/**
 * NAM-403: full-page screenreader announcement helpers for the Vega/Kepler
 * (and shared Expo) renderer. RN-free so the jest node environment can unit-test
 * it (mirrors imageAccessibility.ts). See the TV Full-Page Announcement contract.
 */

export type TextResolver = (value: string | undefined) => string;

export interface AnnouncementPage {
  header?: unknown;
  contentContainer?: unknown;
  footer?: unknown;
}

// Reserved action functions whose buttons never trigger a full-page announcement
// and always speak only their own label. Source of truth: utils/actionHandler.ts
// (duplicated here to keep this module RN-free and node-testable).
const AUXILIARY_ACTIONS = new Set<string>([
  'namiRestorePurchases',
  'namiSignIn',
  'namiClosePaywall',
  'namiNavigateToScreen',
]);

const TEXT_TYPES = new Set<string>(['text', 'text-list']);
// Subtrees never descended into during the page-text walk. Button labels are
// announced on their own focus; media/decoration carry no announce-worthy text.
const SKIP_SUBTREE_TYPES = new Set<string>(['button', 'image', 'videoUrl', 'spacer', 'symbol']);

function childrenOf(node: any): any[] {
  if (Array.isArray(node)) return node;
  if (node && Array.isArray(node.components)) return node.components;
  return [];
}

function collectNode(node: any, resolve: TextResolver, out: string[]): void {
  if (!node || typeof node !== 'object') return;
  if (Array.isArray(node)) {
    for (const child of node) collectNode(child, resolve, out);
    return;
  }
  if (node.hidden === true) return;

  const type: string | undefined = node.component;

  if (type && TEXT_TYPES.has(type)) {
    if (type === 'text-list' && Array.isArray(node.texts)) {
      for (const item of node.texts) {
        const resolved = resolve(typeof item === 'string' ? item : String(item ?? '')).trim();
        if (resolved) out.push(resolved);
      }
    } else {
      const raw = node.text ?? node.title;
      const resolved = resolve(typeof raw === 'string' ? raw : raw == null ? '' : String(raw)).trim();
      if (resolved) out.push(resolved);
    }
    return; // text nodes have no announce-worthy descendants
  }

  if (type && SKIP_SUBTREE_TYPES.has(type)) return;

  for (const child of childrenOf(node)) collectNode(child, resolve, out);
}

/**
 * Walk a page (header -> contentContainer -> footer) in source order and join the
 * resolved text of every `text` / `text-list` node. Skips images, media, spacers,
 * symbols, button subtrees, and any node with `hidden: true` (and its children).
 */
export function collectPageAnnouncementText(page: AnnouncementPage, resolve: TextResolver): string {
  const out: string[] = [];
  collectNode((page as any)?.header, resolve, out);
  collectNode((page as any)?.contentContainer, resolve, out);
  collectNode((page as any)?.footer, resolve, out);
  return out.join('. ');
}

export type ButtonAnnouncementKind = 'primary' | 'auxiliary';

/**
 * Auxiliary buttons (restore / sign in / skip-close / navigate) only ever speak
 * their own label; primary buttons (the default CTA and product buttons) trigger
 * the full-page announcement on first focus.
 */
export function classifyButtonAnnouncement(
  component: { onTap?: { function?: string } } | null | undefined,
): ButtonAnnouncementKind {
  const fn = component?.onTap?.function;
  return fn && AUXILIARY_ACTIONS.has(fn) ? 'auxiliary' : 'primary';
}