const PROJECT_RESOURCE_PREVIEW_CANCELLED_ERROR =
  'project-resource-preview-scope-cancelled';

let projectResourcePreviewOpaqueIdSequence = 0;

function createProjectResourcePreviewOpaqueId(prefix: 'scope' | 'request') {
  projectResourcePreviewOpaqueIdSequence += 1;
  const cryptoApi = globalThis.crypto;
  const randomId = cryptoApi?.randomUUID?.();
  if (randomId) {
    return `${prefix}:${randomId}`;
  }
  if (cryptoApi?.getRandomValues) {
    const randomWords = cryptoApi.getRandomValues(new Uint32Array(4));
    return `${prefix}:${Array.from(randomWords, (word) => word.toString(36)).join('-')}`;
  }
  return `${prefix}:${Date.now().toString(36)}:${Math.random().toString(36).slice(2)}:${projectResourcePreviewOpaqueIdSequence.toString(36)}`;
}

export function createProjectResourcePreviewScopeId() {
  return createProjectResourcePreviewOpaqueId('scope');
}

export function createProjectResourcePreviewRequestId() {
  return createProjectResourcePreviewOpaqueId('request');
}

export function isProjectResourcePreviewCancellation(error: unknown) {
  const message =
    error instanceof Error
      ? error.message
      : typeof error === 'string'
        ? error
        : null;
  return message === PROJECT_RESOURCE_PREVIEW_CANCELLED_ERROR;
}

export function cancelLocalProjectResourcePreviewScope(scopeId: string) {
  const invoke = window.__TAURI__?.core?.invoke;
  if (!invoke) {
    return;
  }
  try {
    void Promise.resolve(
      invoke('cancel_local_project_resource_preview_scope', { scopeId }),
    ).catch(() => undefined);
  } catch {
    // The epoch/owner fence remains authoritative if the WebView is already
    // tearing down and can no longer deliver the best-effort cancellation.
  }
}