1 files changed, 211 insertions, 0 deletions
diff --git a/src/utils/steamLaunchOptions.ts b/src/utils/steamLaunchOptions.ts
new file mode 100644
index 0000000..9c7b5eb
--- /dev/null
+++ b/src/utils/steamLaunchOptions.ts
@@ -0,0 +1,211 @@
+// @ts-expect-error Node's built-in TypeScript loader requires explicit source extensions in tests.
+import { cleanupLegacyWrapper, isLegacyWrapperToken, normalizeLaunchOptions } from "./steamLaunchOptionParser.ts";
+
+// @ts-expect-error Node's built-in TypeScript loader requires explicit source extensions in tests.
+export * from "./steamLaunchOptionParser.ts";
+
+export interface SteamLaunchOptionsSnapshot {
+  appId: number;
+  nonSteam: boolean;
+  options: string;
+  details: SteamAppDetails;
+}
+
+function validateAppId(appId: number): void {
+  if (!Number.isSafeInteger(appId) || appId <= 0) throw new Error("Invalid Steam App ID");
+}
+
+function getSteamApps(): Partial<SteamApps> | undefined {
+  return (globalThis as typeof globalThis & {
+    SteamClient?: { Apps?: Partial<SteamApps> };
+  }).SteamClient?.Apps;
+}
+
+function snapshotFromDetails(appId: number, nonSteam: boolean, details: SteamAppDetails): SteamLaunchOptionsSnapshot {
+  if (nonSteam && isLegacyWrapperToken(details.strShortcutExe || "")) {
+    throw new Error("The shortcut Target still points to the legacy ~/lsfg wrapper; restore its original executable first");
+  }
+  return {
+    appId,
+    nonSteam,
+    options: nonSteam ? details.strShortcutLaunchOptions || "" : details.strLaunchOptions || "",
+    details,
+  };
+}
+
+function asError(error: unknown): Error {
+  return error instanceof Error ? error : new Error(String(error));
+}
+
+function registerSteamAppDetails(
+  appId: number,
+  onDetails: (details: SteamAppDetails) => boolean | void,
+): () => void {
+  validateAppId(appId);
+  const apps = getSteamApps();
+  const registerForAppDetails = apps?.RegisterForAppDetails;
+  if (!registerForAppDetails) throw new Error("Steam launch options API is unavailable");
+
+  let active = true;
+  let unregisterPending = false;
+  let registration: SteamAppDetailsRegistration | undefined;
+  const unsubscribe = () => {
+    active = false;
+    if (!registration) {
+      unregisterPending = true;
+      return;
+    }
+    try {
+      registration.unregister();
+    } catch {
+      // Steam may invalidate registrations during a details refresh.
+    }
+  };
+
+  try {
+    registration = registerForAppDetails.call(apps, appId, (details) => {
+      if (!active) return;
+      if (onDetails(details || {}) === false && active) unsubscribe();
+    });
+    if (unregisterPending) {
+      try {
+        registration.unregister();
+      } catch {
+        // The registration can be invalidated before a synchronous callback returns.
