package main

import (
  "fmt"
  "time"
  "flag"
  "sync"
)

func Worker(name string, done chan<- int, stop <-chan int) {
  for i := 0; i < 10; i++ {
    select {
    case <-stop:
      fmt.Println("Worker stopped:", name)
      return
    default:
      time.Sleep(1 * time.Second)
      fmt.Println("TESTER #", name)
    }
  }

  done<- 1
}

func Supervisor(id int, count int) {
  stop := make(chan int)
  var wg sync.WaitGroup

  for i := 0; i < count; i++ {
    wg.Add(1)
    go func() {
      defer wg.Done()

      for {
        workerDone := make(chan int)
        go Worker(fmt.Sprintf("%d:%d", id, i), workerDone, stop)


        select {
        case <-workerDone:
          fmt.Println("Supervisor: Worker Done")
          time.Sleep(500 * time.Millisecond)
        case <-stop:
          fmt.Println("Supervisor: Stop")
          return
        }
      }
    }()
  }

  go func() {
    // test shutdown
    time.Sleep(10000 * time.Millisecond)
    close(stop)
  }()

  wg.Wait()
}


func main() {
  count := flag.Int("count", 10, "Seconds to wait")
  id := flag.Int("id", 1, "Tester ID to use.")
  flag.Parse()

  fmt.Println(">>> TESTER STARTS, id=", *id, "count=", *count)

  Supervisor(*id, *count)
}