package main

import (
	"bufio"
	"fmt"
	"os/exec"
	"time"
)

func main() {
	cmd := neverReturningThing()
	//cmd := returningThingWithinThreeSecs()
	//cmd := returningThingAfterThreeSecs()
	stdout, _ := cmd.StdoutPipe()

	busy := make(chan bool, 1)
	cmd.Start()

	scanner := bufio.NewScanner(stdout)
	scanner.Split(bufio.ScanLines)

	go func() {
		fmt.Println("starting scanner.scan (blocking)")
		for scanner.Scan() {
			fmt.Println("scanned")
			m := scanner.Text()
			fmt.Println(m)
			if busy != nil {
				busy <- true
			}
		}
	}()

	fmt.Println("starting select chans")
	var err error
	select {
	case <-busy:
		fmt.Println("busy chan")
		busy = nil
	case <-time.After(3 * time.Second):
		pkill := cmd.Process.Kill()
		fmt.Println("timeout triggered? err: %w", pkill)
	}

	fmt.Println("starting Wait()")
	err = cmd.Wait()
	fmt.Printf("done? here's an error: %w", err)
}

func returningThingWithinThreeSecs() *exec.Cmd {
	return exec.Command("echo", "sup")
}

func returningThingAfterThreeSecs() *exec.Cmd {
	return exec.Command("ping", "google.com")
}

func neverReturningThing() *exec.Cmd {
	return exec.Command("ssh", "user@unknown.local")
}