/**
 * 环境配置 —— 只在 app/ 层读环境变量;模块内一律经 port 注入(§5.3)。
 */
import { join } from 'node:path';

export type AppConfig = {
  readonly nodeEnv: 'development' | 'test' | 'production';
  readonly port: number;
  readonly databaseUrl: string;
  /** 原件存档根目录 —— 信封的原件指针指向这里 */
  readonly attachmentRoot: string;
  /** 派发器轮询间隔(毫秒) */
  readonly dispatchIntervalMs: number;
};

const DEFAULT_DATABASE_URL = 'postgres://jcai:jcai@localhost:54329/jcai';

export function loadConfig(env: NodeJS.ProcessEnv = process.env): AppConfig {
  const nodeEnv = env['NODE_ENV'];
  return {
    nodeEnv: nodeEnv === 'production' || nodeEnv === 'test' ? nodeEnv : 'development',
    port: Number(env['PORT'] ?? 8787),
    databaseUrl: env['DATABASE_URL'] ?? DEFAULT_DATABASE_URL,
    attachmentRoot: env['JCAI_ATTACHMENT_ROOT'] ?? join(process.cwd(), '.data', 'attachments'),
    dispatchIntervalMs: Number(env['JCAI_DISPATCH_INTERVAL_MS'] ?? 2000),
  };
}