// +build integration

package boot

import (

	"log"

	"os"

	"syscall"

	"time"

)

// durationMin returns the smaller of two given durations

func durationMin(a, b time.Duration) time.Duration {

	if a < b {

		return a

	}

	return b

}

// killProcessCleanly firstly sends SIGTERM to the process. If it still exists

// after the specified timeout, it sends SIGKILL

func killProcessCleanly(process *os.Process, timeout time.Duration) error {

	err := process.Signal(syscall.SIGTERM)

	if err != nil {

		log.Printf("cannot send SIGTERM to process, sending SIGKILL instead: %v", err)

		return process.Kill()

	}

	const pollInterval = 10 * time.Millisecond

	for {

		p, err := os.FindProcess(process.Pid)

		if err != nil {

			return nil

		}

		err = p.Signal(syscall.Signal(0))

		if err != nil {

			return nil

		}

		sleep := durationMin(pollInterval, timeout)

		if sleep == 0 {

			break

		}

		timeout -= sleep

		time.Sleep(sleep)

	}

	return process.Kill()

}