package main

import (
	"fmt"
	"net/http"
	"time"
)

func main() {
	urls := []string{
		"https://google.com",
		"https://facebook.com",
		"https://golang.org",
		"https://johannes-rothe.de",
		"https://amazon.com",
	}
	c := make(chan string)
	for _, url := range urls {
		go checkURL(url, c)
	}
	for url := range c { // wait for the channel to return a value, then assign it to l
		go func(url string) {
			time.Sleep(2 * time.Second)
			checkURL(url, c)
		}(url)
		//go checkURL(url, c)
		//fmt.Println(<-c) // value through c is a blocking call
	}
}

func checkURL(url string, c chan string) {
	_, err := http.Get(url)
	if err != nil {
		fmt.Printf("%s might be down!\n", url)
		c <- url
		return
	}
	fmt.Printf("%s is up!\n", url)
	c <- url
}