/**
 * Compatibility shim for older in-repository callers.
 *
 * `soma-ai` no longer owns an OOUI vocabulary and intentionally does not
 * depend on `soma-ui`. A Host that still renders legacy `ooui:` declarations
 * must build its own composed pack and pass it here. New Tailwind page
 * generation does not call this module.
 */
import {
  registerOouiPacks,
  resolveOouiEngine,
} from 'soma-core/server/ooui';
import type { SomaOouiEngine, SomaOouiPack } from 'soma-core/server/ooui';

export interface EnsureOouiEngineOptions {
  /** Vocabulary assembled by the Host from the components it actually mounts. */
  readonly packs?: readonly SomaOouiPack[];
}

let memo: { readonly key: unknown; readonly engine: SomaOouiEngine } | null = null;

/**
 * Return the Host-registered OOUI engine, registering the supplied packs once.
 *
 * There is deliberately no default pack: supplying one here would recreate
 * the soma-ai → soma-ui dependency that the package boundary forbids.
 */
export function ensureOouiEngine(options: EnsureOouiEngineOptions = {}): SomaOouiEngine {
  const existing = resolveOouiEngine();
  const packs = options.packs;
  if (!packs || packs.length === 0) {
    if (existing) return existing;
    throw new Error(
      '[soma-ai/ooui] 未注册演绎引擎；Tailwind 生成页不需要 OOUI，旧 ooui: 页面请由 Host 注入词汇包',
    );
  }
  if (memo && memo.key === packs && resolveOouiEngine() === memo.engine) return memo.engine;
  const engine = registerOouiPacks(packs);
  memo = { key: packs, engine };
  return engine;
}

/** Return the current Host engine without providing a fallback. */
export function currentOouiEngine(): SomaOouiEngine | undefined {
  return resolveOouiEngine();
}