/**
 * LLM Client Factory for Simulator Service
 * Provides a configured LLMGateway instance from process.env
 * Completely removes direct OpenAI SDK dependency
 */
import { LLMGateway, type LLMGatewayConfig } from '@wfo/integrations/llm-providers/index';

let _instance: LLMGateway | null = null;

export function getSimulatorLLM(): LLMGateway {
  if (_instance) return _instance;

  const env = process.env;
  const provider = (env['LLM_PROVIDER'] ?? 'openai') as LLMGatewayConfig['primary']['provider'];
  const baseUrl = env['LLM_GATEWAY_URL'] ?? 'https://api.openai.com/v1';
  const apiKey = env['LLM_API_KEY'] ?? env['OPENAI_API_KEY'] ?? '';
  const defaultModel = env['LLM_MODEL'] ?? 'gpt-4o';

  if (!apiKey) {
    throw new Error(
      'LLM API key not configured. Set LLM_API_KEY (or OPENAI_API_KEY for legacy) in environment.',
    );
  }

  const config: LLMGatewayConfig = {
    primary: { provider, baseUrl, apiKey, defaultModel },
    defaultRetries: 3,
    defaultRetryDelayMs: 1000,
    defaultTimeoutMs: 90000,
  };

  // Optional fallback provider
  const fallbackUrl = env['LLM_FALLBACK_URL'];
  const fallbackKey = env['LLM_FALLBACK_KEY'];
  const fallbackModel = env['LLM_FALLBACK_MODEL'] ?? defaultModel;
  if (fallbackUrl && fallbackKey) {
    config.fallback = {
      provider: 'openai-compatible',
      baseUrl: fallbackUrl,
      apiKey: fallbackKey,
      defaultModel: fallbackModel,
    };
  }

  _instance = new LLMGateway(config);
  return _instance;
}

/**
 * Create a per-request LLM client from a provided API key
 * Used when the API key is passed per-request (from CF Worker)
 */
export function createRequestLLM(apiKey: string, model?: string): LLMGateway {
  const env = process.env;
  const provider = (env['LLM_PROVIDER'] ?? 'openai') as LLMGatewayConfig['primary']['provider'];
  const baseUrl = env['LLM_GATEWAY_URL'] ?? 'https://api.openai.com/v1';

  return new LLMGateway({
    primary: {
      provider,
      baseUrl,
      apiKey,
      defaultModel: model ?? env['LLM_MODEL'] ?? 'gpt-4o',
    },
    defaultRetries: 3,
    defaultRetryDelayMs: 1000,
    defaultTimeoutMs: 90000,
  });
}