initial path override ui and be

.codacy/codacy.yaml

@@ -0,0 +1,15 @@
+runtimes:
+    - dart@3.7.2
+    - go@1.22.3
+    - java@17.0.10
+    - node@22.2.0
+    - python@3.11.11
+tools:
+    - dartanalyzer@3.7.2
+    - eslint@8.57.0
+    - lizard@1.17.31
+    - pmd@7.11.0
+    - pylint@3.3.6
+    - revive@1.7.0
+    - semgrep@1.78.0
+    - trivy@0.65.0

src/components/ClipboardCommands.tsx

@@ -1,16 +1,22 @@
 import { SmartClipboardButton } from "./SmartClipboardButton";
+import type { CustomOverrideConfig } from "../types/index";
 
 interface ClipboardCommandsProps {
   pathExists: boolean | null;
+  overrideConfig?: CustomOverrideConfig | null;
 }
 
-export function ClipboardCommands({ pathExists }: ClipboardCommandsProps) {
+export function ClipboardCommands({ pathExists, overrideConfig }: ClipboardCommandsProps) {
   if (pathExists !== true) return null;
 
+  const patchCommand = overrideConfig
+    ? `${overrideConfig.envAssignment} ~/fgmod/fgmod %command%`
+    : "~/fgmod/fgmod %command%";
+
   return (
     <>
       <SmartClipboardButton 
-        command="~/fgmod/fgmod %command%"
+        command={patchCommand}
         buttonText="Copy Patch Command"
       />
       

