package closingchannels

import (
	"fmt"
	"math"
	"math/rand"
	"time"
)

func ClosingChannels() {
	jobs := make(chan int, 5)
	done := make(chan bool)

	go func() {
		for {
			val, more := <-jobs

			if more {
				time.Sleep(time.Duration(rand.Intn(3)) * time.Second)
				fmt.Printf("%d ^ %d is %f\n", val, 2, math.Pow(float64(val), 2))
			} else {
				fmt.Println("No more jobs, goroutine exiting")
				done <- true
				return
			}
		}
	}()

	for i := range 3 {
		jobs <- i + 1
	}
	fmt.Println("Sent all jobs")

	close(jobs)

	<-done

	_, more := <-jobs
	if more {
		fmt.Println("Uh-oh, jobs queue is not empty")
	} else {
		fmt.Println("Jobs queue is empty")
	}

	fmt.Println("Exiting")
}