+                "framegen_backend_label": FRAMEGEN_BACKENDS[backend],
+                "message": f"Patched using {dll_name} with {self.bundle.variant_info(variant)['label']}." if dll_present else f"Marker found but {dll_name} is missing. Reinstall recommended.",
+            }
+        except Exception as exc:
+            self._log(f"get_game_status failed for {appid}: {exc}")
+            return {"status": "error", "message": str(exc)}
+
+    @staticmethod
+    def build_managed_launch_options(dll_name: str) -> str:
+        if dll_name == "OptiScaler.asi":
+            return "SteamDeck=0 %command%"
+        base = dll_name.replace(".dll", "")
+        return f"WINEDLLOVERRIDES={base}=n,b SteamDeck=0 %command%"
+
+    @staticmethod
+    def is_managed_launch_options(options: str) -> bool:
+        normalized = " ".join((options or "").replace('"', "").split())
+        if not normalized:
+            return False
+        return any(
+            dll_name != "OptiScaler.asi" and f"WINEDLLOVERRIDES={dll_name.replace('.dll', '')}=n,b" in normalized
+            for dll_name in VALID_DLL_NAMES
+        ) or "fgmod/fgmod" in normalized
+
+    def patch_game(
+        self,
+        appid: str,
+        dll_name: str,
+        current_launch_options: str,
+        fsr4_variant: str,
+        framegen_backend: str | None = None,
+    ) -> dict:
+        try:
+            if dll_name not in VALID_DLL_NAMES:
+                return {"status": "error", "message": f"Invalid proxy DLL name: {dll_name}"}
+            game_info = self.steam.game_record(str(appid))
+            if not game_info:
+                return {"status": "error", "message": "Game not found in Steam library."}
+            install_root = Path(game_info["install_path"])
+            if not install_root.exists():
+                return {"status": "error", "message": "Game install directory does not exist."}
+            if self.steam.is_game_running(game_info):
+                return {"status": "error", "message": "Close the game before patching."}
+            if not self.bundle.fgmod_path.exists():
+                return {"status": "error", "message": "OptiScaler bundle not installed. Run Install first."}
+
+            existing_marker = self._find_marker(install_root)
+            existing_metadata = self._read_marker(existing_marker) if existing_marker else {}
+            if existing_marker and str(existing_metadata.get("appid")) not in (str(appid), "manual", "None"):
+                return {"status": "error", "message": "Another Framegen patch marker was found in this game install."}
+            original_options = current_launch_options or ""
+            stored_options = str(existing_metadata.get("original_launch_options") or "")
+            if stored_options and not self.is_managed_launch_options(stored_options):
+                original_options = stored_options
+            if self.is_managed_launch_options(original_options):
+                original_options = ""
+
+            if existing_marker:
+                old_target = self._marker_target(existing_marker, existing_metadata)
+                cleanup = self._unpatch_target(old_target, existing_marker)
+                if cleanup["status"] != "success":
+                    return cleanup
+            target_dir, _ = self.steam.guess_patch_target(game_info)
+            result = self._patch_directory(
+                target_dir,
+                dll_name,
+                self.bundle.selected_variant(fsr4_variant),
+                self.bundle.selected_backend(framegen_backend),
+                appid=str(appid),
+                game_name=game_info["name"],
+                original_launch_options=original_options,
+                previous_variant=existing_metadata.get("fsr4_variant"),
+            )
+            if result["status"] != "success":
+                return result
+            backend = result.get("framegen_backend") or self.bundle.selected_backend(framegen_backend)
+            return {
+                **result,
+                "appid": str(appid),
+                "name": game_info["name"],
+                "dll_name": dll_name,
+                "target_dir": str(target_dir),
+                "launch_options": self.build_managed_launch_options(dll_name),
+                "original_launch_options": original_options,
+                "framegen_backend": backend,
+                "message": f"Patched {game_info['name']} using {dll_name} with {result.get('fsr4_variant_label') or self.bundle.variant_info(fsr4_variant)['label']}.",
+            }
+        except Exception as exc:
+            self._log(f"patch_game failed for {appid}: {exc}")
+            return {"status": "error", "message": str(exc)}
+
+    def unpatch_game(self, appid: str) -> dict:
+        try:
+            game_info = self.steam.game_record(str(appid))
+            if not game_info:
