hermes-agent/apps/desktop/src/store/windows.ts

import { notifyError } from './notifications'

// Window flag set by the Electron main process when it opens a standalone
// session window (see electron/main.cjs buildSessionWindowUrl). It rides in the
// query string BEFORE the HashRouter '#', so we read it from location.search,
// never from the router. A "secondary" window renders a single chat without the
// global session sidebar or the install / onboarding overlays.
const SECONDARY_WINDOW_FLAG = 'secondary'

let secondaryWindowCache: boolean | null = null

export function isSecondaryWindow(): boolean {
  if (secondaryWindowCache !== null) {
    return secondaryWindowCache
  }

  let result = false

  try {
    result = new URLSearchParams(window.location.search).get('win') === SECONDARY_WINDOW_FLAG
  } catch {
    result = false
  }

  secondaryWindowCache = result

  return result
}

// True when running inside the Electron desktop shell (the preload bridge is
// present). The "open in new window" affordance is desktop-only.
export function canOpenSessionWindow(): boolean {
  return typeof window !== 'undefined' && typeof window.hermesDesktop?.openSessionWindow === 'function'
}

// Open (or focus) a standalone OS window for a single chat session. No-ops
// gracefully outside Electron so callers can wire it unconditionally.
export async function openSessionInNewWindow(sessionId: string): Promise<void> {
  if (!sessionId || !canOpenSessionWindow()) {
    return
  }

  try {
    const result = await window.hermesDesktop.openSessionWindow(sessionId)

    if (!result?.ok) {
      notifyError(new Error(result?.error || 'unknown error'), 'Could not open chat in a new window')
    }
  } catch (err) {
    notifyError(err, 'Could not open chat in a new window')
  }
}