import { parentPort, Worker } from 'worker_threads'
import redis from '../../redis/index.js'
import initQueue from '../../redis/initQueue.js'

class QueryThreadPool {
  constructor(size = 1) {
    this.size = size;           // 线程池大小，默认为6
    this.workers = [];          // 存储worker对象的数组
    this.initWorkers();         // 初始化worker线程
  }

  initWorkers() {
    //  // console.log('初始化线程池')
    for (let i = 0; i < this.size; i++) {
      const worker = new Worker('./worker_threads/assessment/PreproTask.js')
      worker.postMessage({type: 'once',id: i});
      // 为每个 worker 添加事件监听器
      worker.on('message', (message) => {
        if (message.type === 'ok'){
          // console.log(`Worker ${message.id} 已准备就绪`);  
        } else{
          parentPort.postMessage(message)
          this.workers[message.id].cont -= 1
        }
      })

      this.workers.push(
        {
          worker,
          cont: 0,
        }
      )
    }
  }

  // 将任务发送给任务数最少的线程
  executeTask(message) {
    //  // console.log('分配任务给各线程')
    
    let minWorkerIndex = 0;
    for (let i = 1; i < this.workers.length; i++) {
      if (this.workers[i].cont < this.workers[minWorkerIndex].cont) {
        minWorkerIndex = i;
      }
    }
    
    // 将任务分配给任务数最少的worker
    const minWorker = this.workers[minWorkerIndex];
    // 将message转换为JSON字符串后再存储到Redis，因为Redis的rPush命令要求参数必须是字符串或Buffer类型
    redis.rPush(`${initQueue.prefix}:assessment:${minWorkerIndex}`, message) // message: 前端完全返回
    minWorker.cont += 1
    //  // console.log('分配给线程：', minWorkerIndex)
  }
  // 清理资源
  terminate() {
    this.workers.forEach((worker) => {
      worker.worker.terminate();
    });
  }
}

// 创建线程池实例
const threadPool = new QueryThreadPool(3); // 3个线程的线程池

// 监听主线程消息
parentPort.on('message', async (message) => {
  //  // console.log('接收到主线程消息：', message)
  if (message.type === 'submit') {
    // 提交任务给提交线程池
    //  // console.log('提交任务给线程池');
    threadPool.executeTask(message.data); // 提交任务
  }
})