openswarm/frontend/src/shared/browserRegistry.ts

// Subset of Electron's NativeImage we actually call. resize() returns another
// NativeImage, hence the self-reference.
export interface ElectronNativeImage {
  toDataURL: () => string;
  toPNG: () => Buffer;
  toJPEG: (quality: number) => Buffer;
  isEmpty: () => boolean;
  getSize: () => { width: number; height: number };
  resize: (options: {
    width?: number;
    height?: number;
    quality?: 'good' | 'better' | 'best';
  }) => ElectronNativeImage;
}

export interface BrowserWebview extends HTMLElement {
  src: string;
  loadURL: (url: string) => Promise<void>;
  goBack: () => void;
  goForward: () => void;
  reload: () => void;
  canGoBack: () => boolean;
  canGoForward: () => boolean;
  getURL: () => string;
  getTitle: () => string;
  isLoading: () => boolean;
  capturePage: (rect?: { x: number; y: number; width: number; height: number }) => Promise<ElectronNativeImage>;
  executeJavaScript: (code: string) => Promise<any>;
  sendInputEvent: (event: any) => void;
  getWebContentsId: () => number;
  addEventListener: (event: string, listener: (...args: any[]) => void, options?: boolean | AddEventListenerOptions) => void;
  removeEventListener: (event: string, listener: (...args: any[]) => void, options?: boolean | EventListenerOptions) => void;
}

const registry = new Map<string, BrowserWebview>();
const activeTabMap = new Map<string, string>();

function makeKey(browserId: string, tabId: string): string {
  return `${browserId}:${tabId}`;
}

export function registerWebview(browserId: string, tabId: string, wv: BrowserWebview): void {
  registry.set(makeKey(browserId, tabId), wv);
}

export function unregisterWebview(browserId: string, tabId: string): void {
  registry.delete(makeKey(browserId, tabId));
}

export function setActiveTab(browserId: string, tabId: string): void {
  activeTabMap.set(browserId, tabId);
}

export function getWebview(browserId: string, tabId?: string): BrowserWebview | undefined {
  const resolvedTabId = tabId || activeTabMap.get(browserId);
  if (!resolvedTabId) return undefined;
  return registry.get(makeKey(browserId, resolvedTabId));
}

export function findBrowserByWebContentsId(wcId: number): string | undefined {
  for (const [key, wv] of registry.entries()) {
    if ((wv as any).getWebContentsId?.() === wcId) {
      return key.split(':')[0];
    }
  }
  return undefined;
}

// True if ANY registered webview is mid-navigation. Capturing the dashboard
// (which composites live webview pixels) while a webview's GPU surface is being
// recycled crashes the renderer (SharedImage 'non-existent mailbox' -> V8
// ToLocalChecked), so the thumbnail capture must wait until they've settled.
export function anyWebviewLoading(): boolean {
  for (const wv of registry.values()) {
    try {
      if (typeof wv.isLoading === 'function' && wv.isLoading()) return true;
    } catch {
      // a torn-down webview can throw; treat as "not safe to capture"
      return true;
    }
  }
  return false;
}