import os from 'node:os';

import { z } from 'zod';

import { buildQueueDefinitions, parseQueueSpec, type WorkerQueueDefinition } from './queues';

const envSchema = z.object({
  NODE_ENV: z.enum(['development', 'test', 'production']).default('development'),
  LOG_LEVEL: z.enum(['fatal', 'error', 'warn', 'info', 'debug', 'trace']).default('info'),
  REDIS_URL: z
    .string()
    .min(1)
    .refine(
      (value) => value.startsWith('redis://') || value.startsWith('rediss://'),
      'REDIS_URL 必须是 redis:// 连接串',
    ),
  DATABASE_URL: z
    .string()
    .min(1)
    .refine(
      (value) => value.startsWith('postgresql://') || value.startsWith('postgres://'),
      'DATABASE_URL 必须是 postgresql:// 连接串',
    ),
  QUEUE: z.string().min(1).default('all'),
  WORKER_CONCURRENCY: z.coerce.number().int().min(1).max(64).optional(),
  WORKER_ID: z.string().min(1).max(128).optional(),
});

export interface WorkerConfig {
  nodeEnv: 'development' | 'test' | 'production';
  logLevel: 'fatal' | 'error' | 'warn' | 'info' | 'debug' | 'trace';
  redisUrl: string;
  databaseUrl: string;
  queueSpec: string;
  queues: WorkerQueueDefinition[];
  workerId: string;
}

function defaultWorkerId(): string {
  return `${os.hostname()}-${String(process.pid)}`;
}

/**
 * 加载并校验 worker 环境变量：
 * - QUEUE：`all` 或逗号分隔的队列组名（script/image/video/export/verify）/ 队列名（如 media:verify）；
 * - WORKER_CONCURRENCY：覆盖全部队列并发；缺省取 TASK_QUEUES 中每个队列的定义值；
 * - WORKER_ID：默认 hostname + pid，用于心跳与日志定位。
 */
export function loadWorkerConfig(source: NodeJS.ProcessEnv = process.env): WorkerConfig {
  const result = envSchema.safeParse(source);
  if (!result.success) {
    const details = result.error.issues
      .map((issue) => `${issue.path.join('.') || '(root)'}: ${issue.message}`)
      .join('; ');
    throw new Error(`Worker 环境变量校验失败：${details}`);
  }
  const env = result.data;

  let queues: WorkerQueueDefinition[];
  try {
    queues = buildQueueDefinitions(parseQueueSpec(env.QUEUE), env.WORKER_CONCURRENCY);
  } catch (error) {
    throw new Error(
      `QUEUE 配置非法（当前值 ${env.QUEUE}）：${error instanceof Error ? error.message : String(error)}`,
    );
  }

  return {
    nodeEnv: env.NODE_ENV,
    logLevel: env.LOG_LEVEL,
    redisUrl: env.REDIS_URL,
    databaseUrl: env.DATABASE_URL,
    queueSpec: env.QUEUE,
    queues,
    workerId: env.WORKER_ID ?? defaultWorkerId(),
  };
}