package main

import (

	"fmt"

	"time"

)

type Pool struct {

	Queue chan func() error;

	RuntineNumber int;

	Total int;

	Result chan error;

	FinishCallback func();

}

//初始化

func (self *Pool) Init(runtineNumber int,total int)  {

	self.RuntineNumber = runtineNumber;

	self.Total = total;

	self.Queue = make(chan func() error, total);

	self.Result = make(chan error, total);

}

func (self *Pool) Start()  {

	//开启 number 个goruntine

	for i:=0;i<self.RuntineNumber;i++ {

		go func() {

			for {

				task,ok := <-self.Queue

				if !ok {

					break;

				}

				err := task();

				self.Result <- err;

			}

		}();

	}

	//获取每个任务的处理结果

	for j:=0;j<self.RuntineNumber;j++ {

		res,ok := <-self.Result;

		if !ok {

			break;

		}

		if res != nil {

			fmt.Println(res);

		}

	}

	//结束回调函数

	if self.FinishCallback != nil {

		self.FinishCallback();

	}

}

//关闭

func (self *Pool) Stop()  {

	close(self.Queue);

	close(self.Result);

}

func (self *Pool) AddTask(task func() error)  {

	self.Queue <- task;

}

func (self *Pool) SetFinishCallback(fun func())  {

	self.FinishCallback = fun;

}

func main()  {

	var p Pool;

	url := []string{"11111","22222","33333","444444","55555","66666","77777","88888","999999"};

	p.Init(9, len(url));

	for i := range url {

		u := url[i];

		p.AddTask(func() error {

			return Download(u);

		});

	}

	p.SetFinishCallback(DownloadFinish);

	p.Start();

	p.Stop();

}

func Download(url string) error {

	time.Sleep(1*time.Second);

	fmt.Println("Download " + url);

	return nil;

}

func DownloadFinish()  {

	fmt.Println("Download finsh");

}