src/components/CustomPathOverride.tsx

@@ -0,0 +1,284 @@
+import { useCallback, useEffect, useMemo, useState } from "react";
+import { ButtonItem, Field, PanelSectionRow, ToggleField } from "@decky/ui";
+import { FileSelectionType, openFilePicker } from "@decky/api";
+import type { CustomOverrideConfig } from "../types/index";
+
+interface CustomPathOverrideProps {
+  onOverrideChange: (override: CustomOverrideConfig | null) => void;
+}
+
+const DEFAULT_START_PATH = "/home";
+
+const normalizePath = (path: string) => path.replace(/\\/g, "/");
+
+const escapeForDoubleQuotes = (value: string) =>
+  value.replace(/[`"\\$]/g, (match) => `\\${match}`);
+
+const escapeForPattern = (value: string) =>
+  value
+    .replace(/\\/g, "\\\\")
+    .replace(/\//g, "\\/")
+    .replace(/\[/g, "\\[")
+    .replace(/\]/g, "\\]")
+    .replace(/\*/g, "\\*")
+    .replace(/\?/g, "\\?");
+
+const escapeForReplacement = (value: string) =>
+  value
+    .replace(/\\/g, "\\\\")
+    .replace(/\//g, "\\/")
+    .replace(/\$/g, "\\$");
+
+const quoteForShell = (value: string) => `'${value.replace(/'/g, "'\\''")}'`;
+
+const longestCommonPrefix = (left: string[], right: string[]) => {
+  const length = Math.min(left.length, right.length);
+  let idx = 0;
+  while (idx < length && left[idx] === right[idx]) {
+    idx++;
+  }
+  return idx;
+};
+
+interface ComputedOverride {
+  config: CustomOverrideConfig | null;
+  error: string | null;
+}
+
+const buildOverride = (
+  rawDefault: string | null,
+  rawOverride: string | null
+): ComputedOverride => {
+  if (!rawDefault || !rawOverride) {
+    return { config: null, error: null };
+  }
+
+  const defaultPath = normalizePath(rawDefault.trim());
+  const overridePath = normalizePath(rawOverride.trim());
+
+  if (defaultPath === overridePath) {
+    return {
+      config: null,
+      error: "Paths are identical. Choose a different target executable.",
+    };
+  }
+
+  const defaultParts = defaultPath.split("/").filter(Boolean);
+  const overrideParts = overridePath.split("/").filter(Boolean);
+
+  if (!defaultParts.length || !overrideParts.length) {
+    return {
+      config: null,
+      error: "Unable to parse selected paths. Pick them again.",
+    };
+  }
+
+  const prefixLength = longestCommonPrefix(defaultParts, overrideParts);
+
+  if (prefixLength < 2) {
+    return {
+      config: null,
+      error: "Selections do not share a common game folder.",
+    };
+  }
+
+  const searchSuffixParts = defaultParts.slice(prefixLength);
+  const replaceSuffixParts = overrideParts.slice(prefixLength);
+
+  if (!searchSuffixParts.length || !replaceSuffixParts.length) {
+    return {
+      config: null,
+      error: "Could not determine differing portion of the paths.",
+    };
+  }
+
+  const searchSuffix = searchSuffixParts.join("/");
+  const replaceSuffix = replaceSuffixParts.join("/");
+  const pattern = defaultParts[prefixLength - 1] ?? defaultParts[defaultParts.length - 1];
+
+  if (!pattern) {
+    return {
+      config: null,
+      error: "Unable to infer game identifier from path.",
+    };
+  }
+
+  const escapedPattern = escapeForDoubleQuotes(pattern);
+  const escapedSearch = escapeForPattern(searchSuffix);
+  const escapedReplace = escapeForReplacement(replaceSuffix);
+
+  const expression = `[[ "$arg" == *"${escapedPattern}"* ]] && arg=\${arg//${escapedSearch}/${escapedReplace}}`;
+  const snippet = `[[ "$arg" == *"${pattern}"* ]] && arg=\${arg//${searchSuffix}/${replaceSuffix}}`;
+  const envAssignment = `FGMOD_OVERRIDE_EXPRESSION=${quoteForShell(expression)}`;
+
+  const config: CustomOverrideConfig = {
+    defaultPath,
+    overridePath,
+    pattern,
+    searchSuffix,
+    replaceSuffix,
+    expression,
+    snippet,
+    envAssignment,
+  };
+
+  return { config, error: null };
+};
+
+export const CustomPathOverride = ({ onOverrideChange }: CustomPathOverrideProps) => {
+  const [launcherPath, setLauncherPath] = useState<string | null>(null);
+  const [overridePath, setOverridePath] = useState<string | null>(null);
+  const [isEnabled, setEnabled] = useState(false);
+
+  const { config, error } = useMemo(
+    () => buildOverride(launcherPath, overridePath),
+    [launcherPath, overridePath]
+  );
+
+  useEffect(() => {
+    if (isEnabled && config) {
+      onOverrideChange(config);
+    } else {
+      onOverrideChange(null);
+    }
+  }, [config, isEnabled, onOverrideChange]);
+
+  const openPicker = useCallback(
+    async (existing: string | null, setter: (value: string) => void) => {
+      try {
+        const startPath = existing ? normalizePath(existing) : DEFAULT_START_PATH;
+        const result = await openFilePicker(
+          FileSelectionType.FILE,
+          startPath,
+          true,
+          false,
+          undefined,
+          undefined,
+          true
+        );
+        if (result?.path) {
+          setter(normalizePath(result.path));
+        }
+      } catch (err) {
+        console.error("CustomPathOverride -> openPicker", err);
+      }
+    },
+    []
+  );
+
+  const handleToggle = (value: boolean) => {
+    setEnabled(value);
+    if (!value) {
+      setLauncherPath(null);
+      setOverridePath(null);
+      onOverrideChange(null);
+    } else if (config) {
+      onOverrideChange(config);
+    }
+  };
+
+  return (
+    <>
+      <PanelSectionRow>
+        <ToggleField
+          label="Custom Launcher Override"
+          description="Select launcher and target executables from the Deck's file browser."
+          checked={isEnabled}
+          onChange={handleToggle}
+        />
+      </PanelSectionRow>
+
+      {isEnabled && (
+        <>
+          <PanelSectionRow>
+            <ButtonItem
+              layout="below"
+              onClick={() => openPicker(launcherPath, setLauncherPath)}
+              description={launcherPath || "Pick the EXE Steam currently uses."}
+            >
+              Select Steam-provided EXE
+            </ButtonItem>
+          </PanelSectionRow>
+
+          <PanelSectionRow>
+            <ButtonItem
+              layout="below"
+              onClick={() => openPicker(overridePath, setOverridePath)}
+              description={overridePath || "Pick the executable that should run instead."}
+            >
+              Select Override EXE
+            </ButtonItem>
+          </PanelSectionRow>
+
+          {(launcherPath || overridePath) && (
+            <PanelSectionRow>
+              <ButtonItem
+                layout="below"
+                onClick={() => {
+                  setLauncherPath(null);
+                  setOverridePath(null);
+                }}
+              >
+                Clear selections
+              </ButtonItem>
+            </PanelSectionRow>
+          )}
+
+          {error && (
+            <PanelSectionRow>
+              <Field
+                label="Override status"
+                description={error}
+              >
+                ⚠️
+              </Field>
+            </PanelSectionRow>
+          )}
+
+          {!error && config && (
+            <>
+              <PanelSectionRow>
+                <Field
+                  label="Detected game"
+                  description="Based on the shared folder between both selections."
+                >
+                  {config.pattern}
+                </Field>
+              </PanelSectionRow>
+
+              <PanelSectionRow>
+                <Field
+                  label="Code snippet"
+                  description="This is added to fgmod before resolving the install path."
+                  bottomSeparator="none"
+                >
+                  <div
+                    style={{
+                      backgroundColor: "rgba(255,255,255,0.05)",
+                      borderRadius: "6px",
+                      padding: "12px",
+                      fontFamily: "monospace",
+                      whiteSpace: "pre-wrap",
+                      wordBreak: "break-word",
+                    }}
+                  >
+                    {config.snippet}
+                  </div>
+                </Field>
+              </PanelSectionRow>
+
+              <PanelSectionRow>
+                <Field
+                  label="Environment preview"
+                  description="Automatically appended to the Patch command."
+                >
+                  {config.envAssignment}
+                </Field>
+              </PanelSectionRow>
+            </>
+          )}
+        </>
+      )}
+    </>
+  );
+};