+                return {"status": "error", "message": "Game not found in Steam library."}
+            install_root = Path(game_info["install_path"])
+            if not install_root.exists():
+                return {"status": "success", "appid": str(appid), "name": game_info["name"], "launch_options": "", "message": "Game install directory does not exist."}
+            if self.steam.is_game_running(game_info):
+                return {"status": "error", "message": "Close the game before unpatching."}
+            marker = self._find_marker(install_root, str(appid))
+            if not marker:
+                return {"status": "success", "appid": str(appid), "name": game_info["name"], "launch_options": "", "message": "No Framegen patch found for this game."}
+            metadata = self._read_marker(marker)
+            target_dir = self._marker_target(marker, metadata)
+            original_options = str(metadata.get("original_launch_options") or "")
+            cleanup = self._unpatch_target(target_dir, marker)
+            if cleanup["status"] != "success":
+                return {**cleanup, "appid": str(appid), "name": game_info["name"]}
+            self._log(f"unpatch_game success: appid={appid} target={target_dir}")
+            return {
+                "status": "success",
+                "appid": str(appid),
+                "name": game_info["name"],
+                "launch_options": original_options,
+                "message": f"Unpatched {game_info['name']}.",
+            }
+        except Exception as exc:
+            self._log(f"unpatch_game failed for {appid}: {exc}")
+            return {"status": "error", "message": str(exc)}
diff --git a/py_modules/services/steam.py b/py_modules/services/steam.py
new file mode 100644
index 0000000..c2e90b0
--- /dev/null
+++ b/py_modules/services/steam.py
@@ -0,0 +1,187 @@
+"""Steam library discovery and conservative executable selection."""
+
+import re
+import subprocess
+from pathlib import Path
+from typing import Callable
+
+
+Logger = Callable[[str], None]
+
+BAD_EXE_SUBSTRINGS = [
+    "crashreport",
+    "crashreportclient",
+    "eac",
+    "easyanticheat",
+    "beclient",
+    "eosbootstrap",
+    "benchmark",
+    "uninstall",
+    "setup",
+    "launcher",
+    "updater",
+    "bootstrap",
+    "_redist",
+    "prereq",
+]
+
+
+class SteamLibrary:
+    def __init__(self, home: Path, logger: Logger):
+        self.home = home
+        self.logger = logger
+
+    def steam_common_path(self) -> Path:
+        return self.home / ".local" / "share" / "Steam" / "steamapps" / "common"
+
+    def _steam_root_candidates(self) -> list[Path]:
+        candidates = [
+            self.home / ".local" / "share" / "Steam",
+            self.home / ".steam" / "steam",
+            self.home / ".steam" / "root",
+            self.home / ".var" / "app" / "com.valvesoftware.Steam" / "home" / ".local" / "share" / "Steam",
+            self.home / ".var" / "app" / "com.valvesoftware.Steam" / "home" / ".steam" / "steam",
+        ]
+        unique: list[Path] = []
+        seen: set[str] = set()
+        for candidate in candidates:
+            key = str(candidate)
+            if key not in seen:
+                unique.append(candidate)
+                seen.add(key)
+        return unique
+
+    def _steam_library_paths(self) -> list[Path]:
+        library_paths: list[Path] = []
+        seen: set[str] = set()
+        for steam_root in self._steam_root_candidates():
+            if steam_root.exists() and str(steam_root) not in seen:
+                library_paths.append(steam_root)
+                seen.add(str(steam_root))
+            library_file = steam_root / "steamapps" / "libraryfolders.vdf"
+            if not library_file.exists():
+                continue
+            try:
+                for line in library_file.read_text(encoding="utf-8", errors="replace").splitlines():
+                    if '"path"' not in line:
+                        continue
+                    path = line.split('"path"', 1)[1].strip().strip('"').replace("\\\\", "/")
+                    candidate = Path(path)
+                    if str(candidate) not in seen:
+                        library_paths.append(candidate)
+                        seen.add(str(candidate))
+            except OSError as exc:
+                self.logger(f"[Framegen] failed to parse libraryfolders: {library_file}: {exc}")
+        return library_paths
+
+    def find_installed_games(self, appid: str | None = None) -> list[dict]:
+        games: list[dict] = []
+        for library_path in self._steam_library_paths():
+            steamapps_path = library_path / "steamapps"
+            if not steamapps_path.exists():
+                continue
+            for appmanifest in steamapps_path.glob("appmanifest_*.acf"):
+                game_info: dict = {
+                    "appid": "",
+                    "name": "",
+                    "library_path": str(library_path),
