/**
 * LLM singleton for NoteLett backend.
 *
 * Wraps @bytelyst/llm with lazy initialization.
 * Provider is auto-detected from env vars (LLM_PROVIDER, OPENAI_API_KEY, etc.).
 */

import { getLLM, createLLMProvider, setLLM } from '@bytelyst/llm';
import type { LLMProvider } from '@bytelyst/llm';

let initialized = false;

/**
 * Initialize the LLM provider singleton.
 * Safe to call multiple times — only initializes once.
 */
export function initLLM(): LLMProvider {
  if (!initialized) {
    const providerType = (process.env.LLM_PROVIDER || 'mock') as 'azure' | 'openai' | 'mock';
    const provider = createLLMProvider(providerType);
    setLLM(provider);
    initialized = true;
  }
  return getLLM();
}

/**
 * Get the initialized LLM provider.
 * Calls initLLM() if not yet initialized.
 */
export function llm(): LLMProvider {
  if (!initialized) {
    return initLLM();
  }
  return getLLM();
}