package main

import (
    "bufio"
    "fmt"
    "github.com/gammazero/workerpool"
    "log"
    "os"
    "time"
)

type PingRestult struct {
    ip   string
    time time.Duration
}

func IpGen(urls []string) chan string {
    ch := make(chan string)
    go func() {
        for {
            for _, url := range urls {
                ch <- url
            }
        }
    }()
    return ch
}

func PingIp(ip string) {
    //pinger, err := ping.NewPinger(ip)
    //pinger.SetPrivileged(true)
    //if err != nil {
    //  panic(err)
    //}
    //pinger.Count = 1
    //pinger.Timeout = time.Millisecond * 200
    //
    //pinger.Run()
    //// blocks until finished
    //stats := pinger.Statistics()
    //result := PingRestult{ip, stats.AvgRtt}
    fmt.Println(ip)
}

func suck(ch chan string) {
    //go func() {
    //  for v := range ch {
    //      PingIp(v)
    //  }
    //}()

    wp := workerpool.New(1000)

    for url := range ch {
        wp.Submit(func() {
            PingIp(url)
        })
    }

    wp.StopWait()

}

func main() {
    file, err := os.Open("file.txt")
    if err != nil {
        log.Fatal(err)
    }
    defer file.Close()

    var lines []string
    scanner := bufio.NewScanner(file)
    for scanner.Scan() {
        lines = append(lines, scanner.Text())
    }

    if err := scanner.Err(); err != nil {
        log.Fatal(err)
    }

    ipChan := make(chan string)
    defer close(ipChan)

    //启动100个gorontine 作为worker进行计算 ping 结果
    //for i := 0; i <= 100; i++ {
    //  go func() {
    //      for {
    //          url := <-ipChan
    //          PingIp(url)
    //      }
    //  }()
    //}

    //http://jmoiron.net/blog/limiting-concurrency-in-go/
    //concurrency := 100
    //sem := make(chan bool, concurrency)
    //for url := range ipChan {
    //  sem <- true
    //  go func() {
    //      defer func() { <-sem }()
    //      PingIp(url)
    //  }()
    //}
    //for i := 0; i < cap(sem); i++ {
    //  sem <- true
    //}

    resultch := IpGen(lines)
    suck(resultch)

    select {}

}