+                    "install_path": "",
+                }
+                install_dir = ""
+                try:
+                    for line in appmanifest.read_text(encoding="utf-8", errors="replace").splitlines():
+                        if '"appid"' in line:
+                            game_info["appid"] = line.split('"appid"', 1)[1].strip().strip('"')
+                        elif '"name"' in line:
+                            game_info["name"] = line.split('"name"', 1)[1].strip().strip('"')
+                        elif '"installdir"' in line:
+                            install_dir = line.split('"installdir"', 1)[1].strip().strip('"')
+                except OSError as exc:
+                    self.logger(f"[Framegen] skipping manifest {appmanifest}: {exc}")
+                    continue
+                if not game_info["appid"] or not game_info["name"]:
+                    continue
+                if "Proton" in game_info["name"] or "Steam Linux Runtime" in game_info["name"]:
+                    continue
+                game_info["install_path"] = str(steamapps_path / "common" / install_dir) if install_dir else str(Path())
+                if appid is None or str(game_info["appid"]) == str(appid):
+                    games.append(game_info)
+        deduped = {str(game["appid"]): game for game in games}
+        return sorted(deduped.values(), key=lambda game: game["name"].lower())
+
+    def game_record(self, appid: str) -> dict | None:
+        matches = self.find_installed_games(appid)
+        return matches[0] if matches else None
+
+    @staticmethod
+    def normalized_path_string(value: str) -> str:
+        normalized = value.lower().replace("\\", "/")
+        normalized = normalized.replace("z:/", "/")
+        return normalized.replace("//", "/")
+
+    def candidate_executables(self, install_root: Path) -> list[Path]:
+        if not install_root.exists():
+            return []
+        try:
+            return [exe for exe in install_root.rglob("*.exe") if exe.is_file()]
+        except OSError as exc:
+            self.logger(f"[Framegen] exe scan failed for {install_root}: {exc}")
+            return []
+
+    def _exe_score(self, exe: Path, install_root: Path, game_name: str) -> int:
+        normalized = self.normalized_path_string(str(exe))
+        name = exe.name.lower()
+        score = 0
+        if normalized.endswith("-win64-shipping.exe"):
+            score += 300
+        if "shipping.exe" in name:
+            score += 220
+        if "/binaries/win64/" in normalized:
+            score += 200
+        if "/win64/" in normalized:
+            score += 80
+        if exe.parent == install_root:
+            score += 20
+        sanitized_game = re.sub(r"[^a-z0-9]", "", game_name.lower())
+        sanitized_name = re.sub(r"[^a-z0-9]", "", exe.stem.lower())
+        sanitized_root = re.sub(r"[^a-z0-9]", "", install_root.name.lower())
+        if sanitized_game and sanitized_game in sanitized_name:
+            score += 120
+        if sanitized_root and sanitized_root in sanitized_name:
+            score += 90
+        for bad in BAD_EXE_SUBSTRINGS:
+            if bad in normalized:
+                score -= 200
+        return score - len(exe.parts)
+
+    def best_running_executable(self, candidates: list[Path]) -> Path | None:
+        if not candidates:
+            return None
+        try:
+            result = subprocess.run(["ps", "-eo", "args="], capture_output=True, text=True, check=False)
+            process_lines = result.stdout.splitlines()
+        except OSError as exc:
+            self.logger(f"[Framegen] running exe scan failed: {exc}")
+            return None
+        normalized_candidates = [(exe, self.normalized_path_string(str(exe))) for exe in candidates]
+        matches: list[tuple[int, Path]] = []
+        for line in process_lines:
+            normalized_line = self.normalized_path_string(line)
+            for exe, normalized_exe in normalized_candidates:
+                if normalized_exe in normalized_line:
+                    matches.append((len(normalized_exe), exe))
+        return max(matches, key=lambda item: item[0])[1] if matches else None
+
+    def guess_patch_target(self, game_info: dict) -> tuple[Path, Path | None]:
+        install_root = Path(game_info["install_path"])
+        candidates = self.candidate_executables(install_root)
+        if not candidates:
+            return install_root, None
+        running_exe = self.best_running_executable(candidates)
+        if running_exe:
+            return running_exe.parent, running_exe
+        best = max(candidates, key=lambda exe: self._exe_score(exe, install_root, game_info["name"]))
+        return best.parent, best
+
+    def is_game_running(self, game_info: dict) -> bool:
+        return self.best_running_executable(self.candidate_executables(Path(game_info["install_path"]))) is not None