src/components/OptiScalerControls.tsx

@@ -10,6 +10,8 @@ import { ClipboardCommands } from "./ClipboardCommands";
 import { InstructionCard } from "./InstructionCard";
 import { OptiScalerWiki } from "./OptiScalerWiki";
 import { UninstallButton } from "./UninstallButton";
+import { CustomPathOverride } from "./CustomPathOverride";
+import type { CustomOverrideConfig } from "../types/index";
 
 interface OptiScalerControlsProps {
   pathExists: boolean | null;
@@ -21,6 +23,13 @@ export function OptiScalerControls({ pathExists, setPathExists }: OptiScalerCont
   const [uninstalling, setUninstalling] = useState(false);
   const [installResult, setInstallResult] = useState<OperationResult | null>(null);
   const [uninstallResult, setUninstallResult] = useState<OperationResult | null>(null);
+  const [overrideConfig, setOverrideConfig] = useState<CustomOverrideConfig | null>(null);
+
+  useEffect(() => {
+    if (pathExists !== true && overrideConfig) {
+      setOverrideConfig(null);
+    }
+  }, [pathExists, overrideConfig]);
 
   useEffect(() => {
     if (installResult) {
@@ -76,7 +85,11 @@ export function OptiScalerControls({ pathExists, setPathExists }: OptiScalerCont
       
       <OptiScalerHeader pathExists={pathExists} />
       
-      <ClipboardCommands pathExists={pathExists} />
+      {pathExists === true && (
+        <CustomPathOverride onOverrideChange={setOverrideConfig} />
+      )}
+
+      <ClipboardCommands pathExists={pathExists} overrideConfig={overrideConfig} />
       
       <InstructionCard pathExists={pathExists} />
       

src/index.tsx

@@ -26,7 +26,10 @@ function MainContent() {
 
   return (
     <>
-      <OptiScalerControls pathExists={pathExists} setPathExists={setPathExists} />
+      <OptiScalerControls
+        pathExists={pathExists}
+        setPathExists={setPathExists}
+      />
       {pathExists === true ? (
         <>
           {/* <InstalledGamesSection /> */}

src/types/index.ts

@@ -24,3 +24,14 @@ export interface ModInstallationConfig {
     bin: string;
   };
 }
+
+export interface CustomOverrideConfig {
+  defaultPath: string;
+  overridePath: string;
+  pattern: string;
+  searchSuffix: string;
+  replaceSuffix: string;
+  expression: string;
+  snippet: string;
+  envAssignment: string;
+}