+      }
+    }
+  } catch (error) {
+    throw asError(error);
+  }
+  return unsubscribe;
+}
+
+export async function readSteamLaunchOptions(appId: number, nonSteam: boolean): Promise<SteamLaunchOptionsSnapshot> {
+  return new Promise((resolve, reject) => {
+    let settled = false;
+    let timeout = 0;
+    let unsubscribe = () => {};
+    const finish = (error?: unknown, details?: SteamAppDetails) => {
+      if (settled) return;
+      settled = true;
+      window.clearTimeout(timeout);
+      unsubscribe();
+      if (error) {
+        reject(asError(error));
+        return;
+      }
+      try {
+        resolve(snapshotFromDetails(appId, nonSteam, details || {}));
+      } catch (snapshotError) {
+        reject(asError(snapshotError));
+      }
+    };
+
+    timeout = window.setTimeout(() => finish(new Error("Timed out reading Steam launch options")), 5000);
+    try {
+      unsubscribe = registerSteamAppDetails(appId, (details) => {
+        finish(undefined, details);
+        return false;
+      });
+    } catch (error) {
+      finish(error);
+    }
+  });
+}
+
+export function subscribeSteamLaunchOptions(
+  appId: number,
+  nonSteam: boolean,
+  onSnapshot: (snapshot: SteamLaunchOptionsSnapshot) => void,
+  onError: (error: Error) => void,
+): () => void {
+  return registerSteamAppDetails(appId, (details) => {
+    try {
+      onSnapshot(snapshotFromDetails(appId, nonSteam, details));
+    } catch (error) {
+      onError(asError(error));
+    }
+  });
+}
+
+async function setSteamLaunchOptions(appId: number, nonSteam: boolean, options: string): Promise<void> {
+  const apps = getSteamApps();
+  const setter = nonSteam ? apps?.SetShortcutLaunchOptions : apps?.SetAppLaunchOptions;
+  if (!setter) throw new Error(`Steam ${nonSteam ? "shortcut " : ""}launch options API is unavailable`);
+  await Promise.resolve(setter.call(apps, appId, options));
+}
+
+function delay(milliseconds: number): Promise<void> {
+  return new Promise((resolve) => window.setTimeout(resolve, milliseconds));
+}
+
+async function waitForLaunchOptions(
+  appId: number,
+  nonSteam: boolean,
+  expected: string,
+): Promise<SteamLaunchOptionsSnapshot> {
+  const deadline = Date.now() + 5000;
+  let lastError: Error | null = null;
+  while (Date.now() <= deadline) {
+    try {
+      const snapshot = await readSteamLaunchOptions(appId, nonSteam);
+      if (normalizeLaunchOptions(snapshot.options) === normalizeLaunchOptions(expected)) return snapshot;
+    } catch (error) {
+      lastError = asError(error);
+    }
+    if (Date.now() >= deadline) break;
+    await delay(100);
+  }
+  if (lastError) throw new Error(`Steam did not accept the launch options: ${lastError.message}`);
+  throw new Error("Steam did not accept the launch options before the readback timeout");
+}
+
+const operationQueues = new Map<string, Promise<void>>();
+
+function queueKey(appId: number, nonSteam: boolean): string {
+  return `${nonSteam ? "shortcut" : "app"}:${appId}`;
+}
+
+function queueSteamAppOperation<T>(appId: number, nonSteam: boolean, operation: () => Promise<T>): Promise<T> {
+  const key = queueKey(appId, nonSteam);
+  const previous = operationQueues.get(key) || Promise.resolve();
+  const queued = previous.catch(() => undefined).then(operation);
+  let cleanup: Promise<void>;
+  cleanup = queued.then(
+    () => {
+      if (operationQueues.get(key) === cleanup) operationQueues.delete(key);
+    },
+    () => {
+      if (operationQueues.get(key) === cleanup) operationQueues.delete(key);
+    },
+  );
+  operationQueues.set(key, cleanup);
+  return queued;
+}
+
+export function updateSteamLaunchOptions(
+  appId: number,
+  nonSteam: boolean,
+  transform: (options: string) => string,
+): Promise<SteamLaunchOptionsSnapshot> {
+  return queueSteamAppOperation(appId, nonSteam, async () => {
+    const current = await readSteamLaunchOptions(appId, nonSteam);
+    const next = transform(current.options);
+    if (next === current.options) return current;
+    await setSteamLaunchOptions(appId, nonSteam, next);
+    return waitForLaunchOptions(appId, nonSteam, next);
+  });
+}
+
+export function cleanupSteamLaunchOptions(
+  appId: number,
+  nonSteam: boolean,
+): Promise<SteamLaunchOptionsSnapshot> {
+  return queueSteamAppOperation(appId, nonSteam, async () => {
+    const current = await readSteamLaunchOptions(appId, nonSteam);
+    const next = cleanupLegacyWrapper(current.options);
+    if (next === current.options) return current;
+    await setSteamLaunchOptions(appId, nonSteam, next);
+    return waitForLaunchOptions(appId, nonSteam, next);
+  });
+}